Re: LF: Re: VLF - G3XIZ - 14th May 2011

[Stefan Schäfer <schaefer@iup.uni-heidelberg.de>]

Hello Ken,

Am 15.05.2011 11:07, schrieb Ken:

  in your opinion what would be the minimum height for the E-Probe?, at present I can only make 5m.

Ken.

 

M0KHW

It all depends on the local situation. It should be well above trees and far away from buildings. If it is the highest place, some meters distance is OK. Just like on all the E probes. Due to man made noise sources it is best to place it as far as possible from these sources.
Maybe the signal level is rather poor (it depends on the kind of audio transformer and the winding ratio) compared to the inv-L antenna? If it is just a few dB above the soundcard noise, the SNR will be not optimal. Just one possibility, i just can guess...
Check the background noise without and with the antenna(s) connected. The difference should be 15...20 dB or above. Furthermore check if the signal amplitude not reaching the 0 dB level of the soundcard, anywhere between 0...24 kHz and so on....

Make a wideband screen of both antennas. You may ask other VLF stations like G3ZJO to give you further advice. They have done the same procedure in the last weeks. Of course you can ask me further too ;-)

73, GL, Stefan/DK7FC

----- Original Message -----

From: Stefan Schäfer

To: rsgb_lf_group@blacksheep.org

Sent: Saturday, May 14, 2011 8:44 PM

Subject: Re: LF: Re: VLF - G3XIZ - 14th May 2011

Hello Ken,

Well, it is difficult to comment this if i have no impression of the wideband view between the different antennas. The filter is a 3 stage LPF, cut off at about 13 kHz. Generally the probe works well so it may be a problem of grounding or something elso is wrong. What is your RX, i simple soundcard?
Could be interesting to compare different wideband screens!

73, Stefan/DK7FC

Am 14.05.2011 14:35, schrieb Ken:

LF.

I saw a very faint trace about 10.00UTC using my 'T' antenna at a height of 8M, but nothing on the E-Probe at 5M on a non-metalic pole, the distance between Chris and myself is about 15-18km, I would be grateful for your comments Stefan. Also what are the charicteristics of the filter between the two FETs?

 

73s

 

Ken

 

M0KHW 

----- Original Message -----

From: Chris Osborn

To: LF Group

Cc: Paul Nicholson

Sent: Friday, May 13, 2011 7:57 PM

Subject: LF: VLF - G3XIZ - 14th May 2011

LF,

 

I shall be transmitting on VLF tomorrow: 14th May:

 

 

Time:     From 04.00 Z for several hours.

QRG:     8.976 661 6 kHz

Loc:       IO 92 UB

Power:   120 watts RF

Aer:       40m inverted L, height 10m

Mode:    Constant carrier

 

This should be my last transmission on the existing aerial system as I shall be soon making improvements.

Consequently reports will be especially welcomed.

 

73 Chris G3XIZ