"Sal M. Onella" wrote in message
...

"Mike Kaliski" wrote in message
...


Many years ago I input all the frequencies and wavelengths into an Excel
spreadsheet to find a length of wire which would most closely be
resonant
on
all amateur bands. As I recall 26.5 metres seemed to be an optimum
length
when fed via an ATU. It isn't resonant on any amateur band, but most
ATU's
will be able to tune it. It worked for me anyway 160m through to 10m. As
for
the performance, well it received well enough and obviously radiated
enough
of a signal to work 5000+ miles QRP.
Mike G0ULI

I assume that the directionality was frequency-dependent. At higher
half-wave multiples, it would have been a beverage antenna, with strongest
signals off the end(s). Was that your experience? I'm getting ready to
try
the same thing, although I don't quite have 26.5 meters to play with
unless
I can string part of the wire onto my neighbor's property.


At the time I was fairly newly licensed in amateur radio and just concerned
with putting up any old bit of 'wet string' to get a signal out. My antenna
was orientated East West and probably only 15 feet up in the air. From the
UK I could work QRP into the east coast US and all of Europe with pretty
good success. Of course at QRP power levels you have to pick your
frequencies and operating times:-)

It probably helped that in my early professional career as a Merchant Navy
Radio Officer, I was expected to reliably work the UK directly from on board
ship, from as far as Australia, using 1950's valve equipment putting out
only 100w to a Marconi long wire antenna. It did sometimes take up to four
hours to get message traffic passed, but in those days you stayed on watch
until the job was done; a pretty good incentive!

The antennas were generally directional along the length of the ship, but
the navigating officers always seemed to be reluctant to change course and
steam pointing at the UK so I could send a message. I can't think why.

From a professional basis, the more wire up in the air the better but don't
worry if you have to bend it around corners to fit. Provided the antenna is
20 feet up or so, you can get some good low angle (long distance) radiation
off the antenna and low antenna can also be useful for putting out near
vertical signals to work 500 to 1000 mile distances.

Merchant Navy radio installations always used to be done on the cheap using
the lowest powered equipment available. The antennas were fitted around the
masts wherever they would go without compromising operation of cranes and
cargo loading. Depending on the cargo load, the antenna height could vary
from 40 feet to 70 feet above sea level on a typical cargo ship.

One of the best antenna systems I used had two 30 foot helically wound fibre
glass masts, one main, one emergency antenna. Apart from hosing down the
base insulators once a week with fresh water, these worked pretty well and
were essentially maintenance free.

Wires or whips, the antennas were fed via an ATU for all frequencies from
410 kHz to 22 MHz.

Stick a bit of wire up in the air. If works, great. If it doesn't, try
another arrangement. Antenna modelling software is great and can really help
out when designing a system, but there are so many variables in real life,
that sometimes the craziest ideas work much better than theoretical designs.
Try to use wire lengths that avoid very high or very low impedence matches
at the frequencies you are interested in and don't worry about having to use
an ATU to get a match. ATU's are a lot less hassle than traps and loading
coils for general wide band hopping about on the air. If you find a
particular band that you enjoy working on, then design a more efficient
system just to work that band. Open wire feeder as opposed to coax can also
give some useful extra radiation from the antenna system. All the ship board
stuff was fed around the radio room using copper pipe, feed through
insulators in the bulkhead, and multi stranded bare copper cable for the
external antenna and feeds. When not being used for operating, aerials were
connected to earth through a switch box to minimise equipment damage from
the inevitable lightning strikes, especially in the tropics. I forgot once
and the purple discharge glow and loud bangs in the radio room as lightning
repeatedly hit the aerials and jumped to the nearest earth was truly
spectacular. It took me a good couple of minutes to work up the courage to
snap the switches round to the earth position during a slight lull in the
firework display! Strangely enough, all the equipment escaped unscathed.
That's valves for you :-)

Good luck

Mike G0ULI