Re: VLF: whistler duct AMATEUR propagation

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Hi Stefan,

If I remember correctly, you have to visualise the magnetic field lines going from a point in the  northern hemisphere  to the southern hemisphere at the conjugate point i.e. as far south as north of the magnetic equator. Signals will only be received close to this point at any strength by propagation along the magnetic field lines in whistler duct mode.

With whistlers, triggered by a strong lightning impulse, the signal can propagate back and forth between N/S hemispheres being more frequency dispersed with each pass. The sound is amazing. Helliwell's book shows one strong series of audio frequency echoes lasting over a minute in the sunspot maximum of the late 1950s, but this is rare. With amateur signals we would be lucky to get from Europe to Southern Africa once before signals became too weak to detect.

Who would have even believed that such experiments by amateurs would be seriously considered, even 12 months ago? You and others working on this are true pioneers and you all deserve great credit for this. I am only "dabbling at the edges" and have a great deal to learn.

73s
Roger G3XBM

2010/10/26 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>

Hi Roger,

Am 26.10.2010 23:18, schrieb Roger Lapthorn:

Stefan,

The possibility of whistler duct AMATEUR propagation is fascinating. There are (I think) spectrograms of such propagation from NAA (~14kHz) back in the 1965 book "Whistlers and Related Ionospheric Phenomena" by J.A.Hellliwell (I have a copy). This could mean signals getting to, for example, conjugate locations in the southern hemisphere (S.Africa?) with relatively low attenuation. A chirped signal would also show whisper dispersion I guess.

Yes, absolutely interesting! We will do that! And SpecLab can easily generate such a signal, my PA can easily transmit such a signal and my earth antenna can easily radiate such a (broad band) signal! :-)

Any further hints/ideas, Roger (and the group)?

You will need some grabbers in distant places!

Maybe ZL2AFP can help us here by receiving? :-)

73, Stefan

-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
G3XBM   GQRP 1678    ISWL G11088