Message-ID: <4E0E7F92677E49A49567215BBA4C55B2@gnat>
From: "Alan Melia" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <1115959624.20180313222044@gmail.com>
Date: Tue, 13 Mar 2018 22:40:46 -0000
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Subject: LF: Re: Antenna splitter question
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Chris if you are not listening to the same frequency on both you dont want a 
splitter you need a diplexer. This is effectively two filter with a common 
input, one is lowpass for LF one is HP for MF (though you may also need a LP 
in this side to reject BC TXs. I think there is design gen in Wes Hayward's 
Intro to RF Design

You can make a minimum loss splitter .....I have used one on 136 for two 
receivers but you lose about 4.5dB I think. Mine was 1.4 : 1+1 where ''1'' 
is a winding on a toroid with a reactance of about  250ohms. Its based on a 
Racal design (Brian CT1DRP used to work for them) the 1+1 can be centre 
tapped to ground.

Alan
G3NYK

----- Original Message ----- 
From: "Chris Wilson" <dead.fets@gmail.com>
To: <rsgb_lf_group@blacksheep.org>
Cc: <dead.fets@gmail.com>
Sent: Tuesday, March 13, 2018 10:20 PM
Subject: LF: Antenna splitter question


>
>
> Hello  LF 'ers,
>
> I am trying out a Red Pitaya on LF RX. It's running the open source
> HPSDR software which I have never really liked or got to grips with.
> With huge respect to the writers it always seems like it now needs a
> ground up re write as it has grown beyond its user interface IMHO, and
> is far from intuitive to use. However, I may be stuck with it as the
> firmware for running HDSDR which I am fully comfortable with and which
> has been my go to software for SDR for many years, has not worked for
> me with the Red Pitaya, although I haven't quite given up yet.
>
> HPSDR  allows 2 receivers in effect, but having the one aerial means I
> will  probably have to use a splitter. I would like to RX on LF and MF
> at the same time. I haven't seen a commercially made one that goes low
> enough, has anyone got a link to a DIY one please? Thanks.
>
> I  am running the Red Pitaya for the first tie tonight, I had to add a
> pre  amp  in front of it as it seemed a bit deaf on LF, I will be very
> curious to see how it works. Listening for WSPR2 and WSPR15.
>
>
>
> -- 
> Best regards,
> Chris                          mailto:dead.fets@gmail.com
>
>