My absence

 Ooops. Sorry I have not posted anything since August.

I have been back down the A1 for another operation at the Spire Hospital in Washington.

GM4FVM with many added painkillers at the Spire Hospital Washington (again)

As I have mentioned before here, this was a gearbox change and it involved a full knee replacement.

I had fondly thought that this type of operation would not really affect my radio activities much. Sure, it was painful but what would stop me sitting at my desk using the radio?

ANSWER:- Hamstring and quadriceps muscles take along time to get better.

To begin with I could not sit in the shack at all. Even now, more than three months later, I cannot sit in the shack for too long.

All is not lost though. Lately I have been able to participate in a few contests, for a few hours at least.

Also thanks to various people who have accompanied me to events, I have been able to attend some gatherings.

I can operate the radio now and things are gradually getting better. 

At first I could get about thanks to a stick. Now I can do without the stick for most of the time. However the stick helps to get a seat on the bus.

GM4FVM on a bus in Edinburgh (possibly an image on wall beside GM4FVM himself). Photo MrsFVM.

Hopefully soon I will be back in full operation.

73

Jim GM4FVM

Another high quality piece of engineering from GM4FVM

As Homer and Marge Simpson once sang in a duet ...

"Do a half assed-job -- it's the American way"

Most US products I have are quite well made, so I doubt if that is true.

However, I am following one of Homer Simpson's examples when it comes to warning lights.

Homer used to be bothered by the warning lamp on his car dashboard. So he cut off a piece of insulating tape and stuck it over the warning. After that he could drive about untroubled.

When I made control boxes for my sequencers I ran out of green LED panel lights. These simply show that power is heading for the masthead preamp, but they are very useful for fault finding. Really, they should be green, but when I ran out of green ones I used red ones, and then I ran out of red ones too.

Solution - repurpose an LED lamp intended for a non-radio project. Sadly this was white and very bright, even from the back of the shelving where these things live. 

I made a note to put a higher value resistor in circuit to get the illumination level down a bit.

Fast forward to now and I have other things to do. So I have adopted the Homer Simpson solution. I have stuck a piece of red insulating tape over the white LED. Wonderful. I now have a pleasant low intensity red glow. 

Homer used opaque black tape, I used slightly transparent red wonder tape so that some light might escape. I have finessed his great idea.

1296MHz sequencer at GM4FVM now with red insulating tape "lens"

I have of course done a full risk-assessment of this user-initiated modification of a user designed and built module. There seems to be no apparent heat present which might shorten the life of the adhesive on the new "colourised self-attached lens substitute" as I now call it. I do not have a full data sheet on the red tape, but as I have had that tape for about 15 years I think it can be used under "grandfather rights". The critical fail state would occur if the tape falls off and the corrective action would be to stick in back on again. The critical consequences of failure would appear to be quite small.

If it does fail I can always take it back to the Maplin shop in Dalry Road in Edinburgh and get my money back [it closed years ago Jim].

I suppose I could trim the tape up to precisely fit the LED surround. Hey, that is a further task to be scheduled for some time in the future.

What a pity that I had already used up all the green tape in that Maplin package. Maybe I should nip down to Edinburgh (2 hours each way in the bus) and buy some more.

Now, off for my next challenging job.

73

Jim GM4FVM

Sporadic E and geomagnetic storming.

This is what Solarham (see sidebar for a link) stated:-

"Geomagnetic Field and Aurora - Past 24 hours : Storm."

This suggests to me that an aurora is possible though there was no enhanced propagation of that type noted at GM4FVM. There were however some auroral contacts by stations to the east of me.

This is what I have termed in the past a "geomagnetic disturbance short of an aurora". And frankly these are the ones I am really interested in.

What there was turned out to be a lot of Sporadic E propagation.

Once again this posting is about the close correlation between disturbed solar conditions and enhanced Sporadic E events. I say "once again" as that was the theme behind eleven postings on this site dating back to 2015. You cannot say I have not been banging the drum about the fact that I use sites like Solarham, NOAA and NASA to predict likely Es openings, and then I switch to the magnetometers of the Norwegian stack, GM4PMK and STEREO to monitor the events as they unfold (links in sidebar). 

One of these postings, in 2017, was titled "Using aurora warnings to predict Es". I think it is clear what I am doing. Meanwhile my national society the RSGB continues to bleat on about Jet Streams and make predictions based on terrestrial weather which simply miss entire events.

Therefore you may already have noted that for years and years I have been pointing out that Es is often to found when there is geomagnetic disturbance. You may already be bored by this. Still, here I go again with an even bigger and more conspicuous set of events.

During the peak Es season, say in June, it is not easy for me to see the link because there is just too much Es around which may hide the opening. On the other hand during the least Es activity, say during February, increased activity on the Sun may not open a band which is firmly closed. 

As radio amateurs what we are hoping for at other times is for enough energy to be imparted to "push the ionosphere into producing a Sporadic E opening". My words.

I often see these openings most clearly during the shoulders of the season. April and early May plus late August and September. That is when I believe that geomagnetic storms show that they can produce unexpected Es. At other times it is no so clear but I have posted occasions when I noted that it happened.

There was no Es worked here between 11 August and 17 August. No Sporadic E here at all for a week. The Es season seemed well and truly over.

Then on 18 August a geomagnetic storm reached us, which in my book indicates that Es may be just around the corner. Solarham had issued a warning well in advance.

It is difficult to work out which day the results of the coronal mass ejection might arrive and a second event warning was issued the following day - actually a multi-event warning.

So there were in fact several events on the sun which sent mass ejections earthwards. They generally pass first with a shockwave and then later with a geomagnetic storm which I believe set off the Sporadic E events.

The following image from the GM4PMK magnetometer show the first storm followed by the second shockwave.

GM4PMK magnetometer readings for 18 August 2022

What I would have expected during a period when the planetary index reached K5 as seen here would be an Es event. And here it is as seen at GM4FVM:-

50MHz contacts at GM4FVM on 18 August 2022

My first contact was at 13:09 but it really started to hot up at 19:05 and continued to 20:23. 9H1TX was a new DXCC on 50MHz and a new square for me. After the shockwave I decided to pack it in as that seemed to have ended the event, but I expected things to carry on the next day, which turned out to be the case.

I started on the 19th at 06:00 and the contacts continued until 09:47.

Here is the map of contacts on 6m for both days:-

50MHz contacts at GM4FVM on 18 and 19 August 2022

So in a period less than 24 hours I worked 43 stations on 6m, in 36 squares and 14DXCC. ODX was SV3AUW in KM17 at 2770km.

The PMK magnetometer did not show much effect on 19th but the ionisation from the previous day seemed to continue. Perhaps one of the clearest signals of what what happening was given by Solarham which showed the planetary index at K5 coinciding with the times of the opening.

