SP50 Programming TX

[5FiftyFive]

Hi all,

I tried a search but couldn't come up with anything related to this

My UHF SP-50 has been set up with the 440 amateur band channels using the hex-edited MDF file. RX appears to work on all channels, but TX appears only to work on channels > 445MHz. When the PTT button is pressed on these < 445MHz channels, the TX lamp turns on for about a half second, then goes out.

Any one ever hear of this happening?

Cheers

[Will]

Some of the hi split, 450- 470, SP50's will not work down that low. You may be able to tweek the radio transmitter to go that low, to 440.

Could be as simple as a slight tweek to the TX VCO to get a solid lock.

[5FiftyFive]

Hi Will,

Thanks for the reply. Is the VCO adjustment done via a pot on the board, or is it done in software? I don't have a copy of the SP50 service manual, do you happen to know where I might be able to find one?

Thanks!

[PETNRDX]

I would agree, pretty darn likely the TX VCO needs tweaking.