Well...sorta. The feed line in question is referred to as 'air dielectric', as such instead of a foam or polyethylene dielectric to keep the center conductor centered where it is and provide insulation between the center conductor and ground, there is a spiral piece of dielectric material to hold the center conductor in place. Everything else between the center conductor and the shield is the 'air' part. It doesn't need to be nitrogen, there is nothing particularly mystical about nitrogen, often compressed dehumidified air is used instead, since regular 'air' is made up of about 78% nitrogen.
Will the system function without nitrogen? Absolutely. The purpose of the air or nitrogen is to keep moisture from infiltrating the system. I have never seen the VSWR change at all by simply removing the nitrogen from the system. I've often opened the top of the antenna and 'purged' the moist air out of the system with nitrogen prior to sealing it all back up (after a leak or O ring change) and making sure it will hold. One local broadcast station is notorius for running out of nitrogen on the hill and letting it go for months on end. When they finally decide it is time, I put a new tank on, crank it up, climb the tower and open the valve on the top to push all the old 'air' out with the new clean nitrogen. Again, no change in VSWR unless the system leaked enough to take on moisture. When that happens you can see some VSWR, and often you get arcing inside the feedline (not good). Good Luck! Daron J. Wilson, RCDD ) ) Telecom Manager ( ( LH Morris Electric, Inc. ) ) (541) 265-8067 office _|****| mmm! (541) 265-7652 fax ( | | coffee! (541) 270-5886 cellular \| | [EMAIL PROTECTED] |____| > -----Original Message----- > From: Mark Holman [mailto:[EMAIL PROTECTED] > Sent: Friday, November 19, 2004 6:09 PM > To: [email protected] > Subject: Re: [Repeater-Builder] radial tire static? > > > I will answer that , your antenna cable is using that stuff intead of foam > like the RG series coaxes run, and as long as everything is a tight fitting > you have very good LOW SWR, thing is ...when it leaks a o ring seal the VSWR > shoots up ! > > Alot of this I am learning in Broadcasting since they use power in the High > KW & Mega Watt Range. > > now you can impress your Radio Guy that you learned something, I probably > expect maybe a response. > > Mark Holman, CRO ( Future CTO ) > AB8RU > ----- Original Message ----- > From: "KA9QJG" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Thursday, November 18, 2004 1:11 AM > Subject: Re: [Repeater-Builder] radial tire static? > > > > > > That was such a good explanintion about tires , I recall seeing fittings > > on > > Large coax at the Police Communications Center and I ask the radio Man > > what > > it was for and He just said it was Nitrogen. and I was just a Police Sgt > > and > > a Ham and would not understand , Nice Guy Yea Right So what was it > > really > > for ? > > > > Thanks Don KA9QJG 444.750/R > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > > > > > > > > > > > > > > > > Yahoo! Groups Links > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
