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Dave Woolf wrote:
I had a fellow ham that took the precaution of pressurizing this type of coax to maintain positive pressure and keep out outside air. Seemed like a lot of effort but maybe it is necessary. Just out of curiosity: how exactly did he do this? 73 .... WA7AA -- Anti-spam measu look me up on qrz.com if you need to reply directly |
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On Wed, 31 Dec 2003 07:11:34 GMT, Zoran Brlecic
wrote: Dave Woolf wrote: I had a fellow ham that took the precaution of pressurizing this type of coax to maintain positive pressure and keep out outside air. Seemed like a lot of effort but maybe it is necessary. Just out of curiosity: how exactly did he do this? I'd go the commercial way and just purge it with a slight positive pressure. With 9913 you can seal the ends and use a small plastic tube in through the side. Flood the bottom connector to seal it (just the opposite of normal) then work a small hole through the jacket, braid, and into the inner tube. You can build a tap sorta like they use for a gas line, or water line, but smaller. You can also put a tap on the side of the coax connector. As far as I know you'd have to make your own as I've not seen any for the PL259s or N connectors although they may be available. The only coax I've ever seen purged was commercial hard line. (It looks like copper water pipe) They actually had a tap soldered on the side of the line with a flow meter connected. It was a very low flow and on a 900 foot run that was gasketed. They replaced it with what appeared to be 4" Heliax. (How'd you like to lift 900 feet of that?) You hook up a tank of N2, only run a few inches of water pressure and use a small flow meter to regulate the flow. Typically you'd purge the thing and then flood the top as well. you will still get a small flow. If the coax seal loses integrity the flow will increase. Lot of work and about $20 to $30 for N2 every few months. It's almost impossible to keep something like 9913 completely sealed. Even the PL259s and N connectors will leak through some. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair?) www.rogerhalstead.com 73 .... WA7AA |
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