[Amps] worthwhile patents on RF amplifiers?

[John Bohnovic]

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 at 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
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>

-- 
73..de John/K4WJ
ex KN8PXG K8PXG K8WJ K4WJ ZF2HZ