How often should I call CQ on VHF?

Most amateurs seem to have a simple rule for the right times to be calling CQ - they are correct and everybody else is wrong. Who am I to disagree?

Here comes another rabbit hole for me to race down. I am like a border terrier on a long walk.

I apply a statistical approach to this [and everything else Jim ... try getting a life instead]. 

If everybody just called CQ nobody would ever work anybody. And if everybody just listened and did not call CQ then nobody would work anybody. So there has to be some balance between one and the other.

When I am listening myself I see stations calling CQ constantly and never looking for any one else's CQ calls. They only respond to stations calling them in response to their CQ call. From this evidence I conclude that they are content to do this and it meets their needs. My own experience suggests that this style of operating simply shuts out the possibility of amassing new countries or squares. I find that if I need to reach a new country I need to go after it.

For sure, from time to time, some new DX will answer a CQ, but that relies on luck. Luck works, but not very well if you are square and DXCC hunting. I want to challenge myself, not just accept what comes to me.

Then there are those on data modes who set their Tx watchdog to 99 minutes and call CQ for all that time. I can think of one station south of me on 2m who clearly does exactly that. This tactic might work on the ever changing propagation on HF (how would I know?) but on VHF where the antennas at each station might add 10 to 20dB gain, it is a bit annoying to have one period blocked at 40dB over S9 for 99 minutes thanks to a nearby CQ nutcase.

This is amateur radio. It is self regulating. There is nothing in the rule book so say you cannot do this type of thing. There is no rule book for this type of thing. They may not make themselves very popular, but popularity might not mean much to them. The station I have in mind gets a lot of abuse. Luckily he is hundreds of kilometres away from me so he does not trouble me.

There was a time, years ago, when I had local stations around me. One local, who perhaps might have known better after 50 years of operating, turned his Tx watchdog to 99 minutes and called CQ via his linear and beam on 2m. He used to set this off and go to the pub, running it for another 99 minutes after he came back and went to bed. Sometimes someone would call him once via random aircraft scatter and then vanish back into the noise, which left him sending a report to nobody for another 99 minutes. The inevitable happened of course when the relay in his rig got stuck. After that we never heard him on again. No doubt when he woke up the next day there was that nasty acrid smell of burned components (as well as a stale beer smell).

During the time we are calling CQ we are not listening for Dx. If I call for 99 minutes on one period I will never hear any stations on that period. Old Dx hands know that juicy Dx can turn up on either period.

Calling CQ is all fine and dandy but from what I can see many amateurs don't do it much. These ones just set up their data modes and listen, only replying to DX when they hear it. They take the opposite approach to the CQ-ers and it seems to work for them. But does it? Their success depends on the Dx station happening to call CQ at the right moment. 

I learned what little I know about VHF operating on 70MHz. I spent years listening on 4m, calling CQ when I thought something might be happening. Mostly I heard white noise and got frustrated. However, there were times when I was hearing nothing but when I called CQ someone replied. I could never rely on the other station to be calling CQ just when the path was open.

It is perfectly possible for any VHF or UHF band to be open and everybody is just listening. This does not just happen in the empty wastes of 70MHz. Those pesky Dx stations have a habit of just listening too. It isn't that I miss their activity, they are not going to transmit just because I want them to be (in  order to allow me to simply listen for them).

Today I see that various people are hearing FK8HA on 6m. At present this seems to be limited to stations in Southern Europe. According to PSK Reporter lots of the usual 6m Dx hounds around me are listening. So I am listening too. But what if the band is open to the Pacific and stations in the Pacific are listening too? Then nobody works anybody, despite the path being open.

50MHz at GM4FVM, 14 October 2024

No doubt I would hear a lot more French and other stations calling FK4HA is I was beaming their way, but I am beaming at New Caledonia.

Lets us face it, the chances of me working FK8HA are vanishingly small. The propagation, such as it is, is towards Southern Europe. But how do I know the path is not open? Or more likely a similar path from GM to some nearby exotic Pacific Island location? Propagation changes and moves. I could test this out by calling CQ. How often? But will I annoy others by dong so? Does any of that matter?

I know fine well from my 4m days that often a path can be open with no activity and sometimes the only way to establish that is to call CQ. I also know that frequently calling CQ is both self defeating and sometimes annoying to others. I reckon that there has to be a balance here.

