4 ms·
The current and voltage in coax feedlines varies with length - he is probably looking at spots where current peaks and thus ohmic heating causes physical damage
by someguydave 7y ago
The current and voltage in coax feedlines varies with length - he is probably looking at spots where current peaks and thus ohmic heating causes physical damage.
- taneq 7y agoHot spots was my first guess too, the emphasis on the damage being mechanical threw me off though.
- jacquesm 7y agoI should have used 'physical', my bad.
- CamperBob2 7y agoThe only way there should be significant nodes and antinodes along a transmission line is if the load match is (very) bad. Not sure why this phenomenon would ever happen in the real world, unless there's a mismatch problem. This is basically the definition of VSWR. No mismatch = no standing waves. If you're seeing a pattern of degradation due to uneven heating in a piece of coax, check the antenna.
- nullc 7y agoEven if the antenna is well matched when it's set up... is it still well matched while it's loaded with snow?
- jacquesm 7y agoAt high enough power levels that doesn't even matter. No antenna is perfect and even if it is when it is installed it won't remain so over time.
- someguydave 7y agoIf the coax is operated at max power handling capability with a good match, then it wouldn't take much reflection (anywhere in the system) to cause internal arcs or heating. No real component has an infinitely low reflection coefficient.