snip
That's interesting. Thanks for the tips. At the moment, being new to
HF,
I have only a rudimentary antenna consisting of a copper pipe dipole
(built
for 10m) laying near the peak of my garage roof. Unmodified, it did 10
and
did 15 with a tuner. Then, I made one element longer with an
alligator-clip
lead and about 12 feet of TV-coaxial cable; the garage isn't very long,
so
it makes an L-shape in the roof. Call it an "L" antenna if you wish; I
call it an unholy mess, but it gets me on 20 and 40 with the tuner. I
have
worked New Zealand, Australia, Estonia and the Ukraine as well as any
number
of places in North America. The other hams, who spent their money on good
antennas, made many of my QSO's possible and I thank them.

Speaking of valves, I have hundreds of them. I am restoring an old
military
tester and I'll have the valves available in a few months.

What everyone seems to forget is that modern receivers tend to have signal
gains of 120dB or more when operated with everything turned up full. With
this sort of sensitivity, you only need a couple of watts of radiated signal
to work around the world, given the right band conditions.

With a kilowatt or so and a high gain antenna, it is possible to work just
about anywhere first go. It all rather takes the fun out of operating when
it is that easy.

Interesting you mention using copper pipe for a dipole. Some of my more
successful antennas have been made from aluminium tube. I found they give a
lovely broad bandwidth, generally the fatter the tube, the wider the
bandwidth.

As you say, there are plenty of hams who have spent money on high gain
antennas. Lets give them some signals that allow them to put their expensive
antennas to good use:-)

Having worked passing commercial traffic with high powered equipment, I find
I get much more satisfaction from completing QSO's using QRP equipment and
basic antennas than using the big expensive stuff.

If you do decide to play around with valve final stages, you should find
that they are much easier to tune into virtually any old bit of wire. Just
be careful to monitor the grid current and keep the anode voltages down when
the system is not at resonance. One of my favourite valve matching circuits
was essentially a CLC design with the variable inductance formed as a
goniometer - essentially two concentric tubes with wire coils wound around
them. As the inside tube was rotated, the inductance coupling to the fixed
outer tube varied. This sytem was quite robust and I never had any arcing
problems with the inductors. The capacitors used to flash over in the high
humidity of the tropics on full power sometimes, but reducing power by 25%
usually solved the problem. A modern version could be produced with some
plastic drain pipe and a bit of coiled springy phospor bronze or copper
strip to make the connections to the rotating coil. That way you get
continuously variable capacitance and inductance without any switches or the
intermittant contact problems that modern wound inductors with a contact
wheel suffer from.

All the best with your experiments

Mike G0ULI