Spectra tuning

[cduda]

Hello. Have a Spectra Model number: D43KXA7JA4AK VHF

Local frequencies work fine, Tx and Rx---Distant repeater sites I can tx and rx fine using a HT1250 portable but can not Tx or Rx on the mobile. Even the weather channel is very broken up. All antenna connections are fine, (brand new antenna), all frequencies are correct, PLs are correct

Wondering why these distant repeater sites I cant Rx or Tx on them.

Does this unit need tuned and curious as to why it would need tuned when all the local stuff works fine?

Thanks

[Bruce1807]

Either you have a bad antenna or your radio is off frequency.
Check the antenna first

[kc7gr]

A misaligned reference oscillator can have a drastic effect on receiver sensitivity. You need to check the transmit frequency, using (at bare minimum) a solid dummy load and a known-accurate frequency counter. Ideally, you should use a service monitor. Since the RefOsc influences both TX and RX, a fault will show up on either side.

The other possibility: I've seen the front-end board in Spectras go bad. Not sure if it's the filter assembly or something else, but I've seen them fail. Again, this is something you need the right test gear (and the service manual) to diagnose.

Happy tweaking.

[jmr061]

Poor man's test for the front end: Key the spectra up on a local repeater and have your HT1250 turned on and see if your spectra trips the repeater. If it does but you get no RX on the spectra, the front end more than likely is bad. It is pretty easy to swap out with another one to try it. If your not hitting the repeater then you have TX issues.

Jason

[Will]

A reference oscillator that's off by as little as 1.5kHz can have a drastic effect on receiver sensitivity. .

That would put the Spectra on the next channel on VHF, and the third channel on UHF!!!!!!!!!!!!!

[kc7gr]

A reference oscillator that's off by as little as 1.5kHz can have a drastic effect on receiver sensitivity. .

That would put the Spectra on the next channel on VHF, and the third channel on UHF!!!!!!!!!!!!!

I rest my case.

In all honesty, I think I may have made a typo in my first post. Make that '1kHz' instead of 1.5. And yes, I have seen refosc's that were off by nearly a full kHz. In one case, I was able to retune. In another, I had to replace the actual oscillator module.

Keep the peace(es).

[Will]

Bruce, I read your post to mean that the reference freq. was off 1.5khz, even one khz at the ref would be about 10 khz at the VHF channel.

At VHF the accual RX frequency could be off by 5 khz and that would make the receive sound realy bad from a distant station.


Cduda says both RX and TX problem at a distance, common to both RX and TX would be the REF osc or the antenna.

First make sure the antenna connector center pin makes good connection in the Spectra radio.

Second check the REF frequency. I have seen the ref osc off, and it was caused by forcing a wrong code plug into the Spectra. One REF was way off and that one had the correct voltages, had to replace that one.

[kc7gr]

Bruce, I read your post to mean that the reference freq. was off 1.5khz, even one khz at the ref would be about 10 khz at the VHF channel.

<snippety>

Then I'm really having a hard time making myself clear. I was actually referring to the TX frequency being off that far. I've corrected my post to reflect this. You are, of course, right on about the antenna connection as well.

Keep the peace(es).