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.
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.
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.
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.
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.
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.
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.