Hi Larry watchers,
I attach my report of monitoring for Larry's transmissions on 16/17, 17/18,
and 18/19 of January.
73 John, G4CNN
_______________________________________________________
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I used Easygram to monitor on all 3 nights 16/17, 17/18, 18/19 using the
highest resolution, i.e. an FFT size of 16384, and a Sampling rate of 5512. On
the first night I set the delay so that the window scan time was 5 minutes and
set the timer to take photos every 5 minutes. On the second night the same but
with 10 minute intervals and the third night with 15 minute intervals. This was
because Larry had announced that he would send 1 minute, 2 minute and 3 minute
dashes on successive nights. However it was unclear whether this was an
increasing interval or reducing and in any case it seems he actually sent 1.5
minute dashes.
The first and third nights I did indeed capture dashes and have already
reported to Larry the results of the first night's monitoring. The second night
failed because of problems with Easygram (blank (black) photos). The third
night, I saw the clearest dashes between 22.20 and 23.30 and did notice an
apparent increase in frequency just after midnight. I also saw dashes between
00.24 and 00.39.
In order to determine the exact frequency I copied each image into Paint Shop
Pro and using the vernier scale determined the exact y-coordinate of every
trace, including two frequency markers. Then using the known frequency markers,
I converted these coordinates to actual frequencies.
Then I saw the e-mails from Andy and Jim. I read and re-read these e-mails and
no-way can I match my observations with theirs.
My first thought was that my results must be innacurate. So I have spent a long
time using Spectran at its highest resolution (0.031Hz) and carefully measured
the position of each and every line in this part of the spectrum. Then with a
table of differences calculated from the known Loran line frequencies found a
very good match over 30 or so consecutive Loran lines.
These told me that my receiver was out by 1.7896 Hz. Further I was able to then
accurately measure two strong non-Loran lines that were visible in both
Spectran and the Easygram images and found practically no difference in the
accuracy of the two software packages, and very good linearity in the Easygram
images.
Allowing for the error in the Rx setting, It turned out that the dashes between
0024 - 0039 were at a frequency of 137788.0 +/- 0.1Hz and those between 00.24 -
00.39 were at a frequency of 137789.3 +/- 0.1Hz. So it appears that if any, it
were the latter that were transmitted by Larry, but these were very weak, and
it was impossible to say with any certain where dashes started and stopped.
A few comments on Andy's e-mail. An accuracy of 0.05 ppm corresponds to about
0.01Hz at this frequency, but with Spectran it is not possible to measure more
accurately than to 0.1 Hz.
If we need to measure to this accuracy, how do we do it? What specialist
hardware/software is required?
I list below every trace that I could see in this part of the spectrum
including all of the Loran lines seen and identified with considerable
certainty.
QRA frequency when seen strength
yymmdd:hhmm
Loran 137735.8491 weak
Loran 137738.3651 very weak
137739.6104 010116 wanderer
Loran 137743.2774 medium
FRENCH 137744.4604 010116 strong
Loran 137745.0327 very weak
E/W 137745.7104 010116 medium
137747.0104 010116 weak
N/S 137748.4104 010116 weak
E/W 137748.7104 010116 weak
137750.5104 010116 very weak
Loran 137750.7057 very weak
137751.2104 010116 very weak
Loran 137751.7002 very weak
137752.1304 010118 weak
E/W 137752.3104 010116 medium
E/W 137753.5104 010116 weak
137754.1104 010116 medium
E/W 137756.2104 010116 weak
Loran 137758.1340 weak
Loran 137758.3678 very weak
137760.5704 010118 weak
WHAT?? 137763.8104 010116 Strong carrier
Loran 137765.0353 very weak
Loran 137765.5623 weak
137767.7504 010119: 0130 medium dots
137770.2104 010116 very weak
Loran 137771.7029 very weak
Loran 137772.9906 medium
137774.0704 010118 weak
Loran 137778.3704 very weak
Loran 137780.4190 medium
137784.6204 010118 weak
Loran 137785.0380 very weak
Loran 137787.8473 medium
137788.0004 010118 weak
Larry? 137789.2604 010118:0024-0039 weak dashes
N/S 137790.3104 010117 strong
Loran 137791.7056 weak
137793.4804 010118 weak
Loran 137795.2756 medium
Loran 137798.3731 weak
Loran 137802.7039 weak
137803.1904 010118 weak
Loran 137805.0407 very very weak
Loran 137810.1322 medium
Loran 137811.7082 weak
137816.2704 010118 weak
Loran 137817.5605 not seen
Loran 137818.3758 not seen
137819.6404 010118 weak
137820.2104 010116 very weak
137820.6104 010116 weak
137821.5104 010116 strong
137822.5104 010116 weak
137823.5104 010116 very weak
Loran 137824.9889 medium
Loran 137825.0433 medium
137829.7704 010118 very weak
Loran 137831.7109 very weak
Loran 137832.4172 weak
Loran 137838.3785 medium
137841.5904 010118:2240 strong for 10 mins
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