The closing days of 2019 and what a year it was???

Before reviewing the year in general, it is worth considering the last few days of it in more detail.

That strange phenomenon "Winter Es" made an appearance on 28 December. I first noticed that S52OR was coming in consistently on the 4m meteor scatter frequency. Unlike the usual pings, he was there for the full 15 seconds. I quickly went onto FT8 on 4m and 6m. There seemed to be some action on 2m, but not here at GM4FVM.

VHF contacts at GM4FVM on 28 December 2019

This is my activity map for 28 December (click to enlarge the images if you need to, as usual). The two UK stations were on 2m, the others on 4m and 6m. 15 QSOs in 7 DXCC, bringing a total of 12 squares. ODX was SP8ALT in KO11GG at 1697km. The Winter Es opening lasted 61 minutes here. I suppose in the great scheme of things that is not much of an opening, but it brought a bit of hope to a very quiet scene.

The thing about Winter Es is that you never know if it will happen on any specific day. It keeps you on your toes. I missed out on the 2m part. Grrr.

Another dramatic opening was the tropo event on 29 and 30 December, affecting 4m, 2m and 70cms. Except that from a GM4FVM point of view it hardly happened at all.

15 minutes of 70cms FT8 activity on PSK Reporter on the evening of 29 December.

You may notice from this chart that the event missed my part of Scotland entirely. The lonely pin over GM4FVM is just my alter ego, GM8JWG's short wave listener's posting. GM8JWG hearing GM4FVM does not really count as DX as they are both located in the same building.

The other remarkable thing about that slice of activity is that it is on 70cms. I thrash away on 70cms FT8 all year, and mostly it is a pointless exercise. There are contacts to be made, but nobody there to make them with. This clearly shows that many people have the ability to work on 70cms, but most don't do it.

The Hepburn tropo predictor shows the centre of the tropo over the Atlantic with sideshoots over Southern England and France. Although predicted to make a glancing blow over Southern Scotland we saw next to none of it.

All was not lost though, and in a brief opening I did work some DX on 29th.

Stations worked at GM4FVM on 144 and 432 MHz on 29 December 2019

PA7MM and G8SEI were on 70cms, the others on 2m. As things go, that would be a good haul for me, but this was a day when stations on Central England were working Poland and the Canary Islands on 2m. A lucky few in the Southern parts of Ireland and England were hearing Capo Verde.

Still I cannot complain, in just 11 hours and 22 minutes I worked 6 stations in 5 squares and 4 DXCC. ODX was the ever reliable Charly DF5VAE on 2m, JO46RK at 1001km.

I spent quite some time trying to reach Fidel from Castro, EA1HRR, to see if I could reach a new DXCC on 70cms. Fidel has given me 6m, 4m and my first EA on 2m, so it would have been fitting for him to be my first EA on 70cms. No sir. He could work stations in G-land but not me, sadly. 

The conditions continued on 30 December with G stations reaching all over Europe and I was on duty all day to work GW6TEO and GM4VVX. Both of those contacts were a real struggle but at 505km, GW6TEO probably had the choice of many more exotic stations to work than me.

I have been in touch by email with an amateur in the thick of it in IO82 square. He described to me the excitement of being in the middle of a huge opening. I am genuinely pleased for him. There is learning in this for me too. I have never been just beyond the edge of an opening before. Or, I probably have, but before PSK Reporter and DX Maps I never really knew what I was missing.

In the past I have described the odd feeling that during a DX tropo opening the "normal" tropo stations disappear. When I can work Poland or France the G stations in between seem to vanish. Well now I know what that feels like to disappear like that. While the G stations were working EA8 and SP, they vanished for me. The net result was that I could not hear the EA8s or SPs, nor could I hear anyone else. For hours on end I could hear nobody at all, on 2m or 70cms. Even if their beams are turned away from me, I can usually hear G stations off the back of their antennas. Not this time.

Enough whingeing. Sometimes you win some, sometimes you lose some. This time I lost. I will feel sorry for those just outside the tropo bubble next time I find myself inside it working tons of DX.

I will so.

I will share their pain even as I am living The High Life, and Living It Well (sorry, 1994 Scottish TV comedy series reference).

Honestly. I will share their agony.

I will.

Because they will be doing that for me right now.
=========================
It has been a busy year OK.

Apart entirely from the radio, the three cycling Grand Tours were all brilliant, and the even the cricket World Cup was interesting. No, maybe interesting is the wrong word for cricket, people usually say "absorbing" instead.

Plus by train I made it to Wuppertal with its strange upside-down wobbly monorail, and even to the 2000 year-old Roman amphitheatre in Nimes

Nimes: an ancient monument (and an old Roman building on the right too)

On the radio front there was the arrival of quite a lot of gear left to me by David GM4JJJ. Possessions are just that, and I would rather have had David still with us, but that was not to be. Excellent equipment it has proved to be too.

As for operations, the picture is of some things at FVM being the same, and some very different. The DXCC table of countries worked shows this:-

GM4FVM DXCC table extracted from Clublog

10m varies depending on whether I am using WSPR as normal, or sometimes FT8 which count as QSOs. The big drop in 6m DXCCx worked in 2019 is due to me only having a half wave vertical up, and trouble with my linear. When did I not have linear trouble? In 2018 it seems, but I must have been having trouble with a different linear then.

4m, 2m and 70cms are much as before, but 23cms is a new entry. I do not expect 23cms to provide much action in the next year but I am willing to be surprised. There is something to get sorted for 2020 - some more power on 23cms.

Also on the way is the return of a 6m beam. The new beam is past the design stage and it is now in the cutting metal phase. We shall see how that works in due course.

So an interesting year. Meteor scatter has not been very good. The Geminids in December seemed to be pretty poor. I am placing my hopes on the Quadrantids (or Bootids), this time due to peak on 3 to 4 January 2020. That leaves the meteor scatter diary free until April, but I shall strive for random contacts during the lull in showers.

The tropo opening of 29 and 30 December seems to be rumbling on still. There are suggestions that the barometric systems will continue to circulate nearby for about a week. As usual the Scottish weather is pretty variable and we need to see how this turns out.  It seems it was also affecting UK "Freeview" television signals in the 470 - 700MHz range, something that we do not see too often.
https://www.bbc.co.uk/news/technology-50945421

What does the future hold for this part of the world? Well, I received a parcel by Royal Mail today from Uxbridge near London. On the back was a UK customs declaration. Has Scotland already left the UK and nobody told me? Is this the present or is this for the future? Do I need a new callsign? No comment necessary or welcome on that debate, let us stick to radio here.

Ah well, the future will reveal itself when it is ready.

Have a merry Hogmanay and a great New Year.

Best wishes from GM4FVM

Moving forward with a plan... ?

We do not know what is around the next corner. Perhaps it is just as well.

I could worry about everything, or I could make some plans to move forward.

I guess I will do both. Anyway, the overall outcome will be the same - entropy and decay will win the argument in the long term.

When I was a part-time student long ago I went to evening lectures at the university for 8 years. Sometimes after a long day at work I fell asleep in the lectures. I left a long pen mark across my notes when that happened. I still managed to get qualified, but I am not sure how.

I have forgotten most of it. I do remember the economics lecturer telling us that the ideal savings profile across a lifetime is to start at zero and end at zero. We should have savings, in case of problems. But we arrive in this life with nothing, and we will leave with nothing. He could not see much point saving to build up money to leave to future generations. So he reckoned we should organise our lives to have no savings left at the point of death. He said that the issue for the later years of life should be about spending savings, not adding to them.

Maybe he was right. We do not know when our key will fall silent, so why keep a large sum to be left at that time? OK, save some, but spend a little now too, before it is too late.

Well, that is my story anyway. A reason not to sit and worry and a reason to spend a little now to make life more pleasurable.

For some that means changing a perfectly good radio for an £8000 one on which to work the same stations. Not for me. Time to expand the 1296MHz set-up, and time to get the antennas better organised in the hope of working something new.

So it is that I find I need more storage. My linears are perched on top of my shelving - not good. Where can I fit in a new linear?

I have been busy obtaining more shelving. Not your cheap and tatty stuff, but from a high-end supplier called Ikea. All hand made (hand made in the hall outside the shack and carried in). And another free little quad-key screw driver to add to my collection, courtesy of Ikea.

And not just Ikea, but Ikea's kids range. After all, amateur radio is child's play. I already have 4 sets of their children's range "Trofast", an adjustable sets of boxes meant for toys and therefore holding my toys. Or my components, plugs and sockets.  But now Trofast has a fancy option, finished in white rather than plain wood finish. The other wood finished stuff is hidden away in cupboards, but the new white one can go on view in the shack. Wow! Premium quality.

Ikea Children's Trofast storage unit in white at GM4FVM

If this looks a bit odd, there is only one of them. It looks like two, but the cupboard on the left which contains the older Trofasts has mirror sliding doors. The previous owner of this house used this room as her bedroom, and she had one entire wall covered in MirrorRobes. It has never been clear to me why she wanted to cover an entire bedroom wall in mirrors, but there you go (Jim, really). When we made the room smaller it made sense to keep the cupboard doors, so one side of my shack is mirrors. Now I can watch myself operate. How strange. Why would I want to do that?

