Friday, 15 March 2019

David Anderson, GM4JJJ, SK

I was saddened to hear last night from David's wife Pat that he had passed away yesterday.

GM4FVM with David GM4JJJ in August 2018 - photo taken by Pat
I first worked David on 4 April 1977 when he was GM8HEY and I was GI4FVM. I guess that neither of us expected to still be in contact over 40 years later. Working David then was DX on 2m for me, later of course we ended up about 100km apart and spoke regularly.

David's interests over the years extended to VHF generally and Earth-Moon-Earth communication in particular. The wrote the "Moonsked" software still in use by many enthusiasts to this day. He worked for many years in the electronics industry and his thorough knowledge of practical circuits was offered freely to many amateurs who were having problems.

Our background interests were different, mine more into the physics of radio, David's more into the electronics, but that turned out to be a perfect mix. We found that we were both interested in the particular interests of the other. We shared lots of information, and neither of us suffered the same fools gladly (especially certain equipment suppliers). David also added useful information to this blog.

It was so helpful to have him to bounce ideas off and I miss him already. .

Despite having to deal with a long illness, David remained positive. He continued to offer me advice right up to the point where he found it better to rest than operate on the radio. I will always be grateful for his friendship.

To Pat and to David's family I send my condolences. I have lost a mentor as well as a friend.

73's David


Saturday, 9 March 2019

More tropo, masthead pre-amps and sequencing.

I don't have to look far to find a masthead pre-amp at GM4FVM. The (now redundant) terrestrial TV antenna here has one.

Terrestrial television antenna at GM4FVM, with bandpassfilter and masthead pre-amp
I'll deal first with recent events before moving on to pre-amps etc.

The past month brought record February temperatures to Scotland, reaching over 18 degrees when at the same time last year we were cut off for five days by deep snow and had -11 degrees.

The cause for all this was a high pressure which poked its nose out from Continental Europe and settled down over the North Sea for a while. This is the opposite direction to the normal flow and resulted in the High blocking the normal passage of westerly winds from the Atlantic (or northerlies from the Pole).

This High did bring some tropo conditions, but it wasn't a great event. What has caught the attention is that such wide extreme of temperatures, such as the variation from last year, is exactly the progress we would expect to see if current climate change predictions are indeed valid.

Of course I am worried about the climate, but let us look at the radio for now, and then move on to the spellbinding  subject of mast head pre-amplifiers.

Things kicked off on 2 metres on 22 February when I worked DL3TW at 13:57. It was slow to build up, but I worked DL6BF to round it off on 2 March. Even for a 28 day month it is unusual for an opening to last here from 22 of one month into the second day of the next month. To be fair, there was a tailing off followed by a brief ridge of high pressure at the start of March, but it still lasted a long time.
Pleasing as that was, 70cms was better in my view ...
For all 2 metres business, 70cms produced several new squares, including JO23 for PE1PIX (my first Netherlands station on 70cms), IO65 for GI0OTC and JO53 for DK0HAT. Many of the contacts started out as 2m QSOs during which I was asked to move to 70cms, and once again I was asked several times to move to 23cms which I cannot do (yet). Very good.

I have now reached 12 DXCC and 32 squares on 70cms, and they all feel like a lot greater individual  achievements than 30 DXCC and 146 squares on 2m.

The High has gone, the storms have returned, and all that is left for me at the moment is 4m meteor scatter. Moonbounce has produced few results recently, though I have heard Japan on 2m and China on 70cms.

 Moving on ...

I said last time that I had thrown together a temporary sequencing jig to use while my Gemini 2 linear amplifier was out of operation. It is back now, but I had promised (threatened?) to write something about sequencing.

Before all the complex stuff I just want to say this. Adding a masthead pre-amplifer on 2m and 70cms absolutely transformed signals received at GM4FVM. Sure it is a fiddle, unless you buy a linear with the sequencing circuitry built in, in which case you still have to build or buy the pre-amp, but the results are excellent.

Where you locate a pre-amp becomes very important when dealing with Earth-Moon-Earth (EME) communication, but the same principles apply in all cases, and especially when it comes to using linear amplifiers. If you cannot hear stations you cannot work them.

In EME stations have to overcome very high levels of path losses, around 250dB. This means that the receive sensitivity of the station needs to be very high. Standard transceivers are not good enough for this, so a pre-amplifier is required. However, it is much more effective to amplify the received signal at the antenna before it passes down the coax cable and into the receiver (a so-called "masthead pre-amplifier"). The best signal-to-noise performance is achieved by locating the pre-amplifier before the signal suffers losses in the coax.

Another case is when you add a linear amplifier to an existing transceiver. By raising your transmitted signal by, say, 3dB, you may well feel that you need to raise the receive performance by a similar amount. This is because the stations who can now hear you may only be running the basic transceiver power you were running previously, and you won't hear them. This is why many common VHF linear amplifiers, e.g. RM Italy and Microset, have pre-amps built in. These may or may not be an advantage to your system, but once again a better place to do pre-amplification is closer to the antenna. Most high-end VHF linears do not have built-in pre-amps for the simple reason the makers expect high-end stations to have the pre-amp near the antenna on the mast head.

