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Re: LF: Earth Electrodes

To: <[email protected]>
Subject: Re: LF: Earth Electrodes
From: "mal hamilton" <[email protected]>
Date: Tue, 14 Dec 2010 19:52:34 -0000
References: <80E0204D3E534137903FE0B8E499597F@IBM7FFA209F07C> <[email protected]> <C38D87D2AED243D59ED8357663143FF4@IBM7FFA209F07C> <[email protected]>
Reply-to: [email protected]
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Stefan
You now admit that your antenna is in FACT a LOSSY DIPOLE and not an earth antenna
g3kev
 
----- Original Message -----
Sent: Tuesday, December 14, 2010 6:12 PM
Subject: Re: LF: Earth Electrodes

Chris, LF,

Am 14.12.2010 17:27, schrieb Chris:
HiStefan,
Yes, but 600m is VERY long! The wire even laying on the ground I would expect to radiate quite well at 137 with that length! And how many watts?? ERP??
I am sure 8970 would do well through the ground at the sort of powers being spoken about. Probably ideal for submarines, as Roger says!
Vy 73, Chris, G4AYT.
Well, my earth antenna is grounded at the ends and TX power was about 250 W. The mode was DFCW-600. The receiver was at Michael Oexner using a PA0RDT design. ERP? No idea, probably some few uW. Its not so easy to calculate the losses.

Yes, on 137 kHz the wire length comes close to lambda/4 and above so it acts not just like a pure earth antenna but rather as a combination of this and a very loss dipole. On 137, my power was 100 W at this test.

The antenna was built to do local tests but seems to work suitable on 137. So it is a fixed antenna, my only fixed one. And it is a very quiet location. This makes it interesting to use it as a RX antenna too!...

73, Stefan

----- Original Message -----
Sent: Tuesday, December 14, 2010 2:49 PM
Subject: Re: LF: Earth Electrodes

Hi Chris,

But how do you explain that i have crossed 49.6 km with a 600m spaced earth electrode antenna on 8970 Hz? It was rather summer time than winther (regarding QRN)! With the same antenna, my 137 kHz signal was seen 20 dB above noise near Paris in DFCW-3!?????

73, Stefan


Am 14.12.2010 15:15, schrieb Chris:
Hi Mal,
Yes, that is what I had concluded years ago. No harm in trying though!
Further to your previous e-mail to LF, looks to me like beacons are now becoming the norm on 136/7kHz band and below. I have no problem with that personally, indeed, I think it preferable to a QSO taking forever! I woud like to see full idents though, no matter how slow.
Vy 73,
Chris, G4AYT.
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