But enough of all this. Also left over by the previous owner of this house is the television shelf above the new unit. This was screwed to the wall, and I left it. Now it has my 70cm TE Systems linear amplifier on it. Also there is the temperature controlled fan unit for the linear, the 70cms sequencer and a bias-tee. The Trofast fits below and the 23cms linear will go in there, along with another sequencer and bias-tee. Then there will be the power supplies lower down.

There is also a box in the Trofast for all those cables I never quite know where to store. The ones I need at short notice, but not very often. Patch leads, for example. I discovered that if I put the box at the top of the unit I could save a shelf. I am getting very organised.

This is the point here. I have actually given some thought to where to put something, before the something arrived. It helps that my economics lecturer from 40 years ago gave me authority to spend my savings on this unit. But it is necessary, and is a good way to spend not very much money. The basic frame is £30, and the shelves and boxes are extra.

Come to think of it, he would have called this investment, so it is even more easily justifiable.

The 23cms linear is under construction but I am not sure when it will be ready.

Another investment of my savings is in an experimental antenna for 4m and 6m. I have two perfectly good PowAbeams for 4m and 6m, but that is the problem. There are two of them. For the winter I have put up my old Vine 4m/6m dual bander which is better then as it is only a single antenna, but not very good as it has a single feed. Single feed does not suit my multi-band operating method. And anyway, I like my antennas to be connected to my rigs by co-ax.

The Vine uses the sleeve method of driving the 4m beam. Call me old fashioned, but I prefer a bit of wire to my antennas. Erm, well the sleeve method is old fashioned too, but ... right, ... when I think about it, I have no good reason for not liking the sleeve method, but I just don't like it.

To get round my issues with single feed in the past I built a diplexer for the Vine, which meant that I could use 4m and 6m simultaneously. I was never happy with that either. At this point in my life I reckon it is time to be a bit happier.

Rig - coax - antenna, that is my preferred route.

So I am also gambling a bit of my savings on having an experimental calculation done for a 3/4 element dual band antenna for 6 and 4 metres. This would have two separate feeds and work as separate beams on a single boom. All the commercial ones of my size  (3m boom max) are single feed and have all the same issues as the Vine. My idea is being modelled now so we will see if it works without sacrificing too much.

So there is actually a bit of planning going on here. Life planning, to free up some savings. Room planning, to make some space. And antenna planning, to model something a wee bit different and hopefully more efficient.

Funny, I am not noted for planning.

73
Jim
GM4FVM

Just a bit of fun

I think this hobby should be fun. It should not be all about understanding Faraday Rotation or precision frequency measurement. Sometimes we should just leave the work to one side and do something for ourselves.

The thing I left aside is a posting on this blog about how to tell the difference between the various VHF propagation methods. Stirring stuff. Like many of my postings it is far too long, too wordy, too ... too much like hard work really. They must be a right pain to read.

For a few days the barometric pressure has been rising as an anticyclone passes across Britain roughly from North West to South East.

There was a weather system across Scotland which was likely to spoil things a bit, but for about 5 days the Hepburn Tropo Predictions (see link on sidebar) have been suggesting that yesterday, Tuesday 3 December 2019, would be the day when VHF and UHF conditions might improve.

So I set Tuesday 3 December 2019 aside as a day to work a few stations and see how I got on.

I really enjoyed it. Good fun.

The significance of Tuesday is that it is the "Activity Contest" day in Europe. Well, it was, until we started having 6m and 4m activity days on Thursdays, which is a good idea but does make it all more complex. This was done because, despite the constant nagging from contesters, the national radio societies were unable to fit six Tuesdays into every month. Those national societies - what good are they if they cannot regulate the number of Tuesdays in the month.

First Tuesday in the month is 2m activity contest day. Now, as is well known, I do not enter contests but I do give away points. So the plan for this Tuesday was to operate as much DX as I could if conditions were good during the day, and then help out in the contest for even more DX during contest hours.

The RSGB National Activity contests run from 20:00 to 22:30 UTC for all modes, with earlier contests from 19:00 to 19:55 for FM and data modes. However, as conditions were looking up, I decided to switch to my favourite contest, the Nordic Activity Contest (NAC), which runs from 18:00 to 22:00 UTC on Wintertime Tuesdays (switching by an hour during daylight saving time).

For this contest I decided to stick to FT8. As many of the NAC stations use FT8 in its European contest mode I can get a useful updated conest log on WSJT-X which saves me trouble checking for those stations I have already worked.

Contest log with WSJT-X in the "EU VHF Contest Special Operating Activity" mode

Interestingly the latest entry in the log is at the top numbered one, whereas the serial numbers (which I have not managed to capture in the above screen grab) go the other way.

The signal reports used in the European contest mode are "59" type RS strength reports with a serial number, rather than the conventional FT8 "dB S/N relative to the noise in the SSB filter" type reports. If presented with a Euro contest type report WSJT-X will switch over to that style until you dive into the settings and turn it off. Using two different styles of report in two contests running at the same time causes endless confusion to those in the RSGB data contests which do not use serial numbers or the Euro contest system. It all adds to the fun. 

I like the NAC because of its informality. It also helps that the stations involved are usually at a handy distance if conditions are good. Often I can use meteor scatter, but perhaps this time tropo would be good as the high pressure seemed to be perfectly placed. Tropo openings are often best just as the high pressure is subsiding, which it obligingly did.

As usual, click on the images if you wish to enlarge them.

Stations worked at GM4FVM on 144MHZ on 3 December 2019

As the NAC on the first Tuesday of the month is for 2m I did concentrate on that band, but I did some 70cms too. You don't need a contest to make UHF DX interesting, but sometimes it helps.

Stations worked at GM4FVM on 432MHz on 3 December 2019

Before the NAC began I worked 18 stations. On 144MHz it was 14 stations in 8 DXCC, on 432MHz it was 4 stations in 2 DXCC. I only worked France on 432MHz (twice), the others on 144MHz being G, GM, GW, GI, OZ, PA, DL and ON. ON4POO kicked the whole thing off, as he so often does. The two stations in France were F5APQ and F4HRD both in JO00, which isn't bad on 70cms at about 600km from here. I bet I could have worked more stations on 70cms if there had been more around, and of course during the 2m contest the 70cms activity fell (but did not stop!).

During the NAC I worked 10 stations in OZ, LA, and SM of course, plus PA0O as yet another participant in NAC. I was only on for about 2 hours of the contest as I had to go and watch "Masterchef The Professionals" on the television. We have to keep it fun you know.

After the contest I worked 4 stations on 2m (SM and OZ) and then one on 70cms (OZ).

Grand total
For 2m, 30 QSOs over 13 hours and 18 minutes, 18 squares, 10 DXCC, ODX SM7EGM in JO65 at 988km, and
For 70cm, 5 QSOs over 12 hours and 4 minutes, 3 squares, 3 DXCC, ODX OZ2ND in JO46 at 690km.

I am not sure if 70cms contacts count double the distance but they should. Two other contacts that got away were both GI6ATZ, heard on 70cm and 23cms. Either would have been an interesting QSO, and on 23cms a new country for me. However, as the contest was underway I left him to it.

So, I did not enter another contest. I just did some operating. Including a contest is easy when you do not have the keep any records for your entry and it does not matter much if you slope off to watch the telly for a couple of hours.

There was nothing special about 3 December 2019. It was just a chance to work a bit of tropo with the activity level which comes with the contest.

Along the way I did nip outside and change over my 432MHz masthead preamp. I have done this several times over the past 6 months and I have honed the time down from an hour to just 27 minutes. It is getting like a Formula 1 pit stop. I need to work out what is happening. Perhaps that will not be so much fun as a day's operating.

73

Jim
GM4FVM
  

FT8 and 100hz ripple, a strange one for me

The general idea behind sound-card based data modes is that you transmit some tones from your computer using a transceiver, and then use the computer to decode the tones created by others which you receive in reply.

This makes things pretty easy technically. You need steady tones, stable radios and well adjusted sound levels. Modern equipment available to radio amateurs make the whole process fairly simple and reliable. Having said that, rather than amateur radio gear, the tones come from your computer sound card, and who knows about the purity or fidelity of that?

Neil, G4DBN, gave a useful talk on FT8 at the 2018 RSGB Convention. This was recorded by the RSGB and you can find it on YouTube here. If you use data modes I really do encourage you to take the time to watch Neil's presentation.

Neil suggests that it is a good idea to monitor your signal to make sure there is nothing odd going on.

Now, as it all (i.e. all those modes including FT8) relies on everybody being in the same receive and transmit filter bandwidths, the potential for an unwanted signal getting through are quite high. If you are transmitting a 500hz tone, you might generate a 1500hz harmonic, and as that is within a typical 2.7kHz or so filter, you will transmit that and it will be heard by everyone.

