Other SOTA sites: SOTAwatch | SOTA Home | Database | Video | Photos | Shop | Mapping | FAQs | Facebook | Contact SOTA

A question on propagation.


#1

Next week (6-12 Nov) I will be in EA8 on a family holiday with a few SOTA activations thrown in. This will be the 4th Autumn/Fall trip to EA8 with a view to activating SOTA. As it’s a family holiday SOTA is not foremost on the list of activities but I hope to get 1 or 2 days to myself.

I’ve been looking at VOACAP and trying to make sure I understand what it’s telling me. Sadly I don’t really because I am an opportunistic HF operator, I climb a hill and play on some HF bands till I have had enough of the WX or there are no more stations I can hear to work.

I will have an 817 with me and maybe a small PA capable of 25W. Antennas will be a 17m/20m/30m link dipole, a 15m/17/20m/30m loaded vertical. I hadn’t decided whether taking the 40m/30m/20m EFHW was worthwhile as operation is likely to be limited to 1000Z to 1800Z max.

VOACAP is suggesting that operation on 12m has a high probability that I will be able to make QSOs into Europe. I have a 12m 1/4w GP that weighs next to nothing and is trivial to deploy and I was wondering if it really would be viable. Or am I being suckered into seeing what I want to believe from the predictions? 3 years ago at this time of year I was able to work 60 stations on 10m SSB with a compromised 10m antenna from EA8/LA. It was immense fun. Now 3 years further into the solar minimum I would not have bothered with the higher HF bands. But those charts are seductive and drawing me like a Siren Song.

My question to those with some long term HF experience is simple? Would they really expect to be able to work 12m to EA8 at the current point in the solar cycle? (And yes I am aware HF conditions maybe a bit broken by the imminent return of a coronal hole.)


#2

Doubtful Andy we would hear you on 12m with QRP whatever aerial you use. Looking at the FT8 channels today, `15m EA8DFQ I easily worked - he was SNR +10 on my Hexbeam at. 1510z today. No signals on 12m then at all and none at present. If you are operating in the afternoon 15m and 17m, should be quite effective. We will be looking for you.

Good luck!

Phil


#3

I agree with Phil. I hear occasional activations on 15 and 17 but outside the sporadic E season 12m is very silent here. It may be better in southern EU but we wouldn’t hear that here.


#4

Hi Andy, over the last few weeks it has been very rare that the 3000Km MUF from the UK has got any where near 24MHz, so I’d be very surprised if you manage a contact back to the UK on 12m.

20 & 17m would perhaps have a chance or of course 30 & 40m are better bets.

73 Ed.


#5

Oh, propagation is far, far more involved than watching VOCAP. Myself as well as other Activators and Chasers have made some remarkable DX and DXCC contacts on bands which have been deemed unworkable by the SFI, K index’s and VOCAP. You can discuss the subject of propagation until you’re blue in the face, however, there’s only one certain way for a SOTA Activator to find out about propagation and that is to take a rig and antenna onto a summit.

YYY


#6

Prior to going to Shetland in the early summer I asked the RSGB propagation for their comments on what would work back to middle England. 30m was the optimum with 40 a close second. I was advised to use ITURHFProp, at www.predtest.uk. This predictor was said to be optimised for “short range” prediction. It is easy to use but you have to be a little patient. I have used it since for the path from UK to Malta, predicting best times. But note it does not input short term variations in solar activity. 17m looks best but 25w will be challenging.

David

Regards
David


#7

Well, I love software. Just playing now and I cannot get VOACAP to generate the same numbers as before, something somewhere must be different (something I did or didn’t do last time). The figures for EA8 to G for 12m are now in the 20% chance of success down from 70% when I asked. The figures now look much more like what I would expect for this time of the cycle.

Phil @g4obk, I specifically made a dipole with 17m/20m to give me an edge over the Buddistick clone. Last year from Gran Canaria using the Buddistick clone, I could see a 3:2:1 ratio of the number of QSOs on 20:17:15m. (i.e.12 on 20m, 9 on 17m and 4 on 15m). I didn’t keep accurate records of which were at a higher power and which were barefoot.

Brian @g8add, I’m hoping the dipole will make SSB viable, it certainly was almost impossible last year.
78 CW QSOs vs 4 SSB QSOs on 3 activations. I’ve even fixed both 817 dodgy microphone plugs in hoping for something to work.

Ed @DD5LP, 60m looks good but only when it’s dark. Wandering about extinct volcanoes in the dark is more excitement than I’m looking for! 30m may be viable late afternoon for Europe but it’s CW only. I wont be attempting FT8 etc.