Solarham storm warning and K index on 17 to 19 August.

It seems to me that Sporadic E openings like this are more likely to be related to geomagnetic storm conditions than purely to the K number. Of course those two are closely related but from what I have observed disturbed conditions seem more likely to produce Es than even strong but steady streams heading from the Sun. The proton and X-ray recordings also seem very reliable indicators of useful events on the horizon, as shown in previous postings.

So what causes Sporadic E?

Nobody really knows.

The ARRL handbook refers to possible metallic particles in the E layer and to wind shear. It seems likely to me that the particles become ionised under the influence of solar streams and form a layer located by the Earth's magnetic field. Once suspended it seems inevitable that movements in the atmosphere below the fixed layer (wind shear) will organise and enhance the layer. That is what I make of the ARRL handbook's explanation and it seems to make sense to me.

Reference to metallic particles is sometimes linked in the literature to these molecules having their origin in meteors. This theory does not relate to the ionisation created when we amateurs use scatter propagation during meteor showers. There appears to be no link between meteor showers and Sporadic E. The particles possibly implicated in Es are likely to be from the random accretion of material by the Earth which becomes ionised and formed into the E layer by the processes set in train by the geomagnetic disturbance. That is if meteoric material is involved at all - this seems to be speculation (like so much about Es).

During the peak Summer season there is enough ionisation in the ordinary course of events produced by UV and other radiation for openings to occur regularly. I see a pattern that during the Autumn and Spring geomagnetic disturbances can produce enough additional ionisation to cause periodic openings when otherwise things are quiet.

And as predicted on Solarham  on 17 August, the arrival of several solar steams over a number of days was likely to produce several openings as this table shows:-

Solarham forecast for 3 days plus results for previous days.

The pattern of raised K number shows a close correlation with my log book. Es occurred when the K level rose to 4 or 5.

I cannot continue to report on the events of these repeated disturbances so I will summarise the four days up to the end of play on 21 August. During those four days I completed 100 QSOs into 25 DXCC and 72 squares, compared to the previous four days when the total was zero. That was just on 6m, I worked some on 4m too. Before that there was a week with no Es here. Once the event is over, be it today or another day, no doubt there will be a week with no Es, and geomagnetic activity will eventually subside. In my mind that means 6m Es is closely related to geomagnetic activity.

I have been posting about these openings being related to geomagnetic disturbances on this blog for years. It has stopped surprising me and now I use the signs as predictors. I do not use the other much touted "predictions" produced by the great and good of our hobby, largely because I find that they do not work.

I believe that Sporadic E is caused by a combination of many factors so a simple explanation may never be found. This mechanism seems to have some effect, but I am pretty sure that it is only part of the story. However, I cannot ignore the coincidence of these events and this result:-

50MHz contacts at GM4FVM 18 to 21 August 2022

It is not certain exactly how this works, so I just accept that it does. However, one thing I am pretty sure of. Earth wind systems such as the Jet Stream seem to have no relation to Es openings as seen from GM4FVM. I have looked into the Jet Stream theory for a long time and whilst there may be some connection it looks to me that Jet Streams have no "cause and effect" relationship with Es and have no part to play in their predictability. On the other hand, I got the first warning of these openings on 14 August. That satisfies me that, at least in Spring and Autumn, keeping a watch on disturbed solar conditions is a good guide to finding Sporadic E openings.

73

Jim

GM4FVM and Aurora

Now That's What I Call A Tropo Opening (Number 115)!!

Hot on the heels of the Es opening, along came a Tropo one.

With the UK experiencing a long hot dry spell, another high pressure system arrived from the Atlantic to cause more scorched grass at GM4FVM.

As predicted in the last posting, where I reported DX in the shape of hearing Belfast Coastguard again, even more DX came along with the first reporting here of Holyhead Coastguard in Wales. Ah, a new ... well ... whatever you call VHF marine band DX. And for a time the entire VHF marine band was filled with Danish and Norwegian coast stations which are a bit harder for me to identify.

Amateur radio was also the beneficiary of all this enhanced propagation. Things had hardly begun when the RSGB UKAC 432MHz contest took place on 9 August. Conditions were a bit better than normal but my time at the microphone was limited and I worked only six stations. Maybe only six, but they were stronger than usual.

Dick, GM4PPT in IO75 asked "where have you been?", the answer to which should have been "hiding behind the Southern Uplands range of hills". The path between here and PPT is very tricky even though it is only 153km. My log, which is not very accurate when it comes to contests, suggests that it is eight years since I worked Dick, and it takes a lift to make it possible on 70cms. 

Contest ODX was as GI6ATZ in IO74 at 296km. Notable was a strong signal from GM4TOE in IO87 at 200km. Although I regularly work Barry on 1296MHz, this appears to be the first time I have ever worked him on 70cm. So things were a bit better on the evening of 9 August and everything in the pressure charts pointed to the next few days being open to possibilities.

By 10 August the 144MHz band as seen on PSK Reporter was beginning to look more like 80m:-

144MHz as seen on PSK Reporter at 20:38 on 10 August 2022

Over the four day period of the lift the bands opened in different directions on each day. For this purpose though I am looking at the whole period as one opening.

144MHz contacts at GM4FVM 10 to 14 August 2022

This is a pretty presentable set of results - 28 QSOs in 18 squares. 8 DXCC on 2m in four days is not shabby. The ODX of SM6BUN at 1028km in JO78 is good. Perhaps because I am getting used to fantastic results then just very good ones do not excite me as much. Let me just say that these days if I do not work SP or OM in an opening like this I feel a bit let down. That is crazy of course. This opening was characterised by lots of contacts over four days, other ones have fewer contacts and shorter durations, but they have better ODX. You cannot win them all, though I would like to.

Perhaps the results on 2m were influenced by the fact that I was concentrating on 70cms.

432MHz contacts at GM4FVM 10 to 14 August 2022

I spent more time on the 70cm band, and the result is that the map looks very like the 2m one. The openings covered the period of the "Euro FT8 contest" on 70cm as well as the RSGB UKAC 70cm FT8 contest too. That helped, but most QSOs were outside the contest. The contest certainly increased the QSO numbers to 59, as several stations worked me a second time during the Euro contest (and one three times to include the RSGB Contest too). Then there were several QSOs with G0BIX testing various things which brought up the totals again.

As is often the case during a tropo opening, ducts formed. Sometimes these can be long lasting, and sometimes very short lived indeed. The ducts create very strong signals in both directions but they are usually limited to small areas at each end of the path.

As an example of a powerful short lived duct here is a screenshot of my contact with PA3FWV on 11 August. I called CQ, and after the first call PA3FWV came back to me. We exchanged reports at +19 and +23dB.