During VHF openings I work to a strategy of calling for one or two periods, in other words for a minute or less. Then I listen for a longer period before calling briefly again, possibly on the other period. The reason for this is to be quite sure that there is not a brief opening to a station on that period. It seems to work. When conditions are changing by the minute a long CQ call could be a disadvantage.

When there is no specific opening I use my standard Tx watchdog setting of 3 minutes. This means that I can call CQ but not block my chances of hearing some Dx on that period for very long. I have longer settings for meteor scatter. 

Just like everybody else, I can rely on the certainty that what I do is correct, and everybody else has got it wrong. But seriously, I can see people calling CQ for long periods and working nothing, and others who do not call CQ for long periods and miss the chance of some Dx. It is up to them.

Yesterday I was sitting here fiddling with something. I looked up and noticed that I was decoding FR8UA on 50MHz. Not a new country but a nice one all the same. By the time I had cranked the mast up, turned the beam, fired up the linear and replied he was gone. I decoded him eight times but missed a contact. It is quite possible that he was on before that but he was also listening. If I had called CQ earlier ... ???

These examples are just what is happening at the moment. However there are plenty of examples where I think that if I had called CQ more often or less often I would have done better. 

There is no simple answer to this problem. 

But I know that I am right. Just like everybody else knows the same thing.

73 Jim

GM4FVM

At last some tropo --- and records broken too.

When I am fortunate to work some notable DX, I always wonder why. This is not just looking for some technical explanation, but why now? Why not before? And also --- If I can get so far, why cannot I reach other places at that distance?

This is particularly so recently when I had a contact with LY2WR on 1296MHz in KO24. This was a total distance of 1726km, when my best previous DX on this band was just 1000km.

This contact shows that I can do much better on 23cm than I had previously thought. And the proper contaxt for that statement has to be - I had already been doing much better on 23cm than I ever epected when I started out on that band. Honestly, I had expected a few contacts up to a few hundred km.

The club station at LY2WR is not what I regard as a "superstation". In fact they have similar antennas to mine and they are running 100W and me running 150W, therefore we are both in the "middling" category. This was a notable contact for me, as I pointed out at the time on the microwave section of the KST chat room. The response from LY2WR was to thank me for their first GM of the day. FIRST GM OF THE DAY!!! My first LY on 70cm EVER. Thank you very much.

Just to see how this compares with my previous results on 23cm I created a map of all my 23cm contacts since I started on the band which were more than 600km ....

All 1296MHz contacts at GM4FVM over 600km

As usual click to enlarge images if needs be.

The contact with LY2WR is in a different league compared to the others. It takes 600km for me to reach continental Europe, and than after that most contacts are spread around up to 1000km which looked like a definite boundary.

Then along came that LY2WR contact. The question arose -- where else could 1700km take me for new DXCC? Well Poland for a start. Austria. Czech Republic. Lithuania. Latvia. ????

Maybe those ideas are a bit of wishful thinking. Looking at the path to LY2WR, most of it is over water  -first the North Sea and then the Baltic Sea. I printed out the path and crossing Denmark met with a maximum hill height of 100m, and crossing Sweden the terain was only 150m asl. Those favourable conditions would not really apply if I had to cross the land mass of Northern Europe with its many mountains.

Still, I can dream.

Actually, that sort of diatance might bring me near Spain and Portugal, also a mostly sea path. That is a path I have exploited on the lower bands, and it worked then despite the hills in England and Wales in that direction.

That record breaking LY contact was during a tropospheric opening which lasted at GM4FVM from 17 to 21 September. It has been a terrible year for weather here in South East Scotland. Our apple crop will be poor, the tomatoes have failed to ripen in the greenhouse. Put simply there has been a lack of sunlight.

I put this down to a absence of high pressure systems. This has been true almost all year, but especially in Autumn when such systems usually come in off the Atlantic and are blocked over the North Sea. In previous years we often have had excellent conditions across into Europe lasting for days until the high pressure wanders off or fills in. Anyway, on 17 September my spell of bad fortune finally ended.

I have a composite map of all bands during the period. 6m contacts show with orange pins (only one of those), the 54 2m contacts have red pins, the 51 70cm contacts have darker purple pins, and the 17 23cm contacts have light blue pins. You can see that GM4FVM, who is colour blind, wrote that bit, but even I with my Daltonism can just about see the differences.

