Gerald:
Just curious about the filter delay comment. I always thought the delay
was in the audio/agc circuit which caused it not to respond as fast as it
should. Also can you comment on why you think TT used audio agc instead
of IF agc? I've seen some really simple IF agc circuits that work great.
Do you suppose it was just a carry over from the Triton/Argo days when cw
selectivity was dependent on the af filter being in the agc loop?
N4LQ
-----Original Message-----
From: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
To: Tim English <te@usol.com>
To: <tentec@contesting.com>
Date: Mon, 29 Apr 2002 21:54:06 -0500
Subject: Re: [TenTec] Would like Corsair II comments
> I see reports that the Corsair II is noisy. It just has lots of gain
> but
> the RF stage uses circuitry that should be very quiet. Practically
> quiet
> enough for VHF/UHF without a significant preamp.
>
> The band pass tuning of the Corsair II works very well, even with only
> SSB filters it can be cranked down to really narrow for CW. I've hardly
> ever felt a great need for the narrow filter (which I do have) except
> to
> be able to set the pitch of the received signal where I want it at the
> time. AGC is very good, but more calm on a good antenna with the RF
> gain
> backed off. AGC is audio derived so doesn't rise quite as fast as if it
> was IF derived and strong signals can make a leading edge click because
> of the crystal filter delays.
>
> On 75 with a good antenna I run mine with RF backed to about 3 PM on
> the
> knob and the "attenuator" (RF gain knob pulled, actually no RF stage at
> all) in the circuit. Works really fine. And isn't bothered by the
> strong
> signals on adjacent frequencies that bothered my other brands of radio.
> The filter response also is such that it passes lightning as clicks,
> doesn't convert lightning to crashes (characteristic of most crystal
> and
> mechanical filters) so it works on the low bands in the summertime very
> well.
>
> I'm not interested in any offers for my Corsair II.
>
> 73, Jerry, K0CQ
>
> --
> Entire content copyright Dr. Gerald N. Johnson. Reproduction by
> permission only.
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