[Boatanchors] AM Amplifier

[Bry Carling]

Interesting comment. However contrary to the most manufacturers a really high powered a.m. transmitter‘s have used low level modulation or screen modulation for decades. Not classy with plate modulation. That went out along time ago.

Also, hasn’t this subject being thrashed to this numerous times on this group over the last 5 or 10 years?

Most of the comments I’m reading here seem to be carbon copies of other messages sent over the last few years.

Best regards - Bry Carling, AF4K


On Jul 7, 2018, at 9:39 PM, WA5VGO <hbrnut at suddenlink.net<mailto:hbrnut at suddenlink.net>> wrote:

This is, of course, absolutely right. Allowing for 6dB of headroom, you can expect no more that 30% efficiency. 25% is probably more realistic. Output power simply can not be more that 50% of the plate dissipation - probably less. Linear amplifiers can work on AM. The problem is the poor efficiency. AM broadcasters would have never run class C with high power modulators if they could have used linear amplifiers efficiently. I have a 4-1000A I use occasionally on AM. 1300 watts input power delivers about 400 watts of clean power.

Darrell

On 7/7/2018 5:54 PM, Dale Smith wrote:
I suggest you visit http://amfone.net/Amforum/index.php?board=27.0 and do
a  search or ask over there,a great site ,very knowledgeable ,especially
about the AM mode.
A stock ranger puts out about a  45 watt carrier.Lots of folks including me
do a low power mod ,through the accessory plug on the back,very easy to do.
Gives you 15 or so watts,
that is all you will need with most desk top amps.The limiting factor is
the power supply in these amps.That low power mod will give you lots of
modulation power ,over 100%.
Lets see 450 watts times 4 =1600 watts,what is wrong with this picture.
73/dale/ka5who

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