Problems with my Downeast Microwave 2M75LDPA...

Roy Laufer

I have an early model Downeast Microwave 2M75LDPA (#138), to use my 6700 for 2 Meter operation.

Although it is 'rated for 75W, these days the best I can get out of it is 40W when it is at room temperature...

Unfortunately, it doesn't continue to output at 40W - instead over minutes of FM transmission the RF will drop to below 18W?

No doubt, if I tried this test longer, I could get even a lower power output.

The chassis wasn't warm, even at the 18W output stage.

I don't believe it is my power supply, since everything else has its usual full duty cycle capabilities, and I don't think it is my 6700's drive power, since if I adjust the 6700 to drive it with all the LDPA's LED bar light glowing, they continue to all be lit as the output power declines.

Downeast Microwave sold this model off to Q5Signal, and I have contacted them. They suggest I ship it down to them, to take a look for what might be going on.

Anyone with any similar experiences, or good ideas (I don't have any test equipment at my QTH and getting parts may not be as easy as in 'calmer days')?

Stay safe!
Roy AC2GS

John WA7UAR

Roy, is there a potentiometer or something on the bottom side of the 2M75? I seem to recall that it might tweak your power out levels? I have the same device but never tweaked that element myself. Just trying to remember and make a helpful contribution here. Good luck!

Roy Laufer

John Kludt