[Amps] L4-B

[Paul Christensen]

In another life, I recall changing out the Kapton blocker in a Harris 
FM-35K.  It hadn't failed in 24/7 service at 12KV, but a service bulletin in 
the late'80s called for doubling-up on the sheets to increase the breakdown 
voltage.  A single sheet was likely fine but where routine maintenance is 
lacking, an an accumulation of dirt/dust probably resulted in a few field 
failures.

Paul, W9AC

-----Original Message----- 
From: donroden at hiwaay.net
Sent: Monday, March 31, 2014 9:09 PM
To: amps at contesting.com
Subject: Re: [Amps] L4-B

Harris uses a sheet of it between the cavity and a large square piece
of aluminum for a coupling capacitor @ 11KVDC + RF .  Continental
wraps it around a two piece stovepipe attached to the plate of a
4CX35000 in their design  again 11KV DC + RF.   Pretty tough stuff.

Don W4DNR



Quoting Michael Tope <W4EF at dellroy.com>:

> It is used pretty extensively in the flight hardware that JPL builds  for 
> space. I know for a fact there was a bunch used on the landing  radar for 
> the Curiosity rover. I am sure there is a bunch of it on  the rover as 
> well. In fact, I would be real surprised if there are  any JPL spacecraft 
> in service that don't use at least some of the  stuff.
>
> On earth people use duct tape, in space they use Kapton tape :-)
>
> 73, Mike W4EF................
>
> On 3/31/2014 4:33 PM, Bryan Swadener wrote:
>> Yes, really.
>>
>> We used it for decades, in both tape form and Kapton-insulated
>> wire form, in critical applications at the world's largest OEM
>> of RF-driven sealed CO2 Lasers.
>>
>> The stuff is VERY tough.  The only way we found to remove
>> the insulation from wire ends was by blasting it with one of our
>> more powerful (> 100W) Lasers or, by mechanically scraping it off.
>>
>> vy 73,
>> Bryan WA7PRC
>> --------------------------------------------
>> On Mon, 3/31/14, Mark Bitterlich wrote:
>>
>>  Subject: Re: [Amps] L4-B
>>  To: Bryan WA7PRC, amps at contesting.com
>>  Date: Monday, March 31, 2014, 4:26 PM
>>    Really?   Interesting.
>>  Just FYI, Kapton insulated wire was removed from ALL
>>  military aircraft after some very impressive tests were done
>>  showing how it
>>  tended to blow and burn under certain conditions.  Of
>>  course, that was the
>>  Kapton insulated wire.  I know zip, nada, ZERO about
>>  the tape.  Possibly it
>>  is A-OK.
>>    v/r,
>>    Mark Bitterlich
>>  WA3JPY
>>      ----- Original Message -----
>>  From: Bryan WA7PRC
>>  To: <amps at contesting.com>
>>  Sent: Monday, March 31, 2014 7:18 PM
>>  Subject: Re: [Amps] L4-B
>>      > Also, Kapton(tm) aka polyimide tape will work FB.
>>  > It works well at high temperature and high voltage.
>>  >
>>  > vy 73,
>>  > Bryan WA7PRC
>>  > --------------------------------------------
>>  >
>>  >
>>  > Date: Sun, 30 Mar 2014 23:07:13 -0500
>>  > From: Edwin Karl
>>  > To: amps at contesting.com
>>  > Subject: [Amps] L4-B
>>  >
>>  > Just be very careful with the power resistors used in
>>  the
>>  > bias cutoff/
>>  > bleeder
>>  > They are mounted on long screws that run through the
>>  center
>>  > of the
>>  > resistor. In
>>  > repairing an amplifier for a buddy, I had the
>>  resistors
>>  > short through the
>>  > porcelain of the resistor.
>>  >
>>  > The fix is use good 3m glass tape to insulate the
>>  screw, and
>>  > enough on
>>  > the ends to insure centering the resistors. Unlike
>>  > electrical tape,
>>  > glass tape
>>  > is rated at 240 degrees and will withstand the high
>>  heat.
>>  > Make sure to
>>  > reinstall
>>  > the mica insulators.
>>  >
>>  > Good Luck!
>>  > We're all counting on you ...
>>  >
>>  > 73
>>  >
>>  > Ed K0Kl
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>>
>
>
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