Hi All,

Here's a challenge !

Having recently acquired a Yaesu FT-879 HF transceiver I'd like to use
it for portable operation from my camper van. Ideally to take
advantage of the improving HF conditions during my lunch hour at work.

So I originally thought about buying a Yaesu ATAS-120A, but then I
realised that I wasn't that interested in mobile operation. So I could
consider something a bit more efficient.

I have a 10m fishing pole and a G5RV doublet type antenna which I can
erect as an inverted V when space permits. However this is not quick
or easy to do in the parking lot at work, time taken for assembly and
disassembly eats into valuable operating time.

I then thought about one of the no tune broadband HF vertical antennas
such as the Diamond BB7V, Comet CHA250B and the Maldol MFB-300. These
have the advantage of no-tune operation and only requiring limited
radials (which you can't easily spread out in a car park).

Then it struck me ! I already have a good selection of basic
components to build a vertical antenna of my own.

1. 10m Fishing pole which mounts on the rear trailer hitch.
2. LDG Z-11 Pro
3. Campervan which works as a reasonably good counterpoise.

My design criteria are.

1. Operation on all bands from 3.5MHz to 52MHz (ideally broadband
operation using the Z-11). I would prefer to be able to quickly change
bands from inside the van, as operating time is limited and UK weather
is normally cold and wet.

2. Easy and quick to erect and take down single handed.

3. No radials - but with the option to roll some out if space permits.

4. As efficient as possible - Top hats and loading coils would be
considered but would need to be light weight and inconspicuous. I'm
not interested in gaining fractions of a percentage increase in
efficiency if it takes more than 5 min to erect the whole thing.

5. I would also like to use the same solution for backpack portable or
temporary installation on top of a building roof. But this is not the
main design criteria.

All this suggests using the 10m pole as a support for a vertical wire,
with some sort of matching network at the base (broadband impedance
transformer) fed against the van chassis and the Z-11 inside the van.

Suggestions for alternatives or best length of wire and transformer
ratio would be greatly appreciated.

UKM