In an effort to receive out-of-area television, the terrestrial system at GM4FVM has a masthead pre-amp. Our local TV installer fits them as standard. On receive-only systems this is pretty simple to achieve. To save running a separate DC supply for the pre-amp most systems use a set-up which puts a DC bias voltage on the coax which is peeled off at the masthead and used to power the amplifier. This is done using a "Bias-Tee".

Simple masthead pre-amp arrangement for television reception
Put simply, it looked silly that a standard television installation would have a masthead pre-amp as standard when GM4FVM's VHF set-up did not have one. So I tried it out, and was really impressed by how well it worked.

It gets harder to apply such a simple set-up to a transmit/receive system like in a radio amateur's station. The pre-amp would be destroyed if driven by RF power during a transmission. Thus amateur pre-amps often have an RF-sensing "VOX", which will bypass the sensitive circuitry using a relay as soon as it senses RF power coming up the coax. The drawback of this system is that by the time the RF is sensed it has already arrived, so the damage may have been done. Also, the relays will take time to operate, increasing the risk of damage before the bypass is in operation.

The simplest way round this is to exploit the circuitry used in almost all pre-amps made for amateur transmitting use. By convention, when the DC power to the pre-amp is cut off, the relay is de-energised and defaults to the by-pass route. This allows just a simple on-off supply to the pre-amp. "Power on" activates both the receive circuitry and the relay, "power off" effectively turns it to transmit by turning everything off and so the de-energised relay switches everything out of the RF path. Note this this is the reverse of the convention for linear amplifiers, where the relays are energised on transmit.

Thus at a basic level all you need to do is to turn the pre-amp supply off at the same time as the push-to-talk line from the transceiver is grounded and you should be safe. However, you cannot use the PTT line as it works in the opposite sense, and using a relay to switch it makes it too slow to avoid damage on the pre-amp.

It can get even more complex than that, at least if you want more certainty at higher powers. You know that if something goes wrong with the switching circuit and the pre-amp remains live for any reason, the VOX should operate. However, most pre-amps set a very low limit for the power the pre-amp can handle when switched by VOX. This is because higher power risks building up before the VOX relay has activated.

To be safe, if the pre-amp should accidentally remain energised, it is best to take some steps to prevent full power reaching the pre-amp before the VOX relays have fully switched to by-pass. VOX might protect the circuitry at lower power levels, but it cannot guarantee to do this at high power. You can only really do this by not activating the linear amplifier until after a time lapse. OK, if some power does come through from the radio during that time it will reach the pre-amp at lower power and thus be safe for the VOX to cope with. Once the VOX has switched the relay for lower power then full power should be safe.

This should give you two elements in your system - one turns the power off to the pre-amp straight away, and the second delays any high-power reaching the pre-amp to begin with to allow time for the relays to work. In fact, either should work if the other does not. You might not think you need both, but you do. Or, at least, you will find that out for sure if you rely on either alone. Pre-amps are expensive, and you have to buy two if you blow the first one up.
2m and 70cms pre-amps on the mast at GM4FVM (I must shorten the 70cms cable)
My masthead pre-amp used on 2m has a rating for SSB of 350W on VOX (I can use 300W), but it can handle 750W when sequenced. I am not willing to risk 300W into it on VOX, especially as it it is rated at only 200W for FM, and my JT65 has a fairly high duty cycle. OK, so JT65 is not quite as demanding as FM, but moonbounce calls can be very long (as can meteor scatter ones). So this is where sequencing comes in for me.

A sequencer does everything in a certain order with a time gap in between to give relays time to act.  It does this at the start of a transmission, and restores everything in reverse order at the end. If you have added a pre-amp to balance a linear amplifier then it makes sense to control the linear too. At its simplest level you take the PTT line from the transceiver, which would usually go into the linear amplifier. You take this line instead to the sequencer. The sequencer then takes actions in sequence at the start of a transmission:-

Step 1 - cut off the DC supply to the pre-amp
Pause to allow the relay in the pre-amp to act
Step 2 - activate the PTT to the linear amplifier

This way you delay the possibility of full power from the linear reaching the pre-amp before it has had time to act. In the same process you have also changed the sense of the PTT line to cut off the pre-amp power as the first step to be taken and the last thing to be restored, protecting your expensive components.
2 step sequencing for an amateur station using a transceiver, linear and pre-amp

This is the system in use at GM4FVM. For sure I could add more layers of complexity, but so far it is working well. The only other step I have taken it to slightly increase the built-in sequencing time in WSJT-X ("TX delay") to 0.3 seconds.

You can, however, take sequencing to several further stages depending on your station.

How quickly you radio activates its PTT line in relation to sending out RF will vary - sometimes they might share the same relay, but generally the PTT will be quicker, which is a form of sequencing in its own way. I am content with this, but otherwise you can work the sequencer with a foot switch and let the sequencer operate the radio PTT after it has switched the pre-amp off and the linear to transmit.

Even more complexity can arise with transverters. You could use the sequencer to separate the transmit actions of the transverter from the transceiver, once again to protect the the transverter receive circuitry from accidentally receiving power from the transceiver.

