Re: PCB uBitx -working on it-

MVS Sarma
 

Any audio amp could be tried but it should be generally available in spares market. Perhaps for a design, better to use dip8  or soic8.

This is NOT a reply for Ashhar Farhan's design. M1  and M2 are to be shorted by relay contact 3&5 of K3 as per original design.

 If the  PCB implementer wanted to keep out the Linear PA ha may have to bring out that contact back to  exciter board , if I may call it so.
Sarma
 vu3zmv

On Sun, Mar 12, 2017 at 2:12 PM, John Backo via Groups.Io <iam74@...> wrote:
"the image of first LO+IF will float from 90 to 120 mhz. This is bang inside thr FM broadcast band."

Not only that, but it could possibly interfere with the aviation communication band.
That is a definite no-no in any part of the world. Perhaps a 60-90 MHz image would be better?
Or mandatory heavy shielding.

In researching the TDA2822, I note that there are two versions. One, a 16 pin dip is obsolete.
The current one is a 8 pin dip unit. They have different pinouts and are not interchangeable.

In studying the board, there seem to be several differences between the schematic and the layout.

There is an extra transistor in the AVC interface system. It is used where M1 and M2 are
supposedly connected to the relay. (??)

There is only one relay on the board.

It appears that there is no output to the 2N2219's and final transistors; both transformers are shown
as bifilar whereas one is trifilar and is the output interface.

More works is needed to make this a viable board. Looks nice though.

The suggestion to make modules and interconnect them is probably the way
to go right now.

john
AD5YE






--
Regards
Sarma
 

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