In addition to my IF DSP, I also have the Timewave DSP-599zx and it has AGC
in addition to the noise reduction. It also has a CW Spotlight which makes
the weak CW pop right out of the headphones.
On top of all this, I have the APF turned on. The APF is a triangular filter
in the FT-2000 which really digs cw out of the noise.
So, when you add all of these together, a really weak CW on 160 meters can
sound like armchair copy in many cases.
This Timewave unit might be just what you are looking for.
Cape Cod Instruments www.gnm-inc.com
"Problems cannot be solved by the same level of thinking that created
them." - Albert Einstein
----- Original Message -----
From: "Rick Karlquist" <firstname.lastname@example.org>
To: "Dan Schaaf" <email@example.com>
Cc: "Pete Smith N4ZR" <firstname.lastname@example.org>; "TowerTalk"
Sent: Thursday, January 19, 2012 9:26 PM
Subject: Re: [TowerTalk] Remote Preamp or In the Shack
> Dan Schaaf wrote:
>> My take on this has always been, if the atmospheric noise can be heard in
>> the radio, above the inherent radio noise ( with no antenna connected )
>> then you don't need a preamp. The preamp will amplify the noise as well
>> the signal.
> The problem with this concept is that you end up with no AGC,
> because of inadequate IF gain in nearly all receivers, especially
> when using 200 Hz CW bandwidth. The correct fix is to add about
> 20 dB more IF gain. I actually did this to my FT-757. It worked
> great, I got AGC on the weakest signals. You can also add
> enough preamp gain to get the AGC at the threshold on atmospheric noise.
> The problem with this is that your preamp is subject to overload.
> A third idea I have been thinking about is to build a audio AGC,
> which has the advantage that no receiver modification is necessary.
> It would likely be necessary to have an audio roofing filter to
> get rid of out of band audio hiss and hum. It might be possible
> to find some off the shelf audio processing box with AGC to do this.
> Equipment for DJ's, radio stations and/or recording studios would
> be likely to have an AGC function.
> Rick N6RK
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