Mostly about antennas and masts

I have had to go away for a few days. The long waffle I was writing about conditions now seems old hat. So I will cut almost all that wonderful creative writing, and just summarise it. Most of the rest is about antennas and masts. Antennas like these ones:-

Old 23cms Wimo on the left, new Dual 36el on the right.

First the round up:-

6m... I managed to work trans-Atlantic on 6m barefoot. This surprised me but a linear was not required to work a handful of stations and indeed add a new square.

4m... I managed to work a new country to bring the total to 49. The latest one was Gibraltar. Given that Gibraltar was the pinnacle of 4m DX when I started on the band it is odd that it has taken me since 1977 to work it. Still, it is in the book at last. And an elusive square in the Balearic Islands - JM29 -  was worked today.

2m... I managed to work a new country (OE) during one of several Sporadic E openings. Not sure how OE had evaded me for so long. Once again the basis of "doing the treble" works even if I feel less moved to actually work stations on all bands. I just need to see what is coming in on 6m, wait on 4m for signal to peak about about +05dB, then go for 2m. It does not work on 6m alone, I have to move up to 4m and listen there. Today I have worked EA and DL on 2m that way, and just missed 9A.

70cms... Old news, I worked a new country in the shape of Spain. That was back in March but I have only got round to mentioning it. There were several good tropo openings in late April with some new squares on offer.

23cms... Those tropo openings allowed me to have a couple more long rag chews with OZ2ND. I continue to be astounded by what I can work on 23cms.

Secondly - moving on to antennas and masts:-

This complicated re-organisation, whereby everything ended up back more or less where it was ages ago, started with moving the 2m/70cms dual band vertical.

2m/70cm vertical at GM4FVM, back where it used to be years ago

There was nothing particularly startling about this as that mounting was the first one I used when I moved here in 2009. It was there for years. However, by putting the vertical back up in that place I was able to free up the location it used to use and that allowed me to reuse the coax route to that one for the further developments which I then made later.

This was the first use I have made of Hyperflex 7 coax. I wanted to try it for a lower specification run like this, hoping that if it worked I could use it later for other things. It certainly does work, and the M&P plugs specifically made for it are very good.

The vertical is working very well in its new/old location.

I have mentioned before that I have had problem with mains breakthrough on 70cms. This has rendered my almost new nice high powered Tajfun 1000 linear pretty well redundant. I can use 100W safely with no problems. While moon bounce on 70cms is probably terminally affected, I am doing more work on 23cms instead.

To reduce problems with the 70cms breakthrough I moved its antenna to the mast furthest away from my neighbour's house. To allow for that move I took my 4m and 6m antennas down from that CUG mast. It seemed to me that I could not get both the combined 4m/6m antenna and the 2m/70cms antennas on the one mast. I was wrong about that and I had to reverse the initial thinking and get all four bands onto the one mast.

The problem was that I would need to get four runs of coax to that mast. Previously there were only two. After making a few compromises it worked because of this:-

1) by using Hyperflex 7 (H7) for the 4m antenna it would all fit through my conduits and it is much cheaper that Hyperflex 10 (H10),

2) by moving a run of H10 from the Tennamast and putting in an N-type joint I could save the cost of another run - and an N-type joint is acceptable to me on a lower frequency so that is for 50MHz

3) by using tails of H7 instead of H10 from the 2m and 70cm preamps I can squeeze in enough space to fit both antennas onto the existing stub mast (making the stub mast longer would cause neighbour problems). H7 has a much tighter minimum radius and this made the whole thing possible.

Trying the H7 on the vertical proved I could use it on 4m, and it is a lot cheaper. It is much easier to fit through the conduits in and out of the house. This may open the door to squeezing more runs through in future, though I expect 70MHz is my H7 limit for dx-type antennas. It is fine for the vertical too.

The result looks better to me than what I had before. Previously, as I was using coax with a longer minimum radius I felt that I had to take the coax down vertically from the antenna. This is because the Dual antennas have N-type sockets mounted below the boom, and it was really difficult to bend the coax back towards the boom. Such a problem does not arise with the thinner coax, so I could loop the coax round and run the leads along the boom rather as you might in a conventional single band antenna. Looking at the Dual website revealed that others have done the same.

Dual 2m/70cms yagi about the Dual 4m/6m yagi, with the CUG mast lowered

This gives me 4 elements on 6m, 5 on 4m, 7 on 2m and 12 on 70cm. Boom length is around 3m in total but used length is slightly shorter on 4m and 70cms.

Moving the vertical freed up the Ecoflex coax which fed that antenna in its previous location. The Ecoflex is now eight years old, and it is stiff and rigid. Ecoflex has been a disappointment to me, as it is inclined to form kinks and get stuck in places. When it came on the market it was the best coax I could use. Now I would not use it again.

Then it was time to put up my 36 element Dual yagi for 23cms. This goes up on the Tennamast and is double the length of the previous Wimo. The plan was to get a 10m dipole up there too but a snag developed and I have since taken it down again. For now 23cms is the only band on that mast.

