UHF 3 (non Astro) Spectra. Lower than 450

[WX5812]

I acquired a few uhf range 3 Spectras. 450- 482
Other than Vco tuning is there anything else that can be done so make it more efficient
In the 442-446 range?
I was reading about 5 MHz is all you can go. Didn’t know if there was some components that could be changed to gain some more sensitivity. I would think the transmit side would be fine. I could be wrong on that as well.

 

[a417]

I acquired a few uhf range 3 Spectras. 450- 482
Other than Vco tuning is there anything else that can be done so make it more efficient
In the 442-446 range?
I was reading about 5 MHz is all you can go. Didn’t know if there was some components that could be changed to gain some more sensitivity. I would think the transmit side would be fine. I could be wrong on that as well.

Been here?

[edit]
Sorry, that link should have been to this. There's a link in there to adding a preamp to a UHF unit, as well as some other valuable documents.

Where did you do this 'reading'?

 

[WX5812]

Been here?

[edit]
Sorry, that link should have been to this. There's a link in there to adding a preamp to a UHF unit, as well as some other valuable documents.

Where did you do this 'reading'?

I will have to go replace my steps. I want to say batlabs but done hold me to that

 

[RFI-EMI-GUY]

If I recall correctly, the VCO gets out of lock at around mid 442 MHz on R3 radio. You will see a

FAIL 001​

Synthesizer out-of-lock condition​

pertaining to out of lock. I had a ham repeater in mine that would go out during cold weather at times. The fix is either to pad some extra inductance on the VCO with copper tape or mess with the bias of the Varactor by changing a resister voltage divider. I did neither hence my radio always worked on 446 simplex and mostly worked on the 442 repeater. your mileage will vary.