Sunday, 27 November 2016

PC crashed, PSU blew, and a core melt-down for me.

It's been a funny old month - and it is not quite over yet.

On Friday (it all happened on Friday!) the PC crashed. Finally, after loading more and more on to it, it just stopped. Nothing fatal of course, it just turned itself off.

My fault really as I have been loading more and more onto it. At one stage in the past I had two computers, one for what would now be the Internet programmes, and the other, faster one, ran the Flex SDR and data modes. This would have been fine had not the best faster one made slight but annoying noise on VHF. My numerous attempt to solve this failed.

Usually noise gets out of the computer via the connecting cables. This is something I am well versed in trying to deal with. I have established that some cables are reliable, and ferrite rings and clips are very effective. But with the fastest one nothing I changed outside the computer seemed to matter, and even the cables inside could not be silenced. It seems as if the noise is coming off the motherboard itself, though how it gets out of the computer case I cannot find.

So, I went over to one quiet computer driving two monitors. One monitor covers the Internet and email, and the other shows the data modes. This looks like two computers but of course all the processing falls on just one. I have worked like this for a couple of years.

Constantly adding work to this computer finally pushed it over the edge. I should have realised, because I was watching the processor load climbing higher, but somehow I kept putting off doing something. I seem to be good at that.

Nothing seems to have been harmed, though of course it might have been. In the past I have broken disc drives in crashes like this.

If all this sounds like I should learn a lesson, here is part 2.
=====================================
I have ordered a 5 element 6m PowAbeam yagi from dxshop to replace the Diamond HB9CV. This should be here in a few days.

In the meantime I dug out my old 3ele/4ele 6m/4m dual band yagi. This was stored in the garage for some undefined portable operation at some distant future date. It was a simple matter to make a 3 element 6m beam out of this and it seems to work well. It will do for a few days and it immediately proved to be more effective than the Diamond.

So I have been busy on 6m. The set-up is that the 6m linear shares a 50amp switching power supply with the 2m linear. This does not matter as they are both connected to the same rig and therefore cannot transmit at the same time. The PSU is a MyDel MP50SWIII, but you may recognise it as something else, as it appears under various brands in different markets.
The MP-50 photographed last year in happier times

Having had some success  on 6m for a day, I noticed the PSU making a noise. This was a rattling type noise, which became louder as the current drawn rose. This PSU has been making noises for some time, which did seem odd. I had intended to have a look inside to see if I could work out what was happening. I sat watching the ammeter at 32amps pondering the amplifier efficiency and maybe the rf power meter could be wrong, when the power supply blew.

Current had fallen to 6 amps, the noise stopped and I quickly turned it off. Quickly in my terms, but the damage was done.

I am aware that they can fail with a spike of voltage or current. I disconnected the linears and nothing changed, so it does appear to be the power supply at fault rather than the linears. I hope that the linears are not damaged.
The MP-50 - now in disgrace.


In an attempt to test the linears, I swapped things round and put in an Amperor 25amp supply instead. Both linears seemed to be working up to about the 100W output that was all I would risk.I do not want to blow something else.

I should have had some other 50 amp power supply to back up this one. Yes, I can juggle about my linears and get back to almost full power on all bands, but that is not really the point.  Any of the 25amp PSUs can fail and I have a spare. But if this one fails, 6m and 2m output drops considerably. You might think that the rig runs at 100W for 6m and 50W for 2m and that should surely be enough. Yes, when it comes to SSB that is true.  But for the data modes I use so much, the rigs simply cannot supply that sort of power on a prolonged basis.

I have linears, not so much to raise my power overall, but to provide a buffer to allow the same power to run on the high duty cycles of data modes. I do not run legal maximum on VHF: generally I only send 100 - 200 watts from the linears, from which you need to subtract line losses. On HF, I run a fraction of that.

Hey, I can live with this. Just find a new power supply and then fix this one. Then I will have a spare. In fact, I have a Sharman 23amp one which has died and been fixed twice. But during the downtime things are far from perfect. I think I should have thought that the strange sound coming from the PSU was more important than I did.

Why does a power supply make a strange sound? I had some inkling that this was coming and I did nothing about it.

