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RE: Newly completed vacuum tube coil - pics
Simon,
RE: your VTTC design:
A good reference for a VTTC is an ARRL Handbook for Radio Amateurs.
check libraries, bookstores, radio/electronics swapmeets
example 1995 edition pg 13.49
shows a 3CX800 triode 6 meter power amp.
Note that RFC's are used for BOTH
the filament AC supply and
Plate DC supply
and are absent from your design.
Larger inductances are required for your lower freq amp. such as used in the
8877 amp below.
RF isolation is absolutely necessary.
Also use a parasitic suppression choke in series with and close to the plate
cap.
ref: 1995 edition pg 13.43 8877 tube amp for 160 meters thru 10meters,
> Z1 a few turns heavy wire/strapm around a couple 2W 100 ohm carbon comp
resistors
I'm surprised you've got as good a performance as evidenced in your photo's
w/o RFC's !
Can't wait to see the improvement !
The RFC's (radio freq choke) will help keep RF out of the AC lines
so you're TDS will be happier.
Regards, Dale K3MNN
Redondo Beach, Calif
-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, November 24, 1999 6:25 PM
To: tesla-at-pupman-dot-com
Subject: Newly completed vacuum tube coil - pics
Original Poster: "Simon Winder (Exchange)" <swinder-at-Exchange.Microsoft-dot-com>
Hi,
This weekend I finished my vacuum tube coil. It uses two 573B tubes and runs
at
1.4MHz. You can find pictures and a description on the web site I just set
up
today...
<http://home.earthlink-dot-net/~robotbugs>http://home.earthlink-dot-net/~robotbugs
(earthlink is slow)
It has some teething problems.
Calling all experts in vacuum coil design: Can you answer any of my cocerns
on
the web page?
The output looks very pretty.
My RFI filter hasn't arrived yet, but I powered up anyway! One spark to
ground
is sufficient to cause my very much loved 'scope (TDS3012) to reboot itself
from the other side of the room. All other sensitive equipment was unplugged
(at least in my apartment ;-).
Simon