Hi Stefan,
Roelof, Albert, Markus.
Thanks for the info.
So between 50 dB en 90 dB … That’s quite a range.
I _think_ it is
more than 50 dB, but most certainly not in the 80-90 dB range, alas. Not with
the amount of man-made noise I see here on HF, although on 137 I only hear
(white) noise and some QRN. On HF it is S8 white noise + an enormous amount of
other man-made QRM, sometime peaking to 9+20.
I will build a 40 dB attenuator
to expand the range I can measure with the 897 to approximately 80 dB, I think
this will be enough…
Regards,
Minto pa3bca.
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Ceterum
censeo Carthaginem delendam esse
Sent: Monday, August 08, 2011 13:32
Subject: Re: LF: Re: Re: CW sked on 137 friday
morning?
Hello
Albert, That's quite good. Today it is just 50 dB in 1 Hz here. I have
extended my wideband screen to display DCF39 and HGA22, bottom of http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_LF_DX_Grabber.htmlIn
my RX there is a band pass filter with unknown attenuation at 138.83 kHz. I
estimate it is 15...20 dB. But it changes when the antenna becomes wet :-/
Somehow i think there is a stable and equal distributed noise level here in the
city that limits the sensitivity. But i've learned a bit more in the last weeks
and will investigate things further... 73, Stefan/DK7FC Am
08.08.2011 10:27, schrieb Albert:
Hi Minto, Roelof, Stefan es others,
The difference between DCF39 and the noise floor
on a quiet day is 92 dB in 1 Hz (JO33DE)
Antenna "inv L" 18m V and 34m H
73,
Albert
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