Re: LF: BODGE ANTENNAS

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Mal,

Please, I make no magical claims for the earth electrode antenna I use. All I say is that, in certain circumstances, it works rather better than one might expect both on RX and TX on VLF/LF/MF.

In my view it does work as a loop antenna on 136 and 500kHz with the loop area being determined by the soil conductivity (lower conductivity, bigger loop area).  The very fact that it is low-Q does suggest loss. Yes, a fully "in the air" loop works better on both 136 and 500kHz. On 8-9kHz it is far less clear if this is acting as a loop or just a voltage potential in the ground. Making an efficient "in the air" TX loop at 8-9kHz may be a challenge.

I've managed to receive DK7FC on 8.97kHz - have you? - and this was using the very same earth electrode system being used for my earth mode experiments, and for recent tests on 500kHz. A "proper" loop antenna would have yielded several dB improvement in received signal level on 8.97kHz I do accept.

Again, all I am claiming is the structure is worth trying in some situations, not that it works by some sort of magic potion that has been fermented in my garage. 

73s
Roger G3XBM

On 14 December 2010 18:45, mal hamilton <g3kevmal@talktalk.net> wrote:

I am of the opinion what some on here describe as Earth Mode antennas are BODGE antennas.

Old timers cannot be fooled but it is very misleading for New comers to LF/MF

G3KEV

 

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