My wife goes shopping…works for
her!!
With best regards
Jim
Dr. James Cowburn
Dear Jim (et al),
Thanks for this interesting analysis. It does indeed suggest plenty of
scope for improvement in the coming months.
As I've said several times in the last week, I'm gobsmacked that anyone, apart
from G6ALB 3kms away, is able to hear me with the set-up I have. The 500kHz
WSPR beacon will run one more time overnight tonight then it will be off
for 2-3 weeks.
My wife is wanting her dressing table back as the tiny ATU is sitting on it and
tuning is very sharp; every time she puts anything down I have to check the
antenna current is peaked :-))
You know I'm like a kid: I get so
excited looking at the spots and thinking about gradually making improvements
and seeing my coverage extend on 500kHz.
My wife just humours me!
73s
Roger G3XBM
2009/9/19 James Moritz <[email protected]>
Dear Roger, LF Group,
It is interesting to make an estimate of what G3XBM's ERP might be...
The noise level at M0BMU during relatively quiet daytime conditions I estimate
to be of the order of 3uV/m in the 2.5kHz WSPR reference bandwidth. The
reported SNR gets up to about -25dB, making the signal level from G3XBM about
0.18uV/m.
ERP = (Ed)^2 / 49; with E = 0.18 x 10e-6, d = 69000m , ERP is about 3uW with
only "geometric spreading" propagation losses. But there is some
additional reduction in field strength due to ground wave propagation losses,
perhaps 3dB with "good" ground, so the ERP would then become about
6uW. Diffraction losses due to the curvature of the earth are negligible at
this distance.
Obviously, this could be +/- several dB due to various uncertainties, but
should be of the right order of magnitude. Plenty of potential for improvement
then!
Cheers, Jim Moritz
73 de M0BMU
--
-------------------------------------------------------------
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
G3XBM GQRP 1678 ISWL G11088