 

 

Contact between GM4FVM and PA3FWV on 11 August 2022

I had heard nothing from PA3FWV before calling CQ. I have heard nothing from him since. I only heard him during three 15 second transmissions which were all during that one QSO at +19, +20 and +20. I have never heard him during any other lift. He had never heard me before. This was his first GM contact on 70cms. So this duct made possible a contact at very considerable strength between two stations who have no history of being able to work on 70cms, even during previous routine tropo lifts. 

I had not worked a station for 15 minutes before the contact with PA3FWV - that was SM6VTZ - and I did not work another one for 15 minutes afterwards - that was PA9R which gave me a -19dB report. The contact with PA3FWV stood out as a real indicator of the power of a tropo duct. It was completely out of character with the rest of the opening, as ducts so often are.

It would not be a tropo lift for me these days if it did not involve 23cm.

1296MHz contacts at GM4FVM 10 to 14 August 2022

Six QSOs, five squares, three DXCC, and an ODX to OZ2ND in JO46 or 690km. OZ1FF chipped in with a not inconsiderable 612km. You might think that is pedestrian but I loved it. I always say that raising operations to a higher band doubles the points for each QSO. And "points mean PRIZES" (whatever that means).

As so often on 23cm, OZ2ND and F5APQ are my targets. 690 and 605km on 23cm are quite respectable distances. Of course, when I started on 1296MHz I never expected to get anywhere near that far.

The path to Niels Erik is pretty straight forward - across the North Sea.

Path to OZ2ND from GM4FVM

On the other hand, reaching Jacques, F5APQ, is a lot more difficult

Path to F5APQ from GM4FVM

As usual you can click on any of the images to enlarge if you need to.

To get to F5APQ my signal has to pass over the headland near me, over the Northumberland Hills, across a stretch of sea past Sunderland, then over high peaks via the North York Moors, over the Humber Estuary, then over hills separated by The Wash, finally crossing the English Channel to France. This is a far more complex route than crossing the North Sea but not so far either. Or maybe the path to Jacques is just as long because it is indirect (see paragraphs below)

So working these two station make up two different challenges. The longer distance to Niels Erik is the easier to do, and I work him more often. Working Jacques is quite a task and although it happens less often it is just as pleasing when I can do it. While the hills to F5APQ are all under 400m, the route is bumpy and more obstructed than the flatness of the North Sea. Both tasks have their own issues and I enjoy hearing either station. To work both is a real pleasure.

Another anomaly which affected both 70cm and 23cm is that several station reported was that beam headings were not what we would usually expect. This may explain how it is possible for me to work F5APQ despite the difficult terrain. G0BIX on 70cm, G4ODA on 23cm and F5APQ (both bands) reported getting the strongest signals when beaming further East than expected i.e. towards the North Sea. This was at times when fog and Haar were being seen over the North Sea at GM4FVM, and strong Continental marine stations being received on VHF. 

Clearly it is possible at times to avoid the hilly overland paths (such as the one to F5APQ?) and find a longer but stronger path (reflection or duct or some other scatter mechanism?) by beaming towards a high pressure system off the main path. I knew this might be a factor on 23cm but I never expected it to work on 70cm. I need to learn more about this and try it more often.

The trick, it seems, may be not to beam towards a station when I hear it. My natural tendency is to assume that the direct path will be the strongest. I have had to learn that this is not necessarily the case with meteor scatter, and maybe not during tropo lifts either. 

And then it was over. Atmospheric pressure at GM4FVM started to fall. Rain fell to the benefit of the fruit and vegetables in the garden and to the detriment of radio conditions. Everything returned to normal. If it was not for normal I would never appreciate a lift.

The balance of activity I get by running both low VHF (50 and 70MHz) for Sporadic E etc. and high VHF, UHF and low SHF (2m, 70cm and 23cm) for tropo etc., means that there is often something happening. If you throw in my occasional EME activity then I usually have something to do, or something is about to happen.

This year I have hardly been present during the Perseids meteor shower. I have had a few contacts on 70MHz, particularly to Mek LA/SP7VC, but more on Mek in a later post. I even briefly ventured onto 2m meteor scatter when I heard DH8BQA. In general though I have been busy elsewhere.

That is it for now. Tropo followed Es. Time for aurora to follow Tropo? Or maybe an F layer opening to Australia on 6m?

73 Jim GM4FVM

Now That's What I Call Sporadic E! (Number 113)

Or should that title be, "Now That's What I Call an Obscure Cultural Reference To A Music Album! (Number 114)" ???

There was a nice Es opening here on 6 and 7 August.

Contacts on 70MHz at GM4FVM on 6 and 7 August 2022

That looks like a pretty good haul to me, considering that it was completed in just over 26 hours. That was 30 QSOs in 26 hours, whereas it took me 37 days to make my first 30 70MHz QSOs in 1977. There were only 10 callsigns in those 37 days back then because we used to work each other a lot [that's because there was no other activity then Jim]. We did not have the Maidenhead square system then either, but I guess that all of those 1977 contacts would have been in one square or two at the most. But we were happy.

Anyway, returning to the real world of modern communications, 30 QSOs on 70MHz, 26 squares in 11 countries. ODX LZ1ZP in KN22 at 2455km. Nice enough, but what makes this opening special?

Well, seven of those QSOs were made between 20:50 and 21:30. Working DX on 4m during night time Es is pretty usual, and my beam was swinging around all over the place. OH3NE is 1605km to the North East, LZ1ZP is 2455km to the South East and they were worked with minutes of each other. Sure, I have heard 4m Es at night, but usually only one or two stations on or near the same beam heading.

I eventually went to bed in a huff on 6 August with the bands still open. I called an SV station on 4m but we did not get a completed QSO finished. Then the big guns started working him and I decided to call it a day. Hey, I had worked him before. I was really quite surprised to find things still underway early on 7 August and I worked some more to the East before some solar activity triggered an aurora and Es vanished.

During all this I was paying attention to 50MHz as always, but I did not have enough resources to try to do much. The QRO guys were working the US and Canada, and there were some contacts over to the West Coast of America. Not for me though, of course.

In fact I only worked one station on 50MHz during those two days [one station - this had better be good Jim].

The only 50MHz contact at GM4FVM on 6 and 7 August 2022

JX/LB4MI on Jan Mayen caused a bit of a stir on 6m. He was on CW on 6 August but I missed a chance to work somebody then at a keying speed I could probably just about match. Then on 7 August he re-appeared on FT8 on 50.305. I was pleased to work him though Jan Mayen is not really very far away. I believed that he was in IQ50 square, but his QSL confirms that he was in IQ51. A new square for me then.