All contacts at GM4FVM 17 to 21 September 2024

On this map 70MHz contacts do not show any pin. There were just two of these. One was tropo and the other was a meteor scatter contact which was particularly interesting. This was with SM4POB in that small segement of the 4m band avialable to Swedish amateurs under special licences. It was of course a new square for me, and also for Per. I tend to forget that although IO85 includes the city of Edinburgh, it can be a hard one to reach. It was a great pleasure to work easily into Sweden on meteor scatter, not during a shower and at 18:00. This rather daft idea I keep reading that outside a shower you need to be on the band at 06:00 is nonsense. Of course it helps that 4m is a superb band for meteor scatter, but the same rules apply elsewhere too. Thanks Per.

Apart from that one meteor scatter contact and the 6m one with UT7UA (which was Es), all of these QSOs were via troposhperic propagation. As well as the higher bands there was also some tropo on 4m, where I worked DK8WK. I also might have worked some 4m tropo in the shape of some G stations who I heard. I could not find a microphone which fitted the Anytone FM radio, so that one did not work out. Imagine how crazy you must be to file away your microphones in a box with a "MICROPHONES" label on the front and then not be able to find the right one in there. I have found it now of course, but what use is it when the G stations are long gone.

Lots of these 125 contacts were very pleasurable. Lots of old friends and great DX. I cannot really list them all here, but it might be worth considering the pattern on the various bands as set out below.

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

50MHz

1 contact, best DX UT7UA, KO20, 1891km

70MHz

2 contacts, best DX SM4POB, JP70, 1176km

144MHz

54 contacts, best DX SP5JK, KO02, 1542km

432MHz

51 contacts, best DX SQ4MIK, JO94, 1383km

1296MHz

17 contacts, best DX LY3WR, KO24, 1726km.

Total

125 contacts, 48 squares, 14 DXCC

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

It is not often that my best tropo DX is on 23cm. Apart from that one Es QSO, my greatst distance was that one new record for me. And a new country, LY, bringing my 23cm total to 13 DXCC. It was a good time for 70cm too, psuhing me past 100 squares, in fact rasing my total from 98 to 105. On 432MHz I was also close to a record DX when I worked SQ4MIK in JO94, a distance of 1383km. Piotr just missed out on being a record due to my previous contacts into EA, possibly due to a slightly more tricky path to Poland.

It might be worth noting that during the period 17 to 21st I was in fact away from home for lunchtime on 19 and away all day on 20 September. What could I have worked if I had stayed at my post?

An autumn tropo opening is always a wonderful thing to behold. I manage to attract pile-ups while at the same time breaking new personal best records. There is nothing special that I do, I cannot boast about it when it is the troposphere which is making the difference. It is just another wonder of the world.

I cannot wait for the next one.

73 Jim

GM4FVM

Meet the Masts

I have various antennas here. My two tilt-over masts have been in position for many years and overall they have given good service.

The key thing for me is safety - they need to be strongly mounted and easy to work on. No ladders. Ideally they should be extendable masts meaning that they do not need to be on the skyline for any longer than necessary, with the added benefit that I can lower them out the strong winds we get here. I need to be able to tilt them to work safely.

While my antennas need to have enough elements to serve their purpose, I also need them to be reasonable size. I do not want them to be eyesores, and if they are too big they will suffer in our winds. They cannot be too heavy and over-stress the rotator, nor need excessive bracing. Everything needs to be made of materials which can resist the salt-laden atmosphere created by the nearby North Sea. Above the rotators I use thick wall 50mm diameter aluminium poles to support the yagis, and this also limits the overall size of the antennas.

Finally, I need to strike a balance in relation to the OFCOM regulations for radio amateurs in the UK. To manage enough output power yet stick to the rules needs a bit of thought about mast location. That thinking required me to have two supports as my first one would have been in the wrong place for my current 144 and 432MHz set-up. The OFCOM guidance suggests that if there is an issue with meeting the rules then just raise the antenna - great advice but not practical here. Thus it turns out that my 2m/70cm antenna has to be in the location now occupied by my second mast.

Fortunately it is easy for me to meet the regulations on 70MHz and 1296MHz using my initial mast so it remains in use for those bands. My 50MHz antenna does not fit on the original mast so it goes on the later one. Thus: two extendable and tiltable mast supports. It would be great to have everything on one, but then four antennas on that would become a bit of a nightmare.

The current pattern was not planned but emerged over the years. 