Most designs for home construction, and commercial sequencers, allow you to program various permutations up to about 4, so that you can tailor their actions to your individual needs.
The 4 step Down East Microwave sequencer with 50pence piece for scale

Recognising that most amateurs will want to add a masthead pre-amp to balance the extra transmit power which comes with a linear amplifier, most makers of high power linears will include a sequencer and circuitry to control a masthead pre-amp with it. Certainly my Linear Amp Gemini 2 provides this, and I believe the OM  Power and Beko amplifiers also include it. The Gemini includes a plug which, which correctly wired, applies the DC bias voltage directly to the coax without the need for an outboard Bias-Tee.

If you do not add a linear, or it does not include a sequencer as standard, you will have to incorporate a Bias-Tee to add the DC voltage to supply the pre-amp.
SSB Electronic Bias-Tee
Some radio manufacturers of VHF equipment include bias circuitry in their radios. The IC-910 had such a feature. I imagine that the forthcoming IC-9700 will also have this built-in. This would be very useful if the radio was to be used barefoot, with 100W on 2m and 75W on 70cms being fairly useful power levels.

The results at GM4FVM - spectacular. As you might expect with losses in the coax increasing with frequency, higher frequencies show most potential for improvement. I was impressed by improved signals on 2m, but at 70cms the results were dramatic. For example, the 70cm beacon GB3NGI at IO65vb is 272km from me. On 70cms during flat conditions I can barely hear it. With the pre-amp in circuit it rises to a 569 signal. On moonbounce, signals vanish entirely without the pre-amp. With my linear amplifier in circuit I can work almost anyone I hear, including ones running low power. This suggests that the balance between my receive and transmit performance remains good.

From time to time I turn off the pre-amps just to see what happens. Terrible. I doubt if I could do without them now.

Of course the results will depend on what coax you are using, the performance of the pre-amps and the basic ability of the radio you are using. However, for serious DX on 144MHz and above I think masthead pre-amps are a necessity.

If you use a multi-band antenna with a single feed you can get wide band masthead pre-amps, though of course single band versions are likely to perform better. You can buy various makes of pre-amp, ranging from very high performance ones down to fairly modest ones, with prices to suit. Mine are on the modest side, but still worthy of use. It is something worth considering, I think.




Friday, 15 February 2019

Of tropo, soldering and unusual work

I have been off the air for a while - the dreaded house decoration I mentioned before finally came to happen. I tried to avoid it, but there was no stopping it. So the shack was completely dismantled, everything in the shack was cleaned, and then dumped back where it had been dumped before. Well, not quite, my shelving has been dismantled and strengthened to take the weight of two Linear Amp Gemini amplifiers, which previously caused the top two shelves to sag. A stout piece of dowel now supports each shelf. Expensive stuff, good dowel, so this takes the form of a brush shaft sourced from that well known speciality emporium, "Homebase". That place definitely gets my brush shaft recommendation.
Strengthened shelving unit with added brush shaft and corner plates
The decorating original plan involved moving the shack desk, which did happen, and also moving the amplifiers to near ground level. In the event the amplifiers have remained where they were, but they now seem to be more or less level on a non-sagging top shelf.

Of course, as soon as this work was complete, one of the amplifiers (the 2m one) developed a fault, or rather showed again a fault it has been developing for some months. Thus it returned to the manufacturer for repair leaving a big gap in my 2m armoury.

I have been accused sometimes of writing too much - but regular readers know this cannot be true. It cannot be true because I have said it isn't true at great length. Nevertheless I did write a very long piece about linear amplifiers, preamplifiers and sequencing which I have decided to save for another day. Never mind the theory for now, what about the results?

With Hepburn's tropo predictions showing hopeful signs for yesterday (14 February) - a link to Hepburn is on the sidebar - there were also more signs of a possible lift in conditions. When somebody you respect suggests you should be prepared you take note, and then when two others of the same standing do the same, then you are obliged to get ready. And indeed, Colin GM0HBK, Jeremy, M0XVF and Dirk PA3FMP all suggested I should standby for better conditions. But I had no Gemini, which meant no working pre-amp too. So I needed a Plan B.

Without my Gemini 2 amplifier my hastily assembled Plan B was to use the parts I recently said I was stockpiling for some other, undefined, project. Viz, a second Down East Microwave (DEMI) sequencer, a "Bias Tee" from SSB Electronics, and to add to those my old Microset SR200 200W 2m linear amplifier. This assemblage would get my masthead pre-amp going and get me running enough power to work some DX. The only snag was that, starting yesterday morning, I had precisely nothing working. Some corners will have to be cut.

I had already got the Microset fixed in theory, although it had never been tested. I had called on the assistance of John, G1VVU, to investigate it. John quickly found that one of the output devices (it uses 2 2SC2782s) had gone short circuit and seemed to have died. I was able to find a new one fairly easily, in fact two, as it seemed best to change both of them. Well, not once we found how tangled the inside of the Microset was, so we changed the faulty one and kept the other new one as a spare. So far so good.

