-> There is another major jump in components used as capacitors. HF
> amplifiers need a lot of C for blockers to handle 160 meters.
Most amps have way more than enough C for 160. The largest
problem is generally current rating on 30 MHz, not C on 160.
I remember visiting K8KAS and looking at his homebrew 3-500
amp for 160. He had 100 pF in the coupling cap from a 3-500Z, and
we laughed and teased him. When we replaced it with a 1000 pF,
nothing changed.
If you calculate the amount of C required to not disturb the anode
impedance, you be amazed how small it can be compared to what
everyone uses.
Let me second what Tom wrote above. I used a 150pF, small fixed Jennings
vacuum cap
as a plate blocker on a number of kW amps, ran the calcs he referrs to,
and I can assure the gang that it really worked extremely well on 14mHz.
I made a test, using the conventional pair of 1000 pF 858s, and found no
difference at that frequency. Vacuums will beat the ceramics every time,
hi!
73,
Marv, W6FR
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