[RFI] Auto quieting

[CR]

On 10/5/2015 1:16 AM, Mike Ryan wrote:
> In my case I use inch wide tinned copper strap which cut to lengths as 
> required. I think you would find the flat strap superior to round wire 
> due to the additional surface area they provide.  - Mike 

Different problems may take different solutions.

To carry RF current between poorly bonded body parts we will need low 
resistance, low inductance bonds, the proverbial short, wide strap or 
large gauge wire, sometimes (not always) several of them, in different 
places. To discharge static electricity, higher resistance, higher 
inductance connections will do , even rather high value wire wound 
resistors, and there is no need for copper when stainless steel will do, 
if not over-flexed.  There are other ways to deal with other sources of 
static;  I typically use a base-inductance or choke (even the  L-match) 
to eliminate the occasional tick, tick, tick, pockpockpock whirrrrrr 
WHAM! of precipitation static discharging through gas-tube protectors.

Braid is notoriously prone to fail one strand at a time; my last 
employer sold electronic systems into the aircraft market*, and that had 
to be bonded to the airframe or other system ground (think composites)  
with durable, short, heavy, low resistance strap or wire. The usual 
requirement was no more than 2.5 milli-ohms from chassis to airframe, as 
aircraft quite often carry thousands of Amperes of lightning current and 
it does interconnected equipment some distance apart no good at all to 
have more voltage appearing on power and signal conductors from some 
distance away than internal protectors can deal with.


*Interesting info: 
http://www.interferencetechnology.com/new-emc-requirements-for-commercial-avionics-rtcado-160f/ 
; 
http://incompliancemag.com/article/design-practices-for-military-emc-and-environmental-compliance/; 
www.dtic.mil/dtic/tr/fulltext/u2/a509335.pdf


Cortland Richmond
KA5S