[Amps] OEP caps -------------- TSPA -------

[John T. M. Lyles]

I wonder why OEP chose glass epoxy for the coil form, when there are 
easier to turn materials such as UDEL polysulfone that are extremely 
RF tolerant and heat tolerant. After all, they did use ULTEM which is 
another miracle polymer of recent vintage. Besides having lousy loss 
tangent at 1 MHz and up, Nylon also absorbs moisture, as does Delrin. 
Thanks for the tip about OEP products though. Does anyone know if 
Cardwell is still making capacitors and large coils too?

73
John
K5PRO


>
>Date: Tue, 31 Aug 2004 02:54:43 -0400
>From: Will Matney <craxd1 at ezwv.com>
>Subject: Re: [Amps] load capacitor ratings?
>To: "R. Measures" <r at somis.org>,	"amps at contesting.com"
>	<amps at contesting.com>
>Message-ID: <413420B3.5090709 at ezwv.com>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>I wanted to take a look at OEP's variable inductor and see what it said
>on their website and in the catalog I have here. The website says
>they're using a glass-phenolic core. The printed catalog said it had a
>teflon-delrin polymer core.
>
>  From website;
>
>The new R128C is completely non-magnetic, and all materials are chosen
>for high electrical and thermal conductivity and low loss in RF fields.
>The plated #10 copper bus wire rests in a precision-machined helical
>groove cut into a glass-based phenolic tubular core. This core turns on
>two large sealed stainless steel ABEC-5 instrument bearings seated in
>machined Ultem frames. Incorporated into the design are two of the
>RF-proven high-amperage rotary contacts originally designed for high-end
>variable capacitors.
>
>Will Matney