Apart from the fact that the Microset doesn't have a PSU, fans nor even N-type sockets, it should replace the Gemini fairly easily. The PSU is not such a stretch, as it only draws about 20 amps on full power. Then come the fans, so I dug out two dusty 12cm computer fans and mated them to a temperature controlled (27 degrees C fixed, but good enough) switch. Luckily I had boxed the temperature controller up with suitable sockets and so the cooling side of things could be organised quite easily. It isn't right that a transistorised amplifier should be perched on top of its own power supply as the heat of the PSU will rise, but for now that will have to do.
This jumble is the restored Microset SR200, fans, PSU and (left) the homebrew fan controller
Getting a replacement system going that morning was "the art of the possible". That stack of gear is not tidy but it worked for now.

Next task get the sequencer working. No need to explain what a sequencer is, that is for the later long-winded posting. (Is this not a long-winded posting?). Anyway, you need one if you are going to use a linear and a masthead pre-amp and not blow either or both of those up. With the DEMI sequencer this involves wiring a D15 socket and working out a wiring loom. No time for niceties, I got a bit of surfaced wood the right size for the shelving, stuck the sequencer to the wood with Velcro, stuck a chocolate box connector strip to the board with double sided tape and got soldering.

Oh I hate soldering D15 plugs. Actually, I hate soldering any plugs. I tried to cut a VGA cable in two to save the soldering, but despite it being an "all wired" cable, one pin (pin 5) was not connected. So soldering it was. Mrs FVM, who recently had cataract surgery, donated me her temporary +2.00 reading spectacles for the close work. Working out the sequences and testing the operation is fiddly. Once again lack of time meant a temporary arrangement and here it is photographed while I tested it...
Down East sequencer and wiring tangle under test, with the Bias-Tee lurking in the background.
Once I got this up and tested I even found time to organise the wiring, give it some strain relief and put the covers back on the D15 socket. Not before I got the wiring mixed up - why do I always think a D15 socket is a D18 socket with 6 pins on each row, and then get the rows upside down too?

The result is a total lash-up, and it looks awful. Stuff piled all over the place. The sequencer is on a desk at the other side of the shack. There is an SWR meter perched drunkenly on top of some books. But it was more or less ready when it was needed.

OK, everything working now, but will there be any lift conditions to justify all this work?

Due to the shack reconstruction I had not had a QSO since 25 January. I got basic operations going again in the "new" shack on 11 February with the Gemini but it was showing a fault. The Gemini went back to the manufacturer on the afternoon of 13 February. Thus it was only on the morning of 14 February that I started Plan B. Was there any point? Wouldn't the Gemini be back soon, and would all that work be justified by any DX before then at all?

First contact with the Plan B set-up was on 2 metres at 15:54 on 14 February to Dan OZ1BEF. I can work Dan in most conditions, but still that was positive sign. It proved that the Microset and my lash up were working.
2m FT8 stations worked at GM4FVM, 14 Jan to 12:00 15 Jan 2019
As usual, click the image to enlarge if you need to.

I have to say that I was rather pleased with that result. Could I have worked the same stations without all the work to get the temporary linear amplifier working? Well maybe, but the extra power does help get you noticed. Once they turn their beams it becomes easier and that extra clout means they find you while they are beaming at more obvious targets to the south of me. The linear was secondary, I needed the sequencer for the masthead pre-amp, so I had to do it all anyway.

Before anybody asks, yes both the Microset and the pre-amp have RF VOX and should, in theory, work without sequencing. That is very risky but more to the point, the IC-7100 objects to powering up into either RF VOX and so it cuts the output power. I did try briefly without the pre-amp it it was terrible.

70cms brought a new station worked plus one I had contacted last year. Both are much appreciated
70cms FT8 stations worked at GM4FVM, 14 January 2019
Both these 70cms contacts were the result of the stations suggesting we move band after a successful contact on 2m. This just goes to show that there are plenty of 70cms contacts to be had if we could only find them. DK0HAT even suggested going up to 23cms for a try, but sadly that is something I cannot do ... yet ... but even on 70cms he was new square.

During the opening there were long, strong, ducts forming. For example, Charly, DF5VAE was heard here on 2m for over an hour, and at stages registering +10dB on the WSJT software. That is a good 30dB over the minimum level I can reliably work anyone. I could hear Charly's signal loudly on the loudspeaker. Likewise, DK0HAT was heard calling CQ on 70cms for a long time. There was nobody around in GM to work them, which was a pity.

At the same time, at the other end of the tropo spectrum, there were short openings into various areas which came as a complete surprise. Unlike the ducts they were gone as soon as the contact was complete. SP6MJ calling me was a bit of a shock. Conditions held up just long enough for him to wait patiently while "Auto Seq" on WSJT-X answered and worked another station before reaching him. Then, contact complete, he vanished. SP6MJ, in JO81, was a new square on 2m and the best DX so far in this opening at 1370km. Several other 2m contacts contacts were near 1000km.

Is it over as I write? Well I have just worked OZ1CCM on 2m and he is clearly not beaming my way as I can hear him off the side of his beam working Polish stations. I also just worked OZ9PZ on 70cms after he came back to a random CQ call. He also asked me to go to 23cms - is there a pattern emerging here?

