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AM RF amp
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jbprptco
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Joined: 06 Oct 2005
Posts: 11

Post AM RF amp Reply with quote
Please help. Would like to buy/build/build from scratch AM RF amp approx 5/10 watts. Have US part 15 xmtrs with 100/300/500mw/1w to drive amp. Nothing available here in US that I can find. Thanks, JimB
Thu Oct 06, 2005 1:48 am View user's profile Send private message
pcs
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Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
AM requires linear amplifier operation.
Linear amplifiers are highly inefficient.

It is much better to modulate the final stage of a AM transmitter
and keep final stage in a highly efficient (but non-linear) C
or D/E stage.

This is why what you want to do will generate a lot of heat.
By the way, if you want a 10W carrier, you need 40W peak amp.

The best would be to run your exciter in full power mode (CW)
and take the modulating voltage and use it to modulate a new
stronger extra final stage.

Something like that can be done with AM MAX II DSP with PWM
modulator. PWM output stage can be reinforced with extra mosfets,
a new 100-1000W final stage added and you've got a really strong
transmitter that's also efficient. I believe someone in scandinavia
has done that with am max II.

_________________
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Marko - PCS Electronics
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Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Oct 06, 2005 11:58 am View user's profile Send private message Visit poster's website
static-steve
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Joined: 20 Apr 2006
Posts: 2
Location: Mayo, Ireland

Post Reply with quote
1kw sounds interesting, i am thinking about getting the AM MAX II DSP transmitter but i would require at least 500w to 1kw of power solid state. i have been offered a 2.5kw rig but it is not solid state.

Are 1kw amps hard to come by or would it be best to build a homemade one?
Thu Apr 20, 2006 11:38 am View user's profile Send private message Visit poster's website
pcs
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Joined: 18 Jan 2002
Posts: 3063
Location: Radio Land

Post Reply with quote
You can roll your own. Its a fun project.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Thu Apr 20, 2006 2:43 pm View user's profile Send private message Visit poster's website
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