Ulf I was thinking the 137 Hz was injected differently. But yes its a varicap on the 5 Mhz signal. Still that same effect can be accomplished in the PLL feedback loop. I would simply go try these things but can not hack my one and only 5065. Its working just fine. A question The 137 is injected at 5Mhz isn't it multiplied to a FM swing of 2466 Hz at 90 MHz? Granted close in sidebands would still contain 137 Hz. Regards Paul
On Wed, Aug 26, 2020 at 3:14 AM Ulf Kylenfall via time-nuts < time-nuts@lists.febo.com> wrote: > Paul, > > A 60 MHz xtal oscillator divided by 12 and comparedwith the incoming 5 > MHz. Then there is this thing > how to acheive a good symmetrical FM injecting > the 137 Hz signal without affecting the loop filterparameters. > > Keeping the original design with modern typesof semiconductors is less > work/effort, provided that the > unit keeps working... > The A7 original design used a non selective2nd harmonic detector. And uA > 709's.That one was easy to motivate an upgrade. > > I am a bit lazy otherwise. > > As mentioned, the semiconductors that have failed > in A3 were all dated 1968. > At the time without knowing the exact types of the JFET'sI replaced them > with 2N4416 only to discoverthat that was the type HP specified in a > laterrevision of the A3. > Best Regards > Ulf Kylenfall > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.