[NLRS] Homebrew pre-amp design(s), 144, 222, and 432 MHz?

[Dr. Gerald N. Johnson]

On Thu, 2009-09-24 at 09:07 -0500, David Palm wrote:
> 
> There are a lot of pre-amp designs floating around out there.  Can anybody
> recommend well-established, works-everytime, homebrew designs for pre-amps
> at 144, 222, and 432 MHz?  I'd like to try my hand at building, but it would
> be helpful to start with something pretty well known.
> 
> Thanks and 73,
> 
> David  W9HQ

Designs by W5LUA (and WB5LUA earlier) always work well. Classic designs
by N6CA, Zack Lau (old call KH6CP, now W1VT), and Tommy Henderson,
WD5AGO both classic and recent work well. 

Modern designs with a PHEMT first stage and maybe an MMIC second stage
are in use in most all the EME stations world wide. They work and have
good dynamic range. You will see a bias towards using Avago (used to be
Avantech and before that HP) parts, partly because '5LUA is an
applications engineer for that factory, but also because the parts work
well and can be bought from distributors in the US as well as DEMI. By
the time you find good quality parts, you may find DEMI kits to be quite
reasonably priced. The NF of a PHEMT preamp is more set by the losses in
the input circuit than the active device, so just any tuning capacitor
may not result in the best performance. And it a congested area, you may
want to consider an input circuit more complex than just the series
variable and shunt inductor to achieve more out of band rejection.

73, Jerry, K0CQ