[Lowfer] DK7FC WSPR15 alert ... again tonight

[Michael Sapp]

Doug, Jay & All:

Interesting that Doug also had no captures in the 0300 and 0400 hours. 
Similar result here past two nites...gap from 0230 through 0530 last nite 
and 0330 to 0630 the night before.  I've had a few DK7FC sequences in those 
time frames that might have been "capture-able" if it were not for local 
compact florescent lamp 2nd harmonic QRM wandering across Stefan's 137.610 
signal the past few nights.  The CF fundemental energy is fairly strong 
around 68.8 kHz in the 1,000uV range and comes and goes here. Likely a CF 
lamp in the local neighborhood on it's last legs leaking energy into AC 
wiring.   Second harmonic in the 136~138 range is audible, perhaps S3 or so 
and wandering around.  The problem is not in my house so it is not 
controllable at the source.  When the 68.8kHz energy goes away, so does the 
noise in the 136 ~ 138 range.   Otherwise I seem to hear OK in the 136~138 
range when the local noise environment is low....


 2014-02-06 07:00   DK7FC   0.137611   -38   0   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-06 06:30   DK7FC   0.137611   -37   1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-06 05:30   DK7FC   0.137610   -36   1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-06 02:30   DK7FC   0.137610   -39   -1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-05 07:00   DK7FC   0.137610   -41   0   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-05 06:30   DK7FC   0.137610   -35   1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-05 03:30   DK7FC   0.137609   -35   1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-05 03:00   DK7FC   0.137609   -35   -1   JN49ik   1   WA3TTS 
EN90xn   6636   298
 2014-02-05 02:30   DK7FC   0.137609   -41   1   JN49ik   1   WA3TTS 
EN90xn   6636   298

    I had given some thought to changing the gain resistor on the MC1496 
active mixer in the Heath converter to possibly lower the intermod 
potential.....there is enough system gain to turn the mixer gain down a 
bit.....then again, one would think the MC1496 could handle 1,000uV at 68 
kHz without generating significant intermod products.  I may do the 3dB 
attenuator intermod test on the VLF converter input this afternoon to 
evaluate.....

Thanks in advance for the bandwidth....

73,  Mike wa3tts




----- Original Message ----- 
From: "Douglas D. Williams" <kb4oer at gmail.com>
To: "Discussion of the Lowfer (US, European, &amp, UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Thursday, February 06, 2014 5:56 AM
Subject: Re: [Lowfer] DK7FC WSPR15 alert ... again tonight


> Thanks for the info, Jay. Success here.
>
> -Doug
>
> 0200 -32 0.8 0.137612 0 DK7FC JN49 30
>
> 0230 -37 1.5 0.137612 0 DK7FC JN49 30
>
> 0500 -35 1.8 0.137612 0 DK7FC JN49 30
>
> 0600 -37 1.8 0.137612 0 DK7FC JN49 30
>
> 0630 -35 0.4 0.137612 0 DK7FC JN49 30
>
>
> On Wed, Feb 5, 2014 at 6:07 PM, <jrusgrove at comcast.net> wrote:
>
>> DK7FC transmitting WSPR15 on 136.000 (dial). Appears to be running his
>> usual +1610 and 1st and 3rd quadrant of the hour.
>>
>> Jay W1VD  WD2XNS  WE2XGR/2  WG2XRS/2
>>
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