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Ok Dave,
So much for the skip theory ,
unless its leaking out of the ground , may be the
channel tunnel is acting as a large coax cable
if you have a high noise level to
start with , +10 is not good news , may be the
original wspr slot at the top of the band is
still
the better option , pity the tx
time is so long , its not really matched to LF , if you
only capture regularly 25% of the sync
then sending the other 75% is
questionable ?
G..
Sent: Sunday, November 07, 2010 8:25 AM
Subject: Wideband Noise on 500 kHz [was RE: LF: WD2XSH/17 on
WSPR]
Graham, LF,
I
checked the wideband noise at midnight last night with my SPM-30 (3 kHz
bandwidth). It was clearly audible, and had the sort of buzz-saw rumble that one
finds on HF occasionally. The levels were:-
496.0 kHz - 81
dBm
500.0 kHz -
73dBm
504.0 kHz - 83
dBm
So
it's about 8 to 10 dB above my local background noise level
:-(
No
WSPR stations copied last night on 501 kHz.
73,
Dave G3WCB IO91RM nr Windsor, S.E. England
Dave,
I think the sharp cut-off is
the only elegant part of it ? , using spec-lab , I can see
a drop of 10 to 15 dB over 502 KHz .. suppose its a
good place to try data modes out .. interestingly , wspr is
not producing any false decodes and the WD
signal decoded twice , which I think is
actually times 4 decodes , round 2400 z , but may be
the s/n distorted by the noise floor increase ? my 100
watts crossed once , but gave a better s/n
There may be a possibility , that you
are inside the skip range and out of the ground
75/100 mile range ..?
I see a couple of S points on
the meter as I tune over the noise ..marvellous .. and
the pulse modulated Christmas lights are yet
to come ...... hum-bug
73-G.
Sent: Saturday, November 06, 2010 12:43 PM
Subject: RE: LF: WD2XSH/17 on WSPR
Hi,
Graham.
It's
probably contributing to the overall high level of crud at this QTH, but I'm
not aware of exactly how much it is adding.
I'll
do some tests over the week-end and try to measure the contribution. From what
I've seen on the various grabbers, it seems to have a fairly well-defined H F
cut-off, so it should be easy to identify where the wideband datalink noise
ends and the usual hash continues.
Cheers
Dave
Dave,
Do you see the wide band noise
at + 10 to +15 dB over the background noise ?
G..
Sent: Saturday, November 06, 2010 8:23 AM
Subject: LF: WD2XSH/17 on WSPR
I
snagged WD2XSH/17 last night on WSPR. This is pretty good going for this
QTH, as I have a very high local noise level on 500 kHz.
| 2010-11-06 04:06 | WD2XSH/17 | 0.501091 | -27 | 0 | FN42pb | +30 | 1.000 | G3WCB | IO91rm | 5233 | 3252
73, Dave G3WCB IO91RM nr Windsor,
S.E.England
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