David @G0EVV, thanks for the reminder about www.predtest.uk, I keep forgetting it, bookmarked now. Unfortunately I must have offended it as it runs for a few minutes then tells me there was an error despite trying several browsers. Yes, it was a bit lonely at times when calling last year and it will probably be the same this year. The lack of solar activity is what prompted me to get a dipole built. I’ve noted which way to “aim” it for Europe and for N. America. Looking at last year’s logs, the same stations keep appearing and I think they all have some kind of directional / gain antenna. Hey, I only need 1 QSO per summit to get a unique to my name and the path probability to the very active group of EA2 chasers show good numbers for 17/20/30.

There’s 1 complete to aim for as well. Hmmmm.


#8

I have a spare unused MH31 somewhere, just shout if you need it.


#9

I would guess (without using prop prediction software) you should make plenty of bonus QSOs with USA/VE Andy from lunctime onwards from EA8 through to evening time on the 20m, 17m and 15m bands as well as contacts with western EU. I’m not sure if DL,OK, YO, S5 and the other countries in that part of EU are likely to be able to hear you. Its probably worth looking at some previous visitors to EA8s logs - I imagine you have already done that knowing you! GI4ONL would be a good starting point - Victor’s been there several times and operated SOTA as have loads of other well known participants.

Phil G4OBK


#10

Or just get on the air from anywhere and see what you can hear and then try to work it - it doesn’t have to be from a summit Mike! Like you I’m not a fan of propagation prediction software as when I have tried to use it it hasn’t been particulary effective.

73 Phil


#11

Well that’s what I was doing. See what’s been done and then look at what prop software said for those days and its predictions. Obviously at some point I’ve done a fubar and set the parameters to get the prediction wrong. I looked at the cluster this afternoon and there were plenty of spots for VP6D on 12m in S. Europe. Right now they’re being spotted in USA-W5 on 10m. But the VOACAP numbers didn’t feel right hence the questions.

Of course there’s a tremendous difference in performance between my likely SOTA station (say 25W CW to a dipole 650m up on a Lava summit) and the crew on Ducie Island with a 2 ele VDA sat a few feet from the Pacific Ocean with either 500 or 1500W up the feeder. Those VDAs do work so well by sea. Here’s VP6D’s own photo of the SSB antennas showing the setup.


(Image from vp6d.com website Copyright © 2018 VP6D Ducie Island DXpedition 2018)

I shall content myself with trying 30-15m and paying attention to trying to pick a good site for the antenna on the summits.

@G8ADD Thanks for the offer Brian. I spent an evening fighting with a crimp tool till I managed to fix both cables so I’m good at present.


#12

Hi Andy,
My recomendación is for 17, 20, 30, 40.
You should get into most of EU on 30 and 20m.
40m Will be good for CT, EA, F(South)
20 and 17m Will surely give you the best chances for DX into NorthAmerica.
If you really want yo try, 15m might you some surprise too, but I wouldn’t expect much.
12 and 10m would be a lottery with extremely low probabilities of QSOs other than local station.
I Hope to be able to Chase you. Perhaps with my remote station, which is finally working since last Saturday.
73,

Guru

P.D. it’s been a real pain typing this post on my smartphone always trying to automatically correct everything changing It to some similar Spanish Word.


#13

I feel your pain Guru, having just typed a short speech in Welsh. The next challenge was pronouncing the written words!


#14

Back OT.
Ed, What are programmes such as VOACAP actually basing their predictions on if not the MUF?


#15

Hi Andy,
VOACAP is a statistical prediction system. I am monitoring the actual MUF from the Ionosonde sites via this very nice website:

Which gives updates every 15 minutes of the actual MUF, not any prediction. It is UK-Centric, so less of interest to our NA or VK colleagues but very useful for the UK and western Europe.

MUF of course is only one factor that can decide whether a contact is possible but it does give a guide as to which bands might be the best at the moment to try.

73 Ed.

P.S. their (terrestrial) headline about severe storms over the next 5 days isn’t good news for those wanting to take part in the transatlantic S2S event! Even down here in Southern Germany we had some strong winds overnight that brought trees down and hurricane force winds are forecast for today in the Bavarian Alps.


#16

Thanks for the guidance Ed, I’ll have a look at that site.
I was thinking of lugging the 857 up Helvellyn on Saturday. The weather forecast is not supportive to that idea though! Still thinking about my plans


#17

With the weather, I think a lot of us will be looking for back-up sites for Saturday. I just found a good one, which I have activated before only then to realise it’s no longer a SOTA summit !

73 Ed.


#18

Dr OM Andy,
Since 2010 I activate summits on EA8/GC. My advice, based on experience, is simple: try 20 m cw. I have had several times surprises with propagation from there. The forecast was poor and I worked not only Europe but also USA with my humble 3 W and a W3EDP. Good luck and enjoy your stay there!
73 de Geert, PA7ZEE


#19

Boring plain-vanilla again. In doing so you miss out on that delicious frisson of excitement only felt by the operator who selects a band-mode combination that will have an uncertain chance of success.


#20

OK I’ll try a digital voice mode on 160m as well. :wink: