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From: "Alan Melia" <alan.melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
References: <43D493DB.15534.6E234E@localhost> <000701c61ffc$a1e84010$03b46dcb@cobaltxp>
Date: Mon, 23 Jan 2006 11:18:17 -0000
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Subject: LF: Re: Kahn EER?
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Hi Murray Welcome to the Reflector....a well known call-sign.....nice to see
some more keen active stations from ZL. taking on the LF challenge

I dont know whether it fits you definition but Andy G4JNT and Jim M0BMU did
some work on using switching PAs for BPSK. Andy published a modulator design
which is in the "LF Experimenters Handbook" by Peter Dodd G3LDO. Jim used
this but also developed an "analogue" technique for sliding the phase change
edges. This is obviously a lot easier with a DDS, and Brian CT1DRP has
transmitted BPSK this way. The 136 band is not really wide enough for SSB so
there has been little interest though I have copied Dave G3YXM on SSB using
a linear PA.. The "widest" trasmission I can ever remember seeing in Europe
was a few clover signals. PSK31 has been used but only seems suitable for
short range, and does not stack up with other modes (even morse) for DX
capability. This may be due to the impulsive noise on LF and the lack of
error detection/correction (??)

Cheers de Alan G3NYK
alan.melia@btinternet.com
www.alan.melia.btinternet.co.uk


----- Original Message -----
From: Murray ZL1BPU <zl1bpu@nzart.org.nz>
To: <rsgb_lf_group@blacksheep.org>
Sent: 23 January 2006 09:08
Subject: LF: Kahn EER?


> Is anybody doing any work with Kahn Envelope Elimination and Restoration
> technology on LF? It would be especially applicable to those of us with
> nonlinear LF transmitters (class C, D, E) wishing to run sound card based
> modes (and even SSB).
>
> I'm especially interested to know about any sound card to LF carrier and
> amplitude exciter designs or converters, or I and Q converters.
>
> 73,
> Murray ZL1BPU
>
>