[Elecraft] Is it my KX3/antenna or is it lousy band condx?

Walter Underwood wunder at wunderwood.org
Sun Aug 13 13:32:08 EDT 2017


I should have just said “coupled”.

Without the wire on the ground, the chassis is the other terminal, like your BC-459 (previous message), but also includes your body when you touch it, which changes the impedance of the antenna system. The wire is important to stabilize the impedance. It is also more efficient than having zero radials.

There are more efficient field antennas, but this setup weighs four ounces, including the midi-winders from SOTAbeams. Those are about the same size as the KX3, so they pack nicely. Last time I was on a summit, I was on the air five minutes after choosing a log to sit on.

http://www.sotabeams.co.uk/midi-winders/

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Aug 13, 2017, at 10:10 AM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
> On 8/13/2017 9:09 AM, Walter Underwood wrote:
>> The 16 foot wire on the ground is a radial “system”. One radial is a lot better than none, but you could use more. The length isn’t especially important
> 
> Right.
> 
>> because it is capacitively coupled to the ground.
> 
> It's also inductively coupled. BUT -- that's NOT how or why radials work. AND a connection or coupling to earth does NOT make a transmitting antenna work better. That's because the earth is a big resistor, so it burns any power fed into it, whether with a direct connection or by capacitive or inductive coupling. In other words, it WASTES transmitter power.
> 
>> Ground resistance swamps any resonance.
> 
> Yes, but as noted above, not in a good way. :)   There's a folded dipole antenna made with a big resistor in the middle of it, the effect of which is to "broadband" it by "swamping" the resonance, AND to burn half of the transmitter power. In other words, the transmitter puts power into the antenna, but half of it is wasted in that resistor.
> 
> 73, Jim K9YC
> 



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