The Tennamast

My original 7.6m Tennamast arrived in 2008, 16 years ago at the time of writing. I quickly adapted it with worm gear winches. This means that both tilting and raising are very stable with no ratchets. I raise, lower and tilt the Tenna mast using a battery powered drill. Over the years all that has been needed is occasional greasing plus one set of lifting cables - more on the cable here.

Tennamast at GM4FVM with 36el 23cm and 5el 70MHz, 28MHz vertical alongside

Unfortunately although this location is great for any antenna at 70MHz and above, the longer elements of a 50MHz antenna would get caught in a building when the mast is tilted over. I had not factored this in when locating the Tennamast. While a 50MHz HB9CV type antenna would just fit, it needs to be side on when tilted, and then the longer booms of the 4m and 23cm antennas would hit the building instead. I bodged about for a while and then decided that the only answer for 6m was to locate that antenna further along the house on the gable end of our kitchen extension.

The CUG mast

The first antenna on the gable end was in 2011. I was quick to locate my 6m HB9CV there. Initially I used ladders to reach a set of T and K brackets fixed to the wall. Access got difficult as time went on and I bought a cheap scaffolding tower to make life easier. Despite this there were two "incidents" when I ended up in an uncontrolled descent and plummeted to the ground. In the end it was clear that I needed another tilt-over mast on the extension gable end to ensure safe access.

My CUG mast arrived in 2016, 8 years ago at the time of writing. On it went my 5el 6m PowAbeam and my 2m/70cm antennas.

The 10m aluminium CUG mast was installed by Gary and featured hand cranked winches. It pretty quickly proved to be too weak for the job in hand. As I have mentioned here before, it can get very windy on the East Coast of Scotland. The aluminium mast was simply too light for the stresses it was put under and I knew immediately that this was not my greatest decision. The choice had been made on the basis that an aluminium mast was about 20% cheaper than the steel equivalent. The Tennamst was steel and caused no problem, but I failed to learn that lesson. Aluminium might be a risk but it would probably be OK, or so I thought. That decision might have been a good one if I lived in an inland valley, whereas being not far inland from tall sea cliffs it proved to be not so good. Not that the aluminium mast would fail or anything, it just whipped and twisted about in the gusty winds. Maybe I had underestimated the wind loading of my antennas too.

I have learned over the years that if I make a mistake it is best to accept that and fix it. I contacted Gary and he offered me a part-exchange to trade up to a steel mast, the one I now have...

The steel CUG mast at GM4FVM, with DUAL 2m/70cm and 5el DUAL yagis and 4m vertical alongside

Changing over to the steel mast made a huge difference. The second mast is very stable in strong winds.

The steel mast came with a rotator cage, something which takes the strain off the rotator and reduces the possibility of rotator failure in strong winds. The inclusion of a rotator cage required me to purchase a Yaesu bearing which is fitted to the top of the cage, allowing the top pole to rotate.The winch is fairly noisy and I may have to come up with another winch solution similar to the one I used for the Tennamast.

Steel CUG mast at GM4FVM tilted over for some work on the preamplifiers

The steel mast is a three section version, whereas the aluminium one was just two section. When delivered the upper steel section kept sticking in the raised position leaving the mast unable to be lowered. Luckily GM3PPE came to the rescue with his large set of files, and some rogue galvanisation was filed off the upper box section. The three section mast now works well, but it possibly adds some scope for inaccuracy with antenna azimuth settings due to the extra slack in the two joints. This hardly matters in most cases, but maybe on 70cm moonbounce it might cause some problems.

While I had a issue early on with two broken pulleys on the original CUG mast, the second one has not caused any other problems once the sticking top section was filed down. Just because steel is heavier than aluminium the process of winching the mast over is now a heavy job.

I transferred the antennas from the aluminium mast to the new steel one. At the time these were, a 9el 144MHz and 16el 432MHz DUAL yagi fed separately by two runs of coax, and the 5el 50MHz PowAbeam. After giving eight years good service I recently replaced the PowAbeam with a 5el 50MHz DUAL. I stayed with five elements in order to keep the visual impact low but also to stay with a rigid boom and good wind resistance. While the steel mast could certainly take longer and heavier antennas, I do not want to go beyond self supporting ones into the world of bracing.