36 element Dual 23cms yagi on the lowered Tennamast

I have to accept that this is the best combination of antenna locations that I can do at the moment. Given that I work five bands, having four on one mast and one on the other is not ideal. I have to point all four of the lower band yagis in the same direction, which rarely happened when I could do it differently. The two double band yagis are mounted on the weaker of the two masts, and they are all turned by the weaker of the two rotators. At least 23 cms has the more accurate rotator, which is useful for such a long antenna.  

I am working on all five bands again. I have antennas that many amateurs would think are pretty good. So I should be happy. 

I have been wondering whether a dish would be better for 23 cms but where would I mount it? I did see this idea while I was away recently.

Tree mounted dish seen at Grantown on Spey

All I would need to do would be to chop the top off one of Mrs FVM's trees.

I read that Blogger is going to stop email notifications for new blog postings from next month. That would be a problem for me. We need to see how that pans out.

73

Jim

GM4FVM

25 May 2021 - more Es, only better still

When I was attending the City of Belfast YMCA Radio Club, back in the early 1970s, learning my trade, there were some things I picked up from the old codgers with 2-letter calls who taught me what I needed to know. Everything was available on SSB with the KW-2000 and the magical new band of 15 metres. Actually, SSB and 15 metres had been around for a while, but it was amazing to them at the time.

But principally, in relation to my plan to earn a VHF licence I learned:-

1) VHF is a waste of time

2) The 2 meter band is not worth spending money on because there is no DX

3) The 4 metre band is even worse than 2m, but there is no money to spend there as everybody knows it is useless

4) This "Short Skip" thing gets in the way of DX working every year and only extends to France anyway.

This information rather flew in the face of scientific evidence, gathered during the World Geophysical Year in 1957/8 which showed the relationship between the E layer of the ionosphere, solar activity, and Sporadic E. This was what they called nuisance "Short Skip" down at the YMCA radio club.

I knew that I should listen to my "elders and betters", but I pretty soon came to realise that they were wrong in this case.

25 May followed the usual warning on Solarham. On 23 May a "minor to moderate" storm watch was put in place for 25 May. This followed a coronal mass ejection which only hit the Earth a glancing blow. As it turned out only the minor G1 level storm resulted, but that was enough for me.

23 May 2021 warning on Solarham

The result of this was a K number of 5 on 25 May and a very nice Sporadic E opening on 2 and 4 metres. Well, 6 metres too but I was not much involved in that one. 

Amongst other things, on 6m I worked UN3M in Kazakhstan at 22:41 local which rather gives a lie to the theory of Es as a daytime event but 6m is not what I am writing about today. I am not sure what the time difference to Kazakhstan is, but that was not a day time path. 

Enough about 6m.

Starting on 4 metres, at 06:43 I had a QSO with 9K2YM. I have been hoping to work Kuwait on 4m for some years and when it came I only received a -21dB report, but that will do nicely. I heard him working several G-stations but he was only workable here for a few minutes. Needless to say LL48 is a new square for me. It is definitely a best DX for me on 4m at 4974km.

Stations worked on 4m at GM4FVM on 25 May 2021

As usual, click to enlarge the images if necessary.

This was followed by a prolonged opening into the Balkan region. Over the next four hours I worked another 12 stations in seven more countries. Of the 10 additional squares, four were new.

On 2 metres the action did not start until 10:57. I had spent the previous 20 minutes calling several stations until eventually I managed to work YU7ON. Serbia is new country for me on 2m. In a little under an hour I had worked into 4 different countries.

Stations worked on 2m at GM4FVM on 25 May 2021

This proved that I was wrong two postings ago to say that my best Es DX on 2m was into Southern Spain. On 25 May I worked IT9GSF, who I had worked before. The distance then was 2333km. That must surely be my best DX on 2m Sporadic E. I was also heard on one of the small islands between Sicily and Tunisia but sadly no contact resulted. 

I had also worked YO7FWS before, but both his and IT9GSF's QSOs had been during late June. I was surprised to be doing this in May.

I will skip the map showing 2m stations worked in May to date. That included  42 QSOs to 10 countries. Interesting though that is, the 4m map is more surprising to me.

4m stations worked at GM4FVM, 1 to 26 May 2021

26 countries, 68 squares, 3 continents (Europe, Africa and Asia) in 104 QSOs. On the 4 metre band. In May. Back learning at the YMCA club I would have thought it unimaginable that this would be possible. I would have thought that because I was told that it was impossible. Back then it was the accepted truth that 4m was hardly worth the £10 it cost to buy my AM Pye Cambridge.

I have not done anything special here. I do not use any remarkable gear or even any of my many Super Powers. The special trick was done by the ionosphere. It has proved the doubters wrong. My only contribution was to ignore bogus "Sporadic E predictor" apps and stick by the basics of solar observation. I knew when to look. Joe Taylor and his WSJT-X suite has brought everybody into the same frame of mind and onto the same frequencies. It all helps, but the Sun rules the roost..

Wait, this only covers up to 26 May. Five more days to go! The possibilities are endless and we have not got to the happy times of late June or early July yet. 

