Message-ID: <20100110225447.qai3f5xv0gwkkocw@webmail6.kuleuven.be>
Date: Sun, 10 Jan 2010 22:54:47 +0100
From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>, Roger
	Lapthorn <rogerlapthorn@gmail.com>
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	<20100110204914.7slzdzt6skoww4so@webmail6.kuleuven.be>
	<9afca2641001101154y7b99110l20c6ab44435d4213@mail.gmail.com>
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Subject: Re: LF: Link budget calculation or estimation of dist for given
	power  on WSPR
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Roger, Jim,

On Alan's (G3NYK) website =20
(http://www.alan.melia.btinternet.co.uk/simple.htm) I found:

Allow for an extra "hop loss" of 12dB for every ionospheric =20
"reflection" and 6dB for a land "bounce", say about 1dB for a sea =20
"bounce".

Thus an extra hop would "cost" 13 to 18dB (+ free space loss ?)

73, Rik  ON7YD - OR7T

Quoting Roger Lapthorn <rogerlapthorn@gmail.com>:

> Do we know how many dB loss (over land and over sea) for a single hop Ri=
k?
>
> 73s
> Roger G3XBM
>
> 2010/1/10 Rik Strobbe  =20
> <Rik.Strobbe@fys.kuleuven.be<mailto:Rik.Strobbe@fys.kuleuven.be>>
> Jim,
>
> if ionoshperic propagation is involved signal strength (and thus  =20
> SNR) depends more of the number of hops involved than the absolute  =20
> distance.
> And each hop "costs" a number of dB's in signal strength.
>
> 73, Rik  ON7YD - OR7T
>
>
> Quoting James Cowburn  =20
> <james.cowburn@virgin.net<mailto: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  =20
> james.cowburn@virgin.net<mailto:james.cowburn@virgin.net><blocked::mailt=
o:james.cowburn@virgin.net<mailto:james.cowburn@virgin.net>>
>
>
>
>
>
>
>
>
>
> --
>
> http://g3xbm-qrp.blogspot.com/
> http://www.g3xbm.co.uk
> http://www.youtube.com/user/G3XBM
> G3XBM    GQRP 1678      ISWL G11088
>