Erm, a bit like the computer crash.
========================================
I have been very busy with antennas, masts and domestic duties. So, there are only 15 entries in the log book for the month to date (I do not log repeat contacts in GM or G-land). There certainly have been interesting things, but I will leave that for the end of the month.

The new addition to the skyline, the temporary 3 element 6m beam is working well.
Note the 4m element, which is carried over from its previous life as a dual band beam - it was too difficult to take off! Also, lots of spare coax for the yet-to-arrive 5 element.

I was surprised to have a call from Bo, OZ1DJJ, whilst beaming West on 6m meteor scatter. At the same time I was doing all sorts of domestic things and I committed the cardinal sin in amateur radio or replying to the wrong callsign (OZ1DZZ).

Thanks to David GM4JJJ for pointing this out. David saw that Bo was calling me on the KST chat page to tell me I had made a typo. I had indeed made a typo.

I should explain that I am not on KST. Yes, it would have alerted me to using the wrong callsign, but following KST just adds one more layer of complexity to my already crowded life. KST is both a solution to the complexity problem, and a cause of more complexity.

I suddenly realised that I was overdoing it. There were signs that I was trying to absorb too much information, process too many operations at once, and generally, trying to produce too much power from limited resources.

I should have seen the warning signs. I should have closed a few brain programmes and let my central processor cool down. Instead I battled on and got my callsigns mixed up.

Not that I actually mixed the callsigns up, I just did not think about it because I was thinking about something else at the time. Not a deliberate act, a loss of concentration. Trying to do too many things at once.

Is this sounding familiar? Did I ignore the signs, just as I did with the PC and the PSU, that I am overcooking everything? Yes probably.

I am not about to give up radio, but I do need a reminder sometimes that I tend to over-complicate everything, to the point of overload. You will all be surprised to hear that.

The PC crashed and the PSU blew after I lost track of that QSO, but on the same day. So I cannot say that there was some deep spiritual connection between all this, the warnings of which I had ignored. But it all shows that everything has its limit.

This is only a hobby. It can become an all-consuming passion which fills the mind, empties the wallet and causes you to forget what is important in life.

I am off to let my internal fan reduce the temperature of my overheating regulators.

(IRONY WARNING): There must be a lesson in all this, but maybe I will just ignore it. That strategy has worked for me so far.

73

Jim
GM4FVM

Wednesday, 23 November 2016

More antenna work, introducing MSK144 and streetlights

This mast has turned out to be quite a struggle. It has needed a lot of tinkering, tightening and adjusting. More of that later, no doubt. But I will get there eventually. It may be built down to a price, but I still reckon it is the best solution for me right now.

Actually putting an antenna on it turned into farce, of course. The idea was simple. Just transfer the rotator and 6m antenna which used to be on the temporary mast onto the new one. Then put the Moonraker 6m/2m/70cms vertical on top. Job done. Well, for course it was not like that.

I have written a complete report, but I will spare you the details. Trying to get it done before the RSGB 6m UK Activity Contest was a target of course. An excellent test. Two days work, in freezing conditions, rain, wind. I am not asking for sympathy. You can just be amazed by my pig-headedness.

I should say that the TV rotator can only take a 35mm pole, so everything was organised around that fact.

It took a day to get the previous set-up onto the mast and get a photo of it before I put the mast up.
It is not much of a photo due to the lack of light, but note the frost on the ground. I had just lined the HB9CV with North, by turning rotator and lining it up level with the ground with a small correction for the fact that the house is a few degrees off East-West.

So I put the mast up and the rotator failed.

At first I thought it was the cable, but more work proved it had just given up. TV rotators are not made for a long life. They only fail when you rely on them.

It did not take long to see that I had to give up the plan to use the previous set-up until next Spring, when I planned to put up my Yaesu rotator and a better 6m antenna. So I had to face doing all the work again, but this time with the Yaesu rotator, 6-core cable, and a 50mm pole above the rotator. That should be OK, as the vertical was bought to fit 50mm pole. Plus, all the other kit was in the garage ready, waiting for Spring.