Winches

The Tennamast came with 600lb aluminium winches with ratchets which I replaced with worm gear ones, 1200lb for lifting and 1500lb for tilting. You can read about this here and see photos of the winches. One benefit of using a battery powered drill for lifting and lowering is that as I have three batteries for the drill I am unlikely to get stuck with a flat battery.

The first CUG mast used hand cranked winches which can be hard work. When it came to specifying a successor I opted for an electric winch. It is powered by a 12V lawnmower battery stored in a weatherproof "Dri-box" alongside. The battery can be charged in situ using a weatherproof mains socket nearby, or if it is raining or snowing I can carry the Dri-box into the garage and charge it there. It has to be charged every month or so, depending on use.

Noisy Rhino lifting winch at GM4FVM, with hand winch for tilting seen behind

The winch came with two remote controls and a wired rocker switch. The connections to the wired switch seemed a bit light for outdoor use so I took that off and simply use the remote controls. I only use them standing beside the winch, but even then the signal seems weak and sometimes is interrupted. The winch seems to handle the load easily. 

I fitted a fuse to the battery and used Knightsbridge weatherproof connectors to allow the battery to be removed from the winch circuit and charged. I then fitted a second Knightsbridge connector to a dedicated "smart fast charger". The charger can be used outdoors but it is not weatherproof, hence the need to charge the battery in the garage at times. A basic charge to 90% capacity takes 20 minutes, but for a full charge from empty can take about 40 minutes.

The Dri-box is intended for mains wiring for things like outdoor lighting. Here it only has a 12V battery inside and it seems to have remained watertight. I used heavy outdoor cable to connect to the winch as the current carried for short periods is quite high.

In conclusion

I certainly never set out to have two masts. However I am satisfied with how the present system works. It is surprising how often the two rotators are pointing in different directions. The load on each is reduced and so is the visual impact. Very rarely are both masts raised at the same time. Most of the time both masts are lowered - I would say that one of them is raised in daylight once per week or less. I am not so concerned about antenna height, it is the ability to tilt them for safe work which is most important for me.

The whole set-up meets the OFCOM rules. The masts have been up here for 8 and 16 years respectively with only minimal maintenance being required. Any maintenance which is needed can be done safely from ground level. Overall I would say I am content with the way the masts perform and I would recommend either of them to anybody who was considering something similar.

73 Jim

GM4FVM

New countries worked and DX records reached on aurora recently - thanks to Q65

I have posted before about me using Q65 for auroral propagation. If you need to, you can read about that here. However, this current post is about how much better I have been doing in more recent soar events.

There were two auroral openings here a few weeks ago (4 and 12 August) which I should perhaps have reported on at the time. Well, I had a rough posting in the works but it never got much further. 

Believe it or not I do have to lead a more or less "normal" life outside amateur radio. Sometimes I have to do things like replace 35 kitchen doors and drawer fronts using the skills I learned from "Squarehole". He was my woodwork teacher during our tempestuous time together back in 1968. Would it have helped if I had listened to him? Probably not. It might have helped if he had listened to me from time to time. There is only so far you can go with wooden tea pot stands when you future life is more diverse.

Ah well.

GM4PMK's magnetometer on 12 August 2024

As per usual, click to enlarge the images if necessary.

Anyway, those solar events produced contacts with countries which I have never reached by aurora before. Take for example OH6KTL on 144MHz, my first auroral contact with Finland on that band. I worked Lasse on both events. OK, I have worked Finland on 2m before, on meteor and ionoscatter, plus tropo, so what difference does it make using aurora? Simply that unless we know what propagation method we are using we will not learn anything about propagation. Remember I have this old fashioned idea that amateur radio should be about learning. Woodworking classes should also be about learning, even in 1968, but we will have to let that thought go. Not that I am bitter or anything.

At 1504km the OH6KTL contact is the best DX I have ever worked on 2m Aurora. Also on 4 August I worked OH2BYJ on 70MHz at 1571km, which was my best DX on aurora on that band too. The contact with OH2BYJ is in fact the best DX I have ever worked on aurora on any band.

An aurora almost a mystical event. Radio auroras produce the oddest conditions with roaring band noise, strong distorted signals and dramatic changes in conditions. If the polarity of the matter reaching the Earth reverses then the radio aurora can start or end abruptly. There is also the possible bonus of Auroral Es propagation at the end of an event, but this not so common. We may get two or three days warning of an aurora, or we may not. The feeling in the shack here is of witnessing a remarkable event. So the further I can reach during an aurora extends the majesty of the whole thing.

