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Antenna for SOTA or travelling

You can try EARC antenna
http://www.earchi.org/92011endfedfiles/Endfed6_40.pdf
Good luck!
73,

Guru

You mean “random wire” and 9:1? Some expiriences? Rsults? Tuner needed? Thanks

Yes, random wire and 9:1 unun
Antenna tunner is needed if you want to use it in several bands.
The EARC antenna instructions recommend a wire length between 24 and 60 feet for optimal performance (1 foot=0.3048m).
I’ve used it with 3 different lengths and satisfactory results, i.e. 10, 14 and 21m.
Several DX all around the world on QRP 5W from SOTA summits.
73,

Guru

These SOTA topics should be of help …

Hallo Pavel

You will need some space to fix a 80m - Antenna…

But you if you want, you can built it cheap and easy to carry. This is my ZS6BKW for 80m and other bands. It’s built with twisted wire as a feeder. And yes - i have an antenna tuner.

Ignacio made a beautiful film how to wind it.

I fix it with velcro and carry it in a freeze bag with zipper…

3%20Euro%20Antenne

If you are looking for random wires, here you have the best length:
https://udel.edu/~mm/ham/randomWire/

But there are lots of hompages about different antennas, you can use - for example:

https://www.nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm#top-of-page

If you spend a little time in www you will find a lot!

73 Armin

At the link below are my VSWR measurements (with and without an ATU) for my random long wire (RLW) configured as an ‘inverted L’ with 9:1 UnUn (used and measured at my previous QTH and at my current QTH but haven’t remeasured it).

The “9” side of the UnUn goes to the RLW and a short wire to a ‘dog lead’ screw-into-ground ground stake. A coax cable connects the “1” side to the rig.


A RLW has an ‘up and down’ VSWR pattern plotted against frequency so you will need an ATU.

I get good on-air results and one could easily use a RLW and UnUn when portable (although I usually take a tri-band EFHW when activating for convenience and quickness).

73 Andy

Hello,

You might like to consider the Sotabeams Bandspringer Midi, which is listed with a range of 10-60m. You will need an ATU, but will not need a balun. I found it tunes all the bands 10-60m. It is light, small, and has a relatively small footprint when deployed.

I have used one of these with an elecraft KX3 for a number of activations, and it has been successful. The KX3 will even tune it on 80m, which surprised me.

I use a Sotabeams Compact Ultra Portable 6m mast, which is 56cm collapsed. I have used other poles but find this one more sturdy than others. I have taken this abroad a number of times in my hold luggage.

Regards
David
G4ZAO

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Hi Pavel,
When you say for travelling - if you are travelling in your car, then a fishing pole supported Inverted-V or end-fed is probably the safest option (and not a compromise, except that the end-fed needs wither an UNUN or ATU).

If you’re taking travelling in a plane, then you need something that collapses down - yes there are small fishing poles like the 5 & 6m €30-35 ones from Lambdahalbe
http://www.lambdahalbe.de/zubehoer/gfk-masten/6m-gfk-mast/index.html

but if you also want to be able to set up and take down quickly in a restricted space, then a HF vertical on a modified photo tripod (SO239 socket plus coax and counterpoise/radial wires added) is what I use. My antenna of choice for this set-up is the Komunica HF-Pro2 but it does have quite a long whip on it, a shorter and not as effective similar (tune the bottom) vertical antenna is the Diamond RHM-8B but it also costs twice as much as the Komunica and doesn’t perform half as well.

These are both 80-10m solutions. Komunica also do a wide band (no tuning required) Bazoka Pro - works well on 40m but not so well on other bands - the HF PRO-2 is a far better option.

73 Ed.

Wich lenghts you use for which band? Thanks

Either length I use has a 9:1 unun at the feed point. From that point, the RG58 coax go to the antenna tuner and I use the antenna on many bands.
My impression is that longer wire works better than short, but the 10m one has given me lots of great DX and many, many SOTA QSOs.
The length choice is up to you depending on how much space you’ll have available where you will install the antenna.
Although theory sais the EARC antenna doesn’t need a counterpoise, my personal experience is that the antenna performs better with a counterpoise. For my SOTA activations I use a 6m long counterpoise wire.
For the EARC antenna I have in the balcony of my rental appartment, the counterpoise is the metal fence of the balcony.
73,

Guru

Thanks… And how it works? With QRP…

You can install the wire as a sloper, as an inverted Vee, as an inverted L, as a vertical…
Any configuration will work fine.
There will be differences between one and other but I haven’t tested them at such extent.
I’ve used them as sloper, as inverted vee and as inverted L. All of them have given me big satisfaction and great DX.
Vertical is the only configuration I’ve never tried but it should work fine too.
73,

Guru

If you do a search for EA2IF/P on this Reflector, you’ll be able to read all my activation reports and you’ll see how the EARC antenna worked for me with the 5W of my FT-817ND.
This is the one after my last activation:

73,

Guru

Thanks, I will check and read it.

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I also always use a 35.5 ft (10.82m) end fed wire with a 9:1 supported with a 7.2m carbon fiber fishing pole shortened to 6m for strength on my SOTA activations. For coax I use 25ft (7.62m) of RG-174. A db or so loss maybe but works very well and is very light and easy to coil. This is what works for me and is extremely light and easy to carry on your back.
Tim - K5DEZ

You can try the PE1JXI Multi-endfed antenna.

73 Gomes CT1HIX

Hi, I tried to find this antenna on the internet, but dound just some photos… DO you have some description? Thanks

Does anyone know, how is usual efficiency / losses for solutions like “random wire” (EARC) + 9:1 balun?
(I understand, that it is compromise… not ideal…)

I believe any “random length wire” is going to need an ATU to be able to be used - if your rig has an ATU built in, this is worth considering, if it hasn’t then that’s another box and cables to carry with you, so I’d avoid the solution.
It also requires some way to support it, but I suppose you could get a “throw bag” and look for a suitable tree branch to use as your support if you want to avoid the extra volume and weight of a telescopic fibreglass fishing rod.

73 Ed.

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At the occasion, I would like to introduce my version of the EFHW.

Without any tuner it works on the bands 80m, 40m, 20m, 15m and 10m. With ATU also very good at 60m, 30m, 17m and 12m, so on all 9 bands between 3.5MHz and 28.5 Mhz.

The 9m coaxial cable serves as counterpoise. At 80m, the 20m long antenna wire connects to 50 ohms of the Unun, otherwise at 2.8k ohms.

If there are a least two trees on a summit, I throw the end with 10m rope with the ring nut into the branches, let it down and pull the Unun with the antenna wire up. Likewise I do it with the other end.

If there is only one suitable tree or if I have to use a pole, I install the antenna as inverted vee or a slooper.

The antenna works surprisingly well at 80m. During the day I often reach Lothar, DL3HXX over 200km, Fred, DL8DXL over 300km or Michael, DJ5AV over 500km. Tnx for listening to my call!

73 Chris

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