[Fwd: LF: Antenna]

André Kesteloot akestelo@bellatlantic.net
Tue, 09 Jun 1998 10:22:08 -0400

Mike Dennison wrote:

> For some time I have regarded my antenna as one of the smaller of
> those in use on the LF bands - though recently some brave souls have
> had success with very small antennas. Neverthless it really does seem
> that, as far as LF is concerned, size is important - often more so
> than shape. The age old rule of as much wire as possible a high as
> possible has never been more true.
> In an attempt to find a way to get a bigger antenna in the same size
> real estate, I am currently running an experimental "dog leg" shaped
> Marconi. If you imagine an inverted-L as being two sides of a
> right-angled triangle, all I have done is to take away the vertical
> side and use the long side instead (I tried to type hypotenuse but
> cannot spell it!). So the old "vertical" section now runs out as a
> sloper to the far end of the top section and then bends sharply back
> on itself. I have a loading coil near the top of the slope. The
> antenna is now some 42m long, instead of 30m, yet the equivalent
> vertical component remains at 10m. Some of the horizontal radiation
> should have been cancelled out.
> On receive the German/Swiss beacons went up an S-point on both 73 and
> 136 (but this could have been an impedance issue), and the earth
> current has gone up by between 50 and 80 per cent (but this may be
> dissipated in losses).
> To find out whether it =really is= better, I would appreciate some
> reports, either on air or via this reflector. My beacon schedule is
> on my web site and I use both 73 and 136.
> Mike, G3XDV (IO91VT)
> http://www.dennison.demon.co.uk/activity.htm