[Amps] SB-220 6M conversion
jim.thom at telus.net
Sat Jun 6 12:41:23 EDT 2020
Date: Sat, 6 Jun 2020 09:28:30 -0400
From: Artek Manuals <Manuals at ArtekManuals.com>
To: n2ic at arrl.net, "Amps at Contesting.com" <amps at contesting.com>
Subject: Re: [Amps] SB-220 6M conversion
<Running in the CW position just to be on the safe side ( after all this
<amp is nearly 40 years old) Going easy on the power transformer. I can
<only get about 100 more watts in SSB position
## what EXACTLY are you using to measure power output ???
I have a buddy with a hb 8877 6m amp. Eff was low, we tried
every trick in the book...with small incremental increases.
Turns out the NEW bird slug was way off...on the low side !
Use a bird or coaxial dynamics slug, the 25-60 mhz type, for a
bird 43 line section.
## Toss those useless grid caps...and ditto with grid chokes.
Chassis ground all 6 x grid pins with .375 inch wide strap.
That alone will result in 20-25 watts less drive required....or
conversely, more power output for same amount of drive you had before.
## Use a flat strap wound tank coil, with at least .375 inch wide copper strap,
and preferably .5 inch wide copper strap.
## Use a PI net for the tuned input, with the typ C1 – L –C2 setup.
Use 10-12 gauge wire for the coil on the tuned input. When driven
full bore, you should have 1 to 1 input swr.
## what did you use for the plate choke ?? 10 uh is ample. You want the
1st series resonance above 55 mhz. 22 gauge magnet wire wound on
teflon or ceramic will work.
## Dunno about oem parasitic suppressors. I cant see the oem heath suppressors
working at all on 6m.
## what xcvr are you using for 6M ? What is the max power out of the xcvr ?
How much grid and plate current..and loaded B+ do you have on the SB-220 ?
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