Yes, I have worked Jan Mayen before. However, I had never worked IQ51. At the time when I thought he was in IQ50 I worked him as the previous QSO had been on SSB. It made for a new "data square" - now you probably never heard of data squares before and neither did I. But the info about the square on KST turned out to be wrong. Who would have thought that info on KST could be wrong.

When I looked up the squares it turned out the original info would have had him in the sea, whereas the QSL square shows him halfway up the rather mountainous central section of the island. I cannot be responsible for where he is, I can just believe the square quoted on the QSL card.

I like that type of Es opening. I love the cut and thrust of it all, stations popping up and then vanishing. Spinning the beam and in this case, enjoying an unusually late night long opening.

I normally think that the harvesting of the very large field beside GM4FVM marks the end of the Es season. Of course the farmer plants the crop to suit himself, and the weather can move it several days either way.

This year even more extraordinary weather meant that the field was harvested on 6 August and baled and cleared on 7 August. After that the bands closed and there has been very little Es.

The harvest is almost a month early this year, and several fields I can see were brought in a week earlier still. This has been a very dry and at times extremely hot Summer. Global heating is a fact (the thermometers do not lie). What is causing it is open to some debate. I like a debate but that one is not for here.

Bringing in the Sheaves? The crop was got in, baled and cleared in 24 hours.

No, this surely cannot be the end of the Es season. Can it? Some wag suggested that we now have two Es seasons, one in May and June, and then another one in August. Certainly July was pretty poor and overall I would say we have had a fairly quiet season so far.

Let us hope that there is life in this this year yet. And maybe there will be some tropo on the higher bands soon - I heard Belfast Coastguard today - real DX!

73

Jim GM4FVM

Sirio Tornado 50MHz 6 metre vertical plus my stolen identity.

First of all I have updated my official shack photo. I did this because someone was coming to visit and I thought I should tidy up a bit for that reason. So for once in half a decade I could take a photo of the tidy (or at least more tidy) shack.

Latest gory image of GM4FVM and his shack.

What is male pattern baldness is a sign of?

Now there are few things as good as someone whose views you respect and value coming to see your shack and saying things about it. More on that visit in some later posting.

Anyway, this updated photo shows my "new" £30 second hand display PC screen, a Nikon slide scanner plus my keyboard and screen used for work. Also there are Wallace and Gromit looking down on me, and a photo of Mrs FVM which I printed back to front (seen in the mirrors in the background it is now the right way round).

We still wonder why the previous owner of this house made a wall of her bedroom with mirrors, but I kept them as there are shelves behind now with radio gear in them now.

Also in the corner of the shelving is an Icom IC-705. The existence of an IC-705 at GM4FVM has never been admitted to before. That also will need to await a further posting before more details can be disclosed.

Three SWR/power meters have appeared in place of the Wavenode. For now the Wavenode has been put into isolation while I decide whether I like it or not. Maybe it will come back and the SWR meters will disappear instead. 

Just peeking over the top of the screens is the Tajfun 1000 2m/70cm linear. Do I need a linear as powerful as that? Probably not, but it is a wonderful thing.

The new photo proves what GM4FVM actually looks like. I need to point out that I am not the person with the same name who came 16th in the 2022 Commonwealth Games Triathlon. Nor these namesakes:

the 38th Governor of Illinois,

the guy who writes the books about cats and,

the international squash player. 

I am the person in the photo above and not these others.

==============================================

Not GM4FVM (too much hair)

==============================================

MOVING ON

My destiny is not to put back up my heavy dual feed 6m/4m yagi (see last posting). However, I really do not like the lightweight single coax sleeve fed Vine which is up there. So what to do?

I have consulted widely amongst my elders and betters (plus some youngers and betters) and the they all agree that if 4m is one of my key bands then I need my best 4m yagi up. They reckon that the basic idea of the 6m half wave vertical was a good one. So I will do what I can by going back to the previous situation with something better replacing the 6m vertical. 

Enter the Sirio Tornado 50MHz 5/8th vertical!

https://www.nevadaradio.co.uk/product/sirio-tornado-50-60/

There are other versions with more sections covering the spectrum from 36MHz up to this one which covers up to 60MHz. The images on some sites show drawings with very short radials - in real life the radials are 1170mm long.

Everything set out and checked complete

The basic construction will be familiar to those using other Sirio products. The elements are made of a base with loading coil, two aluminium alloy sections which are attached together and to the base with self tapping screws, and a top section which slides to adjust the antenna to resonance. This top section is held by a "hose clamp" (Jubilee Clip to UK readers), and the lower section is cut to allow it to grip once the clip is tightened. The tubular alloy radials are held in place with grub screws, for which a Hex Key (= Allen Key) is provided. So far so good.

I built the antenna low down where I could adjust it. Setting the length to 3800mm seemed ideal for me and no further adjustments were needed. I tested it with my antenna analyser and it showed an SWR of 1:1 at the bottom of the band, 1.2:1 at 50.300, and it stayed below 2:1 right up to 51.700MHz. Having thus tested it, I was ready to waterproof it and get it aloft.

Not bad on the YouKits analyser, even close to the ground.

Basic waterproofing is ensured by plastic push-on covers on the top section and one on each of the four radials. My 4m Sirio J-pole died when rain water got into it, passed through the PL259 plug, and ran along the inside of the coax. Losing the 4m antenna was bad enough, but losing the coax was expensive. The design of the 4m antenna has since been changed by Sirio but that experience made me fussy about waterproofing. Some time ago I decided to bind my 10m half wave and 5/8ths Sirio Gainmasters up at the joints using self amalgamating tape. This 6m antenna has received the same treatment.

The only problem I encountered was that the PL259 compression plug on this coax was too wide to fit into the weather shield which surrounds the socket. This plug is milled round the outer diameter. I ended up having to screw the plug in using a 19mm spanner. This strong-arm tactic distorted the cover but it was successful in tightening the plug. This is probably due to the type of plug I used. That area then got some self amalgamating tape too.

Milled edge on plug got stuck in the cover. It had to be forced in with a spanner

I am not a great fan of the mounting bracket which is supplied. It relies on four dimples on each side of a plate between the pole and the base of the antenna to locate them while a U-bolt clamps them together. There are two of these brackets. I would prefer a more solid fixing with each pole firmly fixed but I suppose this saves weight. I have better ones in my box of brackets but for now this will do. We shall see how it works in the Scottish winds. It is not likely to fall down, but maybe it could get blown off vertical.

Bracket does not inspire confidence.

Final step was to get it into the air. I had a two metre pole for this but given the weight of the antenna, the unknown strength of the fixings into the house and my rather reduced climbing ability just now, I used a 1 metre pole instead. There is a loop of coax there to get it higher but not just yet. 

It went up fairly easily. Not an easy thing to photograph against the sky. As usual click the image to enlarge if you are having problems seeing it.

