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[Amps] 12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 16

Subject: [Amps] 12 KW CCS ON 160-15M....USING THE 3CX-6000A7..... PART 16
From: "jim.thom" <>
Date: Fri, 19 Apr 2024 07:45:16 -0700
List-post: <>
   - Here all the various tank coil taps are completed.  Adjustable SS
   spark gap installed across the vac load cap. After this video was done, the
   2nd adjustable SS spark gap was installed across the vac tune cap.  Spark
   gap across the load cap protects the load cap. Spark gap across the vac
   tune cap protects the vac tune cap AND the bandswitch.

   There is also a.... '.7 uh pre-coil'...... that is wired between output
   of plate block cap assy....and the hot side of the C1 vac tune cap.  The
   anode to grid C + stray C (lower anode fins to chassis) and this .7 uh
   pre-coil form the step down L network.  This transforms the 1600 ohm plate
   load Z (7200 vdc loaded @ 2.5 amps) down to just 361 ohms @ 21.225 mhz.
   Then a lower, loaded tank Q can be used for the PI network on 15m.   That L
   network also has a lesser effect on all lower bands. IE: 939 ohms @ 14.175
   mhz. 1419 ohms @ 7.150 mhz  etc, etc.

   The original target value for the pre-coil was .6 uh.   (which would
   have transformed the plate load Z down to just 483 ohms @ 21.225 mhz).
    Trying to tap a tubing coil is tough enough as it gets.

   With the temp 1600 ohm resistor from anode to chassis....and analyzer on
   output side (and the pair of RJ2B's relays externally powered on), the  swr
   was 1:1 after tweaking the tune + load to the  calculated values for each
   band = jives with the spreadsheet / GM3SEK software. Previously, both the
   vac tune + load caps were mapped out, with pf vs turns counters....and a
   cheat sheet made up.

   On a similar note, once the tune + load caps tweaked for 1:1 swr, the
   caps are left alone....and the upper / lower freqs for the 2:1 swr points
   are noted down. 160 khz wide on 160m, 310 khz on 80m, 600 khz on 40m, 800
   khz on 20m, and 1 mhz on 15m.

   So far, so good.  All measurements for the adjustment of the tune + load
   caps were done with the top lid on.

   All playlists.
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