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AGC Added to uBITx

Philip
 

I have added audio AGC to my uBITx, its a kit board from Walford Electronics (G3PCJ).
Disconnected the yellow wire from the top of the Volume pot. Yellow wire to the input of the AGC board via a 10 K resistor.
Output to the top of the Volume pot. Removed R235 and connected top of C252, to top of the Volume pot via 1 K resistor and 0.1 microfarad in series  (Cap stops  DC on the input of the audio amp )
This now puts the CW side tone in after the AGC board.

I also replaced the TDA2822M with a LM380-8 will need a bit of jiggling with the pin connections. hint turn it upside down.
The LM380-8 will work from 10 to 18 volts, and has built in thermal protection.

K4LXY
 

I checked into this AGC but it's pretty expensive to ship to the US - the dollar equivalent of £25.


Has anyone found anything similar here in the US? I can build one from scratch but I would prefer one nicely made up on a PCB.
Howard K4LXY

 

Marc Jones
 

Is there a schematic for this  AGC ? .. I've not been able to find one so far .


Philip
 

No.
Its copyrighted
Philip

Marc Jones
 

There must be a diagram or schematic somewhere or it wouldn't be able to he built , Would be good to see it , Get some ideas , Improve on it , Tailor it for the bitx ..


On Wed, 4 Apr 2018 at 21:11, Philip
<philip.g7jur@...> wrote:
No.
Its copyrighted
Philip

Ken
 

Have to buy it to get a schematic.

On Wed, Apr 4, 2018 at 4:25 PM, Marc Jones via Groups.Io <gw0wvl@...> wrote:
There must be a diagram or schematic somewhere or it wouldn't be able to he built , Would be good to see it , Get some ideas , Improve on it , Tailor it for the bitx ..


On Wed, 4 Apr 2018 at 21:11, Philip
No.
Its copyrighted
Philip


Philip
 

Try searching Google images for audio AGC.

VE3MIC
 

How about this? (designed for the BITX40)

https://oshpark.com/shared_projects/6qRXvzZR

Marc Jones
 

I use the NE570 IC for my AGC ...  


On Wed, 4 Apr 2018 at 22:36, VE3MIC via Groups.Io
<ve3mic@...> wrote:
How about this? (designed for the BITX40)

https://oshpark.com/shared_projects/6qRXvzZR

Rahul Srivastava
 

Hi!

There is a nice AGC implementation using  mic compressor chip SSM2166 in Polish SSB transceiver kit "Omega". We can try substituting the AF preamp with a module from  Ali.. (baba..) and his band of...!!!

Link:



73

Rahul VU3WJM

K4LXY
 

Do you mean R253?
Howard