Sirio Tornado ready to use at GM4FVM

When I put up the half wave I said that would put an end to my cross-Atlantic capabilities. I then went and worked cross-Atlantic with it. Theoretically the 5/8ths should give one more dB of gain (wow!). Of course the half wave did not need radials and was lighter. It has to be said though that the half wave seems to have corroded itself to pieces. I think that the Sirio should stand up to the weather better.

Just out of curiosity I decided to try to work some stations around Europe on 6m to see how I got on. When I tried that on the 6m half wave I forgot and worked EA8 on 4m on it instead. This time I managed to stick to the right band (the Sirio has a 8:1 SWR on 4m but that would not necessarily stop me ...). Anyway this was what I managed.

50MHz contacts at GM4FVM on 1 and 2 August 2022 using Sirio Tornado and 100W

This was a nice way to spend just over 24 hours (but only 3 hours 12 minutes actual contact time). 23 QSOs in 22 squares, in 9 DXCC. I did not try very hard as it was just a test, but LA, CT etc would have been easy to add. SE3X and TA7OM were new squares for me.

I also used the new Sirio to hear my first station on the 8 metre band. S5/M0MPM in JN75 heard at -11dB on 2 August 2022.

First station heard on 40MHz at GM4FVM.

No TX on 8m from the UK, or not yet. OFCOM apparently refuse to consider it and no doubt the "existing user" wants to hold on to anything they have. I do think however that a few kilohertz for data modes would be easy to allocate. In any case, who wants to use frequencies there these days when microwaves are the way to go. After all, 40MHz has lots of Sporadic E "interference" ...

The Tornado antenna should be ideal for me to work some EU Es on 6m and gather intelligence about band openings. I know that it is not a DX antenna in the sense that I am unlikely to work Brazil, Mexico or Japan as I have done on the beam.

The basic limitation here is that I only have room for four antennas on the rotators. If I use single band antennas then something has to be vertical. For as long as I find 4m, 2m, 70cm and 23cms more deserving of one of the four places each then 6m is going to end up with a second string aerial.

I am looking forward to using this antenna which I think is better than the half wave.

Actually, if the half wave had not failed I would never have changed it so maybe this is a step forward. A week ago I had never heard of it, and now it is in use at GM4FVM.

73 Jim GM4FVM

The Force of Destiny

It does not seem to be so long ago that I was saying on this blog that I had downgraded my 6m antenna to a half wave vertical so that I could put up my best 4m yagi antenna. I wanted to reach 50 DXCC on 70MHz. It was 4 April in fact.

The vertical has died on me. It seems to be that the RF socket and it's connection have corroded. As this is an integral part of the antenna it is not simple to replace. In fact a close inspection revealed that the loading coil at the bottom and the gamma-match are also corroded. Ah, the joys of living near the coast.

The reference to the force of destiny is of course to "La forza del destino", the opera by Giuseppe Verdi. Being an Italian opera it is a bit more complex than my issues (really?), as it involves all sorts of misery, sword duels to the death and general angst. I recall it mostly for the score which provided the musical soundtrack to two brilliant movies - Jean de Florette and Manon des Sources. Mournful and yet rather scary, Verdi's main theme adds drama to the films, and the many rip-off TV commercials which followed.

Anyway, the force of destiny has affected my antenna choice. It turns out that when I compared my knee to a cronked VFO gearbox I was not far from the truth. Oiling the bearings will not work - I need a full replacement knee gearbox. At the moment it is metal to metal contact down there.

I'll get over it, but for now the knee limits what I can do. As soon as the 6m vertical stopped working I realised how difficult it would be to work on it. I would need to stand on a ladder. It find it hard enough to walk to the ladder, never mind climb it. Of course, I had to limp my way through it.

I used the vertical antenna to work on 50MHz and listen on 70MHz. The only way out of this is either to fix it - a tricky prospect - or put back up some sort of 6m beam. The pressure to have my best 4m antenna up has passed. Thanks to working Cyprus and finally Market Reef I have passed that milestone. So maybe putting back my big dual band 4m/6m yagi was the only way to go. But for that I would need two runs of coax, one for each band.

Somehow I managed to put back the extra run of coax which that beam will need. Then I thought about the antenna, the size of it, the work to put it together and get it back up, and I knew that the game was up. No chance. With such a heavy antenna I could never manage it. I will leave that until I have got my knee working again, which could be a long time.

So a compromise is my destiny. It is a necessity, simply because I cannot do heavy work right now. So in place of the 6m vertical went my old 5/8ths ring base vertical for 70MHz. Just like I was using the 6m one to listen on 4m, I am now using the 4m one to listen on 6m. This works very well for reception.

For my main antenna I have managed to put up my old Vine 4m/6m dual band beam with a single feed. This antenna is not the greatest on either band. It has the key advantages that it is strong, easy to put together and a lot lighter than the huge dual feed alternative. It is also shorter with less windage and thus I used to put it up every winter. I did a lot of thinking about how I would cope with the SO239 socket as the cable has an N-type on the end. I hate RF adapters, especially outdoors. Eventually I discovered that I had changed the antenna over to an N-type socket years ago. If I read this blog I might have known that.

Antennas at GM4FVM, 2,4 and 6m in the foreground, then 4m vertical and 70 and 23cm in the distance.

Destiny has forced me to make this compromise. Better to be operating in a less than perfect way than not operating at all.

My 6m capacity is much improved, and my 4m capacity is reduced. How much, maybe a few decibels. I feel it though.

I really rate the 70MHz PowABeam which I took down to make this change. However, if I had not changed I could not transmit on 50MHz at all. I have a better dual band antenna than the Vine but I can hardly lift it and certainly not carry it, so my destiny is to have it this way. 

As a farewell to my splendid 70MHz PowABeam (it only went into the garage Jim) here is what I have worked on 4m since my last posting on 12 June ...

Stations worked on 70MHz at GM4FVM 13 June to 10 July 2022.

94 QSOs, 21 DXCC, 64 squares. Plus completing the all-time 50 DXCC. That 5 element 70MHz PowABeam certainly works well, in fact so does the 50MHz version which is .. also in the garage. No room for two now but at least I am operating on 50MHz again, and with a beam.

The eagle-eyed amongst you may spot G4KUX on the map who I worked during a very short but powerful aurora on 10 July. A huge signal from 135km away being scattered back to me via an aurora perhaps 500 - 1000km to the north.

So I have struggled to run another co-ax line to the mast and not used it. I wonder what I can do with that? HF perhaps? Anything that I can lift and carry, and which will not fall apart from the jolting of my limping gait.

Am I destined to use only wire antennas?

