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Date: Sat, 17 Jul 2010 00:19:23 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: RE: DLF passive received with earth antenna
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Hello Jim and the group,

Today i did the test with the 1m*1m loop again. It was necessary to go=20
down to abt 750 mHz and indeed, the DHO38 signal appeared at about -100=20
dB when turning the loop for optimal reception (just like the earth=20
antenna). This confirms your calculation of -94 dB in 3 Hz.

So the earth antenna really seems to behave like a loop with an area of=20
18000 m^2.

Additionally i tried what happens when i connect the earth antenna=20
directly to my IC706MK2G, without any matching and resonating. The RX=20
was set to CW mode with the noise blanker and without the preamp and a=20
250 Hz CW filter.
Some results:
DCFG39: S7
129 kHz: S9+10 dB
137.7 kHz: S0, little noise audible
DCF77: S6
75 kHz: RST 409
60 kHz: RST 309
36 kHz: RST 409
425 kHz: ("HDL") RST 559
153 kHz: (DLF carrier) S9+20 dB  AM mode: S9+30 dB (after 18 UTC DLF=20
transmits with 250 kW in 40 km distance)

Since the 706 is rather not one of the top class RX and there is no=20
matching of the antenna these results are not to bad i find.

Maybe Horst St=F6cker can do some similar RX tests? Would be interesting=
=20
to see a difference.

Today i prepared 400m wire and tomorrow i will increase the length of=20
the earth antenna by some 100m ;-) About 600m should be the maximum=20
length to form the first half of a dipole for 137 kHz so the rest will=20
be attached on the other end...

73, Stefan/DK7FC

PS: If David Gibson is right when he says that a earth antenna acts not=20
like a single turn loop there should be some RX results out of a=20
direction of the minimum of a loop. The should be more RX stations in a=20
radius of some Lambda ;-)