I think it is all over for this month but Solarham is suggesting more possibilities for later on 27 May. My own feeling is that the glancing nature of the last CME suggests that we have had all we will get for now, but that is not clear. Predicting both the direction and magnetic polarity of such events remains uncertain.

We shall see.

Actually that is the best bit of it. 

We shall see.

What chance tropo on 2m to fill up the log? It is looking a bit empty.

73

Jim

GM4FVM

19 May 2021 - 2 metre Es DX like I never saw it before

I have said it before and I'll say it again ...

Arrrggghhhh!

Piles ups. Log book out of control. Domestic duties going begging.

It was not as if I had not had warning.

I do not do as others do. I do not look at Jet Stream maps, which as you know I regard as similar to looking at tea leaf patterns, feeling bumps on the head, and testing the dampness of sea weed. I prefer to look at the Solar predictions. I do this because it works for me.

To me this means that I know on 16 May there might be an aurora on 18th and I need to look for Es that day and the next. This is especially so at this time of the year. Experience tells me that early and late in the Es season any major solar disturbance has the habit of generating enough ionisation in the upper atmosphere to tip things over into Es. At the peak of Summer of course Es just happens regularly, and during the Winter it takes a big event to trigger it.

There was not much sign of aurora here but on 18 May the K number rose to 4 and I had a few nice 4m and 6m Es contacts later on. It just proves the link to solar activity as on 17 May, just the day before this event arrived on Earth, I worked nobody at all.

Come 19 May I was on watch from 06:00 looking for Es and hoping for some activity on 4m and 2m. You never know. There is always hope.

Right from the start there was 6m Es, which is what you might expect as I worked a couple of stations in Italy with very large stacked yagi arrays.

I took the precaution of working some EA stations on 6m to be ready in case I could do the treble again. At 09:08 4m opened to Spain and  Sure enough at 09:46 I worked EA6XQ on 2m, for a new DXCC on that band, followed by EA6VQ for a new square on 2m. Later I worked them both on 4m for a station double into the Balearic Islands. Whether a station treble to one of these was possible I cannot say because it all got so busy that I rather lost track of 6m. In fact I lost track of everything, including allegedly "important" things like cutting the grass and fixing the back gate hinge. Huh!

Stations worked at GM4FVM on 19 May 2021. Red=2m, Gold=6m, no pin=4m

As usual, click to enlarge the image if necessary.

The following two metre band opening lasted until 12:12, over three hours. From here it spread over time from the Balearics to Spain and France. The figures on 2m speak for themselves, 20 QSOs, 3 DXCC, 13 squares, and best DX to EA6QX in JM19 at 1878km. During those 3 hours and 6 minutes the area I could work moved around between the Balearics, Spain (Catalonia, Navarra and Bizkaia) and then a swathe up through France from the Mediterranean Coast near Beziers (1448km) north to near Angers (945km) and back again. It was amazing to witness.

New squares on 2m totalled 9 plus another one on 4m, with a 6m/4m/2m country treble to Spain and three station doubles, two to the Balearic Islands and one to Spain (EA2EVY).

144Mhz on PSK Reporter at 10:07 on 19 May 2021 - more like HF than 2 metres??

I do not know what others were doing because I could hear only one G station. I could see DX replying to some people I can usually hear. I suppose that happens when everybody near me beams South.

This was the best 2m Es day since I moved to this location 12 years ago, and indeed the best I can remember. Perhaps not the best in terms of distance, but certainly in terms of coverage and duration.

Have conditions changed over the past 12 years? I doubt it. I think that the emergence of data modes has concentrated DX stations onto a single frequency on each band and this has made all the difference. There is no longer a need to search for the DX. And then the speed of completing a QSO had increased - first PSK took an age, then JT65 and JT9 took 6 minutes, and now FT8 just 90 seconds. With 2m Es being a fleeting thing, often offering only a minute or two to complete a QSO, these things matter.

For me, using digital modes during Sporadic E openings has made little difference to the way I operate. I was using them with FSK441 on meteor scatter for a decade or more before FT8 arrived. What it has changed for me is that others are using it for DX purposes too, and the scope for finding someone ready to work me has increased hugely.

As we study the science of Sporadic E in greater detail we can now have a better impression of what it is and how it develops. As more DX is worked a better picture emerges of how propagation is affected by the Sun's influence over the ionosphere.

It is true that data modes are soul-less. I certainly miss the familiar voices and the chat with people I have grown to know on SSB. However, there is nothing to stop anyone from using SSB, or CW or indeed FM (I did hear Spanish stations on 2m FM during this Es opening). The use of data modes in this rather extreme form of DX-ing shows, in my view, how amateur radio constantly develops and adapts to find the maximum distance to be covered. It is the same process we have followed for generations, whether that was the trans-Atlantic tests of the 1920s or the introduction of SSB, or the adoption of higher gain antennas. 

If anyone still wants to yak reliably every day on with AM on Top Band I say, fine, off you go. But I won't be joining you. For sure I will spend a lot more days like 17 May (worked nobody on any band) than 19 May (pile-ups on 144MHz). VHF DX-ers live for days like 19 May 2021. They tend to forget the 17 Mays, though there are lot more quiet days. 

