Hi Markus,
Hmm, a mystery :-)
Actually the band pass filters should not pass a signicicant strength
of DCF77. And the 10 kHz Ref signal is at -36 dB f.s., i.e. not
overloading anything. Maybe it is a rest of the LO signal (125 kHz)
reaching the ADC input? There is a LPF after the mixer though...
I don't know. I could switch OFF the LO and see if the lines disapper,
HI.
73, Stefan
Am 08.01.2015 22:31, schrieb Markus Vester:
Hi Stefan,
just took a close look and noticed
the 1 Hz spaced lines around 137.5 kHz. They appear to be a replica of
the DCF77 timecode, including the minima at +-10 Hz corresponding
to the 100 ms carrier gaps. Have you tried listening on this frequency?
There must be some combination producing either the RF frequency (eg.
60 + 77.5 = 137.5 kHz) or your IF (12.5 kHz), perhaps including
multiples of the 10 kHz GPS reference. I just cant point my finger
exactly on how it happens.
Best 73,
Markus
Sent: Thursday, January 08, 2015 9:51 PM
Subject: LF: Old version OPERA >> ''Opera Fixed''
<<
Hi Jay,
You have been on air last night in OP32? Unfortunately i got no decode.
I guess it could be due to the local QRM which is still high in this
location. My LF DX grabber shown the RX window looking dramatic in
424uHz and with AGC.
If you continue to TX this night maybe, would you like to try a
frequency which is clean on my side?
Would like to get a decode from you, to reduce the ratio (FC received
by
XNS) / (XNS received by FC)
:-)
73, Stefan
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