After another day, I was standing in the gathering gloom, with frozen ground under my frozen feet, almost ready with the new set-up. Just time to fit the vertical before it gets dark.

Then I discovered that the vertical does not fit a 50mm pole. Nothing else for it, I had to dig out my Diamond X-30. Half the length of the tri-band vertical, and as it turned out, it works better too. And I fitted it, helped by the torch on my mobile phone.
It looks the same. But everything has been done twice. Two lots of cable pulled through, and one pulled back. Two verticals fitted, one removed, two sets of waterproofing PL259 plugs and sockets done, one pulled apart. Two beams fitted and lined up, one removed again.

Another hour's work in the house got the rotator controller as far as my desk and I was ready for the contest.

This was one of the worst contests I have ever listened to. I only heard two stations, and neither was calling CQ. Total result = NIL.

Well, it is not all bad. After the contest I worked DM2ECM on 6m meteor scatter MSK144. More about MSK144 later. But it is all working now, and I can turn the rotator.

So what is this long tale meant to convey? Well, that I am a determined old toad, ready to get cold and wet. It shows that this hobby can drive normally sensible people to do mad things in the winter, and then do them again the next day.

BUT, it also shows what I can do now without climbing. It was all done from the ground or from a three-step handy folding stool. Hooray! I'll get as cold as I need, so long as I don't have to climb to do it. I am too old to climb.
=====================================
MSK144 is a new mode from the Joe Taylor stable. It is designed to improve upon the performance of FSK441 on meteor scatter. There are new versions of the WSJT-X suite including this new mode.

MSHV has been updated to include the new mode.

There are other new modes for Earth-Moon-Earth and other propagation methods too.

At the moment the latest modes are still in the process of completing development, and new versions are being issued as bugs are identified.

I do not have space here to say more, so I will leave it for later to cover it in more detail. But it is clear now that things we used to think were really difficult, like meteor scatter, have been revolutionised. This revolution continues. Nowadays the average amateur with moderate power and fairly simple antennas can communicate efficiently using the WSJT-X suite, whether it be in HF with JT65, or EME with QRA64.

The days of using tape recorders to speed up morse are long gone, the days of building massive linears and huge antenna arrays are coming to an end. WSJT-X and its clones are remarkable.
=======================================
Scottish Borders Council, our municipality, has started a programme of replacing sodium street light elements with LEDs. This has obvious advantages for the council. The new lights have longer lives, need to be maintained less often, produce (almost) white light, and consume a lot less energy for a given light output.

For an amateur, the prospect of have a street full of LEDs outside the shack is a bit scary. That is why I asked the maintenance team about two months ago if we were due to get the new fittings. No, they replied, they are busy elsewhere and it would be a year or more before the change-over happened.

Thus it came as a complete surprise when they fitted the new lights, completing the whole street using the existing lamp standards in a day.
This photo shows the street now looking like daylight. The new lights are VERY effective.

I suspect that they used some of the reduction in power consumption to provide some headroom to raise the light output level too.

I was in fear of the consequences for noise on my radio. I have a very dim view of LEDs in general. We have very few, and those that we do have are either far away from the shack or rarely used at the same time as the radio. So having a street-full outside my control was a worry.

I need not have been concerned. There may be a slight increase in background noise. I cannot measure it, so it must be very low. I can cope with that. There are no terrible consequences on the bands that I use. Or at least none that I have found yet, and I have looked.

Even the sodium lights caused noise, but only for ten or fifteen minutes when they were starting up each night. This actually seemed to be better.

Lets hope that I see a reduction in my local taxes to pass on the savings to me. I am not as troubled by noise as I thought I might be at this stage.

I know that LEDs need not be a problem if they are properly installed. It is good to find some that are.

73

Jim
GM4FVM

Tuesday, 15 November 2016

New mast up at last.

Firstly thanks to those of you who posted and e-mailed about the listening station featured last time. There may be more news on this in due course, but otherwise feel free to add anything more which strikes you.

Gary, MM0CUG, arrived today and installed my new (second) mast.

Firstly I had better explain the background. After a couple of incidents I decided that the second mast I had mounted on T and K brackets on the gable end of the house was not practical for me any more. I am getting too old to go out there and climb, plus it is in the full blast of the wind and there are few days when I can work in the wind at height.

