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Author Topic: dual-section air variable caps  (Read 193 times)

WT1V

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dual-section air variable caps
« on: January 27, 2023, 08:38:11 AM »

In the Jan 2023 QST, page 93 there is an article about a transmatch for a QRP rig. This article was originally posted by Doug DeMaw around Feb 1973. In the circuit there are 2 dual-section air variable capacitors, 140-pF per section and and another similar air varialble capacitor 100 pF per section made by Millen mfg co. (No longer in existence) Anyone have any ideas about finding a replacement to these items.  This looked like an interesting project until I realized that these parts no longer exist.
73 wt1v
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K6SDW

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Re: dual-section air variable caps
« Reply #1 on: January 27, 2023, 08:48:55 AM »

Possibly https://www.surplussales.com// ... they've been around a long time.  Also, good ol' eBay ...

GL/73
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KD6VXI

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Re: dual-section air variable caps
« Reply #2 on: January 27, 2023, 11:53:14 AM »

Palstar used to make caps.  Not sure if they still do.

MFJ sells them.

Dr Alex in Ukraine is still open, still shipping, and has split section and butterfly caps last time I checked.  Takes about a month to get from him, but he's probably the best place to put your money if you can wait.

Ebay has caps.  I've probably bought five hundred or more different caps, vac and air variable, through the last 20 plus years from ebay. 


You can always get one slightly larger in Cmin and Cmax value and trim away some blade, if need be.

Many ways to skin this cat.  Capacitors are available.

--Shane
WP2ASS / ex KD6VXI
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WB6BYU

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Re: dual-section air variable caps
« Reply #3 on: January 27, 2023, 12:52:41 PM »

You didn't get your questions answered on this thread?

It both gave sources for capacitors, and explained why
you don't need dual-section capacitors in that circuit.

N8NK

  • Posts: 179
    • N8NK QRP
Re: dual-section air variable caps
« Reply #4 on: January 27, 2023, 02:52:01 PM »

I built a Z Match, also out of an older QST article, and needed two air variable caps that are dual section. If one doesn't need a dual section- use only one at about 180pf or parallel the two for over 360pf. My Z match is used at a max power level of 100w using CW, and knew that garden variety broadcast band air variable caps would would work great. I bought them on eBay for about $12 each. You can buy about any kind of old air variable you can think of there. Or could, when I build my Z match.
Cheers-
Chuck, N8NK
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