Trevor Day wrote:

In message , Reg
Edwards writes

Trev,
Performance is no better and no worse than what can be expected from
any other sort of antenna of about the same physical size and the same
length of feedline. Try it and see.

I once worked 3 miles on SSB, on 160m, in broad daylight, with about
10 milliwatts, on 8 feet of wire lying on the ground, thrown out of a
downstairs window. The ground connection was via 10 feet of wire from
a domestic gas pipe. But I don't brag about it. The credit all goes
to Clerk Maxwell.

As Clerk implied, any bloody thing works.
----
Reg.


Thanks Reg,

I expect you are quite right, but I am still puzzled about the bandwidth
aspect. Roy states that this is due to losses in the matching system,
in which case would it be possible to 'detune' a similar small antenna
and get similar results in that regard. If I can actually do that and
see the result, then I will be happy :-)

Trev

Try running it it parallel with a suitable resistive load. You will see
increased 'bandwidth', i.e. the SWR will be lower over a greater
frequency range. If you eliminate the aerial altogether then the 'bandwidth'
will cover frequencies up to several GHz with a good quality load ;-)

I have actually worked a local amateur dummy load to dummy load. Both
loads were good quality (one Bird, one Marconi) and all the cabling was
short and good quality coax. Leakage was probably less than a few milliwatts.
The rigs had different IFs so it probably was the signal frequency we were
hearing. Being able to work stations is no measure of antenna efficiency.

Heating is not a good way of determining efficiency unless you do real
calorimetry. I've tried 100W CW key down into a real 100W continuous load
(not one of the Made From Junk ones, which are grossly overrated), for
ten minutes and the temperature increase was just discernible, it
certainly didn't get hot.


vy 73

Andy, M1EBV




vy 73

Andy, M1EBV