Monday, 27 August 2018

Well, I got Tropo wrong

Recently a political spokesperson was being interviewed on television, and she was confronted with the accusation that what she had been saying did not agree with the facts, as had been pointed out by others.

"Well" she replied "they may have the facts, but we have alternative facts".

Her interviewer quickly pointed out that there are only facts. "Alternative facts" are, in fact "falsehoods", the interviewer retorted. I agree with him. The only facts are ... the facts.

I may have got the wording of the quotation a bit wrong - after all who cares about the truth (see later)? But that was the gist of it.

A weighty amateur of many years standing remarked to me that I could hardly keep saying that this QTH is not good for tropospheric propagation (tropo) when I had recently worked the Canary Islands on 2 metres, a (now corrected) distance of 3264km. Fair point.

It is true that I have said many times that this location is not good for tropo. If you were to be mad enough to look back in this blog you would find me saying that lots of times. I also fretted for years over "not being able to" work into France on 2m, due to the presence of "the headland", an outcrop of higher ground to the south of me.

How can I square the "fact" that I still feel that this QTH is not good for tropo and (the alternative fact) that it has proved itself to be rather good for tropo? I think that that both of those things exist at the same time - it depends what you mean by "tropo", but saying both of them looks a bit daft.

I decided to look at a map of my 2m tropo contacts since my last posting on this site (click to enlarge if necessary) ...
144MHz band FT8 contacts at GM4FVM from 14 to 25 August 2018
I have to say that I am pretty pleased with that. However, looking at the 100km radius circles some interesting pattern emerge. I seem to do fine over 400km, and badly under 200km.

Taking the contacts per 100km increase in distance from me...

0 - 100km NIL
100 - 200km 1 GM0NRT
200 - 300km 5 MI6XZZ, MI0KOA, M1AVV, G4JIX, G8EEM
300 - 400km 5 MW0RSS, G7RHF, G8EFU, M0JDK, M0NPT
400 - 500km 2 G3RMD, G4TRA
500 - 600km 1 M0WGF
600 - 700km 1 F1IEE
700 - 800km 2 ON4POO, ON4KHG
800 - 900km 1 F6DBI

There could be all sorts of explanations for this result including the proportion of the area which is sea, and the geographical distribution of amateurs. The 0 - 100km circle has almost 50% land and the 100 -- 200km has more, but in general the total area of land in the other circles does not vary too much. Each more distant circle is larger than the closer ones, but the ever larger ones tend to include more of the Atlantic Ocean and the North Sea which have very few amateurs operating from them.

As for the distribution of amateurs, this often follows city size. Even the 0 - 100km circle has Edinburgh, Dundee and Newcastle upon Tyne in it - though I have never heard a station from any of those cities. Most UK cities are at sea level or very low, and that plays a part too. The 100 - 200km circle has Glasgow, Aberdeen, Leeds, Bradford, Hull and so forth in it. Yet I do not hear from these cities. Just about the only nearby place I do get into as well as I might expect is Fife.

You can only take this city thing so far. I do not live in a city myself. Nevertheless, in general there are more amateurs where there are more people.

I am drawn to the conclusion that I am right that this location is not good for what an FM operator might think of as tropo propagation, but yet it is good for distant tropo from 200km out to 500km and beyond. When I describe this distant propagation I do not mean tropo ducting (of the type which brought in EA8 from over 3000km), but simply "flat band" working. There were no discernible "lift conditions" during the 12-day period covered by that map.

I think that I am not alone. I suspect that others have been fooled by this effect and have also assumed that their site is not good for VHF, whereas in fact for more distant contacts they may be in a fairly good position.

When I do come on for 144MHz contests I am always surprised by noting from the serial numbers that many other stations work dozens (yes, dozens) of stations close to them before turning their attention to dx. These are stations local to them and maybe I just do not have those stations around me. I certainly have no local stations to work. What I think is most likely is that such local stations as there were have given up on 2m dx.