My main mast is a fine Tennamast, but I cannot add more antennas to it without exceeding the capacity of the rotator, or breaking the space constraints and overhanging next door's garden. Apart from that, I am limited to having antennas which are not visible from the road when the mast is cranked down, and adding more antennas would break that rule. I have broken it briefly from time to time, but really I want to be invisible from the road in front of the houses for most of the time.

Thus the second mast appeared almost as soon as the first one went up, to start with for a 4m vertical and then soon after for the 6m beam. This makes for great flexibility working 4m/6m openings, as I do. The two beams often point in different directions, and the inverse square law resolves most overloading issues (though I do have stub filters too). I am thinking of replacing the stub filters with lumped component filters, but a bit of space between the antennas always helps too.

So I wanted to have a tilt-over mast to replace the second pole. The object of the exercise was not to significantly enlarge the antenna farm, though someday a better 6m antenna than the HB9CV may be on the cards. Rather it is to get access to the antennas from the ground. The ground to the top of the ridge tiles is 5.2 metres. I drew up plans for various systems based on home-brew components. I have some winches, all the poles and so forth, but eventually it looked like a purpose-built solution would be stronger and simpler. Once I added up the cost of the bolts, brackets, hinges, concrete base, etc.,  and then I began to doubt my strength calculations, I moved on to the idea of square section inside square section (just like the Tennamast!). That would have brought the cost of changing everything else as well.

Eventually I settled for a simple aluminium tilt-over, crank-up mast by MM0CUG http://www.mm0cug.co.uk/ . Gary does a range of masts, the smallest (which is square section all along its length) is a 10m mast which is 5m when lowered. This is exactly what I needed as 5m, plus the rotator and poles, brings the HB9CV just over the ridge tiles. I then have the vertical on the top, but even that is not visible from the road. Gary has a 12m mast and various other options, such as steel construction. While steel would add more strength and also cost more, I have modest requirements for the antennas. This is, after all, my second mast. So I settled for 10m and aluminium, basically for cheapness, but really because that is all I need. My main mast is 7.2m fully extended, so this is potentially taller, but as I say, I doubt if I will extend it much, if at all.

I did flirt with the idea of another Tennamast, but that would be over-engineered and more expensive. Gary's mast bolts directly to the wall, needs no concrete base, but I suspect, is not as strong as a steel Tennamast. It is horses for courses, and there is no need to spend more money on a stronger mast when all I am doing is replacing a pole on a couple of wall brackets. Gary said his mast could take my mini-beam, so I have plenty of strength in reserve if I need it.

So anyway, it has taken this long to install partly because it arrived while I was away in Italy. We thought it was best to leave installing it until I was here. Gary delivers and installs his masts throughout the Britain and Ireland during runs at fixed dates, so I had to wait for the next delivery round. No problem there. It went up today in about an hour and a half.
You can see that it is neater than the previous muddle of wires and poles. As expected, it sits at just the right height above the ridge tiles. Surprisingly, once the rotator and the beam are mounted up there, just as before, this will not be visible from the street in front of the house. I am basically keeping the same antennas and only altering the mast which supports them. Of course it can be cranked up to double the height, but that is not my intention.
The fixing arrangements are entirely different from the Tennamast as shown in earlier posts. A length of square section is fixed to the wall using six bolts in the form of a large bracket. The mast itself, also square section with the extending section inside, is hinged to the bracket by a single pin, and retained by a clamp with a removable pin. Remove the clamp pin and the mast tilts, supported by steel wire and one winch. The other winch raises the inner section. Simple really.
It doesn't look quite as elegant as some other masts, but it seems to work.
The winches are very strong for my purposes, and probably standard for larger masts too.

Now that it is in place I can think about getting the HB9CV and the 2m vertical on the top. I may leave that set-up, with the Conrad TV rotator, in place until the Spring when I might be able to get up a better 6m antenna and the Yaesu rotator up instead.

So, lets see how it goes. It looks like it may rattle in the wind, like any extending mast. Having said that, I can see how a couple of wedges would lock it up and prevent that.

