Hi Roger,
I'll choose a different subkect now, since it gets confusing slowly ;-)
With wideband i rather mean a window that shows 0...24 kHz (if your
samplerate is 48 kS/s). This allows you to check the MSKs, Alphas and
mains hum and all man made noise sources within this range. Typically i
am using a scroll rate of 1 minute per pixel since this covers more
than a half day or night on a 1024 pixels wide screen. If you want to
try that you may use the attached file or choose your own settings.
73, Stefan/DK7FC
Am 09.03.2011 17:20, schrieb Roger Lapthorn:
Hi Stefan,
I enclose here the full wider band 3 day plot of the noise (and mystery
signal) as received in 424uHz BW here in JO02dg near Cambridge. Do you
have any comments please? The mystery signal appears on all three
nights at 8.9701kHz. It looks like a little "hook" shape over about 4
hours.
BTW, the loop/preamp system is receiving the alpha beacons very well,
typically 20dB over the noise. See http://www.youtube.com/watch?v=TDxRhQYg7lQ
for a video showing alpha beacon reception using the SM6LKM software
VLF receiver.
If the interference/noise at 8.9701kHz was natural then surely it would
be amazing for such signals to exactly repeat 3 nights running at
exactly the same frequency? OK, I agree the general background noise
floor may be partly man made and partly the natural noise floor
changing diurnally but the oddity at 8.9701kHz?
The grabber is currently OFF as I shall be away for a couple of days,
but still in email contact.
73s
Roger G3XBM
2011/3/9 Stefan Schäfer <[email protected]>
Hello
Roger,
Am 08.03.2011 20:51, schrieb Roger Lapthorn:
Nothing visible on my grabber https://dl.dropbox.com/u/15047843/xbm_grab.jpg
yet this evening but I have a high noise level in the evening hours
from lights, TVs etc.Leave the TX running overnight please as I hope to
see your signal after midnight and through tomorrow morning. In the
423uHz bandwidth and with the slow scroll speed it will be more
difficult to see than when you were sending a continuous carrier a few
days ago.
Are you sure it is local QRM? Maybe its just the usual QRN that risies
strongly in the evening. It is as strong as never before within this
year now :-( And things will get even worse. We have to make QRO,
faster than nature does it ;-)
To check the local QRN/QRM situation it would be helpful (and
interesting!) to have a wideband screen from you. If you want, you
could run a second SL instance simultaneously and upload the pictures.
You know how the wideband windows looks, from grabbers like TF3HZ which
is most interesting each day :-)
Also you may arrange a real website and store it on your dropbox. There
you can include several pictures in one link, the link to the website
:-)
Best 73, Stefan/DK7FC
--
g3xbm-qrp.blogspot.com/
www.g3xbm.co.uk
www.youtube.com/user/g3xbm
G3XBM GQRP 1678 ISWL G11088
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