When I arrived here 10 years ago there were local stations on 2m. Now there are almost no stations within 75km of me in any direction. For example to the south the station I would first come across would be Jeremy M0XVF who is 137km away. There may be nearer stations in Newcastle upon Tyne or Gateshead, but I cannot hear them. Even working Jeremy can be a struggle due to the difficult path between us. Yet, in that 12 day period covered by the map I easily worked ON4POO three times and ON4KHG (709km) twice. These long distance results are not a fluke.

I cannot blame anyone for giving up when faced with the evidence. I almost fell for it and abandoned 2m. When I arrived here I put up a 4 element yagi and did badly. Even after I  put up a 10 element I did not do well. I took the absence of stations out to about 200km as a sign that this QTH was not good for tropo. I was under the impression that if there was not much to hear on tropo at that range then there was not likely to me much to hear further away. This was because I knew that tropo has no "skip zone" and that events such as ducting were few and far  between. Whilst I did not give up, I certainly relegated 2m down my priorities.

It has taken years for me to realise that I was wrong about that. The evidence is still there - I have a half wave vertical and an FM rig constantly scanning around and generally I hear nothing at all. The hills mean that I cannot hear any stations from Glasgow (maybe 120km) or Edinburgh (about 60km). I cannot get into Berwick upon Tweed (12km to the south) or Dunbar (15km to the north). It is hardly surprising that I thought tropo was no good from here.

Why complain about not being able to hear any locals? There are lots of dx and contest stations who would love to get rid of their local QRM. Well, the absence of locals almost caused me to give up on the 2m band entirely.

Part of the problem with understanding this is that everybody seems to mean something different when they refer to "tropo". For this purpose I am excluding ducting. I tend to lump in assistance from aircraft scatter with general tropo propagation, though that is not correct. Many of my middle-distance QSOs are a mix of tropo and aircraft scatter. All of the contacts on the map were made during a period when there was no unusually high barometric pressure, no noted temperature inversions, no fog and none of the features associated with a tropo "lift". They were what I call "flat band" QSOs.

So there it is. My view that this site is not good for tropo was based on solid observations that the standard fare of tropo, up to about 200km, was more or less absent. I could have given up at that point, and I suspect that many others around me have already given up years ago (which only makes everything seem quieter). Somehow I kept at it and now I have the help of FT8 to corral all the dx into one place.

I feel fairly sure that several local amateurs who put up a vertical for FM, and who then heard nothing, have concluded that their location is no good for 2m tropo dx. They may well be wrong.

I am going to stop suggesting that this location is not good for tropo. That is an alternative fact. In other words, it is not true.

Of course, more recently another political figure said that "the truth isn't the truth".

P.S. Grand Tour cycling is on again. The 2018 Vuelta a Espana is underway and Uran, Aru, Nibali, Quintana, Porte, several guys named Yates, and the main favourites are all in action. I will be watching them all closely, but especially Michal Kwiatkowski.




Wednesday, 15 August 2018

Unexpected DX and Perseids

In this posting is a report on the Perseids meteor shower and some rather unexpected success on VHF and 70cms. As usual, click on the images to enlarge, if you need to.

First the Perseids. This meteor shower peaks around 11 to 13 August each year. The usual drill is for me to watch a large number of stations being received and not manage a contact with any of them. This is especially true on the 2 metre band, where success has been limited up to now.

Therefore imagine my surprise this year when one of my attempts to work somebody far away on 2m actually came off. For several years now I have been calling R1AY who is 1941km away in KP50. Astonishingly I had a two way success with Serge this year. I almost fell off the chair when I saw him replying to my call ...
R1AY replying to GM4FVM's call on 2m meteor scatter on 12 August 2018
Of course on 2m these meteor scatter contacts can go on for an hour or more, so it is not exactly the place for sudden excitement, but that one moment sticks in the mind. That was the first time anyone has replied to me from Russia on 2m apart from moon bounce.