I do not consider myself to be a true DX-er. I have no free standing 20m lattice mast, I have no huge stacked antenna array and I do not run "full legal" power. But does that matter? Even those with simple antennas like my 7 element can take part, and they make the many days of silence worthwhile.

If you sense enthusiasm here and in my last post I make no apologies for it. More on my quieter time on 23cms later. Much quieter but still fun.

DX can be fun, and as part of a balanced diet can result in boredom loss (as they say on the slimming product advertisements).

Now, back to the silence.

73

Jim

GM4FVM

Aurora! DX Sporadic E! Doing the treble, again!

What is the excitement all about, a seasoned HF operator might say. Sure, don't these things happen every year?

Well, no. We have not seen an aurora here for several years. And an aurora often predicts an upturn on Sporadic E. As it is early in May it would be a bit unusual to have a lot of Es right now. But that is what happened.

Doing the treble again : first the Aurora.

As usual, Solarham correctly predicted the arrival of the aurora, so I had 24 hours notice. I was hoping for some auroral contacts and some Es afterwards. What was not predicted was just how strong the effects actually were. This type of prediction is still developing. The speed of the particles and the magnetic orientation they have when they arrive are still largely a matter of guesswork. This uncertainty is why we need to be on our guard for a big one which could damage communications and power supplies on Earth. In the event the K number went to 6 and possibly more.

It started here around 14:00 on 12 May and on SSB I worked GM4JYB. I was pleased to get a call from GI0OWA to make it two DXCC. A lot of the action was on CW and I heard quite a bit on 2m including an OZ. As my sending is hopeless now I refrained from answering.

I also heard a GM station calling CQ so quickly that I could not make out the rest of their callsign. Some G stations do the same, whereas Scandinavian operators generally seem to go more slowly in the difficult conditions. I always think that working aurora requires pretty slow morse as the signal is always distorted.

The aurora cycle on Earth is tied to the solar one and that explains why we have missed them during the solar minimum. Hopefully now we will see more of them. The wisdom in the books suggests that the aurora cycle runs two years behind the solar one, with a later peak too. Fingers crossed.

The point about the aurora was not what I heard or worked, but that it often precedes better conditions on the Sporadic E front. No point watching weather charts when an aurora had shown me that I should watch out for a Sporadic E opening, even in mid-May. And what an opening!

Secondly the 4m and 6m Es opening.

13 May was packed on 6m from start to finish. There were 894 pages of decodes on my WSJT-X log, each page totalling 52 entries, plus 32 on the final page, a total of 46,520 spots decoded here on my (temporary?) 6m two element. Taking 6 spots per QSO - though sometimes as few as 4 suffice - and maybe 4 more CQs unanswered per contact - there were not many unanswered CQs - that makes more than 4,500 QSOs. Those were just the ones I heard. I am not about to count them individually. So I have little to say other than there was too much going on with 6m for me to describe it here. Not bad for early May.

50MHz contacts at GM4FVM on 13 May 2021

As usual click to enlarge if necessary.

I mostly stayed clear on 4m. For all the activity there were no new countries and only one new square (KO28). I still enjoyed it.

70MHz contacts at GM4FVM on 13 May 2021

As befits a sizeable opening caused by solar action it was still going on 14 May.

50MHz contacts at GM4FVM on 14 May 2021

As is apparent from the map, I tend to use my time on 6m now by ferreting about finding unusual places to work - like the Azores or Gibraltar. A nice one was a new DXCC in Morocco. I heard CN8LI so many times over the years when I used 6m WSPR that is seemed odd that CN was a missing one for me. Well, I got that sorted on 14 May. So for me 6m is a sort of pointer for what I look for on 4m and 2m.

As usual I spent my time on 70MHz, always keeping an eye out on 2m just in case some brief opening would occur on 2m. I tend to find those 2m Es openings in June and July, but you never know...

70MHz contacts at GM4FVM on 14 May 2021

It is becoming clear from those maps that my new policy of concentrating on frequencies higher than 50MHz is having its effect on my activity pattern. There has always been a habit of mine not to do so much on 6m. For the first 10 years of my amateur radio hobby 6m was not available to me, and even when it was permitted the number of European stations to work was initially quite small. I did not really get active until about 2010, and it has, somehow, never found a place in my heart. Sure I still use it, but it just seems too crowded for me (!!!). Well, it was for the past two days.

The presence of a "French" station on 4m was a bit of a surprise. I have worked France several times 4m/6m cross band. This was somebody with /EXP after his callsign. He thanked some of the stations for helping him with his "trial". Was this legal? I do not know. I cannot vouch for the legality of all the stations I work. They should be legal, but we shall see about this one. Any station we work could turn out to be a pirate, we never know, do we?

And finally the cream on the cake ...

Suddenly, at about 14:00 on 14 May, 144MHz took off.

144MHz contacts at GM4FVM on 14 May 2021

I had decoded one G station in the hour to 13:00, and only decoded three in the following hour, and so far I had worked nobody at all. Then suddenly EA1NL popped up at +17dB. IN52 at 1569km was a new square. Then EB1DJ in the same square.  This was followed ten minutes later by EA4BDL in IM69, 1850km and another new square.

