Simple, Cheap, Broadband, Linear, Power Amplifier Circuit Designs...?

[tim123]

Hi Folks,
  I'm calling on the electronics wizards of the forum, to ask if anyone can suggest a simple amplifier circuit that meets the following criteria.

- Input Power: 15v DC, up to 40 Amps
- Input Signal: 10v Pk - from a sig-gen
- Output: Same as input (but AC )
- Fully inverting
- Frequency from 30 KHz to 30MHz (is this range too big?)

I would intend to use this amplifier for the following projects:
- Stan Meyer type HHO Generation
- Vialle Generator Rep
- Any (many) other RF amplification purposes...

Your input is received with thanks.

Regards, Tim

[poynt99]

 

[TinselKoala]

Raid the ham shack!

Collins 30L-1 !
Drake L-4B !
Ameritron AL-572 !

[tim123]

Raid the ham shack!
Collins 30L-1 !
Drake L-4B !
Ameritron AL-572 !

TK, mate, those amps are all a) out of production, and b) over £1000... 

I was hoping for something less than £100...

Is there any current HAM gear that you'd rate - that would be able to use the output from a sig-gen? I know most of them need many watts of input power...

I was expecting more mosfets etc...?


Tim

PS: Poynt99 ?

[gyulasun]

Hi Tim,

Your specifications for a 'simple amplifier circuit' are not readily met: the main problem seems to insure the lower frequency response of 30 kHz. Normally the wideband transistor power amplifiers that are mainly available at relatively moderate price start from 1.5 MHz or so, this 'limitation' is mainly due to
-the nature of the transmission line transformers used for impedance matching
-the need for such wide frequency negative feedback for the active devices used (phase shift in the feedback loop)

See this paper, it nicely discusses these, you get a good glimpse on what are involved when designing such amplifiers:
http://www.nxp.com/documents/application_note/NCO8703.pdf

Also a good paper:
http://www.eetasia.com/ARTICLES/2001APR/2001APR03_RFD_AN3.PDF?SOURCES=DOWNLOAD

Just designing the wideband transmission line transformers, these are very good papers in two parts:
http://www.radio-kits.co.uk/radio-related/Linear_PA/ECO6907.pdf
http://www.radio-kits.co.uk/radio-related/Linear_PA/ECO7213.pdf

One more thing: the 15V DC supply input voltage is a bit low, when you expect 30-40 Amper output current, you would have to trade for 24V or higher supply voltage. If 13V or 15V is a must, you would have to combine several lower power amplifiers (also with power combining wideband transformers) to arrive at the needed output.

Lastly: such amplifiers are designed for driving 50 Ohm loads and you need to protect the active power devices when the load changes in a wide range like during HHO generation or the many other tasks you expect to perform.

See some component prices, out of the many (best prices maybe on ebay?) http://www.communication-concepts.com/index.php/components/rf.html

rgds, Gyula