Aside from that, the usual pattern of seeing CQ calls once from all sorts of places and replying to no effect continued this year, and included EU3CZ and numerous others. I could see many closer stations hearing me on PSK Reporter who did not reply, or I did not hear them. However, the R1AY case shows that it is worth giving it a try.

On 4m the Perseids brought me plenty of action
GM4FVM contacts on 70MHz meteor scatter during the 2018 Perseids shower
The contact with OH1MLZ is certainly the furthest at 1686km it was not quite the most notable.

Przemek, SP7VC, has activated many unusual places on 4m over the years, and given me several new squares. At the start of the Perseids he appeared from Guernsey, in a square and DXCC which I already have. "Why doesn't he go to Jersey?" I asked in my ignorance, before noting on his website that he planned to move on to Jersey too.

When I eventually worked MJ/SP7VC in IN89 I had a new DXCC. I had never worked Jersey from here on any band, so that is one for the record book. Not that it was a new square, as GU8FBO gave me that square some time ago.

Another surprise was working SM7CAD on 4m. I have remarked before on the short-term 4m licenses issued in Sweden and how hard I found it to work one. I have worked Curt before several times on 6m meteor scatter. On 14 August I found him working split on 70.1735/70.167. This took a bit of jiggling with WSJT-X and split on the IC-7300, but I was able to get back to him for a very easy QSO.

So Sweden and Jersey get me back up to 40 DXCC on 4m, and 217 squares. on 2m R1AY at 1946km is a new meteor scatter record for me. I heard some stations over 2000km. Not a bad Perseids after all.

New Continent and personal record DX on 2m
144MHz tropo ducting on 5 August 2018 as shown by DXMaps
On 5 August 2018 I worked EA8TJ by tropospheric ducting on 2m. He is in IL18 square, a distance of 3261.69km. It is also my second 2m continent (Africa). It almost didn't happen.

I had just returned from a trip to visit my sister and I saw that stations in Cornwall were working the Canary Islands and Capo Verde. They have a sea path to those places, I don't. They are a lot closer. Despite this I decided to listen.

While watching the WSJT-X screen I saw Chris, GM4ZJI, work EA8TJ. I sent Chris a congratulation text and he phoned me to warn me about the propagation at the same moment. I told him that I could not hear anything. For about 15 minutes I heard nothing and Chris sent me several texts encouraging me to try to work the EA8. It was only at this stage that I realised this was an EA8 and not a mainland Spanish station.

For some reason I decided to beam towards Chris instead. At this point I could hear EA8TJ. I called him and he came back, but when I beamed towards him I lost him again. So I quickly beamed back to what appeared to be North West and he completed the QSO. David, GM4JJJ, went on to work EA8TJ too.
FT8 QSO between GM4FVM and EA8TJ on 5 August 2018

What was happening? My SPID rotator controller had lost its settings and was pointing the beam 120 degrees off the true direction. I managed to run into the kitchen and peer out the window at the rotator which proved that I was beaming the wrong way. The only way I completed the QSO was by running back and forward into the kitchen, setting the beam heading by eye.

Just to put this tropo contact into perspective, it comfortably breaks my personal 2m Earth- Moon- Earth record of 2727km, and my overall non-EME 2m DX record of 2069km which was done on Sporadic E. It is 2m personal best using any form of propagation and I suspect it will take EME to break it (if I ever reach this distance again).

This was no great feat on my part. I was already aware of the path from EA8 to GM4ZJI when I made the QSO. Not only did Chris do this first, but he can claim a GM 2m tropo distance record as he is 6km or so further away from EA8TJ than I am. He phoned to alert me to the possibility and I certainly appreciate that. So Chris gets the congratulations. However, it is still a personal record for me and it tells us something about the propagation.

