XTL with low output power

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cgroftmc
Posts: 89
Joined: Thu Oct 18, 2001 4:00 pm

XTL with low output power

Post by cgroftmc »

Picked up a mid power XTL recently. I hooked it up to a meter and was expecting to see around 45-50 watts out. I'm seeing around 30. The power settings are set to 10 watts low and 53.5 for high. I also tried to adjust the current settings in the tuner with no luck. Any suggestions?? Did Moto make a low power version of the XTL?

Thanks!!

Craig
Thomas
Posts: 71
Joined: Mon Oct 20, 2008 5:35 pm
What radios do you own?: MCS2K,CDM1250,XTS3000,XTL2500

Re: XTL with low output power

Post by Thomas »

I recently aquired one of these also. I adjusted the power from within cps. That worked for me. Also if you are using the radio out of its specified bands limits power could drop off some depending how far out of band you go. My radio is an S split but I have it on the 440 ham band and its output power levels are right where cps says they are verified with a bird watt meter.

Also as always check your jumpers, connections and antenna. If you havn't tried put it into a 50ohm dummy load and see what it reads.
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Motoboy
Posts: 102
Joined: Wed Nov 11, 2009 1:58 pm
What radios do you own?: HT1250 I saved from the dump

Re: XTL with low output power

Post by Motoboy »

Were you using a power supply or was it connected in a vehicle? If in a vehicle, was the vehicle running?

The most likely explanation is that the power supply (whatever that may be) voltage dropped on transmit, causing low power output. This could be caused by an AC power supply that is not big enough to handle the load, or a linear power supply that has a faulty regulator. If connected to a battery in a vehicle, there could be a voltage drop caused by a loose or corroded connection to power, ground, or both. If the vehicle ignition was on but the engine was not running, the battery voltage could be low due to excessive draw. This would not be the case if the engine was running, unless you have a bad alternator or something related to that.

I have diagnosed several vehicle problems that started out as perceived radio problems.
"I don't have a driver's license, either, and that never got me in trouble!" ~Customer
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Tom in D.C.
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Joined: Tue Sep 04, 2001 4:00 pm
What radios do you own?: Progreso soup can with CRT

Re: XTL with low output power

Post by Tom in D.C. »

What the CPS says is the output power is not what the radio actually does. In other words the CPS adjustment is a relative setting and you're best off using a wattmeter and dummy load to set the power you want. I have a 100 watt UHF XTL trunk mount, used as a base, and I had to set the CPS high power to a ways above 50 watts to get an actual 50 watts out of the unit.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
tvsjr
Posts: 4118
Joined: Fri Nov 28, 2003 9:46 am

Re: XTL with low output power

Post by tvsjr »

If what you're entering in the CPS isn't what you're seeing out of the radio, you need to go through both power calibrations in the Tuner using a properly-calibrated service monitor. Set up properly, the output entered in the RSS should be within a few percent of the actual output.
cgroftmc
Posts: 89
Joined: Thu Oct 18, 2001 4:00 pm

Re: XTL with low output power

Post by cgroftmc »

Thanks for the suggestions guys. I'll give them a try. The radio is hooked up to a ASTRON 20 AMP PS (15A continuous). I have a different higher rated supply that I will try.

Craig
Will
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Joined: Tue Sep 04, 2001 4:00 pm

Re: XTL with low output power

Post by Will »

cgroftmc wrote: The radio is hooked up to a ASTRON 20 AMP PS (15A continuous). I have a different higher rated supply that I will try.

Craig
The power supply you have is sufficient for the 40 watt models.

Check the voltage right at the radio power connector, S/B 13.4 volts .
cgroftmc
Posts: 89
Joined: Thu Oct 18, 2001 4:00 pm

Re: XTL with low output power

Post by cgroftmc »

So I hooked up the radio to a 30A PS with a current meter. The radio is only pulling approx 8 amps. Alignment time I guess.

Craig
tvsjr
Posts: 4118
Joined: Fri Nov 28, 2003 9:46 am

Re: XTL with low output power

Post by tvsjr »

Sadly, even most brand-new A25 and APX series radios need a full alignment... so the ones on the used market really need it!
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