Roger, Jim,
On Alan's (G3NYK) website
(http://www.alan.melia.btinternet.co.uk/simple.htm) I found:
Allow for an extra "hop loss" of 12dB for every ionospheric
"reflection" and 6dB for a land "bounce", say about 1dB for a sea
"bounce".
Thus an extra hop would "cost" 13 to 18dB (+ free space loss ?)
73, Rik ON7YD - OR7T
Quoting Roger Lapthorn <[email protected]>:
Do we know how many dB loss (over land and over sea) for a single hop Rik?
73s
Roger G3XBM
2010/1/10 Rik Strobbe
<[email protected]<mailto:[email protected]>>
Jim,
if ionoshperic propagation is involved signal strength (and thus
SNR) depends more of the number of hops involved than the absolute
distance.
And each hop "costs" a number of dB's in signal strength.
73, Rik ON7YD - OR7T
Quoting James Cowburn
<[email protected]<mailto:[email protected]>>:
Dear LF,
Has anyone any ideas or suggestions on a resource for calculation of
a link budget for WSPR over a set distance?
As it seems I can get up to GM4SLV reasonably consistently on my
current antenna/power setting with a SNR of around -22dB and the
limit for WSPR is around -30dB then is there a means for roughly
estimating or indeed accurately calculating the Expected Max Range
(EMR) at that power setting and antenna configuration?
Clearly, there are differences between separate Rx stations but if
one knows the ratio between two or more Rx stations then it should
be possible to pro-rate or estimate at least the signal strength at
a given Rx based on its performance with other known signals.
If I can do 916km with an SNR of say -22dB then how much further
would the remaining 8dB or so of WSPR detection get me, assuming
the other Rx has the same capability as GM4SLV and if their
capability is different, then is it fine to factor for the dB
difference over known paths/signals?
Thanks in advance for any answers or pointers and best wishes to all
for a great 2010
With best regards
Jim
Dr. James Cowburn G7NKS
E
[email protected]<mailto:[email protected]><blocked::mailto:[email protected]<mailto:[email protected]>>
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