After the first three contacts there was a 20 minute gap and total silence - I even heard nothing from G-land which is only 10km away. I then put out one CQ and back came EA1AF at +13dB. 1658km in IN71, and a third new square. Brilliant.

And finally I worked EA7HLB who is 2145km from here. I had worked him before, in August 2019. Still, I am not complaining.

Five QSOs (one of the stations was worked twice) in a nine hour 2m a day, and all in Spain. Three new squares and my 2m Es record equalled. Now, that makes all the time spent on 6m and 4m worth while for me. Just waiting to "do the treble" by working Spain moving up the spectrum on three bands is my goal. Following the propagation up and down is what I do this for.

I will work anybody in EA who wants to work me. Since I came here 12 years ago I have now only worked mainland EA on 2m on 6 occasions, a total of 13 stations (four of those for the first time yesterday). I had to wait almost ten years for the first one, by which time I had already managed to work EA8. There is something about EA which is tricky for me. I really savour each contact. CT is even harder. 

So that was me doing the treble. EA on Es on three VHF bands in one day.

This is really the sort of thing I strive for. Using the bands as steps and stairs to climb the frequencies is my thing. I still recall my first 2m Es from here, working EU7AA back in June 2011. That was 2070km and stood as a personal record for years. 

That day in 2011 too I had stepped up from working east on 6m to contacts into the Baltic on 4m and eventually to Belarus on 2m. Not quite the same country, but the same idea. Almost doing the treble but not quite, as Belarus did not have either of the lower bands. I decided to make it harder in future - three stations on three VHF bands in one country in one day. Of course doing the treble with locals does not count, it has to be at least a 500km+ series of QSOs.

Since then I have done the treble on 4m/2m/70cms tropo too but that is hardly the same challenge. With tropo you usually have time measured in hours, with 2m Es you usually have five minutes to complete it. Yesterday was unusual in that I was hearing various EA stations over a 50 minute period, albeit with a 20 minute gap in the middle. The trick with 4m/2m/70cms tropo is to get 4m tropo to work, because tropo is not good at lower frequencies.

So working 2m DX is not enough for me. With Es I try to build my way from 6m, working up as I go to see if I can find the propagation to go further. I have done the 6m/4m/2m treble in one day several times now. First with Italy, then with Croatia, and now with Spain. While doing it on tropo is not quite such a challenge, I did it on 6 May 2020 on 2m/70cms/23cms with one single station, OZ2ND. While it was not a one-station version this time, I did work EA1AF on both 4m and 2m yesterday - a station double within a country treble.

What is the point? Well it shows me how propagation moves up and own the bands - broadly speaking Es goes upwards reaching the highest frequency at its height of activity, whereas tropo moves downwards, generally peaking on the higher bands I use. I am curious about how this all works.

The mystery, the unknown timing, and the probability of nothing at all happening is what keeps me going. But most of all, the sudden nature of it all gives me enjoyment. For all the expensive gear anyone could have, nature has the final say. We are powerless to control nature, but we can try to learn about it. Learn to follow the solar activity, learn about the passage of tropo systems, learn some science and learn some patience.

For now, it is over. The Es has gone. Will I ever do it again? Who knows?

An auroral treble? Hmmm. Not with my CW.

Just follow the available information and you shall find Sporadic E.

73

Jim

GM4FVM

23cm progress with the IC-9700 and linear amplifiers

I have worked 9 DXCC on 23 cms in a little less than two years. Some of this has been on SSB (16 QSOs), some on FT8, JT9 or JT4 (30 data contacts) and even one contact to Sweden on CW. This totals 16 squares, leaving large numbers of workable squares not yet reached. Some others are harder to reach but might be workable someday.

All 1296MHz band contacts at GM4FVM up to 26 April 2021

 

Why does Eddie EHV appear to be floating on Dogger Bank in the North Sea? Typo by me - I think he should be in IO84XT. He is appearing under both locators. D'oh. Log book correction needed here.

The distribution on the map leaves some pretty obvious reachable countries not worked, such as GW, EI, LX, ON, SP, OK, LA, and of course GU and GJ. Activity is low on 23cms and several local squares have little or no activity at any time. During contests there is more activity and I can often work four or five stations during UKAC, not that I try to work too many stations during UKAC. I prefer to identify likely targets and work the best DX rather than the maximum number of stations.

During tropo lift conditions it is common to have stations on 70cms ask me if I have 23cms, which often allows some DX stations to be worked. I can also fish on PSK Reporter looking for active stations who I can then try to work - this is another big advantage of data modes.

Aircraft scatter has produced some good results. Two of those countries have only been worked on aircraft scatter, well so far anyway. Those QSOs usually have to be arranged in advance. During lockdown the number of planes seems to have about halved, but there are still quite a few "heavy" aircraft around, including freighters.

So I have gradually amassed a reasonable number of contacts. The total is 47 QSOs  with best dx to DF5VAE at 1001km. These results have exceeded my expectations by a large margin.

I still think that I can do better on 23cms.