The Force of Destiny - looks like a bundle of laughs (Image Wikimedia Commons)

73

Jim

GM4FVM

On having a hunch

OK, I have written a long turgid waffle about a month of 23cm tropo and worthy stuff about gradually improving conditions. It was well annotated and carefully phrased. However, I wouldn't want to read it myself and my belief is neither would you. Nothing new there then.

So this will have to do.

Here is the first image from that non-posting just to make me feel that composing it was worth all the effort. It shows broadcast stations making their mark on 70MHz, which actually has some relevance to this posting too.

OIRT broadcast stations on 70MHz on 9 June 2022

This is about me learning to trust my instincts, or me backing my hunches.

Some of my best radio moments have come from hunches. Like the hunch which kept me on the 6m band for three hours after an aurora had faded just in case there might be an auroral Es opening to the North of me. There was and I worked JX9JKA, the only time I have worked Jan Mayen.

Or the hunch that 2m might open into the Baltic so that I waited from 13:30 to 18:30 on 13 July 2020 before working Estonia, Latvia and Lithuania (and missed out on Kaliningrad). 

Five hours sitting here working a total of two G stations (no disrespect to G stations, but sometimes I need some DX too). Five hours with the Sun beating down outside and grass waiting to be cut. Five hours watching broadcast stations fill the 4m waterfall and having this hunch that something is about to happen on 2m. And I was right.

Let us have no mention of the times when I am not "right". However, I think that the odds work out in my favour most of the time.

It is a bit more than a hunch of course. I follow the propagation across bands and use some dead reckoning to suggest where an opening will happen. I work from given fixed points and fit the variable elements around that. After almost 50 years I am getting almost competent at doing this.

The period covered by this posting is 11 and 12 June 2022. 50MHz was full of stations each day during an excellent Sporadic E opening there. I noted this and moved up to 70MHz on both days. My hunch is that it will open too. Anyway, with just a half wave vertical on 6m at the moment I guess I am not going to work much in the way of DX (wrong, see later).

The result of the first hunch was this outcome on 4m

Contacts on 70MHz at GM4FVM on 11 and 12 June 2022

Click  to enlarge if you need to see the image more clearly.

52 QSOs in two days, 18 DXCC, 38 squares and two continents, with a best DX of 3884km to 4Z1TL. On 4m. The RSGB basic award for 4m starts at 20 squares and four countries. I would not expect to qualify for an award in a day (which I would have done if 11 June had been my first day on the band).

I was not even trying very hard. I heard but did not work Cyprus. If I had really needed more countries I might have worked Scotland (a fair bet if I tried), the Isle of Man or Northern Ireland, not DX but still DXCCs. I did not call stations I heard in Belgium and Netherlands in case they thought I was "too local". What the total might have been if I been looking for a record I cannot imagine. The 55 squares and ten countries needed for the highest RSGB award might have been done in a weekend.

So seeing 6m open and deciding to head for 4m is a hunch that worked. It often does.

Moving up again from 70MHz to 144MHz is not so straight forward a proposition. Sporadic E on 2m is much rarer than it is on 4m, just as on 4m it is rarer than 6m. The frequency gap is wider, the area covered by each opening is narrower, and there is not so much of it (meaning it is just rare). However, Es on 2m seems to be a lot easier to work these days. FT8 means the whole continent of data nuts is listening on the same frequency at the same time. 

I waited for just over four hours between 4m opening and my first contact on 2m. On 11 June 2m opened in the same direction as it had on 4m, which was towards Spain. I worked three stations in 17 minutes and the 144MHz opening was over. That is the way it works. You have to work the ones you hear immediately or they are gone (and a fourth one faded mid-QSO). It only takes 75 seconds to work someone on FT8, but that might be too long to complete on 2m Es.

All three stations were new to me on this band and there was one new square. A good result on 2m into Spain from here.

This could be the only 2m Es opening for me to Spain this year, and after that wait it lasted 17 minutes.

Contacts on 144MHz at GM4FVM on 11 and 12 June 2022

It is not quite so easy is working out if an opening is going to occur towards Italy. For some years now Italy has not granted access to the 70MHz bands for its amateurs. So I watched for stations on 70MHz in that general direction, particularly Slovenia which borders Italy. My hunch then moved to the possibility of an opening into Italy on 4m. There were huge broadcast signals on 4m which seemed to be coming from Moldova, certainly suggesting that pointing the beam at EA was no longer the best bet.

19 minutes after the opening to Spain ended, a prolonged 2m opening to Italy started. I was right to stick to my hunch. I worked ten stations in Italy, only four of which were new callsigns to me. As usual on 144MHz, they barely stayed above the noise for long enough to be worked and I lost five more in QSB.

When I say "prolonged" opening I mean 52 minutes in total. And it is not as though I could hear a station for 52 minutes, none could be heard for more that 3 or 4 minutes each. With a tropo opening you might hear a single 2m station for hours, whereas with Sporadic E I basically had a series of 10 separate short openings with gaps in between filled with failed QSOs to others.

It says something about how obsessed I am about all this that of the ten Italian stations on 2m I had worked six of them before on 2m Sporadic E. Or perhaps it says something about how obsessed they are. 

Anyway, one new square in Italy to add to one new square in Spain, a total of 14 QSOs to 14 squares, best DX being IW8PQU in JM88, 2339km away. Not bad for 144MHz.

Before I leave the 2m side of things it is worth noting that there was no 144MHz Es opening on 12 June. How come I can rely on the evidence of an opening on 6m and 4m to expect a 2m opening on 11 June, and yet the same thing did not happen on 12 June? Well, that is why it is a hunch and not one of the Laws of Physics. Sporadic E does not play by strict rules. All my hunch can do is show where to look, it does not promise where I can find.

As a general rule if I look at 4m and see reports less than 0dB in FT8 it is not worth me looking at 2m. If I see reports about +10dB it is definitely worth looking at 2m. On 11 June 4m reports peaked on 4m at +30dB and were around +05 before I moved up. But of course this is just an invitation to look, not a promise of a find. On 12 June the highest report I gave on 4m was +33, and the highest I received was +38.

Was there no Es here on 144MHz on 12 June? Maybe not. If I was seeking a justification for what I do I could simply point to the fact that 2m Es is very localised and lasts only for a short time. Thus there might have been Es into an area covering a bay or sea, or a region in which no amateur happened to be listening at the time. Given the locations of few amateurs with good VHF DX stations that is certainly possible. 

Looking at the 144MHz map the openings could easily have been into the Western Mediterranean, the Tyrrhenian Sea or the Adriatic Sea instead and I would have heard nothing. There are so few stations operating on VHF from North Africa that openings there might produce no response at all. And from the other end the path might lead into the North Sea and not directly to GM4FVM. So often when I have a hunch and hear nothing, it may not be because there is no opening.

