• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

radio , tv station and radar stations still use the best single end class a amplifier

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radio , tv station and air force radar stations still use the best single end class a amplifier.


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amirmk said:
You are wrong. Haven't used a tube for a radar in years, maybe twenty, and we are the most advanced in the world in that field. On the tight space you get on a fighter or a detachable device there is no room for such things.

Dont they use Magnetron Tubes in Radar anymore? Would have thought so!--Still the easiest way of getting say a kilowatt of microwave radiation, Fairly small, not including the PSU too.........

Local airport used Plessy Radar, with 8KW Magnetron--The tube wasnt physically very big either. Around the size of a large sweep-tube, with strong magnets either side.............:bigeyes:
Replace the cascode with a pentode and call it ultralinear.

Seen this circuit lots of times, implemented with transistors: replace the two tubes on the right with a dual gate MOSFET (or a CA3028) the third tube with an emitter follower, and there you have it: solid state gain block. This is simply a sand-to-glass translation, and should not be patent-worthy. (Although these days, they patent the darndest things with total disregard for prior art.)
Your local airport is behind our air force in about twenty years of technology, which is rather good compared to airports here.
What we've developed in the radar field you won't see in airports ever. Forget about giant revolving antennas, minimizing is the way to go right now.
the most powerful privately-owned Doppler Radar in the United States. 12.5 Gigawatts ERP.

I'm glad I don't live near that beast! Even in the side lobes of the antenna pattern, there are bound to be intense fields of pulsed EM energy. The oft-repeated thermal absorption argument based on duty-cycle averaging wouldn't make me feel very comfortable, when every calcium ion in every cell in my body is vibrated for a few nanoseconds every few seconds!

I guess we've slid off topic!
Title is non-sense

I wouldn't take this thread’s title seriously at all. The William Johnson schematic looks like no RF amplifier I've ever seen.

But to continue with Johnson’s circuit: ARC used a variant in their MCP-33 moving coil head amp, except they drove the signal into the bottom cathode with the grid grounded. Looks like an interesting topology, although I never had a chance to hear an MCP-33. Has anyone here?
"I'm glad I don't live near that beast!"

Don't worry.
The 26 foot radar dish is 250 feet in the air.
There is side lobe absorption material inside the reflector.
The beamwidth is (I believe) .1 degrees.
The radar operates at 5.75GHz with a pulse rate of 250Hz.

The radar doesn't even interfere with our 5.8GHz microwave receiving equipment which is located only 20 feet below the radar T/R dish.
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