My 23cms project started with the arrival of the IC-9700 with its 10W output. Neil G4DBN gave me an antenna, I had enough coax, I bought two plugs and a masthead preamp and off I went. I never expected much and I certainly thought my station would stay like that for good.

Later I added a 100W amplifier from Riccardo IK5CON.

All through this short story I have been plagued by doubts about measuring my output power. The Wavenode power meter I use showed that the IC-9700 only put out about 4 watts and the linear only 50W - both about half what I would have expected. At first I blamed the IC-9700, now I blame the meter. Without any way of calibrating the meter, I was left in the dark.

Lest you think that I am being negligent by operating without a proper power meter, I can measure my mains input power very accurately and I have definitely been operating legally. Unless of course my amplifier has an efficiency greater than 100% and is generating its own power internally.

Recently, Sid, G8SFA, offered me the loan of an amplifier capable of about 200W output. Certainly the Wavenode shows that my power has increased by 3dB over the 100w amplifier.

G8SFA 1296MHz linear amplifier

It is very kind of Sid to lend me this piece of kit. The snag I have now is that despite the extra power I cannot work him using his amplifiers at both ends. In this case it is the terrain which is causing the problems. Sid has improved his antenna. I can hear him but he cannot hear me. He is 100km away in Prudhoe and he cannot detect me, yet I have worked Charly, DF5VAE, on an island in the Baltic Sea at ten times the distance.

Trying to work Sid is the sort of challenge that makes amateur radio interesting for me. There are hills between us, in contrast with Charly. Surprisingly, the path from here to Ruegen is almost line of sight even accounting for the curvature of the Earth. We both have elevated sites close to the sea. There are no intervening hills in Denmark along the way which are high enough to get in the way. Everything else between us is either North Sea or Baltic Sea. Here I have the Cheviots between me and Sid.

I have run tests with Tom GM8MJV and Jon GM4JTJ. They both kindly spared the time to test Sid's linear and the tests confirm that it does indeed produce the expected difference in received signal. It also seems to sound good and looks like it produces a narrow signal. So, thanks to Sid, I have enough power now and the otherwise excellent IK5CON amplifier can serve as a backup.

What I really need is a better antenna for 1296MHz. In the photo below we see a new team member examining the 23cm antenna, or at least, the shadow of the 1296MHz antenna ... she is not impressed.

Paddy observing the shadow of the 23cms and 4m antennas, other masts are in the distance

A new shack companion, Paddy, has arrived safely but so far she is proving to be rather different from the much missed previous Officer Of the Watch, Katy. She does not like the shack for a start. Wait for winter I say. The shoe will be other other paw then.

I am keen to work Sid on 1296MHz. An antenna with more gain should help. Is this my next step on a band I never really expected to be so productive?

73

Jim 

GM4FVM

Icom IC-9700 - "DX Shop PTT multiplier" solves the multiband PTT issue.

Judging by the large number of people who have read my post of two years ago entitled "Icom IC-9700 PTT switching - something I do not understand", I seem to have identified an issue that resonates with lots of people. There is no need to read it now as the problem seems to be solved.

That posting is one of my most read pages. It deals with my early realisation that the IC-9700 (not then released to the public) does not have a separate PTT line for all three bands it covers, nor even one for two as offered on other Icom radios. I called this a deal breaker, though I ended up with an IC-9700 through other routes than buying one.

Like many amateurs using the wild west of the higher bands, I have a separate linear amplifier for each band, 2m, 70cms, and 23cms, covered by the IC-9700. I did muddle through with a relay linked to my 23cms amplifier PSU, but this is not a brilliant plan. Luckily for me I generally only use the 9700 for two bands, but when for a while I was using it for all three bands it got a bit out of hand.

In reply to a helpful comment by Gavin, GM0WDD, I suggested in that posting that somebody should make a "CIV box" and I described it thus:-

The CIV box I have in mind has a simple CIV decoder (maybe an Arduino) and 3 relays (or solid state switching). It just reads the CIV and switches between the relays to select the PTT. No need to sense the PTT from the CIV as it comes out on a different pin on the same socket as the CIV does. Three LEDS on the box to show which one is selected and for fail safe all three work if the box loses the CIV signal.

Enter now the "DX Shop PTT multiplier", which arrived here today...

DX Shop IC-9700 PTT Multiplier

It is in reality almost what I described in principle - more or less. The detail difference is that it uses a PIC microcontroller rather than an Arduino, and it seems to fail safe to no PTT rather than connecting all three. It gets its CI-V signal via the 3.5mm mono socket on the back of the 9700 and its power and PTT signal via the clunky 8 pin full sized DIN socket which Icom also put on the back of the radio. Both leads are supplied.

This pretty well plugs in and works. There are some settings you need to change in the 9700 menu. They are all on the CI-V tab.

USB Port: Unlink from [REMOTE]

DATA Baud Rate: 9600

DATA Echo Back: OFF.

I did all this and it didn't work. I had WSJT-X running and I had lost rig control. Probably no fault of the device, but for me I had to go back into the CI-V settings and change the USB Baud Rate from 19200 to 9600, and then do the same in WSJT-X. I am not sure why this happened but I remember similar problems with the IC-7300 and the remote control software. Anyway, making the baud rate between WSJT-X and the rig the same as that between the rig and the CI-V box did the trick for me. This is one to watch for because I think that the default setting in Hamlib is for 19200 so this might get reset if I update WSJT-X or change the PC.