Luckily, that type of harmonic is not so common and you can solve it by raising your transmit frequency to 1500hz, whereupon that harmonic becomes 4500hz and is way outside the filter. It would still be there but it would never get transmitted and never get heard. If we ever go beyond the standard SSB-type filter to using really wideband signals then we will have to find a better solution than that, but then we will probably have such superb modes then that we won't care.

Returning to the real world, I thought it best to keep monitoring my digital signals and I still check from time to time. I was thinking that I might find a harmonic of the type I describe above, maybe capable of being resolved by altering the drive at some stage or other.

Oh dear. This latest test was not what I expected to see...

GM4FVM monitoring his own FT8 signal producing multiple decodes (click to enlarge).

In this instance you can see two parallel signals on the wide graph, each 100hz away from the main signal. Both of them are decoding and the worst is showing up as -30dB below the main signal. You can just about make out another pair 100hz further out.

The set-up I was using was transmitting into a dummy load on an IC-7100, receiving on an IC-9700. I could juggle it about, tx on the IC-9700, rx on the IC-7100, or between two IC-7100s, on 70cm, or 2m, and then using an IC-7300 and the 7100s, on 70MHz or 50MHz bands the results were broadly the same.

These are not harmonics of the wanted signals. They have nothing to do with over-modulating using the wanted signal. These are extra modulation products introduced either in the computer sound card or the transmitter.

Something was allowing 100hz into my system. The FT8 signal was then effectively being modulated at 100hz in what I imagine to be an AM-style (unwanted) method. The harmonics of the unwanted 100hz signal are producing mirror images 100hz away. All of this is at far higher levels of RF output than I consider to be acceptable. -30dB is FAR too strong for an in-band unwanted signal for me. In this case it is not just in-band, it is in-filter (if such a compound word exists). I was generating something that others could hear, and those others might be listening for weak signals and not liking what I was doing.

I consulted various people about how important this is and the consensus of opinion was that "it depends". "It isn't good but did anyone complain?" "Is it somehow appearing in the receiver and you am not transmitting it at all?" And several who have heard me say that there is nothing untoward visible or audible on my signal. This last comment is very comforting, but of course it only adds to my knowledge of my signal if they are hearing me 30dB above their threshold - if I am weaker than that they would not hear or see the unwanted signals. However, say during a Sporadic E opening when signals are strong, someone else might hear them loud and (not) clear.

Before going too far I checked to see that this was not an artifact turning up in the receiver. Using four radios, both ways, it was still there. And it was not on most signals received from other amateurs. The theory that this was in my transmitted signal was tested later and it certainly does not seem to be the receivers at fault.

Nevertheless, some received signals do have that effect on them and it was pretty easy to see that it was not introduced at my end. I have been on the receiving end of these hums being transmitted by others, but equally strong signals received at the same time are clean. Here is one from a station in Hungary ...

A certain HA station as decoded on 70MHz by GM4FVM in 2019

Note that as this guy faded out as shown by the trace at 13:15:30, the two unwanted signals faded not long before the main one, meaning that they were strong in relation to it. -18dB according to WSJT that day. This evidence made me more certain that I needed to eliminate my unwanted signals. Although some advice was that "if no locals could hear it then it didn't matter", I know that I can see such things on DX stations who are loud. And anyway, I do not want to radiate unwanted signals.

And these things can get worse. The evidence I produced suggested it changed depending on the radio in use and maybe just over time. Here is the worst I saw me manage, with 6 of my traces which were all decoded..

GM4FVM and his unwated FT8 friends captured at their worst by ... GM4FVM

In this case the strengths recorded for the unwanted signals relative to the wanted one by WSJT were -21, -29, -34, -42 and -43. This translates to the strongest unwanted one showing up as a signal of +01dB. As the wanted signal was +19, that means that during a Sporadic E opening similar to the one I saw the HA station, I would decode 3 of his traces and he would decode 6 of mine.

It just isn't good enough. Something must be done.

It does not really matter to me that other stations are doing it too, nor that no locals are complaining (there are no locals to complain anyway). I just had to clean up my signal.

Lacking any calibrated way to measure this, and recognising that some oddities might remain and pass through my filters, the target for fixing it was no decodable traces here apart from the wanted one. That suggests better than -43dB. Further, I wanted to get to no multiple traces visible at all, decodable or not, which looks like -50dB or more.

"ALARP" they called it during my time working with the railway industry. Any unwanted thing not capable of full control should be "as low as reasonably possible". Maybe I could not reach perfection, but I should try.

Turning back to G4DBN's RSGB lecture he quite correctly states that this type of effect is usually caused by 100hz ripple from switch-mode power supplies (SM-PSUs). It is well known that SM-PSUs can produce ripple on the DC output at twice the input AC frequency. Thus in parts of the world with 60hz mains supply this presumably causes traces with 120hz spacings.

My first line of thinking was that the station SM-PSUs must be generating 100hz ripple and that is getting into the radios. I changed all of the main SM-PSUs for analogue ones. There are two PSUs for the main rigs, one for the ancillaries (SWR meter, network radio,  Hy-Gain rotator controller ...) and one for the 70cms linear amplifier. No change. So they are in the clear. Despite this finding, I changed these around several times because I felt sure the fault lay there. No, it didn't.

Second were SM-PSUs which are not directly connected to the radios and are not what you would call "amateur grade" kit. Shop bought things. An early target was the computer, where any ripple reaching the sound card would explain the multiple traces. I changed the computer, but this made no difference. Then there were the computer displays, the supply for a multi-socket USB 3.0 outboard hub and finally one that produces 20 volts for the SPID rotator and 5V for the GPS standard. Nope, nothing.

By the end of this second phase I was beginning to think that the ripple must be generated somewhere else and be getting back down the mains into the equipment. This seemed highly unlikely. The whole idea of an SM-PSU is that it chops up the mains, generates higher frequency AC, and processes that. How 100hz hum would pass through  that I have no idea. For sure, SM-PSUs can generate their own 100hz hum, but can they allow 100hz hum coming down the mains to pass through?

However unlikely something is, if you have eliminated all the likely options, the unlikely ones have to be checked out. Sherlock would have loved me.

By this stage I had checked all the likely and all the unlikely options and nothing was the culprit. I still thought this must be something wrong with the FT8 signal going into the radio.

I should have realised sooner. The audio input graphical display on the IC-9700 and IC-7300 both showed clean audio coming out of the computer into the radios. This ripple had to be getting into the radios by some other means, but the penny had not dropped with me yet. That was a result I dismissed, and thus overlooked a clue.

Phase three had to be more radical. Even while I ignored a clue that proved it, I was beginning to think that this was getting into the radios by some odd means. If it was possible that this effect was not generated or passing through the computer then just monitoring a plain carrier would show no multiple traces. How could it? A plain carrier is unlikely to be modulated by 100hz hum coming from a computer which is turned off and disconnected.

So stage three saw one radio transmit a single carrier (CW key down or RTTY with no modulation), into a dummy load which was monitored by an SDR receiver with the trace observed on the waterfall. Both radios were powered from separate linear PSUs and entirely separate on both the DC and RF sides. Everything else was turned off and unplugged at the mains. Sure enough no multiple images. But then as I gradually connected various parts of the shack and powered them at the mains (there are three separate mains circuits), look what I saw ...

Tah-dah! The effect as seen on an otherwise unmodulated carrier.

When I connected the third mains circuit multiple traces appeared. In fact, I could toggle them on and off.

It took a while for this to make sense. Somehow a radio sending plain carrier and a receiver receiving it were producing or detecting 100hz modulation from some device not connected to them. The only obvious point of contact was the mains and that did not seem like a likely route (though possible). This had nothing to do with sound cards or FT8, though that was how I first noticed it. My computer was disconnected the whole time during phase three testing.

On then to determine which item on that circuit could be doing this. Obviously it must be ... nope, nothing obvious was doing it. The only thing left is the shack light, a fluorescent anglepoise which appears in my QRZ shack photo. As early mains powered LED lights were (radio) noisy I used a U-shaped fluorescent when the shack was built, and later replaced it was an identical one when the base broke. Could this be the cause? Surely not ...

Effect of light on and off as seen on the IC-9700 waterfall (click to enlarge if necessary).

Yes, the shack light was doing the damage. I will spare you the rest of the investigation. I tested with a reasonably close station on FT8 showed that with the light turned off they were seeing no sign of multiple traces. No amount of testing on my part showed any effect on received signals, so I am pretty sure (but not absolutely certain) that these multiple traces were generated on transmit  only. On testing on FT8, with any combination of radio (IC-7300, IC-9700 and two IC-7100s), turning the light on and off produced and removed the multiple traces. With the light off there were NO extra traces here, decoded or otherwise, visible or even partly visible, other than the main one.

The culprit

Gradually turning on the other SM-PSUs there were some slight bumps at 100hz intervals visible on the SDR waterfalls. They seemed to be -50dB or lower as I reached full operation. None of these were visible on the FT8 waterfall. I suppose these are the residual products of the switch mode process and I shall probably have to accept that. Some things, like computers and their display screens, would be hard to convert to analogue PSUs. I have to accept these unwanted outputs as ALARP, as low as I can make them. They have not gone away though, and will still be heard if my signal is very strong. I will return to the task of making them weaker later.

