[Lf] [Fwd: LF: Re.L.F. Antennas.]

[Andre' Kesteloot]

LAWRENCE MAYHEAD wrote:

>  Hi All,When I first set up my 136 station I put up a Marconi "T"
> vertical ant. 15M high 30M long.The best ant. current I could get from
> my 400 watt amplifier was 1.8 amps.The measured ground /coil/copper
> loss was 125 ohm! Over the past 6 months I have tried to improve this,
> I have increased the top to 3 wires,increased the grounding from 2x4
> foot rods plus house wiring/water etc to 10x 4 foot rods, 20 radials
> each about 50 feet long plus one radial 150 feet long ending up at an
> earth rod in sea water! I also re-made the loading coil with thicker
> wire.The total result of all this effort was 2 Amps !!! Not very
> encouraging.This weekend I decided to start again.I replaced the "T"
> with an inv.L using the same support (tree) at one end but 60M long to
> another tree.SO I now have less wire in the air 60M instead of 3x 30M
> but stretched out.The loading inductance has not changed so the
> capacitance is the same. BUT the ant current is now 3 Amps!Does this
> mean that the antenna wire needs to have a longer "footprint " on the
> ground?,presumably the current density is less than under the 3 wire
> top,but the new ant stretches beyond my radial system,and it is still
> much better!.Does this also explain the reported  good performance of
> so called "long wire" antennas on this band?Food for thought.I am
> hoping toimprove things further but I dont have room to extend the top
> wire in a straight line,perhaps I will try a crooked L Hi. Checks with
> Eznec indicate a R.Res of  about .06 ohms for the "T " and .0675 for
> the "L" so with the increased current I hope to have improved my
> signal by at least 3db.73s Laurie.