On Tue, 9 Feb 1999 20:08:54 -0600 Jon Ogden <jono@enteract.com> writes:
SNIP
>>Depending upon the tank coil spacing a steel lid may offer
>sufficient
>>detuning effect without absorbing too much good RF.
>>
>>Bottom line...I think you should concentrate on improving the 10M
>>efficiency while watching for instability with other tubes.
>
>Well, I would agree with you here, Carl. After the recent discussions
>on
>the B&W tank coil and position of tune input circuitry, I am putting
>all
>other stability issues on hold. Looks like I am going to go through
>yet
>another reconstruction project with this thing. This time to modify
>the
>B&W tank coil and also to change the position of my input circuits.
>Only
>question on the coil is how to add significant inductance on 80m
>easily.
Start on 10 and work down since any change to the 10M L has affects on
decending bands.
Dont worry about 80 for now, I've never had problems down there with the
850 as-is.
>
>BTW, how much do you want for a complete set of Arco trimmers and
>torroids?
Trimmers vary roughly $2 to $6 ea depending upon capacity. All mix T-68
and T-80 toroids are $. 80 and $1.00 respectively.
I also have a large selection of 500V silver micas at .50 to $2.00 ea.
The trimmers alone can handle 100+ W but you're better off with a
combination of fixed and variable, makes tuning a lot less touchy.
L can be adjusted quite a bit by varying turns spacing so it is really
not a hassle to tune a toroid based network; it is more of a mental thing
than anything to get weaned off slug tuned coils...took me awhile to
adjust !!
At least you are not experimenting with a 8877 or a fragile tetrode!
73 Carl KM1H
>
>C'est la vie! Learn, learn and learn again..............
>
>73,
>
>Jon
>KE9NA
>
>
>-------------------------------------
>Jon Ogden
>KE9NA
>
>http://www.qsl.net/ke9na <--- CHECK IT OUT! It's been
>updated!!!!!
>
>
>"A life lived in fear is a life half lived."
>
>
>--
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>
>
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