So the obvious thing to do is to turn off the shack anglepoise lamp. OK. I bought a cheap (£6) LED light with a flexible mount. This runs on 5 volts which is supplied by my (now tested) auxiliary PSU for the SPID rotator and the GPS receiver. So that is it sorted.

Or is it?

I am a radio amateur. I cannot just turn off the light without some investigation of how four separate radios managed to produce unwanted products without some explanation. How did it happen?

Also, as a radio amateur I am used to chasing round RF interference, clamping ferrites all over the place. And ferrites really do work very well against RF interference. But I am no expert on 100hz. I have read up that "electronic ballasts" on fluorescent lights, which have largely replaced the "electric" ballasts and starters, can indeed generate 100hz ripple. But how does this get into my radios?

The ballast for the lamp was held in a plastic box which broke up when opened to reveal this

Searching the Internet for the ballast using the reference number finds the manufacturer and the product name but anything else comes up as "404 error, page not found". I suspect that the BS EN standard referred to relates to double insulated (non-grounded) power supplies. Anyway I cannot get into the ballast itself and I only have generic circuit diagrams to work out what it is. Whilst it certainly might produce 100hz ripple, the means of transmission remains unclear to me.


The only suggestion I can put forward is that somehow this hum is being transmitted inductively. My set-up has lots of potential for hum loops. The radios are all grounded in multiple ways which are hard to disentangle - via the linears, at the power supplies, via the computer, via the SWR meter. And then the computer and the SWR meter are grounded together via the computer cables anyway ... and so it goes on. There is a rat's nest of DC wiring to provide lots of scope to pick up some low frequency energy and share it around via various routes with different impedances. Then again it might simply be passing through the mains (though I cannot really see how).

Even if that is the case, how can it be getting into the rigs? All four rigs in fact? I cannot test removing the DC supply cable, but I did remove the USB lead and the GPS frequency standard for the IC-9700. It cannot be getting down the coax, surely.

I am left with the impression that the lamp is leaking 100hz ripple down its mains lead (not grounded of course), and then inducing a similar ripple in the radio DC leads, or in the other DC connections and thus linking indirectly to the radio DC leads. In then gets inside the radios where it must be doing some mischief. How that modulation occurs I have no idea.

The inevitable consequence of all this is that there must a be a lot of energy coming out of the lamp down the mains cable, which also seems intuitively wrong. But then, touching the lamp holders of my bedside lamp in the days of coiled fluorsecents allowed me to feel the 100hz ripple via my skin. Those lamp ballasts must be a big inductive load.

Anyway, it has gone now. Banished from the house into the garage where it can do no harm. I did try it on a different circuit in the house but the effect was the same. As I cannot be in the garage and the shack the same time I doubt if it will cause any harm out there.

As for the future, there are lots of "mains conditioner" type multi-socket boards designed to cope with this type of thing. They are mostly aimed at musicians using amplifiers during stage shows. The drawback is that they generally have no technical specifications worth the title. They claim to stop mains hum, but do they? Even then, they will not stop anything generated in the PSU and passed on down the DC line into the radio, though they would stop anything radiating through the mains (if they work at all, that is).

I am left feeling uncomfortable. After 10 days of heaving about power supplies and digging under the bench I have an answer to "what" but no answer to "why". The lamp and the immediate effects are gone, but my equipment has been shown to be susceptible to a form of interference against which I have no real defence.

The inquiring mind is never satisfied.

73

Jim

GM4FVM

Round the microwave table and more doubts about radio.

I feel like a kid explaining why he has been late for school.

I missed the National Ham Rally as I was away. I was also away for the Fog of the Tyne Rally. I missed the Galashiels Rally because my car was off the road for a week to be fitted with a £900 towbar. A £900 towbar? That is new rig money for something used to haul grass cuttings to the local dump.

I had no excuse when it came to the Scottish Microwave Round Table last weekend (apart from being broke after spending £900 on a towbar).

Heather, G0HMO, giving her talk on SDRs for portable microwave operation

I took the train to Burntisland, and the Museum of Communication is a short walk from the station there. There were 55 people there and it was great to meet Roger GM4PMK, Peter GM8GAX, Andy GM7GDE, Gordon GI6ATZ, Gordon G8PNN, Brian G8KPD, Eddie G0EHV, Norman G3ZWR, Jon GM4JTJ, Geoffrey GI0GDP, Barry GM4TOE, and Tom GM8MJV. Sorry if I missed anyone out of that list and I spoke to several more who I cannot recall right now. There was a lot going on.

In fact, despite the list people I did talk to, there were several more I hoped to meet but who escaped me as I circulated around.

It was a pleasure to receive my latest batch of QSL cards. Andy, GM7GDE, who is the RSGB QSL Bureau sub-manager for my callsign, had gone to the trouble of checking who would be at the meeting and bringing along their cards to save postage and time.

Being the sub-manager cannot be an easy job, and adding this personal element to his already excellent service was really appreciated. Thanks Andy.

The first talk was about Microwave EME. I have dabbled with moonbounce on VHF and UHF, but never on microwaves, so that was interesting.

Then we heard from Sam, G4DDK, about the technical aspects of the Icom IC-9700. Sam has written the review for practical wireless. I provided a link to Sam's article in my non-technical review on this blog here. Various things had changed since the review was written.

It was interesting to hear that some 9700 owners have still felt it is worth fitting an internal modification to the 9700 to give even more frequency accuracy than the 10MHz reference method. This involves swamping the 9700 master oscillator with a board soldered over the oscillator's shielding box. So although it does involve delving into the radio, no actual soldering of wires is needed as far as I can see. The replacement board couples inductively to the existing circuit and overrides the on-board master oscillator with a GPS or similar one mounted (presumably) outside the case. So far I find the 10MHz reference input to be fine for my purposes. So far anyway.

When prompted with a question about the single PTT output, Sam said that someone makes a CI-V operated outboard switching device, but he did not say who. I cannot find any reference to this item being on sale. Someone in the audience suggested using the DC pre-amp bias as a switch but I doubt if this will work as they are all on so that you can receive on two bands at once. I should check if they all go off on transmit or just the one in use for transmit at the time. If that did work, I would need to sequence all my preamps together on the PTT line.Also, can my sequencer supply enough current for all three pre-amps? Probably, yes, but I need to check. I would also need 6 bias-tees, two for each band, or do some surgery inside the case to reduce that to three.

The lunch interval provided a good opportunity for networking.

After that GM8IEM talked about constructing a 13cm home station around the Kuhne transverter. This was interesting, though 13cms is a bit far for me to think about when I am only just starting on 23cms.

Finally Heather, M0HMO, rounded things off by talking about SDRs and software for portable microwave operation. The idea was that a movement could emerge to provide a route into microwaves for new operators by utilising the latest SDR technology. This became a bit complex and I got left behind at times as I tried to interpret the jargon and initials in use. However, I got the gist of it and it seems like a good idea. I doubt if I will be mountain-topping soon though.

Neil, G4BDN, was presented with the constructors prize. The quality of his work is astoundingly good.

I also bought something at one of the sales stalls - an RF transfer relay. This is a possible solution to switching a linear amplifier I plan to use on 23cms. I say plan, but I have not decided which way to go on this project. Bert Modderman, PE1RKI, (site here), makes an interesting range of amplifiers, some of which might suit my needs.

Bert specifically states that you should not use transfer relays with his amplifiers. This is because they usually connect the input to the output of the linear on receive, opening the door to all sorts of problems.

Despite Bert's comments I still bought this one.

The diagram shows J1 and J2, plus J3 and J4, normally open as you would expect, but only J2 to J4 normally closed. So J1 and J3 are always open and I can connect my linear there and activating the relay will bring it into circuit. Otherwise that diagram suggests that the linear will be isolated and received signals can pass between J2 and J4 when not energised.

Well, so it says on the box, and checking it out with a multimeter suggests it should work. This was on sale at a good price for a transfer relay, but still rather expensive for me. I didn't have the money on me and I had to post a cheque afterwards to GM8GAX. Thanks Peter. I didn't have the cash due to spending £900 on a towbar, not that I am obsessed or neurotic about that. Oh no, I have forgotten all about that. Forgive and forget, I say.

This particular transfer relay came from a clearance sale of more items from David, the late GM4JJJ, so I guess he had the same idea as I did. I hope so anyway.

VK4GHZ's posting sets this out better than I could: here  http://vk4ghz.com/transfer-relays/

After reading VK4GHZ's posting I had been looking for one of these rather rare variants for some time. As I pondered it at the sale table, some helpful Microwaver pointed out that the next stand had a transfer relay for half the price. When I explained the unusual configuration of this one he looked blankly at me. The other one might be half the price, but it is not suitable for my plan.

But I don't have a proper plan for more power on 23cms. I have the rig, coax, preamp, sequencer, bias tee, antenna  and now the relay, but not the power amplifier. I am not convinced that the Bert Modderman route is the right way for me to go.

Here is the history for me. On every band I now use I have gone in barefoot or with low-ish power. Then after a while I have bought a bigger amplifier and in every case it would have been cheaper and easier to get the larger amplifier at the start.

