Re: LF: Link budget calculation or estimation of dist for given power on WSPR

[Roger Lapthorn <rogerlapthorn@gmail.com>]

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 <Rik.Strobbe@fys.kuleuven.be>

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 <james.cowburn@virgin.net>:

 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 james.cowburn@virgin.net<blocked::mailto:james.cowburn@virgin.net>

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