It certainly is not a totally sea path as it passes over the Cheviot Hills, the North Pennines and English Lake District, over North Wales, then briefly Cardigan Bay before crossing South Wales, but it misses Cornwall and Cape Finisterre.
144MHz contacts at GM4FVM 25 July to 14 August 2018
Putting R1AY and EA8TJ onto my map rather puts the other 2m contacts into the shade. This would be a mistake as there is interesting stuff in there. More contacts with ON4POO, meteor scatter into Germany, IO61 square activated by the EI9E group, and more. But it is the distance of the other two which catch the eye. For EA8 I just happened to be in the right place at the right time and my own efforts at station building almost prevented me working him due to using the wrong beam heading. With R1AY it is different - I have been trying to get him to hear me for years. Maybe he did in FSK days, but this time on MSK144 I saw his report in return, so I know I am getting there.

Is it FT8 which is making the difference these days? Not for meteor scatter where I was using MSK144. Anyway EA8 has been worked from Eastern Scotland before. However, MSK144 is getting more popular and for now almost everybody is on the same frequency. I haven't used FSK441 for years.

What makes a contact significant anyway? Long ones which are almost flukes, or short ones that prove the reliability of the equipment and propagation (and the superior abilities of the mature, yet technically savvy, operator)?

6m Trans-Atlantic and new 2018 DXCCs from nearer home
DX is one thing, whereas proving your all-round abilities by setting targets and beating them is another.
50MHz contacts at GM4FVM 25 July to 14 August 2018
Not so long ago the idea of working across the Atlantic on VHF was a dream for me. That a period of three weeks could contain six contacts "across the pond" on 6m would have been unthinkable not long ago. But when it happens I move on - what is next? I need another challenge. Working all those stations is a great bonus but now I am focused on maximising my DXCC count for this year!

Yes, working OY9JD and GU8FBO on 6m gave me more satisfaction than reaching the US and Puerto Rico. I have worked both Jon and Richard before on 4m and 6m, but on this occasion they provided the 2018 entries in the logbook to bring me to 65 DXCC on 6m this year.

Collecting DXCCs is a different challenge to working DX, at least until you need the last few. It is more about putting in the hours and taking the time to get things right. And you learn things like it is very difficult to work Netherlands and Wales from here on 6m.

I hope I am not becoming too blasé. Faeroes and Guernsey need to be worked, but working the Americas is very nice too.

6m moonbounce reception.
Following a tip-off from David GM4JJJ on 9 August I heard that W7GJ was being received via Earth- Moon- Earth on 6m JT65. At first I heard nothing, but once the moon elevation fell below 4 degrees I had copy ...
W7GJ heard at GM4FVM on 9 August 2018 on 6m JT65B via EME
I always thought that 6m moonbounce was confined to the realms of the "super station". I thought this because I had read it in a book. However, receiving a signal from Lance confirms that with a super station at one end it is possible. I sent a report to Lance and he sent a courteous reply. He encouraged me to call him if I see him again. I tried to hear him again the next evening but only got traces of Lance and meteor scatter traces of others working him.

I think with my station it is unlikely that I will ever make a 6m EME contact, but that is no reason for not trying. Reading how difficult it is in a book just put me off, whereas actually listening showed it is a possibility, however remote.

There is no doubt about it in my mind. Books on VHF operation for amateur concentrate on the mega-stations and the vast antenna arrays. Yep, I need those at the other end to work EME. They help with other propagation modes too. However, nothing beats just turning on and having a go, even if you only have a simple system.

70cms - it is all great
Anything worked by me on 432MHz has to be good. After all, with only a dozen or so contacts over my entire amateur career it is all new. Pretty well every contact brings a new square.

Several very helpful QSOs have convinced me that there is something for me to do on this band. GM0HBK on FT8, plus GM4JJJ and G0XVF on SSB were all good markers as to how far I would be likely to get. However there was nothing else for it but to try the RSGB UK Activity Contest on 14 August and see how it went. Before the contest I got the sequencer working - more of that in a later post.

