Steel conduit in the air????? I think he meant it was strung "aerially".
Welding arcs are very rich in RF that covers a HUGE amount of radio spectrum at a rather high field strength. You are on the right track with using "chokes"...(I think you misspelled chocks). I don't think grounding the spare pairs at both ends is a particularly good idea as this creates an unbalanced condition that actually makes the cable MORE susceptible to RF and other induced voltages. Ground the protectors at both ends, use all the chokes you can get your hands on (cover as much of the radio spectrum as possible) and then instead of grounding the unused pairs, terminate them at both ends with something like 600-1000 ohm resistors. Just be sure that they are the same value at both ends. You might also experiment with only grounding the cable sheath at one end....it IS aerial and duct cable with a foil sheath isn't it? Good luck! Jim ----- Original Message ----- From: "Donald R. Resor" <[EMAIL PROTECTED]> To: "KXT help List" <kxt@kxthelp.com> Sent: Monday, July 23, 2007 4:14 PM Subject: Re: KX-T: RF & ac noise > This may be a dumb question, but is the 1000 feet of 25 pair run > inside a steel conduit? > > At 01:02 PM 7/23/2007, you wrote: >>I have a digital pbx I look after (ComDial) That has about 1000' aerial 25 >>pair cable between buildings. Each end has a gas tube protection and >>additional analog & digital protection. The problem is RF and >>ac noise. I put am & >>fm chocks on, grounded spare pairs @ each end, and am still getting >>intermittant problems on digital and analog stations. The factory >>has a lot of >>weilding equip. at far end, including mig welders, which I remember >>years ago would >>play hacoc on an old Executone Charter system. Any ideas out there to >>clean-up this big antenna. (Problems amount to digital phones >>locking up and >>analog stations going bad) >> >>Thanks >> >>Kenny > > > _________________________________________________________________ > KX-T Mailing list --- http://kxthelp.com/ > Subscription changes: http://kxthelp.com/mailman/listinfo/kxt > _________________________________________________________________ KX-T Mailing list --- http://kxthelp.com/ Subscription changes: http://kxthelp.com/mailman/listinfo/kxt
