Motorola MSF5000 TLE2522 UHF Amplifiers are now used on our repeaters, because of the massive losses in our 4 channel Decibel Products hybrid combiner which we use to allow all of our 4 UHF repeater to use the same antenna.
In total our Decibel Products hybrid combiner and two TX notch filters put about 10dB of loss into our transmit path.
To get 1w out we need to run 10w and to get 10w out we need to run 100w!
That is why we need big reliable amplifiers which require only 3w of drive to produce 100w.
All of our repeaters have been reprogrammed to run only 3w now which means their PA’s are just ticking over and not even getting warm!
We have also fitted Big 50 Amp ACS758 current sensors to our amplifiers so that our Arduino Mega web server can measure and display the amplifiers performance on a web page.
We have also attached a 7 segment voltmeter display to the green wire in the 6w molex socket so we can see the TX output power forward voltage. This forward voltage is around 8.8v when the PA is running 100w.
The red wire in the socket is connected to a 100k thermistor mounted on the heatsink to allow you to measure the PA’s temperature. Measure between the red wire and the black wire which is ground.
The brown wire is connected to the 100k thermistor mounted on the dummy load of the circulator.