I just got a deal on this from a local ham who used it once or twice with his Elecraft KX3 and then bought something else. This is the older model of the MX-P50A, HF amp, which was built in China.
I think the bent heat since was damaged in initial shipping to him, but it doesn't affect anything. If you're familiar with the size of the KX3, you can tell that the amp sitting next it it is pretty small. It runs 10-80 meters with a band switch on the front. It has the ability to auto-sense the band and switch automatically but that doesn't work with this radio. The specs I found online indicate that it will do 50-60 watts with 5 watts drive; my initial tests into a so-so meter show about 40 watts with 7-8 watts of drive. Since the MX-P50A does not have an internal tuner, my plan is to use it with a little MFJ 904H tuner, which I already own.
This should make a nice little portable setup for my RV, where I typically use a Buddipole antenna (in a variety of configurations) at 20' on the back of the RV ladder. For the price I got it for, increasing the power output from 10-12 watts on the KX3 to 40 is a nice little bump
Update:
I just realized that I forgot to turn of the internal ATU on the KX3 when running the tests. Even into a dummy load, turning it off made a difference, apparently due to a slight impedance mismatch between the rig and amp with it turned on (using whatever the last ATU setting was). I now see full 50 watt output on bands 20-80 meters with a slight drop to 45 watts on 10m. Hey, 10 more watts is 10 more watts!
I think the bent heat since was damaged in initial shipping to him, but it doesn't affect anything. If you're familiar with the size of the KX3, you can tell that the amp sitting next it it is pretty small. It runs 10-80 meters with a band switch on the front. It has the ability to auto-sense the band and switch automatically but that doesn't work with this radio. The specs I found online indicate that it will do 50-60 watts with 5 watts drive; my initial tests into a so-so meter show about 40 watts with 7-8 watts of drive. Since the MX-P50A does not have an internal tuner, my plan is to use it with a little MFJ 904H tuner, which I already own.
This should make a nice little portable setup for my RV, where I typically use a Buddipole antenna (in a variety of configurations) at 20' on the back of the RV ladder. For the price I got it for, increasing the power output from 10-12 watts on the KX3 to 40 is a nice little bump
Update:
I just realized that I forgot to turn of the internal ATU on the KX3 when running the tests. Even into a dummy load, turning it off made a difference, apparently due to a slight impedance mismatch between the rig and amp with it turned on (using whatever the last ATU setting was). I now see full 50 watt output on bands 20-80 meters with a slight drop to 45 watts on 10m. Hey, 10 more watts is 10 more watts!
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