SP50 Programming TX

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5FiftyFive
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Posts: 2
Joined: Sun Mar 17, 2013 6:04 pm

SP50 Programming TX

Post by 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
Posts: 6823
Joined: Tue Sep 04, 2001 4:00 pm

Re: SP50 Programming TX

Post by 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
New User
Posts: 2
Joined: Sun Mar 17, 2013 6:04 pm

Re: SP50 Programming TX

Post by 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
Posts: 872
Joined: Sun Nov 25, 2001 4:00 pm
What radios do you own?: Too many

Re: SP50 Programming TX

Post by PETNRDX »

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