VHF radio repair question
 

Hey guys, I don't know where else to ask so hope someone here can help.

Just fired up a Kenwood TM-742 tri-bander (2M-220-440). Output on 2m & 440 is about as expected but the 220 module appears to have a
problem ... low tx power (2watts). No matter what pwr level (low-med-high) the radio is set too the transmitter only puts out about
2watts!

I can monitor tx audio with a scanner and the radio DOES tx and the audio sounds good. Does it sound like the final is gone? Could
it be something else? Any GOOD repair centers OTHER THAN Kenwood's (I do not like KW service!)?

TIA,
Vic / KE4QJK

On Mon, 30 Aug 2004 18:16:26 -0400, "Vic"
wrote:

Just fired up a Kenwood TM-742 tri-bander (2M-220-440). Output on 2m & 440 is about as expected but the 220 module appears to have a
problem ... low tx power (2watts). No matter what pwr level (low-med-high) the radio is set too the transmitter only puts out about
2watts!

I can monitor tx audio with a scanner and the radio DOES tx and the audio sounds good. Does it sound like the final is gone? Could
it be something else?

Are you measuring power into an antenna or a dummy load?

If into an antenna, make sure you don't have reflected power folding
back the TX power via the SWR protection circuit. A damaged or
nonresonant antenna could cause this.

Checking into a dummy load should tell you if it's the radio or the
antenna system.

Steve WA3SWS


************************************************** *******************
Steve Uhrig, SWS Security, Maryland (USA)
Mfrs of electronic surveillance equip
website http://www.swssec.com
tel +1+410-879-4035, fax +1+410-836-1190
"In God we trust, all others we monitor"
************************************************** *******************

Steve, I've tried both (antenna and dummy load) and both show the same results ... low power no matter what setting on the radio.
I'm confident the problem is with the radio.

Do you know how I would check the power module with a VOM?

Thanks,
Vic
___

"Steve Uhrig" wrote in message ...
On Mon, 30 Aug 2004 18:16:26 -0400, "Vic"
wrote:

Just fired up a Kenwood TM-742 tri-bander (2M-220-440). Output on 2m & 440 is about as expected but the 220 module appears to
have a
problem ... low tx power (2watts). No matter what pwr level (low-med-high) the radio is set too the transmitter only puts out
about
2watts!

I can monitor tx audio with a scanner and the radio DOES tx and the audio sounds good. Does it sound like the final is gone?
Could
it be something else?

Are you measuring power into an antenna or a dummy load?

If into an antenna, make sure you don't have reflected power folding
back the TX power via the SWR protection circuit. A damaged or
nonresonant antenna could cause this.

Checking into a dummy load should tell you if it's the radio or the
antenna system.

Steve WA3SWS


************************************************** *******************
Steve Uhrig, SWS Security, Maryland (USA)
Mfrs of electronic surveillance equip
website http://www.swssec.com
tel +1+410-879-4035, fax +1+410-836-1190
"In God we trust, all others we monitor"
************************************************** *******************