I do not need to make up a theory. I just do not know if there was Es and I missed it, or there was none.

My hunch is just to help me know when to look. The big plus is that I can look at the situation and quickly assess when I can turn off and go and watch Masterchef Canada on the television. Given the variables I cannot say for sure that something definitely will happen, but I can be pretty confident when it won't.

Secretly I might admit to the hope that we never find a way to predict Es more accurately. I love the anticipation. I actually enjoy forming an idea and listening to see if it happens. I get the sense that it is not my equipment that decides how well I can do, but nature itself. 

Nothing I do here is down to me. All of it is thanks to nature. I really enjoy pushing the boundary of what I do until it is nature which is holding me back.

Before I started using these tactics I investigated 2m Es and concluded that it was a pointless exercise to try to work it, especially from this far North. It was too rare and would require too much listening time to cover every chance occasion when it might happen. Back then of course I had not worked out the progression from 50 to 70MHz which would give a clue to the best times to watch. 

By concentrating on 144MHz I do not want to minimise the success on 70MHz. 11 and 12 June netted a lot of interesting QSOs on 4m. I had managed to work SV9FBM on 22 May to achieve DXCC number 49. It looked during 11 and 12 June that I might find number 50. I heard but did not work Albania, which would have done the trick. It is getting close. I have now reached 270 squares too, quite a few more than the 55 to make the highest RSGB award.

And finally, just because I now only have a half wave vertical and 100W does not mean that I have given up on 50MHz. On 17 June I worked HI3T. I have worked him before so Dominican Republic is not a new country, but it is for barefoot with that antenna.

I suppose it just goes to prove that kilowatts and a big beam are not always needed.

73

Jim

GM4FVM

More on masthead preamps.

Can it really be three years since I last opined on masthead preamps? I rarely take so long to ramble on again about things.

http://gm4fvm.blogspot.com/2019/03/more-tropo-masthead-pre-amps-and.html

This time I wish to drone on about how I use the sequencers I have which were made by Down East Microwave Inc (DEMI) in Florida USA. It seems like time for some practical examples.

I have ended up with three of these sequencers. After failing to make a decent job of wiring them up using trailing leads, I built the first one I built into an ABS box with sockets on the outside. The second one had the same box but the sequencer is outside fed by a multicore cable. The third and hopefully final one is built into a much smaller box.

The project to interface the sequencer to the cables is simple. A very low level of technical expertise is needed which can be demonstrated by the fact that I could do it. 

If anyone else wants to try this, the exact wiring they need may well be different from mine, depending on whether they need to run preamps, fans, transverters, or whatever. The DEMI instructions explain which pin does what and I shall not delve into great detail about that.

The DEMI sequencers are available as kit for $60

https://www.downeastmicrowave.com/product-p/ltrsck.htm

or built for $80

https://www.downeastmicrowave.com/product-p/ltrs.htm

As I live in the Scotland there is the International Postage to add, plus possibly also tax at this end if they charge it.

The W6PQL sequencers are good too, and they are installed in my Gemini linears. He sells a rather similar four event sequencer kit which seems to be larger and does not come with a box - but it is only $37.50. You can also buy sequencers that just plug in ready for use. SSB-Electronic make one suitable for 6m to 70cms with built in bias-tee for over £200. I need three, and one of those is for 23cms, so cost comes into this as well as frequency range.

Having chosen the DEMI version, I completed the job on the cheap. These hook-up arrangements I made were built out of my bits and pieces boxes and seem to work fine, and all I needed to buy each time was the basic unit from DEMI. The only exception was the multipin plug which I changed from the one supplied by DEMI.

The DEMI sequencer is not what I would call a stand alone unit. It is a circuit board in a case which is terminated in a 15 pin plug of the type once used on computer monitors. You need to interface to it. I started off just trying to wire directly into the plug, got into a pickle, and then decided to box one up. After that I built the other two as break-out boxes allowing for sockets, switches and fuses on the box which supplies the DEMI unit down a multi-core screened cable.

A DEM sequencer showing stock configuration.

The DEMI sequencer is very easy to wire up for a multiple range of different tasks. It produces four outcomes, all timed to occur sequentially after pressing the PTT and in the reverse sequence on releasing the PTT. Note that, unlike some sequencers which connect into the microphone lead, the DEM ones work on the PTT output from the radio and thus will work with data modes.

There are five options as to what happens at the four stages. These are 

a) Power on during receive (for a preamp) = DC voltage at max 2 amps.

b) Power on during transmit (to power a relay or fans) = DC voltage at 2 max amps

c) Grounding another voltage (to activate a linear amplifier PTT connection)

d) Power on during receive = DC voltage at max 50mA

e) Power on during transmit = 0.7V DC at max 50mA.

You can set the wiring to do these in various (though not all) combinations for the four sequential actions. The ready-made version comes with a standard wiring layout which will suit most situations and you can change that later if you wish. Certainly in my case I do not need all these options and the standard wiring on the built unit is fine for me.

The DC voltage can be between 9 and 17V.

In order, the standard sequence on grounding the PTT line in (when you press the mic button to transmit and your radio grounds its PTT out line) is:-

1) Turn off the voltage to pin 1 (turn off the preamp), then after a pause

2) Turn on the voltage to pin 2 (turn on fans, TX power circuits, etc), then after a pause

3) Ground pin 3 (activate a linear amplifier PTT), then after a pause

4) Ground pin 4 (activate a linear amplifier PTT)

The sequence is reversed when the PTT line in is not grounded, so when you let go of your mic button the steps occur in the order 4 -3 -2 - 1 cutting off power to pin 2 and turning back on the preamp via pin 1.

Pins 3 and 4 could be used to switch a transverter and a linear amplifier in the correct sequence.

The timing gap between the steps is fixed and not defined, but I would guess it is several hundred milliseconds. It is certainly a noticeable between PTT activation and each step after the first one. As the unit is entirely solid state there is no relay delay to add to the sequencing delay, though there is in my linears. It is important therefore to think about the total delay if you are using FM or data modes where hot switching could be a problem. All my radios have adjustable TX delays to account for this.

When it came to the practical installation, the "pin" activations referred to above happen via a DB-15 connector. To begin with I simply wired the unit up in whatever way suited using a DB-15 plug which is supplied with the kit. This requires soldering of a three layer 15 pin computer plug which I never find a very happy task. Then I needed to terminate the resulting wire output with whatever plugs and cables were needed.

This rather ramshackle arrangement ended with me losing a sequencer for some unexplained reason. I suspect that I must have accidentally shorted the coax while working outside on an antenna and this caused something to fry in the sequencer (You should have turned it off first, Jim, so fit a switch and an LED). I had fused the unit on the supply side, but crucially at 3 amps. 3 amps on the input is the recommended fuse as stated in the rather vague instructions. As my preamps draw about 300mA I now fuse the output at 500mA.

