[R-390] Filters

[rbethman]

Why do you think Teflon sheeting is approved for lining the inside of 
aircraft?

It doesn't melt!

"Most" hardline, older, uses ceramic "beads" to allow it to bend within 
the specified bending radius.

HMMW Poly would probably do a very good job, is cheaper that teflon, and 
machines quite well.

The pic I just saw from "this" filter "destruction" is just that. It is 
destroyed.

The wires holding the stack of disks are broken.  Entirely too much 
force used.

My $0.02 - YMMV

Curry Longwave Products NOT available.  Sir Rippel posted this awhile back.

Perhaps putting out a LIST call for filters would have gotten a direct 
message from the small handful of folks that DO have excess R-390s and 
R-390As, AND modules.

Bob - N0DGN

On 2/16/2013 11:24 AM, KA9EGW 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.