Was it worth all that effort to set up a ramshackle pile of gear to work one 18 hour period? I think so. 19 QSOs, 8 DXCCs, two new squares, and a test of my shaky constructional abilities. This hobby has to test us and I think it should never be easy. Certainly, I could have just sat back and watched a re-run of "Rising Damp" on the ITV hub, but that can wait. Radio happens when it happens.

I enjoyed jumping in and getting something sorted out, even if I have to take it all apart this afternoon. Eh? Well, the Gemini was only away for 36 hours - it arrived back at 11:00 this morning. Of course I did not know that in advance.

Thanks to Colin, Jeremy and Dirk for alerting me. The moral of the story, as the great Otis Redding almost sang on  "(Sittin' on) The Dock of the Bay" ... "I can't stop doin' what three people tell me to do, so I guess I'll never remain the same".

Now, I must unpack the Gemini and pull Plan B apart.



Thursday, 17 January 2019

Good blogging and the data mode take-over (not)

I like a good blog. I enjoy reading the thoughts of somebody who cares about their hobby and shares their thoughts with us.

One I have mentioned before is Olli's, DH8BQA, here You can find a link to it on the right hand sidebar too.

Olli is very good at saying the right stuff. He is also direct and to the point, not like me who rambles. He posts occasionally, not too often as I do. He has interests in a mix of subjects from VHF to HF, which makes it interesting.. He does contesting, which I don't do. I find that interesting, and I even hope that Olli will do well in contests because he is "on my side" thanks to the blog. That way I can do contesting without actually doing the work.

We share enough interests to keep me looking at his blog from time to time. The shared interests extend to the 10m band, tropo on VHF and many other things.

Back in October Olli added an interesting coda to his posting about the conditions then His remarks have been spinning around in my head, and I have been waiting to sort them out before posting something myself. Here is what he said about FT8 ...

While I see it’s advantages and therefor use it, too, I really hope it will not be FT8-only in the future because people are just too lazy and make it easy by just clicking around a bit on the computer screen (if at all and not automating things, automated QSOs are just machine to machine, this has nothing to do with amateur radio anymore). As long as it is just complementary I’m fine with it. If it ever turns to FT8-only (yes, there are signs of it ðŸ™) I’ll certainly need to search for another hobby. And that’s from someone who is burning for our hobby … but let’s think positive.

I agree with Olli on this. I have given it a lot of thought over the months. I think my viewpoint on FT8 comes from someone who has been using data modes for several years. OK, I was using RTTY in the 1970s, but I do not mean that. PSK came afterwards and pretty well rendered RTTY obsolete (I am ignoring several other steps here).

When I really got into data modes, it was to do things which other modes could not do. That was:-
WSPR - low power propagation study
JT6 and FSK441 - meteor scatter
JT65 - moonbounce

Possibly because I have never trusted my morse code skills I turned to these data modes as a positive step to explore the potential of our hobby, not to replace SSB and FM.

It turned out that JT65 and JT9 were useful on 6m and 10m for fading long distance contacts, but that was a side issue. I never saw data modes taking over, and I hope they never do.

When MSK144 became available I stopped using JT6 and FSK because I found what Joe Taylor said was correct - MSK is better. When FT8 appeared I started using it instead of JT65 or JT9 on terrestrial stuff and now I keep JT65 for EME and beacons. Simple, I have not changed my methods other than updating the protocols as new ones come along.

Then recently I heard this mad howling from offended traditionalists. It turns out that they never noticed me on JT65 but now I am on FT8 I am a threat. Well, not me so much, but hoards of folk who think that HF = WSTJ-X = FT8 = data modes. NOT TRUE. WSJT-X is a resource of several protocols for various purposes, I have been using it since WSJT-X 1.3, and there has always been a lot more to it than one mode.

It turns out that newcomers are using FT8 in their droves, and this may or may not pose a threat to the world of amateur radio, or maybe the world in general. But how can I be part of that threat when I haven't changed? I have been using data for the majority of my contacts since 2010, so nothing new there.

So what is different is not that enthusiasts are using data modes for doing things that voice cannot do, but they are using it more widely - and getting further at the same time. And I can see the issue. When I tune to 80m or 40m the FT8 segments are totally overcrowded. There are signals everywhere, and most them seem to be doing exactly what can be done easily on voice modes. Of course, they are perfectly entitled to do that.

I say again, I agree with Olli. A fully FT8 world would would be terrible. I still use FM to talk to my pals, and I use SSB in contests. Sometimes I just use voice (because I want to). I find the mass use of FT8 on HF soul-less and rather pointless. Sure if I am in search of DX then FT8 offers advantages, but for QSOs round Europe on 40m? Even top band, that chat band par excellence, is full of signals relentlessly exchanging callsigns (is anyone home?). They would be better, in my view, changing over to WSPR and going to bed while leaving the rig on. If all you want to do is exchange callsigns you might as well give up.

I do WSPR and pour over the charts looking for patterns. I use FT8 on VHF probing the edge of the tropo or Es. But using FT8 just for local contacts? Come on! This hobby is supposed to be a challenge, or at the very least, an exchange of ideas. What personal growth can come from routine machine exchanges?