However, I live in this twilight world of love/hate for radio. Every so often I want to go QRT and take up quilting. Or follow in my Granny's footsteps and try crochet. Making blankets is an Edgar tradition and radio isn't.
======================
I enjoyed the Scottish Microwave Round Table, and it was great to meet so many friendly and helpful people. I should be content but I am not. I cannot just throw money at a big linear for a band I hardly know. It might be a mistake not to buy the biggest boots I can find, but comfort counts in the boot world too.

I might be more comfortable with a small linear and make the same mistake as before. At least that will be simpler for me if I decide in a fit of pique to go QRT and adopt bear stuffing instead.

That is making stuffed toy bears, by the way.

Anyway, even if I do get into sewing and stuffing, I will always have the right transfer relay.

73
Jim
GM4FVM

The joy of coincidence

Coincidence No. 1

Last weekend we reverted from Daylight Saving Time to GMT. It was GM4FVM's job to correct the clocks at FVM Towers. I did the heating clock, the shack analogue clock, etc. I couldn't do the clock on the oven as Mrs FVM was baking bread in it. I did the kitchen clock. I forgot the clock on the mantelpiece in the living room. I forgot one clock, just one.

Mrs FVM took  her time from the one in the living room, which was wrong (my fault). In the kitchen the kitchen clock decided to stop as soon as I corrected it due to a flat battery - coincidence 1. Just by chance, it stopped when I changed the time on it. The one on the oven just confirmed her view of the time - it was wrong because of the baking bread so I hadn't been able to change it yet.

So the FVM family tea had to be held an hour early, because everything had been prepared following clocks I hadn't fixed. Kitchen clocks that were stopped (I pointed out), or otherwise impossible to change by FVM, but he still gets the blame for those coincidences.

I tried to protest, pointing out that there is a clock in the kitchen on the radio which updates automatically, but then I was confronted with the evidence of the living room clock. Guilty!

Coincidence number 1a

Well, not really relevant to the radio blog, but I was on my way to see my ham pal "Gouda" at the garden centre tea shop the following day (what a crazy life I lead). I called in to get my hair cut by Chris the Barber in Duns. His clock was also still on BST - so not such a surprise at all really. This is just to show it isn't just me at fault. And radio amateurs do sometimes spend money on their appearance, despite what people say.

Coincidence number 2

What are the chances of these 2 drives failing at once? Or me misunderstanding the whole thing?

My shack computer has been suffering from over use. So I have replaced it. I might explain why and what with later, if anybody is interested. Or maybe I will explain someday even if nobody is interested.

As soon as I connected the backup drive to the new computer it failed. Exactly when I needed that drive, it failed. The click of death, that scourge of mechanical discs. What a mess coincidence number 2 was. Mind you, it did that once before and then it came back to life again later, but there is not much chance of that happening now, I thought.

I decided to use a different backup disk which had some of what I needed on it. Let us call the second one, backup disc 2.

Coincidence number 3

The new computer was acting up. It kept losing the USB sockets. I could not get through a complete backup without the transfer failing repeatedly.

I decided this must be due to a new 5 USB 3.0 socket extension card. However, I did have a 2 USB 3.0 one to try instead. I did not have enough of the right power sockets to run the only replacement I had and power the DVD drive at the same time so I decided to power the temporary extension card using a separate power supply. Could that cause some earthing problem? No, it seemed to work.

I climbed under the bench to try the sockets and suddenly there was a blue flash, followed by a loud bang and a nasty burning smell. I lay there and noticed that it was now dark, as the lights had gone off, and there was that sound of slowly stopping fans. I have described this sound before and it never leads to anything good.

Oh bother.

Please excuse the unparliamentary language. Jings, crivvens.

I had hoped that would be a nice new computer, but what have I done? Oh deary me.

Extricating myself from under the bench I found that I had blown the earth leakage circuit breaker on the main house fuse board, the switch fuse for the circuit covering the shack plus half the house, and the 10A fuse in my main "big switch" for the shack sockets. Probably I had blown the computer and everything else.

Having this blow loudly about six inches from my left ear made me a bit unsettled. Why had more than one fuse gone? Why the main earth leakage circuit breaker gone? Was this the earth fault I had feared?

It took me a while stop hunting for earth faults and remember that this had  happened before. One of those power supplies had blown in the same way a couple of years ago. Luckily that time I was not stretched out beside it. They are just cheap throw-away devices. So this was coincidence 3. I had decided to put my head right beside an exploding PSU, and it has decided to blow just as I did. And this had nothing at all to do with the USB extension board. Multiple coincidence.

This is the only one of three PSUs which hasn't blown ... so far.

After resetting the safety breakers and replacing the fuse, the computer powered up again.

But all the mains clocks had stopped and needed to be reset ...

Coincidence number 4

None of this solved the fact that the USB sockets still appeared to be failing. Connections to rigs kept stopping, my rotator boxes kept losing contact with their software, and all seemingly at random. It took a while for me to realise that it was not just that the second backup disc was failing as a result of the USBs going down, the second backup disc was causing the USBs to go down.

The second disc had decided to fail on the same day as the original backup disc, and even more puzzlingly, every time it went down it took the USB connections with it. Or at least the ones on the extension board. So that was coincidence 4.

It was easy to prove when I worked it out. Just introduce hastily thrown together backup disc 3, and everything was fine. So what are the odds of backup disc 1 and 2 failing at the same time? What are the chances of disc 2 having a fault that affected other USBs?

What are the chances of me completely missing the point and blaming myself?

I tried very hard to save that disc 2. I used AOMEI software to try to repartition it, format it, or whatever, but nothing worked. "Bad sector" stopped it whatever I did. Something is seriously wrong beyond bad sectors. I got the data off it by a three hour session of keeping pressing "retry" every time it failed.

So, when I stopped trying to use the second backup disc, the USBs all started to behave themselves. Then the postman delivered the cable I needed for the extension card and everything went back to normal.

Strange event number 1

Not exactly a coincidence, but after all this I tried the first backup disc again and it worked this time.

AARRRGGGHHH!

What a rigmarole. Certainly backup disc 2 would have proved to have failed whenever I tried it, but that would have been obvious if I was not trying to set up a new PC at the same time. I cannot trust the first disc but it is working again now. I spent ages with that extension board when there was nothing wrong with it, and my idea of an earth fault was just me trying to make sense of the temporary PSU blowing up spectacularly just when I decided to use it. Mind you, it had been sitting in a box for a couple of years, so blowing is not a real surprise - or so it looked when I calmed down.

When I was lurking under the bench in the dark, listening to the silence and smelling that awful burnt smell, I did wonder "why do I do all this?". I mean, here I am, in my sixties, stretched out on the floor in an awkward space, having just blown everything up (or so I thought). Will I ever mature and become one of those amateurs whose QRZ.com photo shows a clear desk, a rig and a microphone? Nothing ever blows for them, and their tea arrives on time in all time zones thanks to accurate clock regulation.

I would show you a photo of the blown power supply but I couldn't wait to throw it out. The photo above is the only one of three still working. No doubt it will blow soon too.

I have ordered a new case for a new backup drive (number 4), using a disc salvaged from an old machine. Maybe this is my problem, salvaging things and using them for years beyond their "use-by date". But hold on Jim, Backup discs 1 and 2, plus the PSU, were all bought new by me and are not salvaged at all.

Moral of the story?

Diversity and redundancy. Have two of everything. Or three. Then you can be totally mystified when they all break down together.

Or, to put this another way ...

If it can go wrong, it will. And it will go wrong just when you expect it not to.

73

Jim

GM4FVM

What kind of a radio amateur am I anyway?

Aircraft scatter showing Doppler on G4RQI's signal on 4m. Curious? Interesting? Not in Ayton it isn't.

"Who do you speak to on that radio of yours anyway?" asked the neighbour.

Er, um.

How do I answer that one?

How do I define myself as a radio amateur?

I suppose they expect me to say "someone in Outer Mongolia". You know, somewhere exotic, where we might exchange cultural greetings and perhaps I could chat in my rusty but effective Outer Mongolian (which I have to confess, comes with an Ulster/Scots accent).

But, I do not really speak to anyone. Hmmm, maybe good old Gouda, with whom I exchange the odd word on 2m FM as our cars converge on the Garden Centre Tea Room. "I'm in the car park" - "I'll be with you in 2 minutes".

This does not seem to justify the eyesore which is my antenna farm, which the neighbour is balefully examining as we speak.

Hold on, I do use the microphone during contests. Yes, Eddie G0EHV, Jon GM4JTJ and David, G4ASR, every Tuesday or Thursday night. What if he then asks what we say to each other which is "You are 59 002 in IO85wu, 73". That hardly counts as a cultural exchange, and anyway these people are all in this great United Kingdom of ours (note: before posting this, check that the UK still exists). IO84 is not exotic.

That won't do for my sceptical neighbour.

Pretty much everything else I do is data.

