Ok, Jay. The effect is intruiging. The Russian line
on 775 tells me that the receiver had stayed in lock all night, so it must be
real.
Yes it would be good to try the same parameters
again. There's a lot of QRN now, but the forecast says it should quiet down
later tonight.
I'm not hooked to 780.30, just left the slot where
it was after I transmitted near Chris' Loran line in Haifa. So in
case we would really cause a problem for Mitch we might as well move down a
tick, even a posteriori as long as it's between 774 and 781. I think Chris could
do the same both in 4X and YO if required.
Actually after
John's email I tried to look for a trace of VE3OT as well. There were
some bits below the Eu Loran line 780.419, but nothing conclusive. Do
you happen to know his precise QRG?
Best 73, and have a nice Sunday
Markus (DF6NM)
Sent: Sunday, September 04, 2011 6:08 PM
Subject: Re: LF: Weak signal on 137780.3
Markus
Yes ... it was a continuous transmission with no
frequency step. Interesting observation on midnight crossing the middle of
the path.
Picked 200 watts as a starting point to see
how well it was received. The transmitter here is capable of 1 kW
output. It appears that only your grabber was able to 'see' the signal.
Weather permitting, I can run further tests
tonight. Do you have anything in mind? Might be interesting to do a repeat of
last night's test to see if the midnight/midpoint anomoly shows up.
Jay W1VD WD2XNS
WE2XGR/2
----- Original Message -----
Sent: Sunday, September 04, 2011 9:56
AM
Subject: Re: LF: Weak signal on
137780.3
Excellent Jay, thanks very much! I am really
happy about this result. Attached is a spectrum
graph, showing your peak at 3:16 UT, with about 12 to 14 dB SNR in the
0.438 mHz FFT.
Do I understand you correctly in that you
transmitted a continuous carrier, without a frequency step? Then the apparent
3.8 mHz shift must have been a transient propagational Doppler effect.
Remarkably, this lines up with observations of John Andrew's tests
in 2006, which had also shown two long stable runs, with a dip and
rapid phase change inbetween. The dip seems to roughly coincide with
midnight crossing over the middle of the path, but I'm not aware of any simple
physical explanation for this.
BTW Your transmit situation must be similar to mine: I
have about 200 W available into a Marconi antenna, which is about
0.1 percent efficient now, and up to twice that in a cold winter
night.
Best regards, and thanks again for the
test
Markus (DF6NM)
Sent: Sunday, September 04, 2011 1:27 PM
Subject: Re: LF: Weak signal on 137780.3
Markus
The mystery signal was from WD2XNS ... you have
the time and frequency perfectly correct and the color DF also provides
corroborating evidence. Note that there was no break in the
transmission. The frequency is controlled by a GPS disciplined
oscillator (accuracy about 13 ppt). Transmitter power was 200 watts ...
radiated power is not known. During winter, with frozen ground,
additional radials, lower R and less foliage, the radiated power
would have been about 0.5 watt. Expect last night's test would be at
least 3 - 6 dB (maybe more) below that level.
Jay W1VD WD2XNS WE2XGR/2
----- Original Message -----
Sent: Sunday, September 04, 2011 4:45
AM
Subject: Re: LF: Weak signal on
137780.3
The mystery signal was received between about
0:15 and 3:30 on 137780.310, with a 3.8 mHz downward shift from
about 1:30 to 2:15 - somewhat reminiscent of a DFCW "GM". Greenish
colour indicates southwesterly origin. The attached screenshot was
taken at 8 UT, timescale is 10 minutes per FFT.
I checked the other available TA grabbers
around 4 UT, but no trace of the mystery signal.
73, and have a nice sunday,
Markus (DF6NM)
Sent: Sunday, September 04, 2011 5:39 AM
Subject: LF: Weak signal on 137780.3
LF,
there seems to be a signal on 137780.300 Hz,
about 60 nV/m here.
Wondering whose it may be...
Best wishes,
Markus