Am I saying that I am better than them, or that they should "do as I say, not what I do"? I do not think so. What I am saying is that I think a moon bounce QSO from here to North America, or one discovering winter Es on 6m, is more meaningful than 100 "Inter-G" data contacts on 80m. You can disagree with me if you wish, but I really cannot see the point of using a strict mode which limits your interaction in a general chat arena.

I bet this is fashion. Or at least I hope it is. I expect that a lot of people are just trying out FT8, and as they are only on 80m, then obviously FT8 is busy on 80m. I suspect that over time 80m FT8 will become the preserve of DXers and enthusiasts, and the bulk of the activity will move back to SSB or CW. If I was on 80m on a regular basis I bet I would have done the same. I do not blame FT8 for being popular, but I think that over time it will reach its own level (and mostly amongst the DX enthusiasts).

There are all sorts of doom-mongers around in this hobby. For example, they predict that digital voice modes and network radio are going to kill our hobby. To these people I say "nonsense". Our hobby has to be attractive to people, and if something else is more attractive then off they will go to those hobbies. We need to win them over, not blame them for making a logical choice. They said the same thing when VHF-only licences arrived in the 1960s. Then it was said that many people would go onto VHF and never bother "advancing" to HF licences. But I did. And today new entrants may well go into network radio, get a taste for communication, and see amateur radio as their next step. In the meantime, established amateurs are using network radio to support their needs, and attracting people over from there. Network radio can be the recruiting ground for amateur radio, just like CB was years ago.

Like those in the Navy, we in amateur radio are in "The Senior Service".

And, in my case, proud of it. Aye aye, Captain.

I think I have been moved to write this because a rather boisterous local told me that he had worked 500 stations on FT8, as if that required a medal or a certificate.We do not weigh our QSLs to see how many there are, we look at each one and judge its significance. One good QSO is better than a night full of clocking them off routinely on 80m. For me anyway.

I need a photo or the thumbnail of this post will look bare. Here is a photo of an IC-7100 with a nice new N-type socket added to the VHF side ...
... haven't we seen this before? No, because this is a second IC-7100. Do I need two IC-7100s? Probably not, but another one has appeared. Once it has proved that it works perfectly I may sell it on. It was in need of some TLC, new USB lead, firmware upgrades, and general tidying up. So far so good.

My FT-817 is seriously clunked. Its processor keeps locking up and while a reset brings it back, not for long. Unusually for me, the arrival of the second IC-7100 comes at the right time. The two things were not connected, but seem to fit together. Now, is the FT-817 worth fixing? The 7100 is vastly superior.

What does annoy me, still, is that the only place I can find an N-type panel socket with two holes is at Radioworld who charge £10 for them! Grrrr. I have plenty of 4-hole ones, but RS and eBay have none of the 2-hole ones. £10 for a socket. That is crazy.

D'oh. Am I ever likely to need another 2-hole N-type panel socket? No.

I said that the last time.




Wednesday, 9 January 2019

Never mind the Tropo, feel the Angst

I do feel amateur radio is a love/hate relationship for me.

Here I am off again. I said before that it is my "bad mistress" (not a good expression but it seems to fit).

I love it. There are lots of challenges and I am moderately good at some of it. But ...

I hate it. Things keep breaking down and I have to fix them. I have to. Or at least I have to try.

If there are no problems on the horizon, I invent some more problems. If I have a few minutes to think I will add a new mode, add a new band, try a new antenna. And each of these has the potential to be a new problem to solve.

That's it! For me, amateur radio is about finding problems to solve. If there are no problems, I invent some. I do not need to do any of it, it is a hobby. I do not earn a living at it. I could stop tomorrow. But if I gave up what would I do? Invent some new problem to solve. Standing still is not an option.

My Yaesu FT-817 decided to die on me. I do not have to run WSPR on HF, but I choose to. In the middle of everything else, it went potty, with a readout suggesting I was on broadcast frequencies with a locked radio. Various re-boots did nothing. Nor did a partial reset. Then a full reset and it is going again. I had to do all the settings again. What was that all about? No time ... got to deal with the 2m linear.

Oh dear. Is this a hobby or an obsession?

I am not a great admirer of the FT-817. Portability is its main plus. I would rather have something better for my HF activities, but then again I do not rate a bit of WSPR as something which justifies using a really nice bit of kit.

If I did not say all this it might look easy. All those maps of mine showing QSOs all over the place where VHF is not supposed to go. How does he do that with such ease, you ask? EASE! I am permanently flustered. I am in a constant campaign against entropy - the physical property of all things to revert to disorder. Entropy is about everything striving to reach the lowest energy level, which in radio terms means broken down and falling to pieces. My task, which I have chosen to accept, is to prove that VHF radio (and a bit more) can do brilliant things, but I admit it is hard work to stop everything constantly breaking down and reverting to chaos.

The problem of the moment is that everything appears to be falling apart at once. Including me.

Moving on ...

