I have received quite a few requests for info on my simple mod to put my
Heath SB-1000 on 6 meters. Here's how I did it.
With the aid of my MFJ 259B and a bit of research using the ARRL Handbook
chapter on Amplifiers and more than one note to Mr. Measures, I came up
with this:
Input pi network: 33pF on rig side, 1 1/2 turns on 10 meter slug (iron core
all the way out) and 10pF on tube side.
Output network: Move 10 meter tap out towards the tune cap until there is 1
turn left between your tap point and the tuning cap (about 1 1/4 turns).
With 80 watts input (Icom 551D) I get 725 watts output into a non radiating
load. On air reports indicate clean audio, clean signal. Tuning is touchy
in that small adjustments make big differences very quickly as opposed to
the more relaxed rate of tuning on the lower bands. I still have full
functionality on 160-15, the way the amp was designed originally. I only
lost(?) 10 meter capability.
Parts required for the mod: 1 10pF 500V and 1 33pF 500V capacitor available
from Mouser for about $.80 each. I spent $300 for the amp at the
HossTraders spring meet so I have nearly a King's ransom in it now
($301.60!!).
Hope this info proves useful to the reader.
John Wilcox NS1Z
FN44rn
ns1z@agate.net
fon: 207-364-2246
871 Route 120
Rumford, ME 04276-3836
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