I do not really talk to anyone. Sometimes the Postie calls with a Jiffy Bag from China with some BNC plugs in it and we compare notes between his guitar amplifier and my linear. All about harmonics, but not really radio chat. Once a year at the Galashiels Rally I meet ... well Gouda again. And maybe somebody else, you never know, like the man who prints out the callsign plates, or the chap selling the old valves (he never has the one I want, and I am never going to use it now anyway, even if he had it, which he doesn't).

The club? Aw, the club.  Half of them got fed up and the other half died.

Seriously, so many amateurs are passing away that we should be protected as an endangered species.

Harrumph. There isn't a simple answer to this. I am not in the business of talking to people on the radio. Sure, I used to be, but then I discovered the mobile phone, Skype, network radio etc. Back in 1974 the idea of talking to people in exotic places did really appeal. Not now.

Then, once I was licensed, I discovered that many of them would just tell you their name was Igor and they lived in Novosibirsk and that was it. You might improve your geography by finding out where Nizny Novgorod actually was, but how significant was that? You might even find the odd YU who would say something more than "rig home brew" like the other Easterners, but so what?

I am glad that these days people in Plovdiv, and Ulan Bator for that matter, have their own mobile phones, and are no more interested in talking to me by amateur radio than I am in talking to them. They have some freedom to talk now, and that is all for the good.

When you couldn't talk to people far away as an everyday event, then it had real interest. Now it just doesn't. We amateurs have to face it, the days when just the ability to talk to people was enough to keep up an interest in this hobby are long gone. Talking isn't the thing it was, and it certainly is not why I still follow this hobby.

Not that I am much of a home brewer either. As the years have gone on, that is an even lesser interest of mine. I admire those who do, and I often have discussions with them about that. Would my neighbour think more of me if I told him that? Probably not. This is the sort of neighbour who devours modern technology but who has no interest in what is inside it. Actually, all the other neighbours are the same.

No, I decide to answer along the lines that I am a curious radio amateur. I have suggested this on this blog before. I'll explain the fascination I have for it all and he will be impressed by that.

It went something like...

"I don't really talk to people on the radio these days, I tend to use computers". He now has a far-away look in his eyes. "For instance I can bounce signals off meteors, or the ionosphere, or even the moon".

He has accepted that I am not talking to actual people by radio - he now thinks I am sending emails to The Man in the Moon.

He takes a moment to absorb this remarkable fact I didn't tell him.

"Well, you have put up a bigger aerial to do it". He says.

I haven't. I think he is getting confused as my antennas now are smaller than they have been for years.

I reply "You probably just saw them side on, which is longer than end on" I am trying to explain the Yagi in this way, but he seems to be losing interest.

"Eh?" is his inspired response. Could this be curiosity in him ? (no Jim, get real)

"They turn you know. I rotate them ..." I can see that his eyes have glazed over again. I tail off trying to explain the concept of a directional antenna.

"Aye, well ... " he says, and then he turns and stomps off to go back to raking up his leaves.

That went well.

I am glad that the community appreciates my particular take on amateur radio.

Curious, that's me.

And the rest of them? They aren't curious, at least not when they find out I do not actually speak to anybody.

The scary thing is that they all have a vote.

73

Jim

GM4FVM

Icom IC-9700 operational review.

Please forgive me if I have forgotten anything or if I get anything wrong, there is a lot to cover with this thing. I will correct as necessary.

I find it hard to know where to pitch my review of the IC-9700.

IC-9700 at GM4FVM in single receiver mode.

There are quite a few reviews on the Internet. Many of these seem to come from either retailers who want to sell you one, or those "opening the box" type articles. Both of these seem to have missed the point when it comes to actually using the thing, which is where I am trying to pitch this posting.

There are also some reviews which seem to originate from one individual who appears to have a very cosy relationship with Icom. I have no relationship with Icom other than as a customer. I am not an Icom fan, and the only reason I have Icom equipment is that it seems to meet my needs in certain areas. If anybody else made something suitable, then I would try that. Over the years I have had Yaesu, Kenwood, Flex, ... you name it. I am what the marketers call a "brand tart", someone who has no brand loyalty. Why should I be loyal to them?

I should say early on that I do not use amateur satellites or DStar digital voice mode. I cannot test this radio for those uses and therefore if that is your main interest maybe some other review would be better for you.

1: So what is it?
The IC-9700 is a multi mode (FM, SSB, CW, AM, DStar DV, various data), three band (2m, 70cms, 23cms), transceiver using mostly software defined radio techniques.

I am not going to try to set out a technical review. Not only do I not have enough test equipment, but also it has been done elsewhere. There was a four page review in the RSGB magazine Rad Com in September 2019. That was fairly soul-less, but it has the data in it, so look at that if you need the hard facts.

A much better review for an operator to consider would be this one which appeared in Practical Wireless magazine:-
 https://www.radioenthusiast.co.uk/articles/review-icom-ic-9700-vhf-uhf-transceiver/
Note that the review at the above link was written before the firmware update which allowed the 10MHz frequency standard input to automatically control the frequency and thus resolve the drift issue. 

This article correctly pointed out that I might not understand the full implications of the Nyquist frequency. For a Software Defined Radio ("SDR") like the IC-9700 or the IC-7300, I understood that the Nyquist frequency was twice the highest operating frequency - so in the case of a radio covering up to 52MHz this would be at least 104MHz. that would mean that the clock in the sampling oscillator would need to run at at least 104MHz. It is possible to go slightly beyond the Nyquist limit, in other words, to operate the radio beyond half the clock sampling frequency but at reduced efficiency, a fact which the IC-7300 uses to cover up to 72MHz in European models.

So, with the difficulty of getting stable oscillators at a reasonable (amateur) price beyond a couple of hundred megahertz, difficulty which increases the higher you need to go, it seemed to me that there was no prospect of an amateur VHF SDR in the near future. But I was just ignorant of the facts (not for the first time, Jim). As G4DDK explains in his review, you only need to raise the clock frequency high enough to cover the range of frequencies the radio operates at, not the absolute frequency. So the trick used by Icom is to offer the IC-9700 without general coverage between the amateur bands. This reduces the ranges to 2MHz (for 2m), 10MHz (for 70cm) and 30MHz (for 23cms), which can all be covered by a clock oscillator speed similar to a standard HF radio.

2: The benefits of being an SDR...
The general idea behind an SDR is that most of the processes inside the radio are defined in software, which means that you can change them at will. There are of course some things that Icom will reserve to themselves, and which you cannot change - this is to meet their regulatory requirements, or for commercial reasons about not letting their secrets out. How easy it is to change these things is something which Icom seem to be getting good at. With the arrival of the IC-7300, and further developed in later rigs, the touch sensitive screen is exploited to make changing those many aspects easier.

The main display on the IC-9700, single RX, spectrum scope showing +-100kHz

For a simple example, take mic gain. Suppose you want to change it. You just have to press the "Multi" button and up on the screen comes a display showing RF Power as well as Mic Gain (showing the current level of Mic Gain, 38%, as I write this).

IC-9700 display showing mic gain level ready to be altered

The clever thing then is that you just press the Mic Gain area showing on the screen, it is highlighted, and then turning the Multi control will alter the Mic Gain. I can raise it or lower it. This is very user-friendly. You don't have to plough through menus - when Mic Gain is showing all you do it highlight it and you can change it. The same knob (Multi) selects the display - push - as changes the level - turn. Very sensible ergonomically.

And this approach extends to the more complex settings. Sure, as you get further away from the few settings you use all the time (Mic Level, RF Power etc) you move into some menus. However, these are easier to navigate thanks to the touch screen. Pass band tuning, for example, it shown up graphically on the touch screen by pressing the "PBT" button.

IC-9700 PBT display ("Pass band tuning").

You can then see the exact alignment of the pass band tuning filters. If you then press the display on the filter area and turn the Multi button, not only do you move the passband filter, but you can see the result immediately on the screen.

Adjusting IC-9700 PBT filters

The display shows the central area of the filters, showing how wide you have set it, shows in figures the bandwidth (2.25kHz) and the offset (+375Hz). Also shown is a white dot to remind you that passband tuning is offset (handy if the offset is low) - if you want to cancel your settings just press and hold Multi and the two filters return to full overlap, the dot disappears, and normal filtering is resumed.

What I am trying to get over here is how simple the process is to use and how natural it all appears to the operator. In reality, at the heart of the SDR, there is no pass band tuning in hardware sense. You are looking at a representation of two filters, and the radio behaves as if there are two filters, but the whole thing is done in software.  To the operator, you get the display, and you do not need to worry about how it is done.

This approach is common in SDRs, but with the IC-9700 the ease with which you interact with the radio has been brought to a high level of simplicity. The buttons, the knobs and the display all work together seemlessly. My Flex 1500, which had similar features required a lot of fiddling with the computer to access them - with the IC-9700 a radio with knobs and displays working in an integrated way is vastly more user friendly.