All I need to do now is get the antennas and rotator installed, plus the co-ax extended, ...

Happy Radio.

73

Jim
GM4FVM

Sunday, 6 November 2016

Galashiels Rally and World War 2 listening stations

I mentioned that I visited the annual Galashiels Rally recently. It has been a few years since I went, and in the intervening period several old regulars can no longer attend. If we do not recruit new members to our ranks the amateur population around here will eventually fall to zero.

Still, there was still a fairly good crowd coming from a wide area. The stalls are always interesting, and I bought a few odds and ends ranging from used re-chargeable batteries to crocodile clips. Where do you go for things like that nowadays?

I will not be going back to the retailer who sold me two Panasonic AAA alkaline industrial cells when I asked for rechargeables. They are perfectly good batteries, and I will use them, but not what I asked for. The old AA rechargeable ones are fine though.

As usual you meet lots of people at such events. In fact, meeting people is the real purpose of going for me. One such was Bruce, GM4BDJ. Bruce gave me a photo, apparently taken by David GM3BFU (SK). It is dated 25 December 1945 and has written on it "H/F D/F", or high frequency direction finding (or Huff-Duff as it was called).

Now Huff-Duff was the cutting edge of technology in the late 1930s, though as World War 2 progressed it was steadily overhauled by VHF and UHF radar. Nevertheless, it has its uses when it came to finding clandestine transmitters or locating shipping traffic. Huff-Duff continued in use up to around the 1970s, before satellites and frequency-hopping rendered it more or less obsolete. Not completely obsolete mind you, but it is a lost art now when it comes to intelligence work.

Here is the photo Bruce kindly gave me, with some notes added by me.
It is not very clear, and I have further affected it by scanning it in, but that is the only way to get it onto this blog.

On the left we can see two HRO receivers. Next to that is a Cathode Ray Tube display, which would have been pretty high tech and expensive at that stage. In the centre is a classic Bakelite telephone, two sets of HRO coils (marked M and W). To the right is a loudspeaker, oddly, as listening stations used headphones. Below the loudspeaker is something difficult to make out but it might be a small domestic radio. Note the blacked-out window and the wall construction (it seems to be a solid wall rendered with plain plaster).

To me, the presence of two HROs makes this look like a WW2 listening station. No amateur of that era would have had such things until they appeared on the surplus market. In any case, although some mysterious German amateur stations remained on the air during the War, in the UK amateur activity was officially forbidden. So I doubt if we are looking at someone's shack. This appears to be official premises. 
 
The CRT display was described by someone as "looking like a home made oscilloscope". I very much doubt that it was home made, but rather an austerity "Supplied for the Public Service" type-model. I also doubt if it is an oscilloscope. Such a thing would have been confined to high-end RF research, not sitting beside a receiver in some out-station. Rather I think it is a display for direction finding (or some rudimentary radar). Early in WW2 "DF" (direction finding) equipment usually had mechanical readouts, but later CRT displays became more common. After all, although the theoretical idea of the CRT was the best part of 40 years old at the start of the War, the practical and widespread introduction of such exotic valves took the impetus of war to push forward (note the huge cost of pre-War television sets!).

So to my eye anyway, the H/F D/F comment on the back of the print looks to be correct. But how dare a serviceman (presumably) take a photo of such advanced equipment? Maybe by 25 December 1945 he thought it was all over. It wasn't over, and he was taking quite a risk with this photo.

Looking a bit more closely, there seems to be a morse key in front of the telephone. A listening station hardly needs a morse key - reception reports travelled out by land line which would surely have been telephone or telex. Huff-Duff stations would not normally have been taking down the content of messages. They would have been getting a bearing as part of a wider effort to get at least three or more bearings and thus triangulate onto the position of the transmitter. So why have a morse key, if that is what it is?

At the time, late in the War, Huff-Duff would still have been useful looking for "spies", survivors of downed aircraft, submarines, ships or any enemy traffic which would allow a location to be pin-pointed. Even intelligence coming from Allied spies and implanted agents had to be subjected to Huff-Duff to check that the station had not been captured by the enemy and moved to more friendly surroundings (from their point of view!).
 
