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MoiInAust March 10th 09 08:22 PM

Old brass variable condenser
 
Looking for a variable condenser (capacitor to you new people) .0005 Mfd
brass plates (500 pf), square law moving plates, as used in 1920s.



Harold E. Johnson March 10th 09 08:36 PM

Old brass variable condenser
 
Find an old BC-221. Frequency meter at a hamfest.

W4ZCB

"MoiInAust" wrote in message
...
Looking for a variable condenser (capacitor to you new people) .0005 Mfd
brass plates (500 pf), square law moving plates, as used in 1920s.




Harold E. Johnson March 10th 09 09:21 PM

Old brass variable condenser
 

"MoiInAust" wrote in message
...

"Harold E. Johnson" wrote in message
news:2bAtl.10383$DP1.7359@attbi_s22...
Find an old BC-221. Frequency meter at a hamfest.

W4ZCB

"MoiInAust" wrote in message
...
Looking for a variable condenser (capacitor to you new people) .0005 Mfd
brass plates (500 pf), square law moving plates, as used in 1920s.


Thanks for the tip but that instrument was much later than the 20s. Also I
meant to say single gang.


Well, the BC-221 capacitor IS single gang, ~500 pF fully meshed and would
cost you hundreds if you bought it new today. It also has a superb anti
backlash reduction gear. I used several in a noise bridge and bought some
for $5 and one was given to me.

W4ZCB





MoiInAust March 10th 09 10:37 PM

Old brass variable condenser
 

"Harold E. Johnson" wrote in message
news:IRAtl.606228$yE1.69436@attbi_s21...

"MoiInAust" wrote in message
...

"Harold E. Johnson" wrote in message
news:2bAtl.10383$DP1.7359@attbi_s22...
Find an old BC-221. Frequency meter at a hamfest.

W4ZCB

"MoiInAust" wrote in message
...
Looking for a variable condenser (capacitor to you new people) .0005
Mfd brass plates (500 pf), square law moving plates, as used in 1920s.


Thanks for the tip but that instrument was much later than the 20s. Also
I meant to say single gang.


Well, the BC-221 capacitor IS single gang, ~500 pF fully meshed and would
cost you hundreds if you bought it new today. It also has a superb anti
backlash reduction gear. I used several in a noise bridge and bought some
for $5 and one was given to me.

W4ZCB

Thanks. But looking for simple one with no reduction gear. Rather like the
ones used in 1920 crystal sets.






Bill M[_3_] March 11th 09 12:16 AM

Old brass variable condenser
 
MoiInAust wrote:

Thanks. But looking for simple one with no reduction gear. Rather like the
ones used in 1920 crystal sets.




Drop me a line: radioexray at gmail dot com

-Bill

Scott Dorsey March 11th 09 12:24 AM

Old brass variable condenser
 
In article , MoiInAust wrote:

Thanks. But looking for simple one with no reduction gear. Rather like the
ones used in 1920 crystal sets.


Why not cut your own out of sheet brass and silver-solder to some rod
stock? That's what kids in the 1920s did...
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Bill M[_3_] March 11th 09 01:30 AM

Old brass variable condenser
 
Scott Dorsey wrote:


Why not cut your own out of sheet brass and silver-solder to some rod
stock? That's what kids in the 1920s did...
--scott


Name one kid in the 20s that used silver solder :)

They made some truly great variable caps in the 20s. Brass isn't really
the cats meow but the physical rigidity and thinking about the low loss
insulators and the exaggerated plate shapes for best tuning rates are a
big plus.

Not silver-plated and ceramic, mind you, but close to it :)

-Bill


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