JGBOYLES wrote:
As to this particular project, I've received several interesting
suggestions, some modifying the shape/size, some adding a tuner at the
base. I'm probably gonna try both. I have a line on an extra tuner,
which I'm gonna try to weatherproof and install (single band)

Dan, I homebrewed a remote controlled tuner that would work with your antenna,
and you could change bands without ever leaving the shack. It uses a motor
driven roller inductor and variable capacitor in an "L" network. I also have a
relay switching scheme to reconfigure the "L" network. With this tuner at the
base of a vertical or inv. L you can match a wide range of impedances. The L
and C in this tuner are rated at legal limit.
Obviously the only thing standing in the way of you using something like this
is obtaining the parts and building it. The inductor is surplus, about 30 uH.
MFJ sells one that they use in their 1 kw tuner, around $65. The capacitor is
a Ten Tec 500pf variable cap. kit, around $45. The drive motors came out of a
kids battery operated car, 12vdc around .5 to 1 revs/sec that can be changed
with the supply voltage. The hard part is coupling the motors to the L and C.
The control cable is 100' of 8 cond.#20 shielded industrial control cable,
about $45. Forward and reversing was done with relay logic.
This was not a weekend project, but it wasn't that bad either. If you want
some more details, email.

A few more thoughts, in case they're useful to Dan or anyone else:

* It's sometimes possible to make an automatic two-band network. For
example, the same 33ft end-fed vertical can be matched as both a
half-wave on 20m *and* a quarter-wave on 40m, with one network and no
switching. The same goes for a 66-footer (vertical or inverted L) on
40/20, or a 130-footer on 160/80.

* Remember that the remote network doesn't have to give a perfect match.
If the SWR on the coax is below about 3, the extra losses won't be
significant (except in extreme cases) and you can always do the final
"flattening" to 50R in the shack.

* Instead of remote rotary switches, consider latching vacuum relays
which don't require power to hold them closed. There are surplus vac
relays at very reasonable prices at:
http://www.mgs4u.com/#president

* You can reduce the number of control lines by sending cunning
combinations of positive and negative DC, AC out from the control box,
and using steering/blocking/rectifying diodes at the remote end.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek