14-02-2013, 06:49 PM
LW is still bugging me. Changed the silicon TR1 to an AF139.
This has made the MW unstable with lots of whistles and morse code and SSB type sounds. Checked the switches S1 and S2 changed C10 to 270pF TR1 now oscillates on LW , added 39 pF in parallel still oscillating but the range is still too high adding another 18pF cap (337pF) stops it oscillating again. I don't seem to be able to get it to oscillate below 675 KHz. I'm using a Sony 7600 as a frequency meter. I'll have a play with L5 tomorrow and go back to the silicon and also change the resistors as per the RP25A.
Anyone else had problems with LW?
BRs
Mike
This has made the MW unstable with lots of whistles and morse code and SSB type sounds. Checked the switches S1 and S2 changed C10 to 270pF TR1 now oscillates on LW , added 39 pF in parallel still oscillating but the range is still too high adding another 18pF cap (337pF) stops it oscillating again. I don't seem to be able to get it to oscillate below 675 KHz. I'm using a Sony 7600 as a frequency meter. I'll have a play with L5 tomorrow and go back to the silicon and also change the resistors as per the RP25A.
Anyone else had problems with LW?
BRs
Mike
