Re: ULF: RE: A new distance record on 970 Hz / 309 km band ...earth antennas

[Chris Wilson <dead.fets@gmail.com>]

Hello Stefan,

Wednesday, April 5, 2017



What  impedance did you have to match with such an antenna used for TX
Stefan?  Congratulations  on  your remarkable experiments at ULF, I am
stunned by what you are achieving "down there"!


>  Hi Jim,
>  
>  Thanks for your comments. You bring me (back) to the idea of using
> an earth antenna, this time for receiving. 
>  In 2012 i build up a 700m long wire antenna in the forest. It was
> grounded on both ends. I run a few 100 mA into the wire. 
>  One day i put 250 W into the antenna and got 10 dB SNR in 3.8 mHz at 8970 Hz 
> in 45km distance.
>  I remember G3XBMs blog entry:
> http://g3xbm-qrp.blogspot.de/2010/09/vlf-dx-transmission-with-earth.html
>  That was quite a nice time. Activity was much higher these days, not only on 
> VLF.
>  I also used the antenna for reception and was impressed by the interesting 
> frequency response.
>  In the next 970 Hz experiment i want to drive to
> http://no.nonsense.ee/qth/map.html?qth=JN49JM36. During the
> recording of the E field signals are running i have some time.
> During this time i could try to use an earth antenna for ULF
> reception. It has the advantage that it is easy to build it up in a
> forest. Just 300m length or so. There has always been the discussion
> if such an antenna (with grounded ends) acts rather as a loop or as
> a dipole on the ground. I would expect a loop and so i will build it up.
>  Comments/Ideas?
>  
>  73, Stefan
>  


-- 
Best regards,
 Chris                            mailto:dead_fets@gmail.com