On 4 April I worked F1FPL on 2m for a new country on aurora. I had never even heard a French station from here on aurora on any band.

Auroral contacts at GM4FVM, all bands, 4 and 12 August 2024

It is not just 2m where I have been doing well. I have been working quite a few stations during 6m and 4m auroras. However, there is no doubt that 2m has shown the greatest benefit lately.

So what might have changed which makes for greater success? Obviously every event is different but over time I can average that out. I am doing better now. 

It appears to be largely down to my use of Q65. My hearing has never been good at picking out either SSB or CW during an aurora. As the distorting effect of the Doppler shift is worse for higher frequencies, that made me shy away from 2m during auroras. Q65 has lifted that barrier and allows me to spend time on 144MHz.

70MHz auroral contact with OH2BYJ on 4 August 2024

When it came to the contact with OH2BYJ on 4 August I could hear nothing but noise on the loudspeaker and see nothing on the waterfall. I could never have made this contact any other way simply because I could not hear him.

It is not just the removal of my hearing from the scene which helps. It is pretty clear to me that using Q65 is very effective. I am working further afield, reaching more stations and filling in some gaps. I recall receiving stations on SSB who were strong but I simply could not decode any modulation in them. Q65 seems to be able to reach those ones too.

In the past, auroral openings for me (especially on 2m) tended to be limited to within these islands with the occasional LA or OZ. Now the field is opening up for me to reach further. This can only be regarded as a victory for Joe Taylor and his team. I doubt if they had me in mind when they created Q65, but it certainly works for me.

Nothing that I say should be taken to suggest that we should not use CW or SSB during auroras. That is our choice. All I am saying is how effective Q65 has been for me. During the 12 August opening I was happy to work GI4SNA and GM4CXM on 70MHz SSB. Those were very pleasant contacts and let us keep that option open. However, they are examples of the shorter range contacts I used to make. SSB does not work well for me on 2m, and CW is doubly difficult for me on that band, and the distance I could work was always relatively short.

Maybe I am odd, but I have no problem tuning around looking for signals and switching mode as I think fit. I cannot see why some people see data modes as the road to extinction of our hobby - we are not obliged to use them. We can use data for some contacts and anything we like for others (and I do).

Q65 is very adaptable, and there are a range of settings you can pick. Most stations seem to be using Q65-30C during auroras. I have tried other permutations, but that one seems to work for me. I am still happy to work stations using another other variation, but I use 30C for calling CQ.

It seems that Q65 allows me to reach further, and for others in areas not often affected by auroral propagation it allows them to reach me. Over many years I had success on this amazing propagation method but it always seemed limited, especially above 50MHz. If Q65 opens the door to more contacts during auroras then I will be very happy.

I could go further and repeat my view from previous postings. I find that Q65 is better than FT8 for contacts in any situation on all VHF and UHF bands, right up to 1296MHz which is as far as I go. The higher the frequency, the better the outcome from using Q65. I cannot really see a reason why VHF+ operators continue to use FT8 when Q65 can produce more reliable, better, DX. I also cannot see why the RSGB have a 70cm FT8 contest when a 70cm Q65 contest would produce better results.

OK, maybe at 50MHz the benefits would be less apparent, but as we go up through the bands the disadvantage of using FT8 increases. An SP station was keen to work my on 70cm tropo recently, just as I was keen to work him (I have 99 squares on that band). It had not worked on FT8 so he suggested Q65. As it happened Q65 did not work either (it is not a miracle worker) but HE suggested it to ME. Come now, this is not just my hobby-horse now. It is time for us to face reality here.

73 Jim

GM4FVM

Is this the end of Summer, and Summer Es?

I tend to see the harvesting of the wheat field beside GM4FVM as bringing the end of Summer Es season.

That used to happen regularly early in September. However, last year it was a month early, and this year it happened on 18 August.

So I guess this is a silly romantic idea I have, as surely the 2024 Summer season can hardly end on 18 August?

Well the schools around here have gone back from their Summer Holidays - they reckon Summer 2024 is over.

In many ways I hope the 2024 Summer Es season does end now, because hopefully Autumn will be better.

The difference between 50MHz Es this year and the same time last year is pretty stark.

