[AMPS] Home Brew Tubes
Colin Lamb
k7fm@teleport.com
Thu, 5 Jul 2001 14:13:12 -0700
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As long as you are going to build your own tubes, there are a couple of =
modifications that might make sense. =20
1. Instead of using electricity to operate the filament, try propane. =
Use an external heat source and a good heat conductor to emit the =
electrons inside the tube. Charcoal would work, but qso's would be =
short. The advantages are that you would not need to worry about =
bypassing the filament leads and if you need more power, just turn up =
the heat. =20
2. Make the plates with a special Measures material that will reduce =
parasitics without the need for external suppressors. =20
3. For the ultimate in efficiency and harmonic reduction, build the =
vacuum input capacitor into the final tube. No more long leads. =20
If you can make the tube out of material that would otherwise be thrown =
away, you get extra bonus points. Old tin cans for the plate are good. =
Even better are old beer bottles for the home brew 807. Instead of the =
tube getting brown with age, perhaps it will get lighter
With a forge arrangement, even wood from the back yard can be used to =
create free electrons. Firing up the linear will no longer be a figure =
of speech. =20
73, Colin K7FM
=20
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<DIV><FONT face=3DArial size=3D2>As long as you are going to build =
your own=20
tubes, there are a couple of modifications that might make sense. =20
</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>1. Instead of using electricity=20
to operate the filament, try propane. Use an external heat =
source and=20
a good heat conductor to emit the electrons inside the tube. =
Charcoal=20
would work, but qso's would be short. The advantages are that you =
would=20
not need to worry about bypassing the filament leads and if you need =
more power,=20
just turn up the heat. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>2. Make the plates with a special =
Measures=20
material that will reduce parasitics without the need for external=20
suppressors. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>3. For the ultimate in efficiency =
and=20
harmonic reduction, build the vacuum input capacitor into the final =
tube. =20
No more long leads. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>If you can make the tube out of =
material that would=20
otherwise be thrown away, you get extra bonus points. Old tin cans =
for the=20
plate are good. Even better are old beer bottles for the home brew =
807. Instead of the tube getting brown with age, perhaps it will =
get=20
lighter</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>With a forge arrangement, even wood =
from the back=20
yard can be used to create free electrons. Firing up the linear =
will no=20
longer be a figure of speech. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>73, Colin K7FM</FONT></DIV>
<DIV> <SPAN =
id=3D__#Ath#SignaturePos__></SPAN> </DIV></BODY></HTML>
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