It became clear to me that this trailing wire system is not likely to protect the units sufficiently in the environment that I run. Thus I took a sequencer and built it into an ABS box. I decided that it needed (a) fuses on both the input and output, (b) reverse polarity protection, (c) properly fixed sockets so that PTT lines could by fitted (d) a switch so that I can easily turn off the voltage in the coax while working on the antennas and (e) some sort of LED to show it was working. The sequencer has a red/green LED to show it is working but as I was burying it in a box that would hardly help unless I drilled viewing holes in the box which seemed a bit pointless.

The point of the box is really to provide mechanical stability. I found that flexing of the wires in and out of the BD-15 plug would pull the solder joints apart, causing unreliability. The resulting unit mounted in an ABS box looks a bit over-engineered but it has survived for three years without incident apart from the odd blown fuse. It need not be a thing of beauty but it will rarely be seen behind the shelving.

The first boxed DEM sequencer at GM4FVM (the lid is on back to front)

The sockets on the back are phono 1 (PTT in) phono 2 (linear PTT out), 2.1mm DC in, on the side is a phono for preamp out and on/off switch, and on the near side are two fuse holders, on for input (1000mA) and one for output (500mA). The front panel has two LEDs for transmit and receive. On the top you can just discern the trace left by a tea cup, showing that this item is multi-purpose.

I needed sequencing because I use an IC-7100 for 432MHz, and that radio cannot supply the voltage for the preamp. I then acquired a splendid linear amplifier for 1296MHz. This had previously been used by Sid, G8SFA, and I drive it as a second stage with my existing 1296 linear fed by the IC-9700.

Whilst the 9700 can supply the voltage for the preamp, I could not arrange the two 23cms linears to switch simultaneously (one has a sprung antenna relay, the other a latching one). It occurred to me that the DEMI sequencer could switch two linears via pin 3 and pin 4, and that all the output pins are isolated. I had a spare sequencer left since I had used one for 2m with a transverter, so I put it to use. I needed to rewire it as I had never used pin 4 before but it all worked fine.

This second installation actually used the first sequencer I bought and this was the one which had been initially wired up with trailing leads which was an unreliable method to use. At first I thought of putting this one in a box too. That seemed crazy so I decided to use the box as a break-out box, leaving the smaller sequencer unit itself at the front of the bench. The larger break-out box will lurk at the back out of sight. This one has the same plugs, fuses and on/off switch as the first one, with an extra socket for "linear 2". There is still an LED, but just to show that the preamp voltage is reaching the break-out box. I did wonder if this LED was necessary, but I managed to blow the output fuse at an early stage and the LED proved where the problem lay.

Now using the two timed grounded outputs on 1296 means that there is a slight delay between the two linears switching, but this does not seem to matter at all. The advantage is that they are isolated from each other. The preamp is powered directly from the 9700 so no need to use that socket for now, but it is still available should I move it somewhere else. I also used a DB-15 plug with screw terminals just in case I wanted to alter the pin wiring later too.

Screw terminal DB-15 plug saves soldering 3 rows of tiny pins.

There was a slight delay in building it when it turned out that the DB-15 plug with screw terminals, which I had been safeguarding for this purpose for years, turned out to be male and I needed a female one. D'oh. They come from China and take weeks to arrive. Luckily I could buy a cheap "MINI GENDER CHANGER" to tide me over. Because I had not discussed my plan in this direction with her, Mrs FVM was a bit surprised to see a gender changer arrive in the post for me.

My MINI GENDER CHANGER & sequencer - what a relief.

I might point out that a lot of this effort would have been saved if DEMI had used similar pin connections to those on standard SVGA display leads. These leads are terminated in DB-15 plugs. Long ago I thought I could just cut an SVGA lead in two and use both ends as two sequencer leads. Sadly standard SVGA leads are not "all pin wired", and several pins you could need for the sequencer are combined as ground connections. Ironically, I ran out of the 9 core screened cable for my next sequencer project and I had to use an SVGA cable instead - I had to cut the DB-15 plugs off and throw them both away and then connect one end to a new DB-15 plug.

Next, for another project I needed a third sequencer. Once again I have bought a DEMI one. I have finally decided to use a smaller box. And, oddly, I am using the same way of getting the cable from the sequencer into the box - an ugly gland. For the second sequencer the original plan was to use an 8 pin DIN plug and socket. Then it occurred to me that I was never likely to disconnect it and anyway there is a plug and socket at the sequencer end. So I delved into the "gardening electrics" box hoping for a grommet and found instead a waterproof gland, total cost zero. So if the tide ever rises 60 metres above mean sea level at least that aspect of the GM4FVM set-up will be safe. Mind you the water will just get in down the centre of the phono sockets instead, but more gradually, allowing me time to bale it out again with a spoon.

Break-out box for third sequencer under construction

This new smaller box features the same over-sized (but cost free) gland for wire access, on/off switch, LED plus output and input fuses. The five sockets are on the rear panel. At last this beginning to look a bit neater.

I suspect that the DEMI sequencer is based on the circuit used by them on their transverters. As such I guess that most of the ones they supply get built into other equipment and not too many end up stand-alone. My use of them initially standing beside the rigs with trailing cables simply connected into the plug on the back was pushing things. I think they really need a break-out box if used in that way, even if only to protect the wiring and tidy things up.

My preamps all have RF VOX switching, which I regard as a back-up safety system. I know that some people rely on using this to switch a preamp or transverter rather than installing a sequencer. When I have tried it I can see the SWR spike in the rig when going to transmit. There is a risk here of either this damaging the output stage of the radio, or of hot switching damaging the preamp. Given the cost of preamps and radios compared to the cost of sequencers, I know which solution I would choose.

Box number 3 being tested.

The first basic one has been in continuous use on the 70cms radio for 3 years. The second one has seen a couple of stretches of use, and I am happy now that it is tidied up and working on 23cms. The third one ... well you will just have to wait and see what that project is.

Finally, with the last sequencer came a strange note from DEMI stating that the latest release has a wrong package style for Q2 installed causing incorrect operation of sequenced step 2. It did not explain whether this applies to my one, only that kits and some assembled units dating back to Dec 2020 are affected. It states that "the assembled units will pass out test fixture testings to verify switching but the units will not operate correctly with a current drain above 10mA". It then goes on to show a modification using a leaded 220 ohm resistor to replace SMD resistor R2 in a different place. This looks like an easy modification to make.

I was not exactly sure if that meant the unit I had was affected. If I did the modification would that stop my unit working if it was not affected? Anyway, I decided to test it with the masthead preamp which draws about 300mA and it worked fine. For the moment I will leave it at that.

73

Jim

GM4FVM