[R-390] Filters

[Bob Camp]

Hi

One very common way to strip teflon wire or cable is a pair of "hot tweezers". They simply melt the dielectric or insulation. They aren't a whole lot hotter than a soldering iron. 

Having just melted a teflon insulated sensor wire (like yesterday) - it's not all that hard to do.

Conventional coax is rated to some very high power levels. The energy to get it "glowing red hot" is simply not anything you are going to run into in an amateur environment. 

Bob

On Feb 16, 2013, at 2:57 PM, ka9egw1 at britewerkz.com wrote:

> So if not PTFE, what sort of coax was he speaking of, do you suppose?  Is
> there a 'special' teflon good to extreme temps?  Would that be the stuff
> used in PTFE-dielectric PL-259's?  Or was he maybe just exaggerating in
> the interest of emphasizing a point that Teflon is harder to melt than,
> say, polyethlyene?
> 
> <NOW I'm confused>
> 73, Brian KA9EGW
> 
>> Hi
>> 
>> Most teflon is rated to about 450 to 550 F.  You can indeed melt it with a
>> torch.
>> 
>> Bob
>> 
>> On Feb 16, 2013, at 11:24 AM, KA9EGW <ka9egw1 at britewerkz.com> wrote:
>> 
>>> If it is actually teflon, good luck trying to get it to melt.  Years ago
>>> when I was a Novice, WA9TIR told me [speaking in praise of
>>> Teflon-dielectric coax] "you can get that stuff glowing red and it won't
>>> melt".  Whehter he was exaggerating I know not.
>>> 
>>> if it's polyethylene, good luck keeping it from melting.
>>> 
>>> 
>>> On 2/16/2013 8:00 AM, quartz55 wrote:
>>>> I've got some 1/2" hardline.  Wonder if I could cut out enough teflon
>>>> foam or whatever that dielectric is to use for the filter spacer?  Then
>>>> how do you keep it from melting when soldering back together?  Or like
>>>> someone said, use JB Weld.
>>>> 
>>>> I've already sent the IF output (16KHz) to an SRA-3 mixer to mix the
>>>> 455 down to 12KHz and fed it into my soundcard, used 'Dream' to
>>>> demodulate it.  I made up a 467KHz oscillator to drive the mixer. It
>>>> seems to work, but is a pain to work with.  I couldn't seem to get the
>>>> Radio Mondiale to demodulate, but then was not sure I had the signal.
>>>> 
>>>> BTW I put the Fluke ohmeter on some of that foam used to put ICs into.
>>>> It measures about 2Meg at 1/4" spacing, about 3Meg at 1".  Don't think
>>>> that's a good solution.
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>