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HF High bands antenna


#1

Hi All
With 10 thru 17m looking good at present I feel like having a go. Anybody in SOTA land have a good performing lightweight aerial capable of 17 thru 10m? I am still using the faithful link dipole from 20 to 80m (resonant without a tuner).I carry a 5m pole, but if needed could up this to an 8m if it would help. Would also prefer not to carry additional kit so resonant would be good. The link dipole is performing well so a little hesitant to start hacking it up to add more links.

Cheers

Tim

G4YTD


#2

In reply to G4YTD:

I’m halfway through building a link dipole for 10 - 15 - 20 - 40 - 60 to go on my 9m fishing pole for SOTA. I thought that would be the most useful combination for SSB. Once I get my cw upto snuff I’ll probably either adjust that or build another.

I used a Clansman dipole element to construct it. You get 45m of good wire, a winder and about 60m of paracord all for less than 20 quid on Ebay.

Colin G8TMV


#3

In reply to G4YTD:
Hi Tim,
I use an EFHW vertical for the higher HF bands, 20M with links for 17,15,12M. It is a resonant antenna but does require a matching box to transform the HiZ feedpoint to 50 ohm. For 17M and above you could get away with a 8M pole. For SOTA activations it is easy and quick to erect and if you use a reasonable length of coax between the matching box and the rig you don’t need a counterpoise wire. The matching box is easy to construct.

So an alternative approach for you to consider.

Andrew,
G4AFI


#4

In reply to G4YTD:

How about parallel quarter-wave ground planes, you could reduce the number of ground plane elements to four with an acceptably small loss of efficiency, or use the 8 metre pole and have elevated ground planes which would also guy the pole and as they slope would bring the impedence closer to 50 ohms.

73

Brian G8ADD


#5

I use a 6m vertical, 4 radials of 10m and a homebrew tuner inspired on the MFJ-16010. This setup works from 40 to 10m.

Peter - ON4UP


#6

In reply to G4YTD:

For a link dipole 15/17/20/30/40/80 m I use about

  • 15 m 2 x 343 cm
  • 17 m 2 x 62 cm
  • 20 m 2 x 111 cm
  • 30 m 2 x 210 cm
  • 40 m 2 x 315 cm
  • 80 m 2 x 930 cm

Normally I do not carry the 80 m band wire with me. The dipole could be extended to 160 m too. See

73, Jaakko OH7BF/F5VGL


#7

In reply to G4YTD:
Hi Tim,
You could do worse than make up separate linked wires for 10m to 17m to complement the 20m to 80m linked wires that you already have .
I have made up several sets of linked dipole wires.
I limit each linked dipole to 3 bands , so as not to have too many links to operate on any given activation.
Depending on the dipole deployed I sneak an extra higher frequency band by adding a small amount of extra wire at the ends , held to the guys by washing line pegs.
For example a 5mhz dipole can be made to work on 14mhz by adding extra wire to make it a 1 1/2 wave dipole.
A 7mhz dipole can be made to work on 18mhz (as well as 21mhz).
A 10mhz dipole can be made to work on 28mhz.
All operate without the need for an ATU.
Make the extensions longer than than their calculated lengths and trim for best VSWR in that part of the band you want to operate.

David G3RDQ


#8

In reply to G4YTD:
Life is too short for resonant antennas :wink:
80-6m doublet http://www.flickr.com/photos/egsise/sets/72157627734845961/detail/
It aint lightweight, my setup with 7m pole and all the wires and T1 autotuner weights almost 2kg.
More details from here, in Finnish but at least the links work and theres the mmana-gal file… http://www.radionuoret.net/foorumi/24-antennit-ja-kaapelit/1002-80-10m-doublet-avolinjasyoettoeinen-monialuedipoli.html

I know that it needs a tuner, but in exchange the band swithing is really easy and it works on all bands including 6m and WARC.
Because the two antenna wires are guy wires too you need only one additional guy wire and setting up this antenna takes only 10 minutes.

Jani OH9FZU


#9

Hi All

Wow, thats a response and a half!

Loads of things to consider, thank you all.

Going to investigate a bit deeper, and hopefully have something new to try out on the next activations.

Thanks again to all who replied, I am sure the information will be of use to many more people too.

73

Tim

G4YTD


#10

In reply to G4YTD:

For something simple with more gain you could always use your existing 80m dipole as a sloping v beam. One backstay and a tuner should do it.


#11

In reply to G4YTD:
I just finished translating that 80-6m doublet setup: http://forums.qrz.com/showthread.php?311414-80-Meter-Dipole-Fed-With-Ladder-Line&p=2373390#post2373390

Jani OH9FZU


#12

In reply to OH9FZU:

Any QSOs so far with the antenna?

73, Jaakko OH7BF/F5VGL


#13

In reply to F5VGL:

No not any SOTA qso’s because I got my license just a few months ago and I’ve been busy with other things.
My first ham qso was with this antenna, 5W power 80m band distance 32km and with smartphone using PSK31.

I built one 80m doublet with 13m/100mm(lenght/spacer) ladder line to my home qth, one with 6m/60mm ladder line as prototype and finally built one from lightweight materials and 6m/40mm ladder line for portable use.
I gave my friend the one with 6m/60mm ladder line and he’s been happy with it.

Last week I needed a 10m vertical for emcomm test and I had no time to build anything so I used the 80m doublet, the other station had j-pole.
5W power 10m band and distance was 138km, test was done between two small summits and I pointed the doublets other leg towards the other station.
I calculated that the LOS covered only 100km so I think the doublet works like the antenna modelling software shows.

I’ve had qso’s on all bands except 6m, on low bands it works as NVIS antenna as predicted and same on high bands, the radiation angle is lower.

Like I said, building antenna for my needs was just reinventing the wheel, after all it is just a doublet.
I have to admit that I don’t collect qsl cards, or try to work all the countries etc, my satisfaction comes from testing things and seeing that they work as intended.

Jani OH9FZU


#14

In reply to OH9FZU:

I can try to listen your signals from JN26xf, if you do not want to jump directly to a SOTA pile-up from a nearby summit.

73, Jaakko OH7BF/F5VGL oh7bf at sral dot fi


#15

In reply to F5VGL:
Thanks, I’ll email you.

Jani OH9FZU @omakutsutoimii