To take another example, but one which I will not illustrate, we could discuss the notch filter. Press the dedicated button "Notch" once and the display shows the message "AN" (automatic notch). Press it again and you see "MN" for manual notch, and in my case also "NAR" meaning narrow. Press and hold the Notch button and a familiar bar display appears at the right hand side of the screen - rather like the one for RF Power and Mic Gain, but this time showing Notch - Position and Width. With the Position highlighted turning the Multi knob moves the notch filter and also moves the graphical representation of the notch. This means that you can see the notch in your passband and move it accordingly. Touching "Width" on the right hand side display cycles between Narrow, Mid or Wide notch. You can adjust that and then press the bottom of the screen to return to normal display.

I find this notch adjustment very useful indeed. Sometimes on VHF some very strong local signal will appear inside the data mode passband of my receiver. In narrow setting I can notch it out. Not only can I hear the effect of the notch, I can see on the display where the notch is. It might seem obvious, but somebody has spent time making the interface so naturally user-friendly that it just disappears from the operator's consciousness.

Another aspect of SDR is the ability to alter the characteristics of the filters themselves. We have been able to use radios with digital signal processing for several years. This has allowed us to have digital filters like this for some time. But now with (more or less) fully SDR radios like the IC-9700 the whole filtering processs is done in software which is integrated with the entire signal path. At the same time, the complexity of the software has developed to the stage that we are not just turning things on or off, but can change almost every aspect of them on the radio itself and not via an attached computer.

Not only can we alter the notch and the filter width, we can alter the slope of the filter edges. The IC-9700 allows you to choose between "soft" and "sharp" filtering. How simpler could it be? Just press the screen on the FIL (filter 1 in my case) and up comes a screen showing the filter in use and you can change between filters and sharp versus soft. Not only is that set for the settings you are using, but there are different settings available, for mode. In my case, FIL1 is set for 3.0kHz soft for data (USB-DATA mode) and 2.4kHz sharp for SSB (USB mode), and the filters change as necessary as I change mode.

IC-9700 filter settings for data ("SSB-D") for filter 1 (FIL1)

Why would I want to change between soft and sharp, or one filter and another? Well, between data and voice in my case. And the IC-9700 will remember that choice on each band and switch between. So  you customise each of the three filters and select which one to use on any band and mode. Actually, I prefer soft, generally, but I do use 3.0kHz on data and 2.4kHz on SSB. Set it up and forget it because the 9700 does the remembering.

Lest we forget how far we have come here, buying a radio used to involve working out which filter we would be likely to need, and then buying it as an expensive add-on. You might only have room for one more (with the FT-817 you choice was very limited). Needless to say, you got somebody else's idea of whether you needed soft or sharp filtering. I remember buying an expensive CW filter for my FT101 (+ 2m transverter), and an equally pricey "SSB" filter for my FT-817 to use with data modes. Now with this IC-9700 I have a wide range of filters which are easily configured and structured seemlessly into the digital structure of the radio. Not only can you configure lots of settings, but you can often see on the screen exactly what you are doing. SDRs are now delivering the ability to be customised we were promised, in a single box VHF/UHF rig, and in a seemless, user friendly, way.

You have even more choice on the PBT front too. There are, in fact, two Pass Band Tuners to choose from - PBT1 and PBT2. You can customise them and select between them.

The layout of buttons and knobs on the IC-9700 is similar to the IC-7300. Most of the functions are similar too. However, to cope with the fact that the IC-9700 has two separate receivers some changes have had to be made. The IC-7300 has a dedicated pass band tuning control, whereas on the IC-9700 there is a PBT button and after that you use the multi button instead. That is the only drawback I can see to the different layout - and maybe many users never alter the PBT. Also, as there is no auto tuner in the IC-9700, that button is used for CALL/DR for DStar.

So you have buttons for Power, Transmit, Call/DR, VOX/Bk-In, PreAmp/Att, Notch, Noise Blanker, Noise Reduction, Menu, Function, M. Scope (shuttles display settings), Quick (often used settings) Exit, RIT, kHz/M-Ch, Split, A/B (VFO), VFO/Memory, Scan, Tone/Rx-CS, Memory Pad, AFC/Auto Tune, Speech/Lock. I hope I have made these as self-explanatory as I can as it would take an age to define them all. The basic manual is 96 pages and the advanced manual is 173 pages, and I am not about to repeat all that here.

The knobs are for
1) Main: AF, RF/Sql (concentric), select main/sub (press),
2) Sub: AF,RF/Sql, (concentric), sub on/off (press)
3) Multi (turn) Clear (press)/
4) VFO
Obviously the touch screen can be used for many things, often after the appropriate button has been pressed to activate changes.

With that array of buttons and knobs you can see that you have a wide array of things to keep you busy. As I have been droning on about, during the early implementation of amateur SDRs a lot of this was only alterable using the attached computer, whereas the IC-9700 can operate as a free standing radio. You can alter just about everything you need in settings and leave the computer (if you use one) to run data software.

The wheel has gone full circle. That Flex 1500 I keep talking about had one switch - on/off - and everything else was adjusted in the computer. The Icom IC-9700 has all the switches and knobs you are likely to need. The designers of those early SDRs thought we would enjoy using our computers to access the rig, but we amateurs thought differently. Now Flex sell (expensive) computers to act as front panels for their radios. Perhaps they forgot how important human/ machine interfaces are to our construction of a meaningful operating environment. To sum up - we wanted the knobs back. So radios become more like computers, and took back the processing from the PC, and better chips and technology helped that along.

You only have to look at the IC-9700 and its great big VFO knob to see that the designers of SDRs have got the message. As Kenneth Horne often said in "Round the Horne", there is nothing quite as satisfying as a great big knob. Or he said something like that anyway.

And finally, a key advantage of an SDR is that the nice folk at Icom can make available firmware updates to fix any glitches which come to light. This means that the old way (if you bought an early rig you bought problems which were fixed for those who bought later ones) should be abandoned, and our expensive radios should be upgradeable. And so it proves (see later).

3: .. and how is it not totally an SDR after all.
For all the SDR credentials the IC-9700 has, it is not entirely an SDR. In perfect form, an SDR would convert incoming RF at the earliest stage into digital information, then process it as a digital data stream before either converting it back to analogue for output on a loudspeaker or shipping it off as a data stream to be decoded as FT8 or whatever in our computers. And the reverse would happen on transmit.

The IC-9700 meets that ideal in most respects, but not on the 23cms band. In the case of 23cms there is an intermediate frequency at 311-371MHz (for the European model, varies for other markets). So in that case the radio does not convert to digital directly at 23cms, but in the IF range. Am I bovvered? No. It is a little bit of superhetrodyne- type twiddling to allow a radio to cover the three bands, and seems logical to me.

It is a bit as if we are using an SDR to tune the IF produced by a transverter. Ignoring the fact that this is also like the execrable Liner 2 (with a CB radio rather than an SDR in that case, but the same idea to extend a simpler transceiver to a higher frequency range without having to complicate the basic rig), why not? If we have to wait for SDR technology to make the whole radio general coverage from DC to 1300MHz, plus make it affordable, it will take a while. There have to be some trade-offs, and I can accept losing general coverage and full-SDR ability to give me something which works.

Not quite being a full SDR is a fact, but not a very significant one to me.

Incidentally, before I had the IC-9700 I was using an IC-7300 and a transverter on the 2m band. This was a great combination. Now I have the IC-9700. I took out the IC-7300 and slotted in the IC-9700. For a while I used the 9700 only on 2m. Frankly, I hardly noticed the difference in operating terms. Tuning a transverter with an SDR might not be technically perfect, but it was better for me than tuning a transverter with a superhet.

4: Issues
Issues are things which are not problems, just irritants, things to get used to, etc. Things that bug me about this radio.

As I said, changing over from the IC-7300 and transverter combination to the IC-9700 went almost un-noticed. The low-noise quality of the SDR all- the- way showed through.

The biggest issue from an operational point of view was, oddly, the second receiver. What seems like an unqualified benefit actually worked out a bit hard to get used to.

I am something of a dinosaur with radios. Rather than use expensive ones with multiple receivers, I have used two simpler radios which just had one receiver each.

Now I have an IC-9700 which has two receivers. To shoe-horn the two receiver details onto the display, the Icom designers have to let something go somewhere.

IC-9700 display with both receiver turned on.

When you are using both receivers you get to two frequencies displayed on the screen. You can select either VFO (in which case the other is greyed out) and change the frequency for that one using the VFO knob. You can only transmit on the main one - the top one.

So let us say that I am listening to the GB3NGI beacons on 144.482 and 1296.905. Both beacons can be heard because each receiver has its own audio gain control. You can switch the VFOs between the "main" receiver (top) and the "sub" receiver (bottom) just by pressing the top AF control (marked M/S) for 1 second.

Switching between main and sub (or rather swopping the VFO frequencies between them), is handy for, say, when you are monitoring another band and decide you want to go there and call somebody. Not beacons of course, but other stations.

Only the top frequency is sent to the digital output on the USB lead. Although I can hear the 1296 beacon on the loudspeaker, I cannot decode the data via the USB lead because it is on the sub band. If I switch over between the main and sub then the other one cannot be decoded via the USB lead. EDIT This is wrong. As delivered it is true but you can change your computer over to receive a stereo signal via the sound card on the USB lead, and the two signals are on opposing sides of the "stereo" data soundtrack. This is covered in later postings on this site. However, as set out below, there is no CAT control of the sub-band receiver.

