The Bellefontaine, OH is probably Dishtronix which makes the Prometheus
solid state amp. I believe this guy is in the process of buying TenTec.
73..de John/K4WJ
On 2/12/2016 7:13 PM, jtml@losalamos.com wrote:
I was looking through some recent solid state RF amplifier patents,
and 2 stood out for comment here. You may be able to view these or at
least the cover sheet and abstracts with online free patent viewers
now that you have these numbers:
US0285168 was awarded by the USPO around Dec. of 2007, invented by
Steven Dishop of Bellefontaine, OH. The address is given Pearce and
Gordon LLP in Cleveland. In it claims are made for a solid state
module that has push pull MOSFETs operating at least 200 watts and 50
volts. An input and output transformer or balun is used to convert
single ended to balanced for the transistors and match (1:4 on
output). Then there is a claim for a four FET similar amplifier where
a pair of FETs are operated in push pull, with drains tied together,
and these are then operated push pull with another similar par, driven
out of phase with the first. This one is 400 watts. I don't understand
what is unique about any of this, and have seen similar amplifier
constructions for decades. How can this patent hold valid?
The second one, US5187580, assigned to Advanced Energy Industries in
Ft Collins (a real RF company, BTW) was awarded in Feb. of 1993. In
this one the inventors suggest making a single ended MOSFET class E
amplifier that works better without a shunt capacitor across D to S of
the output device. They claim that the varactor capacitance of the Cds
alone is sufficient, even better, and that the larger devices can be
made to work at higher power and frequencies this way. Multi-kilowatts
and 65 MHz. Normally in class E the voltage at the device is forced to
zero before it switches, in this one it switches with substantial
voltage across it, even suggests this is better. I don't see mention
of improved efficiency with this technique, just very high power
availability. Something bothersome is the claim that it must operate
in a different class than A, B, AB, C, D, E, F...but no real math or
proof of anything other than a suboptimal class E. Its the first RF
amplifier patent I have seen where the invention is of a strange
performance without sufficient explanation. Maybe I am being stupid
and should just take these at face value? One has to wonder if their
wattmeters were tricked, or harmonics were excessive, or whatever.
None of this is described.
Solid state RF amplifier experts, chime in!
73
John
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73..de John/K4WJ
ex KN8PXG K8PXG K8WJ K4WJ ZF2HZ
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