In my opinion the Corsair 9 MHz filter is exactly where it should be and
there should always be that one IF stage after the balanced mixer to
properly terminate the filter from LF to VHF for better intermod
performance. The RF and IF stages used in the Corsairs are capable of
greater dynamic range than any used since, the three winding transformer
circuit was Ulrich Rohde's favorite for those applications.
Pure audio derived AGC has a fundamental flaw that its slow to attack,
but it doesn't pump when its after an audio filter, and the fundamental
flaw that the time delay of the bandpass filter can allow a strong
signal to exist before it gets to the AGC audio detector, hence in that
environment it will have clicks on attack for that signal stored in the
crystal filter. Adding more filters in cascade can only make it worse.
Adding filters with poorer time response (possibly true of Inrad
designs) will only make it worse.
Then there's the CW sidetone, but the relaxation oscillator will follow
your fist precisely and a keyed sinewave oscillator won't nearly so well
at high speeds.
73, Jerry, K0CQ
On 12/7/2010 5:18 AM, Barry N1EU wrote:
> On Tue, Dec 7, 2010 at 5:13 AM, CSM(r) Gary Huber<firstname.lastname@example.org> wrote:
>> The Corsairs may not be near the top of the Sherwood list or work that
>> as a contest, but they still are great radios for working DX and for the
>> price a fantastic buy.
> Has anybody successfully installed the Inrad roofing filter mod in the
> My main knock on the Corsair is the AGC circuit - wish there was a major
> surgical mod for it . . . .
> 73, Barry N1EU
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