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Date: Fri, 13 Jul 2007 23:23:55 +0100
From: John GM4SLV <gm4slv@sighthound.demon.co.uk>
To: rsgb_lf_group@blacksheep.org
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	<PAEFLMFGBDKKCONLMLBICEEFCLAA.ganymede444@btopenworld.com>
Organization: The Gammy Bird
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Subject: Re: LF: [500] 500KHz signals in Shetland
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On Fri, 13 Jul 2007 23:08:37 +0100
"Dave G3WCB" <ganymede444@btopenworld.com> wrote:

> Hi, John, LF
> 
> It sounds like you're making good progress. I looked up your QTH on a
> locator map last night - it's nearly a thousand kilometers from
> here...serious DX for 500 kHz!
>

Hi Dave,

Yes, just about everywhere's serious DX from up here!


> Your RX might benefit from having a tuned pre-amp in front to add a
> bit of extra gain and selectivity. I'm using a design with a J-310
> FET, taken from G3YXM's LF web-pages. IF transformers robbed from
> junked transistor portables are ideal for the purpose.

The AR7030 has a MDS of around -123dBm so I'd guess it's not going to
improve much by adding gain. I always though that "if you hear the
noise increase on a quiet band when you plug the antenna in then you've
got enough receiver sensitivity" I'm happy to give a pre-amp a try
though to see if it helps.

> If you need a QRSS beacon signal while you're tweaking you
> antenna/RX, drop me an e-mail via the reflector or direct. I would
> think that evenings would be best for these sort of distances, but
> who knows? We're all still trying to understand how the band works,
> especially over long-ish distances.

I'm happy to give reports/screen captures to anyone who's interested in
how well they're reaching this far flung outpost.

I'm currently hearing GW3UEP's CW beacon on 501.1 amid the static
crashes. 

If you fancy a try at QRSS let me know. My XYL is down on Orkney for
the weekend, so I've plenty of time to play radio!

Cheers,

John


-- 
G-GRP-Club 2377, QRP-ARCI 12384, SKCC 3214
Member : RSGB, ARRL
Shetland Islands (EU-012) IP90GG 
Lerwick Radio Club : http://www.gm3zet.org