I was really happy with the way the contest went, hearing well over 30 stations and working 10. There was lots of activity. According to reports from participants afterwards I think that conditions were just moderate. A slight lift would have dramatically improved my contact rate as I heard so many borderline stations. The last half hour was poorer for conditions but I still managed to work some stations rather closer to home during the period.

You may know that my attitude to contests is not really to engage with them. Rather like Jeremy Corbyn in Tunisia, I am taking part but not participating at the same time. I am happy to give away points, but not so committed that I cannot make tea, toast, have a Fig Roll, feed Katy the cat, stretch my legs and make a few phone calls during the session. At my level of limited participation it was GREAT FUN. I lasted for the full 2.5 hours with a good few breaks along the way.

No new DXCC to report (I missed GW and GD during the contest), but I have very quickly reached 15 squares to add to my 5 DXCC. Given that I only have 25 watts and a 12 element antenna I am really pleased with that.

And all this activity has made my map since 25 July look much more promising
432MHz contacts at GM4FVM 25 July to 14 August 2018
70cms seems like an interesting band. Where has it been all these years? I cannot blame anyone but myself. I keep saying that others should try VHF, and then I did not try UHF at 432MHz.

In Summary - what do I mean by unexpected DX?

Before the past three weeks:-
Working Sweden on 4m is not something I had expected to happen soon,
Reaching 65 DXCC on 6m in a year is not something I had expected to happen soon,
Being heard in Russia on 2m meteor scatter is not something I had expected to happen soon,
Working the Canary Islands on 2m tropo is not something I had ever expected to happen,
Hearing a US station on 6m EME is not something I had ever expected to happen,
Working 15 squares on 70 cms is not something I had expected to happen for years.

Phew! What next?

At this stage of the year I expect radio to wind down for the winter. "I expect"?

Some things are certainties. I am certainly taking "The Message" by Grand Masterflash and Furious Five as one of my eight discs to any desert island that I am sent to. And "Police and Thieves" by Junior Murvin (the long dub version please, not the rip-off recorded by The Clash). Do they have to be discs? Could I not have an MP3 version? Anyway there might be certainties with the musical choice, but on amateur radio, as in life, maybe nothing is certain.




Wednesday, 8 August 2018

70cms, television coverage and TVI

Well, my dual band 2m/70cms beam is now aloft, and with a bit of mixing of cables I am now on 70cms. The antenna has 7 elements on 2m and 12 elements on 70cms with a boom length of almost 3 metres. Thus it should in theory match my previous 2m beam with the added advantage of giving me 70cms as well. Claimed gain figures are 12.6 dBi for 2m and 14.6 dBi for 70cms. I might have got more gain from a separate 70cms antenna but another boom is not really practical on my mast.
New Antennas-Amplifiers 2m/70cm dual band beam with pre-amps above the 4m beam at GM4FVM
I have bought from Goran at Antennas-Amplifiers in Serbia before. While this antenna is not cheap, as a dual band antenna it is cheaper than two separate antennas. High quality materials such as driven elements made of brass are impressive. The extra weight of the strong boom raises the overall price once you add the postage, but I am very pleased with it.

Results so far are good and I will go into that in a later post. Well, "good" if you mean beating my previous 2m DX record by a very large margin. That tale is for another day.

Given that I was using some less than brilliant coax on 70cm and also that I have little faith in the Icom IC-7100 as a DX receiver on that band - though it is fine for what it is - I decided to fit a moderately priced 70cms mast head pre-amp.

