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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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15th Feb 2017, 6:27 pm | #1 |
Hexode
Join Date: Feb 2014
Location: Southampton, Hampshire, UK.
Posts: 419
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Circuit needed for simple AM Modulation monitor
Hi
During the summer a few of us work our local top band AM net portable home brew. I am looking for a simple stand-alone modulation meter that can be used to get an approximation indication of AM modulation. I have test gear to do this at home but need something simple for field use. Lamp indicators are pretty useless in the sun so will be going for a metered design There are plenty of circuits on the net but I wondered if anyone had any prefered or proven design. With the addition of some updated components I was leaning towards the one attached Ref AM Phone . Pete |
16th Feb 2017, 9:09 pm | #2 |
Rest in Peace
Join Date: Feb 2004
Location: Hexham, Northumberland, UK.
Posts: 2,234
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Re: Circuit needed for simple AM Modulation monitor
Seems like a workable circuit. I would probably redesign it to run off a PP3 or something a bit more obtainable than the 22.5V battery specified. With a bit of careful thought you should be able to work out the different component values, or simply connect two 9 volt batteries in series to run it of course. You could add a small audio amp or headphone amp after the demod so you can actually hear the modulation quality. A worthwhile addition I think.
Alan. |