Many of these old transmitting mica capacitors have reliability issues.
Their foil-mica technology is very obsolete and their molded enclosures
often leak moisture and contaminants. On the good side, unlike many
other capacitor designs they're capable of the handling high currents
and high voltages found in many antenna tuners.
Its wise to use more modern capacitors if you can.
73
Frank
W3LPL
----- Original Message -----
From: "Richard (Rick) Karlquist" <richard@karlquist.com>
To: "HP" <pfizenmayer@q.com>, topband@contesting.com
Sent: Saturday, February 8, 2020 6:19:21 PM
Subject: Re: Topband: .TX Mica Caps
On 2/7/2020 6:15 PM, HP wrote:
> FWIW -- I was looking at All Electronics website last night - looks like they
> have
> unearthed a bunch of WW2 TX micas -at what looks like reasonable prices
>
> Reduced Price
> 0.0004 UF, 5000 VOLTS MICA CAPACITOR
> CAT# MC-401V5K
> Sangamo Type F2L Mica Capacitor. 2.32" x 1.25" x 1.73" high. Screw/nut
> terminals. Mounting holes on 2.63" centers....
> [
> https://www.allelectronics.com/item/mc-401v5k/0.0004-uf-5000-volts-mica-capacitor/1.html
> | ]
>
> $3.50 each
>
> Hank K7HP
An alternative to these legacy Mica's are:
Cornell Dubilier (CDE):
MC (100 to 1,000V) (1 to 2,000 pF)
MCM (300 to 1,000V) (1 to 1,500 pf)
MCN (500V) (33 to 470 pF)
MIN (300V) (1 to 350 pF.)
All are surface mount
Available from Mouser and Digi-Key
I have had good results with these, and they
are MUCH smaller than the legacy ones.
Rick N6RK
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