Then it only seemed to work on 23cms which was definitely my issue. At some stage I had tinkered about with the "ACC SEND OUTPUT" settings to stop the radio using the 70cms and 2m PTT while I was using 23cms. I needed to go back in and turn all three bands to "ON". I suspect that these are normally ON by default and it was my settings than had changed them.

When the box does not have CI-V communication all three LEDs flash. A quick test suggests nothing happens if you press the PTT in that condition, so no linears would be keyed but the rig still transmits. Whether that is an issue for you depends on your setup. For me I would have preferred all of them to be keyed, which would have triggered my sequencers and turned all the masthead preamps off. I can see also that this might not be possible with the setup inside the box (which I can only imagine because I am not opening it until the warranty has expired). Anyway, I doubt if it will lose the CI-V in normal use. I have RF-VOX protected preamps but not everybody has and even non-amplified RF might be too much for their preamps.

In normal circumstances the box has CI-V working and one LED is lit green. Changing bands moves the LED indication along to 70cms or 23cms as selected on the radio. When you press the PTT the LED changes to red. Perfect. I have buried it inside my shelving - I have no room to put it in front. However I can still see it and the LEDs in the background.

I connected the 2m and 23cms linears up, including the additional SWR cut-out trip I have for my Gemini linear. If it ever trips now only the 2m amp will go off rather than the other ones as well as heretofore. Just to test it I wired up my 70cms sequencer to see if it worked on all bands. It did.

During testing the LEDs displayed perfectly and the box followed the frequency on the rig as you would expect. The DX Shop say that it works in satellite mode which I cannot test. 

The frequency followed in normal operation is the main band, which is correct for the IC-9700 for non-satellite working. If I highlight the sub-band this does not change the PTT connection away from the main band which is also correct for the way the IC-9700 works for non-satellite operation. 

The frequency readout on WSJT-X produces interesting results when using the sub band but the CI-V box always selected the correct antenna for transmitting. I may go further into this later as there is a quirk using the IC-9700 with CAT control when switching to the sub band. This quirk has my head spinning sometimes, but the presence of this box does not change anything.

The result of the test showed that once I had set the PTT multiplier up I could forget about it. The box just changed the PTT line to the right amplifier as required. That is what I have been waiting two years for.

It appears that this issue is resolved, for me anyway. What a pity that Icom had not covered it to start with, just like the frequency stability issue which I had to solve with a GPS frequency source. I had to pay extra for those items which should have been included for no extra cost if somebody had thought about them at the design stage.

So the DX Shop PTT Multiplier costs £59.99 and you can find it here. 

Thanks to G0DJA for pointing this product out to me.

73

Jim

GM4FVM

OFCOM RF Field calculations and some modest openings.

First, a general update:

I have been too busy to be on the radio much. Work, sadly, still has to be done. But...

I have been around often enough to watch the tropo predictions. There was one opening which was predicted and just did not happen. then another which produced good results on 2m. 

The one that did happen produced these maps:- 

144MHz FT8 contacts at GM4FVM 27 February to 3 March 2021

2m:  52 QSOs, 8 DXCC, ODX DL1BAK JO43 775km. 

This tropo opening lasted for several days, as they often do, and just managed to extend into the RSGB 2m FT8 contest, which occurs at the same time as various European data contest. Surprising that, having good conditions for a contest.

432MHz FT8 contacts at GM4FVM 27 February to 3 March 2021

70cm 17 QSOs, 5 DXCC, ODX DL7APV in JO62 1027km

23cm Nothing heard during this event.

Plus I noticed that there was a ionospheric disturbance predicted which resulted in me being ready for a small Es opening early on 13 March on 6m.

50MHz FT8 contacts at GM4FVM 13 March 2021

Just imagine it, successful predictions of a 6m Sporadic E opening and no jet streams involved.

Now, on to the EMF calculations:

For a few months I have been watching developments with the consultations the UK regulator Ofcom, has been having regarding their proposal to apply RF field calculations to radio amateurs (and marine band operators amongst others). These standards already apply to most operators of transmission equipment in the UK, such as at sites where mobile phone towers transmit RF as part of the cellular network.

Phone mast less than 2km from GM4FVM, no doubt ICNIRP compliant (no signal at FVM though)

Strictly, Ofcom proposed to extend the International Commission on Non-Ionising Radiation Protection (ICNIRP) general limits on Electro-Magnetic Field (EMF) exposure to apply to all spectrum users. Which for me means that I have to calculate a horizontal separation distance which, if it falls within the property, will ensure that nobody outside the property will encounter higher levels of EMF than would be wise.

There seemed to be quite a lot of fuss about this proposal in the radio amateur community. The Radio Society of Great Britain responded to the consultation in a way (or so it seemed to me) that this is all fine and good for everybody else, but radio amateurs should not be affected by it. They described complying with the measures as "onerous".

