Just a few comments for the gallery...
I've used a 4-1000 single/pair on and off for about 15 years now...from
4-6kv with a transceiver with 6146's to a FT1000 rice burner...monoband
20M with vacuum C1/C2...the original design (W4GD) used no tuned
input... the suppressor was a globar with 3-4 turns of #12 bus
wire...never had arc/spark with the tube exciter...the RF choke was
about ~60uh and never had a choke fire <hi> ...>>1kw was a breeze...with
the ss exiter things changed...the input got picky and I decided to go
to a tuned input...parasite city... I brought a spectrum analyser home
and saw a 130Mhz spike...Ig/Ip without drive...key the PTT and the
tube/s would glow like a jack-o-lantern....the solution to the problem
was not anode parasitic changes, which I tried in vain, but, getting the
tuned input at (physically) at the filament pins of the
tube/s...IMHO...with the 4-1000/s keep your input circuitry AT the
filament pin/s and use RF rated caps for Cblock, and Cin......chassis
layout/ is paramount....Been there, got the tee shirt
Mike, WD4EFI
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