AM RF amp

Discussions regarding our AM transmitters, DX reports, antenna designs, problems...

Moderators: Sir Nigel, Nina, pcs, 5r, phpBB2 - Administrators

Post Reply
jbprptco
New registered user
New registered user
Posts: 11
Joined: Thu Oct 06, 2005 1:06 am

AM RF amp

Post by jbprptco »

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
User avatar
pcs
Site master
Site master
Posts: 3131
Joined: Fri Jan 18, 2002 1:00 am
Location: Radio Land
Contact:

Post by pcs »

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.
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
static-steve
New registered user
New registered user
Posts: 2
Joined: Thu Apr 20, 2006 11:28 am
Location: Mayo, Ireland
Contact:

Post by static-steve »

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?
User avatar
pcs
Site master
Site master
Posts: 3131
Joined: Fri Jan 18, 2002 1:00 am
Location: Radio Land
Contact:

Post by pcs »

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
Post Reply