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Title: Coax leakage? Post by: KC2TAU on August 26, 2015, 10:24:53 PM I have a roller cart that has most of my equipment on it and I'd like to make it easy to disconnect the multiple coax cables running to it without having to disconnect each coax cable at the source on the cart. With that in mind I've decided to build a simple junction box that consisting of little more than a Hammond case with three holes drilled in it to accept 3 Amphenol UG-363/U bulkhead coax connectors. Essentially they'll thread through the holes and be secured on each side with nuts. The coax cables coming from the various pieces of equipment on the cart will connect on one side where the coax cables coming from my various antennas will connect on the other end. One of my antennas is a PA0RDT active whip antenna. Given how it uses various transistors that are most likely sensitive to RF I was wondering about RF leakage at this junction box. The bulkhead connectors will probably be spaced at about an inch apart from each other. Maximum power through the junction box would be about 100-120W carrier. I'm not well versed on where and how much leakage occurs in coax assembles but would this setup be a concern to the RF sensitive active antenna? Title: Re: Coax leakage? Post by: W7TFO on August 27, 2015, 12:04:09 AM If things are matched (none or little VSWR), there will be negligible leakage from the bulkhead connectors.
The leakage, if any, will come from coax with just braid shield. Coax with foil under braid will perform better in that arena. It will also depend on the power levels involved. 73DG Title: Re: Coax leakage? Post by: KA0HCP on August 27, 2015, 12:19:39 PM Be sure to mop up any electron spills so no one is injured in falls!
p.s. Light colored clothing may be stained. ;) Title: Re: Coax leakage? Post by: WD5JKO on August 27, 2015, 01:25:56 PM If I were worried about "coax leakage", then I'd do two things: 1.) use double shielded coax, such as RG-223, or RG-400 for the little stuff, or RG-214 for the big stuff. 2.) use a controlled impedance connection that screws on, such as a TNC, or type N. The BNC is OK, but can leak if tugged from a side angle. For sure, the SO-239/SO-238 and UG-363/U are out the window in any RF tight application. They have an impedance bump, and connection leakage is hard to keep low. The slightest loosening can have a profound effect on "coax leakage". Jim Wd5JKO |