Re: LF: more from loaded aerial

[Jacek Lipkowski <sq5bpf@lipkowski.org>]

On Fri, 11 Jun 2010, Wolf Ostwald wrote:

> I think one of the problems with detection in the near field was, that I am
> transmitting an H-field and DD7PC uses an E-field antenna. I guess that was
> the problem here.
You've touched upon a common problem with vlf tx tests. Most tests start 
in the near field. For these tests you should receive the same field that 
you're transmitting. but as soon as you get close to 1/2 wavelength the 
other field peaks. So if you're transmitting H-field, than try an E-field 
antenna 17km from a transmitter site, or a H-field if you're closer.
Please look at this (outdated) table: http://qru.de/vlf.html see "Current 
Achievements on VLF". The maximum distance that anyone got was around 1/3 
wavelength (10km).  This is probably because during the tests the testers 
didn't try to switch the antenna type, with this the 10km record distance 
would be probably broken earlier.
VY 73

Jacek / SQ5BPF