re:Re: LF: Almost

["Michael Sapp" <wa3tts@verizon.net>]

Hello Markus:  Ah, similar noise gremlins all over the globe.... During spring cleaning of all the EWE connections last week, I added a perimeter ground wire around the four ground rods of the two EWE antennas (Think of a square area with an X inside, 10:1 matching xfmr each end of each EWE). The extra grounding appeared to reduce the power line harmonic situation in the 10~20 kHz range. It will take a few weeks of listening to evaluate....

 

I can split my LF converter IF output and run two receivers and PCs. But the IF radios, PCs, and sound cards are not identical which makes comparative tests rather subjective.   I have tried that twice in the past week but no joy on 630m wspr2 & 15.  May give that a try again this evening if no "Blizten-storms"...

 

73, Mike wa3tts 

----- Original Message -----

From: Markus Vester

To: rsgb_lf_group@blacksheep.org

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)

From: Michael Sapp

Sent: Saturday, May 30, 2015 8:33 PM

To: rsgb_lf_group@blacksheep.org

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....

 

https://www.dropbox.com/s/wkfcl9gfyac5nlm/F5WKMAP.JPG?dl=0

https://www.dropbox.com/s/fzox0bk492h20dq/IMG_4142.JPG?dl=0

----- Original Message ----- a

From: Markus Vester

To: rsgb_lf_group@blacksheep.org

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?

 

https://dl.dropboxusercontent.com/s/hferguh5tdeaccw/IMG_4352.JPG (direct link)

 

73, Markus (DF6NM)

From: Michael Sapp

Sent: Saturday, May 30, 2015 4:41 AM

To: rsgb_lf_group@blacksheep.org

Subject: LF: Almost

Stefan: Close, but no cigar..... local QRM.....

 

https://www.dropbox.com/s/hferguh5tdeaccw/IMG_4352.JPG?dl=0

 

73 Mike wa3tts