----- 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