It has been a notable few days at GM4FVM from the radio point of view. As reported last time a high pressure system dropped anchor south of These Islands. This is rather unusual as long-lasting highs are more usually over the North Sea. So instead of the more typical openings from here into Netherlands and Germany, this time we had openings into France and Spain.
144MHz contacts at GM4FVM 3 to 8 January 2019
No chance to put the callsigns on that map because there are so many they overlap. I did however put on the 100km circles. I did manage many QSOs into France, all of which I regard as good going.

Best contact in France was F4EZJ in JN05, 1170km. That is near Angouleme which is a long way - I know because I drove there once and I remember vividly how long it took. I would be happy with that, were it not for two new countries as well and even further DX.

A new country on 144MHz was Spain. Somehow I have never worked Spain from here and I certainly did not expect to do it barefoot. It seems fitting that my first EA contact on 2m was with Fidel, EA1HRR (IN83, 1387km). I have worked Fidel many times on 4m and 6m, so he now joins the select group who have worked me on three bands. Fidel is always cheerful and enthusiastic on the air. I have also visited the Basque Country a couple of times and I do have some sort of affinity for it (but then that applies to most places I have visited). This may be a scientific hobby but there is some room for feeling in there somewhere.

I actually managed to work three Spanish stations during the lift. After one failed attempt I tried again the next day and finally worked EA4GMY in IN80 (1717km) near Madrid. I have never been to Madrid but I'll take that one, thanks. That counts as good 2m DX in my book.

There were repeated ducts during which stations between South West and South East from here were appearing and disappearing. Some stations in Northern France were audible for most of the three days the lift lasted. Stations in Netherlands and Germany could not be heard by me, but they seemed to working West into Wales and Ireland. I could see other GM stations in the Highland and Islands working far into South Western Europe, much further than me. If you happened to live outside the area covered you missed it completely. Such is amateur radio.

The other new 144MHz country was provided by a contact with Richard, GU8FBO (IN89, 714). That means Richard also joins the three band (50/70/144 MHz) club, and some other club I have not yet started for propagation modes (tropo/aurora/meteor scatter/Es). Maybe I need yet another for transmission mode which Richard could join (JT6M/SSB/MSK144/FT8). I am very clubbable. Or am I?

432MHz was also pretty good during this lift too...
432MHz contacts at GM4FVM 3 to 8 January 2019
France and Belgium on 70cms tropo! I think that is a great success from here. I also feel that 70cms could be a lot better if there were more stations active.

F6KBF in JN18 is 820km, good for 70cms from here. And my first QSO with G0MJI on any band was notable too.

Of course, all that still is not enough for me. I have still not managed to work the Netherlands on 70cms. Another place I have fond memories of visiting, and surely fairly easy to reach form here. Not during a southern facing lift. I need to find one of those old fashioned North Sea highs.

I am not easily pleased.

This period of enhanced propagation thanks to tropospheric conditions fell at about the same time as the Quadrantids meteor shower. That shower looked pretty good but I only have time for a few contacts such as these on 4m ...
70MHz contacts at GM4FVM 1 to 8 January 2019
I suppose that the tropo opening was distracting me, plus the absence for now of my 2m and 6m linear amplifiers. As I said last time, power is not everything on meteor scatter, and I was happy with these contacts on 70MHz.

So all in all a good period for DX. There may be a wee bit left in the High. At the moment a weather system is tracking down the North Sea, but we may have a day or two of high pressure left after that.

When it gets to the middle of January we reach "the end of the VHF season", meaning that high pressure are less frequent (round here anyway), and the meteor season goes into a lull until April. Sporadic E is more or less absent until May. Sure, there may be some moon bounce or aurora work to be done, but broadly it is time to polish up the antenna for next season. And what about fixing all those things that were bugging you?

On the cards for GM4FVM is a complete removal of the shack while the room is repainted. This is an opportunity to get the vacuum cleaner into nooks and crannies not often visited by cleaning apparatus. Time to check all the RF plugs, clean out the fans and put everything back in a different place than before. Whoop-de-doooh.

I will keep you posted on that exciting prospect.




Wednesday, 2 January 2019

The frailty of modern technology (and my ego)

Mrs FVM can certainly take a flattering photo
Katy and GM4FVM enjoying the Hogmanay celebrations.
Least said about that the better.

"Lose some weight you doughball" might be the least said then.

Moving on.

I feel that modern solid state power amplifiers are a weak point when it comes to being "brittle". They break easily. It is not surprising as we expect so much of them. We push them to their limits, we expect them to be sold a low prices and yet we also expect the highest level of reliability from them. They are generally made by the second-string producers, the big three having more or less backed out from this sector (maybe because of the reliability issues). So probably I can expect these things to have short lives and need regular repairs.

Or maybe I just break them.

Maybe I am careless with these fiddly devices. I could say that, but regular readers here know that I have had the same experience with good old solid reliable valve ones too.

Could it be my fault? Nay, surely not.

When my latest 2m linear arrived just 9 months ago and I placed the Microset SR-200 into reserve. I meant to fix it at some stage. Why did I not fix the Microset? I have just found, having a reserve that does not work is rather like not having a reserve at all.