My experience with the SSB Electronic 2m pre-amp showed me how useful these things could be. However, SSB Electronics products have a high price to go with the high performance. For 70cms I decided to trade down a bit. Another German company, SHF-Elektronik of Darmstadt make a more affordable range of pre-amps for both 2m and 70cms. The 70cms one, "Mini-70" looked just fine and that was the one I went for. To save cabling I used a Bias-Tee arrangement, this time from DK4MM.
Bias-Tee, SHF Mini 70 pre-amp and fitting kit

I know the theoretical benefits of having the amplifier at the mast head, though I am sure that in many situations it is a luxury many people will do without. I have been using shack pre-amps for years. However, as I was doing a new set-up putting the pre-amp at the mast head seemed worth it. The results are that all the signals I have copied so far disappear if I unplug the pre-amp.

Although the pre-amp has RF VOX switching I decided to fit a sequencer. I have bought the Down East Microwaves one. It is very compact in the supplied enclosure. Although in theory all I need is a breakout cable I have decided to mount it in an ABS box with the type of plugs I use on the outside of the box. I have all the plugs and sockets to do it now, but even though it is small it does not fit into my standard ABS box unless I leave the DB-15 plug case off it. Not wanting to be a bodger more than I have to, I have ordered a bigger box. The initial plan to mount it in a plastic food container which came with a Chinese meal has been rejected - but it was the perfect size.
DEM sequencer with 50 pence piece for size purposes
The mast head pre-amp does need to be sequenced, and some day I may add a linear amplifier too. Just with the pre-amp working in VOX mode I can see the SWR spike in the IC-7100 before the RF VOX works. The pre-amp is rated at 150W but even with my 20W I fear that one day the pre-amp will burn out due to the RF VOX delay.

Anyway except for the sequencer, which took a very long time to arrive in the UK and for the tax to be paid so that it could be delivered, everything was up and working. Then I found that my efforts to prevent TVI on 70cms had not gone far enough. Ooops. TVI was still there on 70cms (though not as bad as it was).

This is not really 70cms fault. For a variety of complex reasons the "Freeview" terrestrial TV signal we get locally is limited to a handful of channels. Not enough channels for the FVM household. Whilst more channels are available from the main transmitter at Selkirk, the minor ones are transmitted from there with 3dB less power. Our location is outside the Selkirk service area, and it is officially only served by the Eyemouth TV repeater, which does not carry most of the channels.

The underlying problem stems from the rather strange way the UK implemented the changeover to digital television. If you live outside the UK I suspect that this will sound very odd indeed. I'll not go into it further here. Suffice to say that after years of trying to get a reasonable signal from Selkirk I have given up on terrestrial TV. If like me you live in an area of the UK served by a TV repeater (rather than a main transmitter) your choices are very limited.

We could sometimes get a signal on the minor channels from Selkirk but for much of the time we had patchy reception. Often we could fill in the gaps with internet streaming. The final straw though was Mrs FVM trying to watch programmes recorded from Selkirk which had bad picture break up and finding that these programmes are not available via internet streaming. So we were sitting watching the television equivalent of a migrane headache appearing on the screen, with no alternative at hand. I mean, who doesn't want to watch "The Good Fight"? That Christine Baranski is a bit of favourite of mine ... not that my personal viewing is very important here.

So, simply to improve the number of channels we could see reliably we have installed a satellite system called "Freesat". In the absence of the correct wall bracket, my old T and K brackets which used to hold up the 6m beam and rotator are now in use to hold up the satellite dish. Given that the dish is very light weight it hardly needs such elaborate metalwork. The pole is a bit longer than necessary too but there wasn't the time to cut it. There might be room up there for a vertical on top someday ...
New Freesat TV receiving dish at GM4FVM on oversized brackets and with long pole...
More TV channels.

That's the reason. The fact that the previous very weak signal was overwhelmed by my 70cms signal was not the reason for spending good money getting us a satellite service. Oh no, amateur radio could not justify doing all that. Of course, this money was spent to improve the minor TV station reception. The fact that I can now run full power on 70cms on any beam heading (impossible before) has got nothing to do with it.

Oh no, nothing at all.

I wonder how many amateurs have been blamed for TVI when a weak TV signal was the real cause.