Has anybody ever used the K7DYY AM modulation monitor?
If so,what's your opinion?
W9BHI
What are your requirements? It may or may suite your needs depending on what your looking for.
It appears to be more of a modulation alert than a true instrument to measure percentage of modulation. It does alert you if you over modulate in the negative direction. That is a good feature, but if your looking to measure your actual percentage in the positive and negative direction you will need to do some work. With a scope and a sine wave generator you should be able to come up with a calibrated scale based on the bars that are lit. It also appears that anything above 100% may not be seen on this monitor. Some folks like to keep within 100% positive modulation, so for them it may be fine. In addition it appears you get a low distortion audio detector to listen to your actual transmitted signal.
I have never owned this device so I have no first hand knowledge in using it. I would suggest an email to Bruce, K7DYY and see if you can get any of your questions answered.
I use an REA modulation monitor and think its fantastic. Unfortunately its no longer available but I heard some time back that Steve developed a software version. You may send a note to Steve of REA fame!
Used Belar modulation monitors are available from time to time. They have been pretty much the standard in the AM broadcasting business for many years.
Good luck in finding something that satisfies your personal requirements.
Joe, W3GMS