I think we have to understand the power structure here - Ofcom is the boss and they make the rules. Radio amateurs follow the rules. Ofcom, of course, were using "consultation" as meaning "we intend to do this anyway so you can write to us, but you might as well save the wear on your keyboard".

With people making up stories about EMF issues Ofcom say that they have to ensure that everyone toes the line. Quite so.

And anyway, isn't amateur radio liable to be onerous? It is hard to get into this hobby. The exams are difficult and so they should be. Is it really all that bothersome to do a few sums just to check that you are not allowing someone, including yourself and your family, to encounter a high level of EMF energy? I know that the ICNIRP limits are set very much on the side of caution, and it would take many times that level of EMF to come any where near affecting anyone, but still we radio amateurs should comply. In my view.

So a few months ago I decided to have a try to check what my minimum separation distances actually are. I already had done some effective radiated power (ERP) calculations a couple of years ago which I updated. Then I tried to work out what the field strength might be at various places around the FVM Estate Grounds. The idea is that "the general public" should not be exposed to field strengths which might cause them bother ... which sounds like a good idea to me.

In the past I had taken my ERP as being more of a target I should aim for. This is at least in part due to my interest in moonbounce where every last decibel counts. The same argument applies but less so to meteor scatter, and to some extent to my efforts to work DX on 6m.

I started off by trying to update the earlier calculations to fit the model Ofcom were using. For the earlier calculations I had taken my maximum transmitter power, subtracted losses in the coax, added the antenna gain (in dBi) and came up with an ERP figure for each band and antenna.  

For this first attempt at calculating separation distances I took the ERP figures and the antenna heights and put them into a spreadsheet on the Ofcom site. At the time the information available from Ofcom on how to use the spreadsheet was a bit sketchy. It looked initially that I might have to re-organise my antennas a bit to comply. In other words, the horizontal separation distances in a couple of cases extended beyond the property. But as we shall see, my initial calculations were wrong due to lack of information.

To align with the Ofcom proposals I tried to sort out the "mode factor" and the "Tx percentage". This is the equivalent to working out the average power (100% for FM, lower for SSB) and then applying the average percentage of time you would transmit over 6 minutes. This flummoxed me a bit. There are a few windbags on FM who could easily waffle for 6 minutes and get this to 100%. Me, I guess being mostly a data modes operator I would never transmit for more than 50% of the time on any mode in any 6 minute period.

I had not considered that my ERP figure, which I was trying to work out using the ISO standard, was based on gain over an isotropic point radiator. Later I discovered that the RSGB were using dBd gain figures based on gain over a dipole (and hence my 10m dipole records zero gain by their reckoning). So all my calculations were on the wrong side by a factor of almost 2.5dB which, was as if my power was almost double what it really is. I decided to wait for more guidance from the RSGB and Ofcom.

When more guidance came, the RSGB website contained a spreadsheet based on the Ofcom one. This is more amateur-friendly, and I decided to follow it. For the most part it produced figures very similar to my own, taking into account the change from dBi to dBd. And it handily does a calculation relating antenna height to distance on the ground, saving me my "square on the hypotenuse" calculations in my home-brewed version.

My maximum output leaving the shack on any band is 200W or less, and a bit less again at the antenna. First I started thinking about all my lower powered activities, with 4m being about 150W and 23cms 50W. Lately I have decided to back things off a bit on 6m and after a successful spell on 200W with a 5 element beam I and going over to barefoot with a HB9CV. 

These three bands, 23cms, 4m and 6m, looked fairly easy to declare compliant. So too did my 2m and 70cms FM activities. I hardly ever transmit on FM anyway. Nevertheless I decided to do the calculations for that and even for my 4m FM vertical, which is presently in the garage. I know where I would put it up if I decide to listen to a closed squelch again this summer.

Fitting it all into the RSGB calculator showed that the separation I needed to do for all of those bands and antennas is NIL, save for the 10m vertical. In every other case the recommended minimum separation is short enough that the antenna height accounts for it.

I will put a screen grab of one of the calculations in here, but I doubt if you will be able to read it. You can click on the page to enlarge it but I doubt if that will show much detail ...

Separation distance for 6m at GM4FVM using the RSGB calculator.

Things are a bit different for the 2m and 70cms horizontal yagi antennas where the antenna gain is much greater. The ERPs are about 10dB higher than on 6m. With the mast down the antennas are about the same height as the 6m one, but the horizontal separation distances are 10.3 and 9.3 metres respectively.

Luckily, here I have enough space around the mast to provide this separation distance comfortably within our property and leave several metres to spare. It is fortunate I had the earlier calculations in mind when I moved the antennas around because it would have been tricky where they all were before.

I am aware that for some amateurs their calculations are going to produce be uncomfortable reading. For those using masts on gable ends of houses there may be very little separation available to the edge of their property. They may be helped by having more antenna height than me, especially if they live in two story houses.

The Ofcom advice suggests that if it is difficult to comply other measures should be considered including raising the height of the antenna. Grand idea, and it would work, but my neighbours would not be pleased.

For me, I am considering myself fortunate to be able to fit it all in within the boundaries here.

73

Jim

GM4FVM