It was apparently possible for good Huff-Duff operators to get a bearing on a signal as short as 10 seconds or less and get the information anyway down the line to HQ within a minute. There is no sign of the paper and writing equipment you would need to copy down the messages, so direction finding seems to be the game for this set-up. If there are headphones which we cannot see, some identification details of any messages would be included if possible, and a paper log kept.

Aside entirely from the mysteries of the display, the key, the role of the equipment, etc., the location seems particularly intriguing. There was a chain of "Y" stations which used Huff-Duff. Often they were in former pre-War GPO listening posts or in remote and hard to spot locations (hiding in plain sight). Often the vertical antennas were mounted in wooden mast, and the stations located in either wooden sheds or tanked underground. They were definitely not conspicuous or large. In the photo though there is a window, which has been blacked out. I doubt if a window would have been added to a purpose built station, just to black it out. Windows in buildings where you are figuring out the enemy's secrets are not common. So was this an existing building into which a listening post was installed?

There has been plenty written about the "Y" stations (you can look them up on Wikipedia). However, the exact methods used are still a mystery to me. I have read out goniometers and phased verticals, but the actual physical set up is still confusing to me. At this stage enter Roger, MI0WWB, who is interested in the former Y station at Gilnahirk. We can perhaps gain a little knowledge from Gilnahirk as it continued to operate into our lifetimes whereas most other stations disappeared after WW2. Roger wrote ...

Gilnahirk, nestled in the Castlereagh Hills overlooking east Belfast, was one of Northern Ireland's best kept secrets.  Opened before WW2 it continued in active service right up to 1978 as a secret listening radio station.  It's work was classified secret and few people were aware of its existence.

A collection of wooden huts originally built by the GPO as part of the Radio Security Service it was quickly militarised being put under the control of MI8; it was quickly transferred to MI6 as part of the Special Communication Unit and later through reorganisation it became part of GCHQ.  During the war its role was to intercept transmissions, record the codes and to relay them to Bletchley Park for decoding.  Other tasks included direction finding to pinpoint the location of transmissions.

Gilnahirk played a significant role in intelligence gathering during the war and well into the Cold War period.  It played a role in the famous operation mincemeat and in helping to locate the German battleship Bismarck.  This work was augmented by Voluntary Interceptors throughout the UK, as many as 1500 radio amateurs, who used their own listening equipment to record data and forwarding it on a weekly basis to HQ.

The Station's importance was demonstrated by a new and enlarged station being built and opened in 1952, with antenna arrays established in the fields around the location.  This is the station I remember as a child, it continued in operation during the cold war right up to 1978 when it closed, becoming obsolete with the development of new technology. 

So, we know there were well established stations like Gilnahirk, and we know that there were Voluntary Interceptors, but yet Bruce's photo looks to me like some intermediate arrangement. No amateur would have had such complex and modern equipment in their shack (as far as I know!). So is it a photo of a Y station? The substantial walls and the window make this look like a converted building, not the low profile look of a Y station. What is the key for? What is the display for?

The fact is we shall probably never know.

But it interests me all the same. I, like many of my generation, were amazed by F. W. Winterbottom's book, "The Ultra Secret" when it appeared in 1975. I went straight to the library and devoured it. The secret surrounded the cracking of the Enigma and other codes during WW2. The book has various flaws, but it opened the door to a secret which had been carefully held by the people involved since 1945. I think some of them might have frowned upon the photo we have seen taken on 25 December 1945. Nevertheless, Huff-Duff is not directly to do with code breaking. Vital in an indirect sense, and in a way we never understood until even more recently.

During the long periods before the high-level German codes were cracked, and during quite long periods whilst the code-breakers had to re-crack the codes, the Enigma and other codes were incomprehensible. All the signal intelligence community had to work on were the Huff-Duff and traffic volume reports. Even without the code, the signal intelligence experts learnt how to deduce lots of important information just from these reports. Of course, it was better when they could read the code, but there is a lot of information hidden inside the direction and traffic volumes.

