On January 15, 2006 at 20:48, bcf1963 said...
A metallic staple that does not pierce or physically
deform coax will have absolutely no effect on
the signal traveling inside the coax.
Very true! Metal staples are often erroneously thought to affect coax by somehow inducing a magnetic/electrical field or interrupting signal flow.
The myth comes from staples that pinch, even slightly, coax cable.
A cable's impedance is dependent upon its ratio of core size and dielectric width to outer shield. Once that ratio has been compromised i.e. pinched, overly bent or otherwise deformed it changes the impedance which then decreases the ability for maximum power transfer. That typically shows up in broadband cable by attenuating certain frequencies.
Metal staples are simply more apt to do this because they lack the flexibility of plastic. Of course, the correct size staple is fine.
For those of you still using crimp connectors this is also true. Many designs have minimized the effect of changing the impedance but none can eliminate it completely, though I'm sure some marketing departments at the manufacturers may disagree. Compression connectors do a slightly better job of spreading the pressure equally around the coax and therefore minimizing the impact of the connector.
See you got me rambling again... sorry.