There are two COM ports created when you plug the USB lead into a computer, but the second one is for GPS data to be used with DStar digital voice mode.

 There is no "CAT" type output from the sub VFO. I wasn't really expecting a two receiver radio to allow separate CAT control of sub-bands, though I believe that the ELAD FDM-DUO does (with up to 9 receivers!!!). So I am not too disappointed with this. It would be VERY handy to have. After all, in these data-mode days it is hardly surprising that we might like to decode signals as well as listen to them.

So that is an issue but not really a big thing for me. Neither is the fact that you cannot run the two receivers on the same band. It might be very handy during a contest to leave one receiver on a station who is busy working others, and then listen to them in the background while you pursue other DX until you can call in. Sure, you can do that by putting the frequency into VFO A while working on VFO B, and then switch between them. However, you switch between, you cannot listen on two frequencies within the same band.

I see that issue, but it is not a deal breaker for me.

A spin off from not being able to set the same frequency band on both receivers is that when you have both receivers working you cannot, say, leave the main receiver decoding 2m FT8, go to 1296 to listen on the sub, and then nip across to check something on the 2m band on the sub receiver. As only the main receiver outputs data, you cannot swap that with the sub without losing the data stream.

If you don't use data modes most of these issues do not pose major problems. But only having one data stream out, and only allowing the two receivers to operate on different bands, can produce the need to apply weird patterns of juggling between VFOs and receivers to sort things out.

The band stacking register is very clearly displayed, which is great. You use the band stacking register to change band, and this initially struck me as odd. It works, and if you have both receivers turned on it shows which band option you cannot chose - whatever band is in use by the other receiver is greyed out. If you want to use that band with your current receiver then you have to juggle them around.

IC-9700 Band stacking register

I am not expecting to use the two receiver capability much. So far I have been using the IC-9700 as a single receiver rig switched between two bands - 2m and 23cms. I usually have the second receiver turned off. That way the operating frequency always follows the instructions from WSJT-X. Also, there is just one frequency on the display, which eases the strain on the tiny processing capacity which remains operational in my brain.

I am sure that in the long run I will get the hang of the dual receiver function, but right now it just gets in the way.

Why did this radio appear with an SO-239 socket on the 144MHz RF output (in Europe at least)? I keep having to spend £10 to buy new sockets as the 2-hole ones are hard to find at a decent price. Grrr, that's my issue for sure.

Finally, an issue I am not so sure is really an issue. There is a facility to turn on a DC voltage to power a mast-head amplifier, customisable to any combination of the three RF outputs for each band. I cannot work out if, or how much, this is sequenced to the PTT operation. The manual does not seem to explain. I guess it must be as otherwise I usually get a momentary high-SWR as the RF VOX in the preamp works. Properly sequenced DC bias causes no SWR problems and I have no SWR problems. But why does the manual not clear that up? I'll need to measure it to satisfy myself.. 
EDIT ... More on the DC output for running pre-amps here.

5. Problems.
For me there were two main problems with the IC-9700 when it arrived. One is the frequency stability, and the second is the single push to talk output.

Dealing first with frequency stability, this has been well covered elsewhere in the specialist magazines and the internet. It was widely reported that on receive things were fine, but if the rig was used to transmit long enough for it to warm up and the thermostatically controlled fan come on, then it drifted quite significantly. Quite significantly means too much for WSPR decoding, but then not many of us use WSPR on VHF.

I have made a separate posting about this problem here. Basically, I added a Leo Bodnar GPS disciplined frequency standard and the problem (if there was a problem) went away at a cost of £100.

There is a lot of complaint on the Internet about this problem. True, Icom should have discovered it before the radio was released, and also true they should have offered the solution much more quickly. But the solution now exists (thanks to a firmware update), so we should move on. 

EDIT - this second issue has now been resolved for me by using a DX Shop PTT multiplier - see here.

Secondly, the IC-9700 has only one PTT output on the accessory plug for linear amplifier control. This is a big surprise for a three band VHF/UHF radio as there is no practical option for one linear to cover all three bands. It is a baffling error for Icom to make, as earlier Icoms covering these bands had provision for at least two PTT outputs. I wrote about this here.

Rear view of IC-9700 - no room on ACC socket for multiple PTTs (Icom Brochure)

So concerned was I that I decided not to buy an IC-9700 until I could find some resolution. As it turned out, an IC-9700 arrived anyway so now I will need to resolve it myself. I worked out a way of avoiding any potential damage to my mast head pre-amps by simply turning all of them off when transmitting on any of the three bands. That solves that problem but it is not practical for the linear amplifiers. Switching a linear to TX when there is no RF signal on the input opens (in my mind anyway) the door to self-oscillation in the linear. It is not good practice in my book.

I see on the internet that at least one other amateur has thought about reading the CI-V line and switching the PTT that way. I must contact them and ask how they are getting along. In the meantime, the single PTT configuration remains a problem for me.

6. Using it
Nothing adverse to report here, apart from the issues and problems reported above. The HM-219 hand microphone gets favourable reports. The large VFO knob with the freely rotating finger cup is a nice feature. The colour display looks great, but there is not much room for the waterfall when both receivers are switched on. There is no socket for plugging in a bigger display.

Knobs and switches are generally well laid out and easy to use. As with the IC-7300, the buttons under the upper dual AF/RF controls (P.AMP.ATT and NOTCH) are difficult for me to see. Perhaps my shack illumination needs to be mounted lower down.

Speaking of those dual AF/RF level controls, it is a pity that adding the Sub AF/RF controls on the 9700 rules out the inclusion of separate PBT controls as on the IC-7300. I guess there is no room, and you cannot have everything. As I usually keep the second RX turned off, those controls are out of use most of the time. Ah well.

I have used the IC-9700 on SSB and data modes on all three bands. I have gone onto RSGB UKAC contests with SSB on all three bands. The radio performed just as I would have expected - well. The receiver is quiet and the ease with which you can adjust the filters is a joy. Well, the ease with which you can adjust anything is a joy. The flow of the process from finding the function to altering it while seeing what you are doing is an exemplary model in ergonomics.

Having a radio which is very easy to handle is all well and good. Is it top in its class for performance? As this is not a technical review I cannot say for sure. The test for me will be moonbounce performance. Of all the modes and bands I use, only EME really tests my equipment to exacting standards. On 144MHz I have heard stations via EME using the IC-9700 and I have been heard via EME. Clearly it is stable enough and sensitive, but I have not yet had an EME QSO with it.

This is a pretty sterile debate as EME conditions are so variable and open to many interpretions. My set-up has marginal performance as a moonbounce station. I am always relying on good stations at the other end, due to my (self-imposed) limits on antennas and power output. Ask me for a subjective opinion based on too short an operating period and I would say that the IC-7300/ME2T-Pro transverter combination is slightly better than the IC-9700 when it comes to sensitivity. With the GPS frequency standard connected, the IC-9700 is better for frequency stability - and everything else.

There might be 1dB in it, if anything at all. The benefit of having the whole thing in one box, and rock steady in frequency terms, leads me to prefer to IC-9700 over the transverter set-up. We should not forget that my transverter drifts a bit too.

We shall see in the long term, and for now I still have the transverter, because I think it is, very very slightly, better at the very edge of weak signal performance.

On the other hand, if I got a good offer for the transverter I would probably give it up and go 100% for the IC-9700.

7. Conclusion
I like it.

If I had been spending £1800 of my own money I doubt if I would have one yet. I had decided to wait for a resolution of the single PTT problem. Somebody will crack that someday. In the meantime the problem still isn't resolved, I am using the IC-9700, and I like it. Make of that what you will.

The radio closest in specification to the IC-9700 I have used was the Icom IC-910. That was ten years ago in superhet days. It had the 23cm unit installed but not the optional digital audio processing unit. I think from memory that the digital audio processor worked at audio frequencies and was not operational at RF. Anyway, it sounded very noisy on receive. From an operational perspective the IC-910 seems like a generation ago rather than ten years. It was hard work to adjust anything, you just had to take what you were given. The IC-9700 is a huge leap forward compared to that radio.

I have a (sort of) feeling that the IC-9700 is not the end of the line for Icom VHF/UHF offerings. I might be wrong here! Sure they will be busy launching the IC-705. But I sense another rig on the horizon. This is an SDR featuring the broad outline of the HF abilities of IC-7610 married to the high band ability of the IC-9700. Something like an Kenwood TS-2000 but this time with a sensitive receiver and also being an SDR - or a Yaesu FT847 that worked and was an SDR too. This would be expensive, but the problems of building the 9700 down to the £1800 price tag would be lifted. It would have two or three PTT outputs customisable by band, it would have a built in GPS standard, it will have the ability to have both receivers on the same band, both receivers will have CAT control and USB data output for each, there would be a separate PBT control ... and I for one won't pay the extra money.

Possibly.

In the meantime we have to IC-9700, which seems pretty good to me.

73

Jim

GM4FVM