Date: Sun, 30 Apr 2017 02:11:02 -0400
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: amps@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
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