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AM modulation depth

Jim,

I never heard of the 'old light bulb trick', even in those pre-SSB days...

I'll definitely try the diode-detected DC level method. But I still wonder how simple 2 or 3" CRTs would behave at airband frequencies. Wave envelope and trapezoidal patterns might be useful to check linearity. Bad modulation is a common problem. And dynamic or electret mike adaptation to the old standard carbon-mike input often seems to be the culprit. I never found a good publication addressing those interface problems.

Willy

Reply to
ON5WV
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Ignore dimbulb. He is the resident troll who uses over 100 nyms to avoid kill filters.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

There were replacement mics with dynamic or electric cartridges for use with older commercial two way radios, and some drop in replacements for 1A2 type telephone systems to replace failed carbon microphones. I think I tossed out what I had a few years ago, when the last 1A2 system I serviced for a radio station was replaced.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

There are lots of modulation meters around, both new and used. Since it's an aeronautical application, some sort of traceable calibration will likely be necessary, and it will be best to go to a supplier who can offer this.

A quick search shows Wayne Kerr, in London listing three models. They'll definitely be able to supply with a cal. cert. suitable for the EU.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)
Reply to
Fred Abse

Tried the InGaAs darlington MMICs? Things like ERA5 and such? They have gain from audio to many GHz, but are cheap and stable.

John

Reply to
John Larkin

a

I have heard of one but it was from telephone land rather than radio = land, about the time touch tone dialing was introduced (about 1960s?).

?-)

Reply to
josephkk

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