[R-390] Product detector kits

[Bob Camp]

Hi

AGC is a pretty darn important item. Audio derived AGC is about the 
only way to go with SSB. One way or another the radio has to have AGC 
to  make a product detector work well for band cruising. Matching the 
AGC to the detector is an important part of the design. Manual gain 
control works, but it's a pain as you tune through a crowded band.

That said just about any kind of product detector is going to work 
better than the BFO in a stock R-390. A lot of this comes down to 
outboard boxes versus internal modifications.

Maybe Jan will offer a product with the full circuit in it ...

	Take Care!

		Bob Camp
		KB8TQ

On Feb 14, 2005, at 12:07 AM, DJED1 at aol.com wrote:

> Jan's detector is a varient of a circuit I offered to the board 
> several years
> ago.   I have one problem with his circuit in how it differs from 
> mine.   As
> best i can tell from his published notes, he has included the product
> detector, but not the auxiliary fast attack AVC which I included in my 
> circuit.   He
> says in his writeup that you need to reduce the RF gain for strong 
> signals,
> while my AVC allows full gain on signals up to 80-100 dB.   His 
> detector may work
> well if you have modified the radio's AVC with the Lankford 
> modification.
> Ed   WB2LHI
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