[Elecraft] field ops

[Ron D' Eau Claire]

George, W5YR, wrote:

> For some time back in the 40's I used a 260 ft "longwire" antenna that was
> end-fed from a parallel resonant circuit on the shack wall near a window.
> The coil was center link-coupled to the center swinging link on the final
> tank circuit with a length of 300-ohm twinlead. (Anybody recognize those
> terms thes days?)

Sure do. My 1941 ARRL Handbook discussed end feeding antennas like that.

When I was a Novice in '52 I found myself with no feedline and a long run
available from my shack to a support, so I put up an end fed 80 meter half
wave antenna for my 6V6 crystal oscillator (making about 5 or 10 watts
output). I just tapped the end of that halfwave antenna right on the output
tank coil of the oscillator, adjusting the tap and "dipping" the plate
current (to resonate the circuit) to provide the proper loading with good
keying. Since the oscillator used series d-c feed, the plate voltage
appeared on the tank coil and so the antenna was hot with 450 VDC as well as
with r-f.

It worked just fine on 80. And, considering that there was virtually no
harmonic suppression, it probably worked fine of 40 meters and 20 meters and
10 meters. (There was a reason the Ham bands were harmonically-related!).
Indeed, it was my ability to wipe out TV channel 2 up near 60 MHz that made
me give it up. But I did have a smaller scale installation like yours a few
years later for my Viking Ranger. It worked just fine, even without the high
voltage on the antenna wire.

Ron AC7AC
K2 # 1289