[Amps] MRF151G Vs VRF2933

[Jim Thomson]

Date: Sun, 30 Apr 2017 02:11:02 -0400
From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
To: amps at contesting.com
Subject: Re: [Amps] MRF151G Vs VRF2933



<<Thanks for the input Jim.

<<I wonder how a passel of these 151Gs in PP / Parallel as in the Quadra 
would compare to the boards coming out of Israel?
The 151Gs, running the legal limit would be running near half their 
capacity. In a circuit "almost" identical to the Quadra they should 
produce a very clean signal at a good efficiency Near as I can tell, 
they need a 1 ohm resistor in series with each gate and possibly some 
tweaking with the transformers / combiners

For those not familiar with the quadra, it uses 8 MRF151s rated at 150W 
out.  The G "appears" to be a pair of 151s in a different package.

73, Roger (K8RI)

## The yaesu quadra does not use MRF-151s.   It uses 8 x MRF-150s. 
The MRF-150 is rated at 150w out.  Quadra is rated to run 1000 w pep
out, so they are running each device at  83.3 %  of its max rating.   They
run em in 4 x pairs.   Each pair is push pull, with its own combiner. 

##  the MRF-150 has been around for a loooong time. yaesu really needs
to update their SS amp.    8 x VRF-151Gs  would be a big improvement. 

##  either way, heat could be managed better, being dumped over 8 x devices. 

##  I noticed that OM  runs its  600S  maxed to the peg, with both devices. 
Each device contains 2 x transistors. Each device can be run PP, with a combiner
at 300w out.... or  if  2 x devices used,  each device has its pair of transistors in parallel, 
then ditto for the 2nd device, then only one combiner required.   The 600S uses the
latter scheme, with just one combiner. 

Jim   VE7RF