Shack is dark ...will post pixs tomorrow
The old "tune" cap is now the load cap
The "new" tune cap measures 7-55pf and it is about 1/2 way meshed at
resonance...getting a nice sharp dip in plate current at resonance
Using about 2 1/2 turns ( going from memory that might b +/- turn
played with a lot of "taps" with no real difference)
Have not done the short the grids to ground yet ...Did that on my TL-922
last year didn't change power out noticeably.But will try that tomorrow
if I don't get a better suggestion
Dave
NR1DX
On 6/5/2020 11:22 PM, Jim wrote:
Did you directly ground the grids with short wide straps? (best not to
use braid).
What did you change on the 10/15 meter coil to use it on 6 meters?�
What are you using for tune and load caps? What is the minimum
capactiance of the tune cap?
Post some pictures so we can take a look at your layout, tank circuit,
and the tuned input.
Thanks
73
Jim W7RY
On 6/5/2020 10:10 PM, Artek Manuals wrote:
I have enough HF amps here (four at last count) One of them is an
ancient SB-220 , so I thought what the heck I would "hack" it and
turn it into a 6M single band. I have a folder� full of articles on
how to from the last 20 + years.
All done "physically" but try as I may I can not get more than about
600w out .
1) Two different tank circuits , one with a section of the original
10/15� coil from the SB220 and a 2nd one with a a piece of flat
copper strap ...no difference
2) Changed the parasitic chokes
3) Tried� "T" input match. Pi input match , straight through ...no
difference
4) Plate voltage is 2400 unloaded and about 2050 loaded in CW position
5) Bias measures 6V
7) Has new Hardbach bias and diode and metering board
8) Older set of Eimac 3-500Z and newer set RF Parts 3-300ZG ...no
difference
What am I missing, ?
What else to try?
Dave
NR1DX
manuals@artekmanuals.com
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Manuals@ArtekManuals.com
www.ArtekManuals.com
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