Many wonder why the enigma secret was so well hidden when the basic technology was outdated at the end of the War. Well, in part it was to continue to hide this other secret. To this day, the modern equivalent of Huff-Duff is a major part of signals intelligence. When we hear from reports of "whistle blowers" that the security services are following billions of emails and phone calls, you can bet that they are not listening in to them all or reading every one. No, their first line of enquiry is, how much of this is there, and where is it coming from? Which is what someone sitting at that listening post was doing during World War 2.

So at this humble station, we know-not-where, the momentary lapse in security which took the photo, our memories of shadowy places like Gilnahirk, raise more questions than they answer. The questions may never be answered as the basic task of signals intelligence in finding out "how much and from where?" remains vital to this day.

Thanks to Bruce and Roger for their input.

We as radio enthusiasts look at the equipment, and we lose sight of the actual task at hand. This is very useful to the spooks. Maybe it is just as well if we never really know the answers.

Luckily, as I do not know how to put the question, the answer may remain shrouded for ever.

73

Jim
GM4FVM
P.S. Was the operator left handed?

Friday, 4 November 2016

A little bit of band action, antennas down, and Gainmaster replaces Gainmaster,

I had planned to write something about computers and EMC, but that seems to be taking longer than expected. So here is a round up covering what has been happening chez FVM.

There have been a few short openings here on the VHF bands, notably an aurora on 25 October. Not a large event but nice all the same. On 4m I worked GI4OWA (again!) and G8VZT, both on SSB, and LA9BM on CW. I am trying harder with CW, particularly during aurora.

Towards the end of October there was a period of high atmospheric pressure. As I do not get out well on tropo to the south I had to wait for an opening in other directions. On 30 October I worked  Denis EI4KH via the Mullaghanish repeater on 145.750, in County Cork. The distance to the repeater from here is 628km and nicely positioned at South West and clear of the hills at my end. I could not raise anyone else either on the repeater nor on simplex. I did however work Derrick, GM4CXP, in Kelso, also via the Cork repeater. I also worked Eamon, GI0BDX on 2m SSB.

On 31 October I worked OZ5NJ and OZ1BEF on 2m SSB. Once I had realised that I was not beaming the right way, and conditions came up a bit too, I was hearing them both almost 59. At 664 and 704 km that is good for tropo for me. During the same event other GM stations with a clear take-off to the South were working into France. I have to take the rough with the smooth. OK, I do not hear stations in that direction, but I do well enough in other directions.

HF has been quite good too, despite the sagging solar index. The same heightened solar activity which pepped up VHF has been good to 10m. I read all the woe and misery in the band reports about high K numbers, but never a word is spoken about the Es this can bring on 10m (and 6m). EA3LX was worked on 6m 15 October when I was running up and down the bands following the variable MUFs caused the fluctuations. The 10m Es in this period were very nice, bringing in several far-away Russian stations such as RN6AM (KN95 3086km) and RX6DF (also KN95, 3096). I doubt, though, that Es was responsible when I called CQ on 10m JT65 and immediately worked VU2PCL in Bangalore (MK83 8090). That, I suspect, was just being in the right place at the right time. Likewise on 31 October I was appreciating the 10m Es by working EA3GJO on JT65 when I worked PU1KDX (GG87 9565). This followed PY4XX (GG88 9458) caught in similar fashion on 27 October. Best DX on 10m was CX8ABF on 17 October (GF15 11301).

Who said 10m was dead? (FVM never gives up on projecting his own sweeping generalisations onto others, does he?)

These things go to show two points. Es is around a lot, and like the same period last year, it is easy to see the link between enhanced solar conditions and bursts of Es. Then again, if you are around enjoying the Es you might work VU or PY alongside your other activities. The secret, as always, it that to work people you need to be on the bands. Sitting watching computer screens just does not do it.

40m produced the same batch of surprises as it has done for some time. With my lowly dipole I have been hopping round Europe, adding the more distant W8FHF for good measure. Calling CQ on 22 October brought back VK5ZK (PF94 16303), a surprise at just 20:32 on JT9 mode. 40m continues to amaze me.