50MHz contacts at GM4FVM from 19 July to 18 August in 2023 and the same period in 2024

Only around 10% on the 2024 contacts were multiple hop DX ones (that equals two contacts) compared with 32% last year (36 contacts).

Things on 70MHz were similar. On 144MHz Es openings are unusual this far north so this is harder to judge on that band. There was one big single hop opening between those dates in 2024 on 2m, on 6 August, and just one small one in the same period 2023. If I could see any pattern in the 2m openings I would be very happy because they are rare as rare things.

What can explain the significant difference this year? Well it could just be down to the random nature of Es. You cannot count on Es at any time of year, and maybe this is just natural variation. 

On the other hand I have spoken to several people who are certain it is due to the sunspot cycle peak. I do not recall this happening at the last sunspot cycle peak but then everything was much less organised on 6m then. The season was much shorter and ended about now in the year in those days, but surely that was due to lack of activity. After all it did not resolve immediately outside the peak sunspot period. Anyway, this was discussed here and after reviewing the data I cannot say that anything remarkable pops up. I need to look more closely.

Perhaps because I have read in several texts that Es is not affected by the sunspot cycle (or not noticeably anyway) then I am reluctant to accept that it might be. The upside of the sunspot peak would be F-layer propagation which I have yet to see.

I doubt if harvesting the wheat really indicates much, but it feels like it does - and may be that is as good an predictor of Es propagation as the various websites which claim to know all about it.

Harvesting under way near GM4FVM, 18 August 2024

Whatever the cause, the effect is pretty clear. For a lot of the time (days on end) I have been looking at empty waterfalls and blank "band activity" lists. Thank goodness for aurora and meteor scatter.

Yes, they call it sporadic for a reason. So therefore it could recover tomorrow.

WELL, GET ON WITH IT.

73 Jim

GM4FVM

Tracking the path of Sporadic E openings

The paths of Sporadic Es (Es) openings can often be seen to move across the Earth in regular patterns.

At one extreme, at higher frequencies we regularly get openings which only include one or two stations, and there is no movement discernible there. At other times especially at lower frequencies there is so much activity from multiple areas of Es that we cannot make out any detail out at all.

From time to time I find an opening which shows up the movement in a clear way. I have described two of these before on this blog - 

1) here, where a 50MHz opening to Japan showed an east-west pattern at the Japan end and suggested that whatever propagation method opens this path it looks very much like Es at the Japan end.

2) here, where on 144MHz the distance of the path shortened 700km over a 22 minute period.

On 6 August 2023 there was a 144MHz Es opening which showed a definite east-west transit at GM4FVM.

As luck would have it, this was a good opening with me contacting 31 stations in 103 minutes. This covered 6 countries and 18 squares, with the best DX being IK7UXW in JN80 at 2236km. On the other hand luck also dictated that I was absent from the shack for 28 minutes roughly in the middle of the event, but this did not seem to make much difference. This time the average lengths of the paths changed very little but the azimuth angle moved steadily (roughly) from "south east" to "south south east". Overall the path traced by rotator was in an arc which headed from east to west.

I have dithered a bit over how to represent this on the blog. I have plotted graphically the azimuth (my beam direction) against the time and produced a line of best fit, but somehow the graph does not show how the Es shifted very well. 

So what I have done is to show the map of the contacts with a text box showing how the front of the contacts moved across, expressed in terms of time and azimuth. The azimuth (my rotator angle) is at the top, and the time that contact occurred is below. The azimuth figures were calculated from the locators of the stations I worked.

144MHz Es contacts at GM4FVM on 6 August 2024

You will probably need to click on this image to enlarge it to see the detail.

I have listed the contacts in two different colours - red for the first phase, blue for the second phase, and I was out of the shack in between.

The leading edge of the contacts moved from 122 degrees at 09:22 to 156 degrees at 10:33, that is 34 degrees in 71 minutes or almost half a degree every minute. In reality it was not evenly spread and at times (especially at the start and end of the event) it was moving more quickly.

The "searchlight" of Es propagation shining on the ground was tracing a path which moved past stations at a surprisingly fast rate. Generally as it moved on contact was lost with those behind, with only the odd contact in the rear of the leading edge.

During the period I was out of the shack it did not seem to move much at all. I must go back in the log and try to work out what was happening then.

It would be easy to dismiss this as an opening into Italy and France, with one contact each in Croatia, Switzerland (with a very determined 2E0 stations adding to the fun on tropo). Looking at my normal map of an opening it just looks random. However, looking at the timings the Es path seems to be moving in an organised way.

