BC-Tune modification
The option for Auto BC-Tune between 600 and 1600 kHz.


The DC data from 13 measured frequencies is with the aid of VB software converted to a continous stream of data and later put in an EPROM.
The D/A converter now makes the correct tune Voltage.
CW (zero-)/ BFO tune is usable now in the BC range. (for DX)
A few percent of BC-Tune remains to check the auto-tune.

Rather tricky and complex modification,
NOT adviced if you are not very experienced!

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  © PROJECT ENGINEER:
WALTER - PE1ABR.


BC_tune.jpg

BC_tune circuit board

Alignment (D/A-00 on 500 kHz and
D/A-FF on 1700 kHz) can only be done connected to the display inputs for the correct D/A information.

New ZIP file
EPROM creation program in VB6
BC_tune.jpg

BC_tune underneath Rx board (removed) together with synth backup option




gap
2x BB212 (L)   or   4x single (R)
(both in new frame)
It is allways needed to adjust the high frequency tracking (1200 - 1600kHz) with 2 extra trim C's.
Sometimes it is also needed to replace all 8 diodes with 4 new duo's type BB212 for a perfect tracking.
BC_tune.jpg

BC_tune - try to see the display connections




BC_tune.jpg

BC_tune - try to see the display connections




BC_tune.jpg

BC_tune - Only now you can see the position of the left white and gray wire - Overthere are extra connector poles for tune voltage in and out
the wiring to those poles is on the back, so the front has to be dismanteled too
 
Original first HTML code: C.L. van Soelen


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bctune.htm
by Walter - PE1ABR - 2020-07-30