Motorola XPR 4550

[KF5CJG]

I have a Motorola XPR 4550 being used for Amateur Radio. It should output 25 to 48 watts according to the CPS and the model number. However, output power per a Daiwa Meter shows almost exactly half of the rated power on both Low and High settings on both analog and digital channels.

I've checked the voltage and used two different Astron power supplies with similar results. The channels that actually register 25 to 48 watts are the programmed Digital Simplex channels.

My antenna has low SWR and my Icom 5100 registers its rated power on the same meter.

Otherwise the radio works as expected.

Thank you for any help provided.

Nick

 

[N4KVE]

Check power output in analog mode only.

 

[N4DES]

Did you confirm the model # on the physical label because none are noted at 48 watts.

Motorola XPR 4550 Models​

AAM27JNH9LA1AN 136-174 MHz, 25 Watts, 1000 Channels
AAM27JQH9LA1AN 136-174 MHz, 45 Watts, 1000 Channels
AAM27QPH9LA1AN 403-470 MHz, 25-40 Watts, 1000 Channels
AAM27QNH9LA1AN 403-470 MHz, 25 Watts, 1000 Channels
AAM27TRH9LA1AN 450-512 MHz, 1-40 Watts, 1000 Channels

 

[KF5CJG]

Did you confirm the model # on the physical label because none are noted at 48 watts.

Motorola XPR 4550 Models​

AAM27JNH9LA1AN 136-174 MHz, 25 Watts, 1000 Channels
AAM27JQH9LA1AN 136-174 MHz, 45 Watts, 1000 Channels
AAM27QPH9LA1AN 403-470 MHz, 25-40 Watts, 1000 Channels
AAM27QNH9LA1AN 403-470 MHz, 25 Watts, 1000 Channels
AAM27TRH9LA1AN 450-512 MHz, 1-40 Watts, 1000 Channels

It's the 25 to 40 watt model.

Should I change the power setting in the CPS to this?

 

[kb9klc]

That Daiwa won't show the right output on digital. Did you check the model number as indicated above? I've never seen a 4580 rated for 48 watts.

 

[mmckenna]

Trying to read TDMA transmitter power output with a meter not designed for it is going to be very inaccurate.

Unless you are testing into a true 50Ω dummy load, that's going to throw things off, also. And many of these meters have pretty poor accuracy. Even something good like a Bird is going ±5% at full scale, lower at less than full scale.

 

[N4DES]

It's the 25 to 40 watt model.

Should I change the power setting in the CPS to this?

If the option is there in CPS and that's what you want, then the answer is Yes.

Like others have said, only test the power output in analog and don't expect a full 45 watts on the meter due to accuracy issues. A calibrated service monitor will provide a more accurate reading.