Ok, Kaos;
What's going on in that radio?
I see the following from you...
Then...
Then...
Ok, you are aware of the "shift" (455kHz) for TX to RX - so RX can have the 455kHz 2nd conversion IF.
So then I ask, if you see that and the Xtal stays - but the loop frequency is changing - it's supposed to.
Am I following you here?
(Check Pin 7 of the PLL - LOW on RX - Hi on TX - 22K resistor R131 - PULL DOWN resistor)
(PLL Pin 4 - Scope it - is it clean? TP4)
Ok, from my point of view, FWIW. Used to have a guy with the handle of Mosquito - used to hang out on Channel 19 - live by the freeway, 23 channel Cobra - so not much choice there beyond what the truckers usually ran.
I used to hang out on 21 - I also used an HR2510 (bad Andy - BAD!) but when he got on the channel he sounded more like a SSB'er - so with an RIT tweak and bang - THATS HIM - OMG - sorry Mosquito...
So yes, Delta Tune, Voice Lock or Clarifier - narrow band receivers can take issue with it being off, but ONLY if the Xtal i(per this PC66) s already off by more than 1kHz in he first place - the multiplier error in the synthesis for image capture/detect can cut off an older Xtal - based radio - but you can also have another type of RX noise, the hash noise from the detected carrier is closer to the passband than the audio info riding in on it. Same radio, just a different issue of the noise. The IF stages are ok, just the IF frequency used, if it's off, can make radios on frequency, sound like SSB modes - or like "they're off in the ocean surf."
So I can sympathize, just not sure if RX or TX shift isn't not occurring or if it's a regulation issue or if the varactor is the problem.
So, Kaos, how is the voltage at the PLL pin 1 - steady in any mode? IF not, look into the zener - I use / upgrade to - 5.6 V ones to handle the older days voltage drops.
And of course, the loop/phase detect caps - if they are old, may need to be replaced too...
So Xtal synthesis had it's drawbacks - just off enough to be outta' my receive
:+> Andy <+:
What's going on in that radio?
I see the following from you...
Then...
Then...
Ok, you are aware of the "shift" (455kHz) for TX to RX - so RX can have the 455kHz 2nd conversion IF.
So then I ask, if you see that and the Xtal stays - but the loop frequency is changing - it's supposed to.
Am I following you here?
(Check Pin 7 of the PLL - LOW on RX - Hi on TX - 22K resistor R131 - PULL DOWN resistor)
(PLL Pin 4 - Scope it - is it clean? TP4)
Ok, from my point of view, FWIW. Used to have a guy with the handle of Mosquito - used to hang out on Channel 19 - live by the freeway, 23 channel Cobra - so not much choice there beyond what the truckers usually ran.
I used to hang out on 21 - I also used an HR2510 (bad Andy - BAD!) but when he got on the channel he sounded more like a SSB'er - so with an RIT tweak and bang - THATS HIM - OMG - sorry Mosquito...
So yes, Delta Tune, Voice Lock or Clarifier - narrow band receivers can take issue with it being off, but ONLY if the Xtal i(per this PC66) s already off by more than 1kHz in he first place - the multiplier error in the synthesis for image capture/detect can cut off an older Xtal - based radio - but you can also have another type of RX noise, the hash noise from the detected carrier is closer to the passband than the audio info riding in on it. Same radio, just a different issue of the noise. The IF stages are ok, just the IF frequency used, if it's off, can make radios on frequency, sound like SSB modes - or like "they're off in the ocean surf."
So I can sympathize, just not sure if RX or TX shift isn't not occurring or if it's a regulation issue or if the varactor is the problem.
So, Kaos, how is the voltage at the PLL pin 1 - steady in any mode? IF not, look into the zener - I use / upgrade to - 5.6 V ones to handle the older days voltage drops.
And of course, the loop/phase detect caps - if they are old, may need to be replaced too...
So Xtal synthesis had it's drawbacks - just off enough to be outta' my receive
:+> Andy <+:
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