[TowerTalk] 3M™ External PIM Absorber 1000 | 3M United States

[Jim Brown]

On 11/18/2023 8:57 PM, Jim Lux wrote:
> I was using 31 mix more as an example.  The data sheet for the tape or
> sheet gives curves for R and X. The big issue is, for HF, you don’t want
>   the stuff for microwaves (which is what most of them are).

Yes, exactly what I was thinking once you described what worked for you 
-- it's a new way of doing what W2DU did with beads 50 years ago.
> 
> I’ll see if I can find what we used - we were in the 100kHz -23 MHz
> range.  We got rolls of stuff that we could wrap our cables with, or put
>   around holes in the chassis where the wires came through.

That sounds like a shielding failure if the conductor isn't either 
bonded or bypassed at the point of exit. I'm sure I'm not the only guy 
here old enough to remember feed-through caps! I don't see stuffing the 
hole as a solution. I DO see a length of a suitable material forming a 
W2DU-style choke.
> 
> I should point out that this is a “fix” - people should really design
> things that don’t radiate on their wires (other than antennas!) or are
> susceptible to signals, or that have nonlinear characteristics.

Right -- like practicing proper shielding of equipment, proper bonding 
everywhere.

73, Jim K9YC