Re: uBitx AGC mod

Diver Martin <diver.martin@...>
 

Herman ON7HC,

Interesting.  Maybe I'll have an AGC-off... my usual PCB vendor is $9.50 for 10x PCB's, but $18 shipping if I want fedex (HK Post $6 if I want to for the slow boat, or $12 for DHL if I want the packaged delivered to me Ace Ventura style...).  I'll look at the schematic a little more closely.  Might be able to use the variable attenuation part as the current IF amp has enough gain as-is in the uBitx... A hybrid of the two perhaps?

Chris:  They look correct to me, both in the original schematic and my version... Emitter towards ground (pin 2 on the SOT23 form of MMBT3904)...

On Wed, Jan 3, 2018 at 5:01 AM, ON7HC <herman.docx@...> wrote:
Hi Martin,

Please read #32103 + 14 related messages.

It's a AGC developed by Jim, ND6P.  I build it some time ago and it's working like a charm !
The AGC is audio derived, but attenuates the RF input, using pin diodes. I've used it on my Bitx40 build. The AGC acts like in a commercially build radio :)
Could be interesting ...

Herman - ON7HC




--
Martin Held - AE7EU
http://ae7eu.com/
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