A more conventional view of the opening on 6 August 2024

When viewed in DX Maps it is possible sometimes to see areas of high frequency refraction which appear to move between squares in a westerly direction as the day progresses. I can see a similar effect in openings such as this. What the cause is could be difficult to determine. At first it looks likely that the Sun's movement relative to the Earth might be the cause. Certainly the Sun plays a part by driving the air movements which create and organise the Es layer. Ripples in the Es layer could also be a factor. However it might be more complex that that.

I wonder if this was one event or two separate ones. The fact that the propagation did not seem to move much during around half an hour when I was not in the shack might suggest that. Also, the full picture may be hidden due to the geography. Obviously there are not many stations in the Adriatic and Tyrrhenian seas. Signals from there might have given a fuller picture. Still it looks pretty clear to me that the paths were moving steadily westwards.

Here is the summary from that first map, still with the first phase in red and the second phase in blue:-

  156        151        148         144        140        139         136        131        122       Azimuth

10:59     10:44     10:42     10:35     10:00     09:41     09:36     09:31     09:22     Time

 More research necessary.

73 Jim

GM4FVM

I saw the propagation arrive from far away

I was out on my afternoon walk when I noticed a cloud formation which suggested enhanced propagation on VHF. It was a still sunny day on 31 July with some "nuisance" cloud towards the horizon. A careful look revealed a dark grey band below the distant cloud level. I recognised this as a band of still air above the North Sea, which indicates that a temperature inversion may be underway.

I put an inch to my step, hurrying down Ayton Law, past the alpacas sunning themselves in the still air, and home where I had a look at 2m and above.

Dark grey band just above the horizon, Ayton Law, 31 July 2024

Click to enlarge images if necessary, as per.

The dark grey band can form over the North Sea when pressure is high. When it comes ashore it produces the effect known in Scotland as the "haar". When warm air passes over the sea a foggy layer of condensation forms also known as a "sea fret". The large bank of air can be very still and stable, but the entire bank can sometimes extend ashore producing very strange conditions. When the haar arrives near GM4FVM it can be seen pouring over the headland to the south, spreading down the slopes and into the valley of the Eye Water in which this station is located.

On shore the haar produces a damp fog which feels wet and yet can be surprisingly cold for something produced below warm air. On 31 July when I approached home I also noticed a cold wind which often arrives at about the same time. This feels like the output from an air conditioner, and circulates around the stable air system. The Scots word haar is derived from a Dutch word for cold. Inside the fog it can be quite dark as if enveloped in cloud as in an aircraft, and with the Sun blocked out also strangely cold. A short distance away, outside the cloud, it will be sunny, still and warm. Overall these can be a remarkable effects.

A large bank of still air over the North Sea is just what is required for tropospheric propagation. The tropo predictions had not been too hopeful for that day, showing a detached patch of enhancement north of me and then some more over on the Denmark coast. Not promising as tropo requires a continuous path.

Hepburn Tropo Chart for 18:00 on 31 July 2024.

It seemed likely that a mass of air had formed over the North Sea and this was allowing propagation. The QSOs showed two distinct paths, one to the east to to SM and OZ, and one to the south east to DL and PA.

144MHz contacts at GM4FVM on 31 July 2024

Conditions on 144MHz have been pretty awful this year, reflecting the lack of these very conditions. So it was very agreeable to be able to work 15 stations across the North Sea, and the best DX to SM7KMJ in JO66 at 947km was pretty good.

On 70cm I worked across the North Sea to OZ2ND and PA3CWS both of whom I also worked on 2m. I saw nothing  on 23cm, despite trying hard.

Haar coming ashore is fairly rare round here. This time it did not arrive on shore, well not as far inland as GM4FVM anyway. However, seeing it in the distance and feeling that cold wind on an otherwise warm day put me on alert.

Now two days later the pressure has fallen and the usual strong winds associated with a weather system coming from the West have returned. There is no possibility of still enough air over the North Sea to hold a bank of air, and the warm weather has gone. VHF conditions have returned to their usual sleep. Even the alpacas are sheltering under the trees today.

Alpacas sheltering on Ayton Law, 2 August 2024.

Most propagation enhancements arrive silently and invisibly. Actually seeing one was a bit of a surprise.

73 Jim

GM4FVM