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New antenna build success


#1

My favourite HF band for activating is 20m, and my favourite antenna for 20m is the quarterwave vertical with elevated groundplane. I’ve had a lot of DX success with this type of antenna on SOTA activations over the years, but I’ve bashed a few of them up in the process.

My most recent one was needing a new repair after every activation, so it was time to retire it and chuck it away. I had all the stuff to build the replacement but just never got round to it with distractions from, mainly, music work, strong winds on summits, and Fusion.

Anyway, this morning, I awoke at 0630. I tried to go back to sleep but all I could think about for the next hour was my 20m GP antenna. Yes, I’m afraid so. So at 0730, I got up, put the kettle on and got the tape measure, wire cutters, choc block, reel of green military spec heavy duty wire, RG58 feeder (from an old SOTA Beam, so already nicely terminated with a BNC) and wire winders out. I also got the very nice laser cut centrepiece that Jonathan GW2HFR kindly sent me. This was based on the SOTABEAMS kit version - https://www.sotabeams.co.uk/content/20m%20GP%20Instructions.pdf - but redesigned to accommodate a fourth radial and the thicker antenna wire and feeder cable.

It took me just over an hour to build the antenna - probably stupidly slow by most adept people’s standards, but very pleasing progress for me personally and my historic low confidence with practical stuff.

But would it work? It’s a bit of a squeeze and a flaff to test antennas in my garden, and if going out to the local park, I might as well go out to a local summit. Richard G3CWI was at a loose end and wanted to perform another C4FM activation, so I picked him up and off we went. It was a stunningly beautiful sunny morning, albeit very cold if you sited yourself in an unsheltered position. As Richard discovered.

I knew the driven element on my antenna was easily too long. I had been cautious with my cutting earlier. I also needed to be cautious with putting my antenna up and down; The Cloud G/SP-015 was extremely busy, as to be expected on such a fine day. It took a bit of work to get the mast upright with viable pegging positions few and far between; most of the ground was frozen.

Once everything was set up, I was quickly able to determine that the antenna, at present, was resonant around 13.6MHz. Good - exactly what I had expected. I lopped some of the wire off the driven element and retied it to the small acrylic piece that sat on the top of the mast. No further adjustments were necessary. Resonance was now at around 14.150MHz with the whole band showing as viable.

I kept one eye on the RBN spots which indicated some good data from Eastern Europe and North America. I made 13 QSOs on 20m CW, including two US stations. After returning home, I was pleased to see that lots of beacons had received me:

http://reversebeacon.net/dxsd1/dxsd1.php?f=0&c=M1EYP%2FP&t=dx

Richard inspected the antenna and acknowledged, with some understandable surprise, that it wasn’t too bad an effort. He did advise me to protect the ends of the radials where they were close to the corners of the square centrepiece though - which I will do shortly with some sleeving or tape.

We drove back to Macclesfield but accidentally fell into the Harrington Arms at Gawsworth for a pint and a homemade Scotch egg on the way. These things happen.


#2

Well done Tom with the antenna and also with the pit stop you had at the pub. We all need some reward after a finished successful good job done…

About the same thing I should be doing one of these very next days in oder to prepare 6, 10, 12, 15m band 1/4 wave GP wire antennas for the coming 1st edition of TEP WW SOTA WEEK.

73,

Guru


#3

Hi Tom,

Your antenna was apparently receiving well, too, as you heard my 12 watts from Northeastern US.

Thank you again for the contact,

Paul - N1ZF


#4

I’m not about to make that antenna myself (I copied Andy’s!) but I was very impressed by the instructions, I would say they were foolproof (except that fools are so ingenious!) :wink: Kudos to Richard!


#5

OOPS I thought TEP was only VHF, so 6 metres makes sense but can we have TEP on 10,12 and 15m as well?

Ed.


#6

Yes, 12m TEP was how I worked several African stations one afternoon in the challenge. Swaziland, Malawi and somewhere else, maybe Zimbabwe. Need to check the log.


#7

Well we live and learn … Great news then - so when is the TEP SOTA experiments week going to start Guru?

73 Ed.


#8

Hello,
I really hope the TEP WW SOTA WEEK event to raise enough interest and have a significant number of participants in the 3 established zones.
We will have aTEP (afternoon TEP) and eTEP (evening TEP)
In the site http://www.qsl.net/vk2kfj/tep.html we can read:

Maximum observed frequencies (MOFs) for afternoon TEP are typically 40-55 MHz, and occasionally extend to the 60-70 MHz region.
For paths oriented generally north-south (eg. VK - JA/HL), afternoon TEP generally occurs between 1400 and 1900 local mean time (LMT), occasionally extending as early as 1200 and as late as 2100 LMT.

Maximum observed frequencies (MOFs) for evening TEP extend to at least 432 MHz.
No upper limit has been established.
Evening TEP has a peak diurnal occurrence between 2000-2300 LMT (at the midpath, where it
crosses the geomagnetic equator). It may open a little earlier, and extend past midnight on
the lower frequencies, but openings on the higher frequencies rarely extend past 2300 local
time.

My intention is to be activating at aTEP times , not for eTEP, as being that late in the mountains in not possible for me. I’m interested in finding out whether we can have aTEP contacts on 6, 10, 12 or even 15m.

I e-mailed the plans for this to some SOTAist in South-Africa and also in South and Central America. I haven’t got any feedback yet but I’ll insist probably this week, as well as here on the Reflector in order to increase the interest within the SOTA community hoping for a good number of participants.

I hope this will be a really interesting experiment and we all may end up learning a lot from it.

73,

Guru


#9

Friday 6th April 2018 - The Cloud G/SP-015

I headed out early with my 20m GP antenna, hoping for some Far East or Pacific DX. Ha - no chance - in my first 20 minutes of CW CQing, only G4AYO came back to me. Eventually, from about 0718z, Russian stations started replying, along with a few from Greece, Serbia and Romania, but it definitely wasn’t the best morning to be out playing radio.

An otherwise boring and unremarkable activation finished on a high, with S2S with Eva YO6EVA/P and Csaba YO6PIB/P on Hoapecu YO/EC-367.


#10

Sorry to hear that the trip was less than exciting Tom, but the two S2S contacts (albeit to one summit) was something at least.

I’m going out to try my luck early tomorrow at Eisenberg DL/AL-171, the castle ruins summit that was rained-off for me about a week ago. Lets hope the weather stays fine, it’s nice and sunny at the moment.

73 Ed.


#11

Thanks Tom for the s2s, really helped us in qualifying the summit. Today was not a good day for my 20m GP, in almost an hour CQ I had only one QSO, and in the end you coming in for the s2s, it took me a while to recognize you in the heavy QRN. Otherwise the 20m was completely dead for me and had to throw some long wire for 40 to get a few more QSOs and another s2s with HB9DBM/p barely readable.