Yes, to add to the list which already contains the 6m linear, my main Gemini 2m linear has also developed a fault. SWR trips when there is no SWR problem. As it is only 9 months old it has been packed off back to the maker and so I dug out the Microset. Surprisingly, having sat in the cupboard for 9 months it has not fixed itself.

Discussing it with John, G1VVU, he immediately suggested power starvation. Of course! Why did I not think of that. I am a chump. One of the DC supply leads looks the worse for wear. It turns out that is not the fault (John was just making a suggestion), but I certainly blamed myself for a basic error. Basic errors I can do well.

So what is the fault with the Microset? We don't know. Investigations continue. Perhaps I should put it back in the cupboard and see if another 9 months will help.

Leaning against the wall on the other side of the shack is the 6m linear. I should be fixing that too. But wait a minute, I decided to do without it for a while and working barefoot seemed OK on 6m. Why not just stick with barefoot on 2m for a while longer?

So, with 50 watts I venture onto 2m FT8 ...
144MHz FT8 contacts at GM4FVM 29 Dec 2018 to 2 Jan 2019
Well, maybe there was a bit of a lift on, but 50 watts of 144MHz seems to be OK really.

Click the images as usual if you need more detail.

I also wondered what 95 watts of FT8 on 70cms would do ...
432MHz FT8 contacts at GM4FVM 29 Dec 2018 to 2 Jan 2019
I am pleased with that. Working France on any VHF band is very good for me, but F6DBI (IN88) on 432MHz it is a bit special, and at 833km not bad on UHF in any sense. I worked the same station on 2m this week (three times actually), and I would have been happy with that. As it turned out, F8DBF (IN78 at 849km) and F6APE (IO97 at 949km) on 2m are not shabby either.

OK, I am making a meal of this. My linear amplifiers are really just here to get stations to turn their beams towards me. In almost every case, 50 watts is fine, and usually much less is enough. Living rather out of the usual line stations beam in, I find a bit more umph is handy to get them to turn their antennas and beam at me. I live in the south east corner of IO85 square, and that is not where most stations think Scotland belongs. If they are already pointing at me, barefoot is plenty.

Having no linear certainly rules out moon bounce on 2m - but I am still active on 70cms, and this past few days I have worked Germany (first time on EME) and Switzerland (first time on 70cms by any means). 95 watts - Phew! - QRO for now.

Yes I will get those linears back into action soon. In the meantime, I am very happy to go along with what I have.

Sometime I must tell you how 2 watts on HF is doing for me - rather well in fact.




Friday, 21 December 2018

VHF Sporadic E when you least expect it.

It is sunset here as I write this - today sunset is at 15:36. Only seven hours of daylight today, with the Sun rising at 08:37. Not exactly the type of day one might associate with Sporadic E. Yet I am reporting on a really good Es opening the day before yesterday, the 19th of December.

This is my second post today, the other one is here

In the midst of being on the lookout for December meteor showers it is easy to overlook seasonal Es. The same applies in early January. The things to look out for are when your MSK144 graph fills with a single strong station. Watching 10m is another trick, which is how I found it (thanks to Jaap, PA0O, whose 10m WSPR drew my attention to it). Then again one could watch DX Maps, PSK reporter or set up alerts on your phone with EsSense.
PSK reporter showing 15 minutes of 6m Es on 19 December 2018. Note that was already dark at ground level.
Or maybe just listen for it ...

There is often Winter Es about at this time of year, which is frequently wrongly called "Christmas Es". That name tends to makes people look at the wrong time. It could happen during my annual appearance on the RSGB Christmas Cumulative contest, but it never does. Not yet anyway. Sometime between early December and mid January seems to be the time. You just do not know exactly when or how often. It is usually a middle of the day thing, so having it in the dark is a bit unusual.

The opening here lasted two hours and 40 minutes, and I worked 36 QSOs, 22 squares, and 8 DXCC in that time. Plus I had a contact with Dale MM0INH at the end, when we tried to express how tired we were using the few characters you get in the FT8 mode.
6m Es contacts at GM4FVM on 19 December. The guy due South thinks he is at the South Pole (he isn't).
9A3ST (JN75) looks like the best DX at 1652km.

Great fun, totally unpredictable. All we need now is an aurora and a strong tropo opening and Christmas is complete (well, unless I get any "Co-op for Men" that is).

This says to me that the 50MHz band is a key part of my all-round VHF activity. I do find it a bit "easy", but then again not when I am pushing for DX. However, when I am putting together a year-round schedule of things to do, 6m has a habit of surprising me (in a nice way).

Simple antennas are very effective on 6m. Wire dipoles, crossed dipoles, HB9CVs, and verticals can all play their part. I was still using only 50W or so from the IC-7100. Being around at the right time is always important.

I did not do much on 4m during this opening, and I find that Winter Es rarely reaches 70MHz. However, I did hear a German station on FT8, but just long enough for one decode. 10m was also quiet, perhaps because activity is low. This is especially true on the WSPR mode which I use so much. I am beginning to think that WSPR is doomed, which is a pity given its ability to make antenna comparisons and run all night. I will not give up on WSPR in a hurry because I think that it still has relevance.

Anyway, that is amateur radio. Like life, you just never know what is around the corner.

Perhaps that is just as well.