Message-ID: <20100110204914.7slzdzt6skoww4so@webmail6.kuleuven.be>
Date: Sun, 10 Jan 2010 20:49:14 +0100
From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
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Subject: Re: LF: Link budget calculation or estimation of dist for given
	power on WSPR
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Jim,

if ionoshperic propagation is involved signal strength (and thus SNR) =20
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 =20
>  a link budget for WSPR over a set distance?
> As it seems I can get up to GM4SLV reasonably consistently on my  =20
> current antenna/power setting with a SNR of around -22dB and the  =20
> limit for WSPR is around -30dB then is there a means for roughly  =20
> estimating or indeed accurately calculating the Expected Max Range  =20
> (EMR) at that power setting and antenna configuration?
> Clearly, there are differences between separate Rx stations but if  =20
> one knows the ratio between two or more Rx stations then it should  =20
> be possible to pro-rate or estimate at least the signal strength at  =20
> 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  =20
> would the remaining  8dB or so of WSPR detection get me, assuming  =20
> the other Rx has the same capability as GM4SLV and if their  =20
> capability is different, then is it fine to factor for the dB  =20
> difference over known paths/signals?
> Thanks in advance for any answers or pointers and best wishes to all =20
>  for a great 2010
> With best regards
>
>
> Jim
>
>
> Dr. James Cowburn G7NKS
> E james.cowburn@virgin.net<blocked::mailto:james.cowburn@virgin.net>
>
>
>