Hi Martin, I would estimate the field strength from DCF39 in your area is
about 0.5mV/m (from measurements done by PA0SE in the UK) and from your data
that gives about 1.5uV at the RX input as the level of the noise. If that is
in an SSB bandwidth that is not bad. I remember the noise plotted on my CFH
measurements in around 2002 was in this area but in a 300Hz bw, on the
AOR7030 (Remembering WSPR s/n is related to a 2.3kHz bw if I remember right)
My minimum signal detection using a waterfall on the audio was 5nV (rx bw
not relevant) but 0.3Hz bin size using a good sig-gen. I guess this was
little more than 1 to 1.5dB above the noise. I think it was probably quieter
here in East Anglia 15 years ago than it i now.
I hope that helps (saves you ripping your station apart :-)) )
Alan
G3NYK
----- Original Message -----
From: "Martin Evans" <[email protected]>
To: <[email protected]>
Sent: Monday, January 22, 2018 4:51 PM
Subject: Re: LF: 136kHz - this is how badmy system is!
Watching Roger's adventures on 136kHz, I thought I'd go take a look and I
wondered -
DCF39 is about 50dB above the noise at 16:44UTC.
I'm using a 150ft inverted L, untuned, stuffed directly into an Elad
FDM-S2 SDR.
Decoded G3XIZ, G4FTC, G8HUH & G4GIR between 16:12 and 16:44.
What does this say about my setup?
Is it deaf/average/ok?
How far above the noise is DCF39 in an optimised "good" setup?
Anyone tell me?
Martin GW3UCJ Swansea.
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