Portable antenna for 40, 60 and 80 m

LA4TTA

Member #321
New member
I've been scratching my head and searching the web for an (diy) antenna that is light enough for backpacking, siple to set up, efficient and covers 40, 60 and 80m.
Preferably endfed.
I'm close to the point where I'm starting to think that I should bring an separate antenna for 60m.

So far the best solution i have tried is an 14m (ish) wire and an 9:1 unun with four different lengths radials.
I have made an endfed windom ( http://51.175.186.36/la1dsa/Endfeed_windom.pdf for those of you that understand Swedish ) But it is quite heavy, and cumbersome to set up.

Does anybody have any ideas and/or experience they would like to share it would be appreciated.
 

LA4TTA

Member #321
New member
That is an great suggestion. I already have an linked 12, 17, 20m dipole i use for sota. But this antenna will be more for camping use, and i would prefere not to have to leave the comfort of my sleeping bag to change bands. I should have mentioned that in my opening post.

So far it stands between an dublett feed with 300ohm line and unun with an appropriate lengt of wire and counterpoise.

Does anyone know if there will make annny difference if I connect the counterpoise to the unun vs grounding point of my radio? Does the coax lengt matter in respect to that.

73.
 

LA4TTA

Member #321
New member
Ah good point about not wanting to leave your sleeping bag.
Don't know what power you are using but SOTAbeams have some very small (and light) traps.
this is the 10W pico, they do 100W ones.
http://www.sotabeams.co.uk/pico-traps-kit-pair/


I actually have inquired him about them, and it he seemed like he doubted that they could be made for 60m so I'm considering building from scratch. It's an valid option. Just not sure if I should try an dipole or 1/4 wave with radials.
 

G1YBB

Member #381
New member
I actually have inquired him about them, and it he seemed like he doubted that they could be made for 60m so I'm considering building from scratch. It's an valid option. Just not sure if I should try an dipole or 1/4 wave with radials.

Ah Ok. I am a big fan of resonant antennas to save the weight and extra connections of an ATU.
Same as qrp radio+linear v higher output radio. I like simplicity.
 

LA4TTA

Member #321
New member
Ah Ok. I am a big fan of resonant antennas to save the weight and extra connections of an ATU.
Same as qrp radio+linear v higher output radio. I like simplicity.

Agreed. Now my KX3 have an built in tuner that actually works so non resonant antennas is actually no problem. But I still would like to get most of my 10w out of my antenna, so efficiency is important to me. Also simplicity of erecting and using the antenna.

Now. most of the areas suitable for camping in my part of Norway is mountains with little or no trees. This adds complexity to the "erecting the antenna" part. I will have to bring some sort of pole. An end-fed antenna could be erected in an inverted v or sloping configuration using a single pole. An dipole could also be erected using an single pole, but to get the ends at some height long guy lines must be used for an 80m antenna. So I think I will prefer end fed antenna to keep it simple.

Thinking about it now as I write, I realise that I could build an trapped gp antenna, with three trapped radials and use two of the wires as an dipole when appropriate spaced trees are available.
 

G0DZB

Member #84
Award Moderator
A trapped inverted L with lots of radials might be a solution. 10m Up and 10m Out for 80m, 60m trap half way along top section, 40m trap at junction of vertical and horizontal sections (at top of 10m pole). Bu tit might be a bit much to carry !
 

LA4TTA

Member #321
New member
A trapped inverted L with lots of radials might be a solution. 10m Up and 10m Out for 80m, 60m trap half way along top section, 40m trap at junction of vertical and horizontal sections (at top of 10m pole). Bu tit might be a bit much to carry !

The pole(s) Would weigh more than the wire. The pole weight vs radiation efficiency is poor from 6 to 10m antenna height I believe.

I'm also looking at poles. It would be great to find a pole that would also support my tap. Maybe about 4m tall. Tie the tap some where up the pole an have the antenna feed point on the top. Then run the wire to another taller support.
 

G0DZB

Member #84
Award Moderator
The pole(s) Would weigh more than the wire.
Use thicker wire then ! ;-) That will get the ratio back the "right way round" :)
The pole weight vs radiation efficiency is poor from 6 to 10m antenna height I believe.
Radiation efficiency is far more to do with the earth system than the pole height. That's why I wrote "with lots of radials".
I'm also looking at poles. It would be great to find a pole that would also support my tap. Maybe about 4m tall. Tie the tap some where up the pole an have the antenna feed point on the top. Then run the wire to another taller support.
I'm sure you've seen these already : http://www.sotabeams.co.uk/compact-light-weight-10-m-30-ft-mast/
PeterO
G0DZB
 

LA4TTA

Member #321
New member
Use thicker wire then ! ;-) That will get the ratio back the "right way round" :) Radiation efficiency is far more to do with the earth system than the pole height. That's why I wrote "with lots of radials".
I'm sure you've seen these already : http://www.sotabeams.co.uk/compact-light-weight-10-m-30-ft-mast/
PeterO
G0DZB

I actually have one. I found that its so flexible in the top sections that with an 80m dipole it bends down to the point that i have almost the same height with my fishing pole, at 1/3 of the weight.... It is however great for long wires and vertical antennas. Use it for an 30m 1/4 wave when car portable, and for an 20m vertical dipole. And the fact that it bends and not breaks.
 

LA4TTA

Member #321
New member
Did you mean 40m 1/4 wave ? Mine is resonant on 40m and with the addition of 8 x 10m radials it is a near perfect 50Ω match as well.
PeterO

Nope. 30m. For pskmail. The feedpiont is on the roof of my car, an toyota hiace, about 2m high, the top mount (from sotabeams) slides down 2 or 3 sections.
The mast is mounted to my tire and bends a bit and and keeps tension on the wire.
 

G0DZB

Member #84
Award Moderator
I see. I have a wire up the centre of mine so it goes the full length. An SGC ATU at the bottom will tune it on all HF bands above 40m. I think it will tune on 80m as well, but I don't think I've actually worked anyone with it on 80m. It's probably not very efficient on that band.
PeterO
 
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