View Single Post
  #3   Report Post  
Old August 9th 09, 11:26 PM posted to rec.radio.amateur.homebrew
Stuart Longland Stuart Longland is offline
external usenet poster
 
First recorded activity by RadioBanter: Aug 2009
Posts: 8
Default Homebrew 2m (and maybe 70cm) linear (solid state, 20~30W)

On Aug 9, 10:58*pm, Scott wrote:
You can homebrew a very simple amp that should meet your specifications....

A generic PC board can be found athttp://www.rfparts.com/pcb.html
and I would recommend part number DEM2330. *There is a link to "View a
pdf of the DEM2330 Instruction Sheet." *You could build everything as
they show in the instruction sheet (which is for a 1300 MHz amp) and
just substitute the RF module with the Mitsubishi RA30H1317M module for
2M or the RA30H4045MR for 70cm. *The data sheets for the modules are athttp://www.rfparts.com/module_sau-sav.html#raand there are also more
module choices there.


Ahh right... I had a look around, looks like Minikits[1] sell the
power modules (and even a PCB). This looks promising.

*Both modules specify an input power of 50 mW
maximum, so you would need an attenuator (pi type is easily done by
cutting a break in the input lead on the circuit board and installing
the correct resistors around the cut). *If you have 1.5W from the HT,
you would need about 16 dB of attenuation.


The handheld can be wound right back to 50mW when running off
batteries... otherwise 0.5W. A pi network isn't hard though. That
said... I won't make the mistake I made last time -- last time I tried
making it with 5W wire wound resistors... and wondered why it didn't
work.

I shall do some further investigation.

Thanks.

Stuart Longland VK4MSL
1. http://www.minikits.com.au/kits2.html