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Original Message -----
Sent:
Saturday, May 30, 2015 5:56 PM
Subject:
Re: LF: Almost
Hi Mike,
thanks for the explanations, nice
work indeed!
I am are also plagued by a lot of
local interference from our dense suburban neighbourhood. especially on
MF there seems to be a surprising diversity of signatures: there's
the plain common SMPS hash, usually 100 Hz FM-modulated across several
kHz. At times I get what looks like just plain white noise, with
variable power density. But then there are also apparently crystal
controlled carriers going on and off, often with sidebands which
sometimes mimick intelligent modulation.
Are you currently monitoring WSPR-2 only, or also -15?
All the best,
Markus (DF6NM)
Sent: Saturday, May 30, 2015 8:33 PM
Subject: Re: LF: Almost
Markus: I do not think the QRM
signals are spurious. I have built the W1VD preselector for 475~500 kHz
range and the offending signals are still present when the preselector
is used. Same with the FZ-02 filter. There are some commercial and
retail shops to my NE about 300~400 meters away, possible that is the
source. However, the offending QRM signals are not consistent in
frequency or strength from one day to the next. QRM signals are not
very strong, but strong enough to interfere with a -27 to -30 SNR
desired signal.
I use a pair of crossed EWE
antennas to have four-way selectable cardio patterns for NE, SW, SE,
and NW directional reception. If I switch to the NW direction, the QRM
signals go away, but then directivity to DK7FC would be about 4~5dB
down. To the SW and SE directions some QRM sources disappear, and
other QRM sources appear. I may try some phase steering between the
two EWE antennas. It is an ongoing learning process. Random chance
could always prevail, so I continue to listen, tinker, and occasionally
even learn something ~:). 73,
Mike wa3tts
PS: I have received several F5WK
wspr2 captures on 630m this last December....
-----
Original Message ----- a
Sent:
Saturday, May 30, 2015 6:20 AM
Subject:
Re: LF: Almost
Looks like Stefan ran into a
Loran line... but wait, Loran is no longer there in North America, and
anyway we're on MF not LF. Mike any idea what is causing those spurs?
Sent: Saturday, May 30, 2015 4:41 AM
Subject: LF: Almost
Stefan: Close, but no cigar.....
local QRM.....
73 Mike wa3tts