[Amps] Plate Loading Padding Caps

[n4is at comcast.net]

Rob

You are right the current at 1.8 MHz is the issue. Check the current rate
for doorknob capacitor, like HT50 page 11, blue line. 

http://www.highenergycorp.com/High%20Energy%20Corp.%20Ceramic%20Capacitors.p
df

73's
JC

-----Original Message-----
From: Amps <amps-bounces at contesting.com> On Behalf Of Rob Atkinson
Sent: Saturday, December 22, 2018 12:39 PM
To: amps at contesting.com
Subject: [Amps] Plate Loading Padding Caps

>I know I need class 1 NPO COG caps with 1 KVAR but a source for these 
>eludes me. Most web locations have either no data sheets or data sheets 
>that give little useful information.

>Where can I find the proper RF transmit caps. I have no room for 
>doorknobs so ceramic is my only choice. I have located caps with NPO 
>and COG rating at the proper Kv rating but no data sheet so they are a crap
shoot.

You don't need NP0 temp coefficient.   A ceramic RF cap rated for the
current and voltage is needed.  The temp. coefficient can be N750 or even
N3300 if the cap can handle the current and v.
They are handling bypass current in the output pi network.  A cap rated for
2 amps or more at 1000 kc will be fine and not drift.  I'd look for 7.5 KV
or higher.
By the way, doorknobs ARE ceramic caps.  No idea what COG means.
Please explain.

73

Rob
K5UJ
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