[AMRadio] New Topic - moniitoring modulation help please


Bry Carling bcarling at cfl.rr.com
Thu Nov 14 07:20:09 EST 2013


Brett's remarks were very positive and helpful... thank you!

I have a question for the seasoned AM ops here. 

Some of us (like me) need a little help.  I have read a lot of articles on how one goes about 
proper moniitoring of our AM signals, but I have never understood how to properly couple an 
RF sample into my oscilloscope and determine the %mod. etc. 
I have also never felt comfortable trusting the mod meter designs I have seen. Most seem to 
involve some magic comparator that I am supposed to trust - like, "when this little light comes 
on you are at 85% mod and the other opne tells you you are hitting 100%." 
How can I be confident?

Those of you who have actually DONE this and are confident with your method and 
equipment please enlighten the rest of us with something simple enough and reliable enough 
to motivate us to either build or buy the necessary equipment to check our modulation. 

Anyone needing help - I have available one extra frequency meter with digital readout to 
several places if anyone needs it.  It's a nice clean Haltronix - good to 600 MHz very cheap to 
anyone in this group, or I am open to trades,,,

Please elucidate fully or point us to web sites that will demystify the AM monitoring process in 
easily uinderstood terms.  No deep calculus or excessive formulas if possible (grin!)

I would not mind buying a commercial signal monitoring meter for my station if it was 
reasonably priced. 

I think the real question some of us have is "How clean is my signal?"

I could be running 200% modulation and stays within a 6 kHz bandwidth  if the signal is clean 
andI would be happy with that. I am thinking of my DX60B (or FT857D) + TenTec 422 setup 
that will soon be pumping some tall ship signals into the sky.

73 - Bry AF4K




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