Meteor Scatter has not been great here. I worked OZ1JXY and SP9HWY on 4m, but conditions were not as good as I hoped. The Orionids did not produce much of a peak.

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I have taken down all the antennas on the gable end of the house extension. This involved removing the 4m vertical, the 6m beam and the 40m dipole. Also removed were the rotator, the brackets and the guy wires. I am still in business with the 2m and 4m beams, plus the 10m and 2m verticals.

This all stems from the realisation that climbing and using wall brackets is not practical for me any more. Supporting the weights involved is no longer something I can do on a regular basis. So I have decided to go for a second tilt-over mast. That might sound a bit excessive, but I have no intention of putting up any more antennas. I just need to be able to work on them from the ground now.

Although the new mast can be cranked up, I do not intend to raise it above ridge tile level (5.2m) plus space to turn it. Once sorted, the 6m HB9CV will go up there, with the 2m vertical re-located from the other mast. I am not sure if the 4m vertical will ever go back up given the collapse in activity on that band round here.

So it will look like what has been up before, with the 2m vertical replacing the 4m one, and without guy ropes and so forth. I can hang the 40m dipole from it too. It should reduce the ragged appearance of all the guys and rationalise two masts into one. Maybe later I will put up a rather better 6m antenna, but that is not crucial.

It looks a bit bald, after I used the scaffold tower to remove all the clutter ...
I will have to manage without 6m and 40m until the new mast is up aloft.

Maybe soon I will not need the scaffolding tower either...
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Part of the same anti-clutter movement, also intended to make things look less conspicuous and more robust, I have changed my beloved Sirio Gainmaster vertical for a Sirio Gainmaster HW vertical.

When first released the Gainmaster had just one version - a 5/8th dipole, end fed. This is what I view as the ideal 10m antenna, requiring no radials and capable of working reasonably well on 12m. However, the years have passed and Sirio have released a half wave version, the HW.

I have been very happy with the original version, save for a couple of points. It is very long. In fact, in old money, 28 feet tall. This is high enough to be seen all round the village. Also, being fibre glass, it whips about a lot in the wind. We get a lot of wind here, up to 130km/h and more. So it is not just large, it is whipping about like a demented bamboo cane.

The Sirio instructions advise that the original version should be guyed in high wind locations. I am very reluctant to guy it as I already have guys for the 40m dipole and it might just attract more attention to it. So the half-wave version, which is "5 feet" shorter looks like just the job.

I have remarked before in this blog that it is very difficult to replace a good antenna with a less good one. It is hard to step back from performance you once had. All the same, I am doing it in this case. I know that the HW Gainmaster will not perform as well as the Original. But I have a need for something smaller, less wind attracting, less conspicuous and with most of the performance. So the HW it had to be.

The two antennas are constructed much the same way. The HW does not need the tuning arrangement in the middle, and only has three fibreglass sections. It is easy to construct, with the sections joined together with "Jubilee Clips" (aka worm drive hose clips).
The photo shows it stretched out before assembly (as usual, click to enlarge if necessary). The internal cable can barely be seen above the lowest section. You feed this through the upper fibreglass tubes and cut to length.

There is a table to show how to set the length of the upper sections. I set this for the bottom of the 10m band, allowing some extra for a later fine cut. Once connected I got a very strange reading from the antenna analyser in the shack which showed a resonance below 10m and a stronger one above , at 32MHz. Once I left out the co-ax from shack and measured the resonance at the antenna, this top resonance disappeared, so there is something wrong with the co-ax. I have wired it up as roughly cut and I will run new coax later.

It works. I have already been using it on 10m. Unlike the Original, it cannot be seen from the street. However I am not going to kid myself. This half wave version is never going to work as well as the 5/8ths one. In general terms, less wire means less performance. The angle of radiation will be higher and the efficiency lower. Not much mind you, maybe a couple of dB, which I am willing to accept for now.

I have taken the 5/8th Gainmaster apart and it is in the garage antenna mortuary. It might yet come to life again and see the light of day, later.
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That is it for now. Since we last communed I have visited the Galashiels Rally and I hope to say more about that later. For now though, as the great Edwin Starr might have wished you: Happy Radio.

73

Jim
GM4FVM