At 1/5/2006 21:55, you wrote: >I am not the most knowlegeable person but noticed a couple of comments >about your feel line without an explaination. > > >Feedline = RG8, mentioned 9913 when I went to the shop but the coax has > no markings on it when I got it so >I'm not quite sure if I got it or not :) > >RG8 is not suitable for duplex operation. There is insufficient shielding >and will most likely result in receiver desense while the transmitter is >operating. You might look back in the archives on the Repeater-Builder >there has been extensive discussions about this problem and also on the >use of 9913 for duplex operation. As mentioned by others ... a change to >some other type of a 100% shielded feedline will probably do wonders for >your receive problem. > >Good Luck >Larry
Shielding percentage of the antenna feedline has nothing to do with duplex suitability. 9913 is 100% foil shielded. The problem is the type of shield metallization used. Silver-plated RG-214 can be used but is just as lossy as RG-8, so not good for long lengths. Given your operating frequency & required cable length, I'd go with 1/2" Heliax or some other solid-shielded feedline. Bob NO6B >----- Original Message ----- >From: <mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] >To: <mailto:Repeater-Builder@yahoogroups.com>Repeater-Builder@yahoogroups.com >Sent: Thursday, January 05, 2006 8:18 PM >Subject: Re: [Repeater-Builder] Repeater Assistance in Michigan. > >I'll try what Eric mentioned when I get a chance to go out to the site... >as for now, I'll try to answer Mathew's questions... > >Antenna Height = 27.0m, rooftop tripod >HAAT = 16.4, elevation gains going south but drops quite a bit going north. >Gain = purchased an Antenex FG1523, 3dB Fiberglass Omni >Feedline = RG8, mentioned 9913 when I went to the shop but the coax has no >markings on it when I got it so I'm not quite sure if I got it or not :) >Power of Transmitter = 50w, 35w after duplexer >Duplexer = Sinclair MR256B*2 - Mobile Type, tuned by shop >VHF-Hi, 152.8850 & 159.5400 > >Thanks! > >-----Original Message----- >From: Mathew Quaife <[EMAIL PROTECTED]> >To: Repeater-Builder@yahoogroups.com >Sent: Thu, 5 Jan 2006 18:47:36 -0800 (PST) >Subject: RE: [Repeater-Builder] Repeater Assistance in Michigan. > >It would be helpful to know how high the antenna is, gain, feedline and >power of the transmitter, and as Eric said, what type of duplexers, >etc....Are we dealing with VHF or UHF? > >Mathew > > > >Eric Lemmon <[EMAIL PROTECTED]> wrote: >Since a repeater's range is limited *primarily* by its ability to receive, >you should concentrate on those factors which directly affect receive >sensitivity. One of the most common problems is the use of a duplexer that >has insufficient isolation for the combination of transmitter power and >receiver sensitivity. A transmitter PA that produces a "dirty" signal (one >with spurs) coupled with a broadband receiver will require much more >isolation than a pure-carrier tube PA and a very narrow-band receiver. > >Does the range improve if you reduce transmitter power to, say, 20 watts? >Does the range improve if you remove any preamplifier on the receive side? >Does the range improve if you put a single bandpass cavity with 1.0 dB of >insertion loss between the duplexer and the receiver? Is the duplexer >*known* to be properly tuned? > >73, Eric Lemmon WB6FLY > > > >-----Original Message----- >From: Repeater-Builder@yahoogroups.com >[mailto:[EMAIL PROTECTED] On Behalf Of kfd29 >Sent: Thursday, January 05, 2006 3:29 PM >To: Repeater-Builder@yahoogroups.com >Subject: [Repeater-Builder] Repeater Assistance in Michigan. > >Looking for assistance w/ a new repeater system in GR, Michigan... Could use >a hand in finding out why we can not pick up 5 watt handhelds only 5 miles >out, maybe we missed something in setup? If anyone is knowledgable in >troubleshooting repeaters or in the GR area, please contact me! Small >business that can't quite afford the $70/hr charge for a tech right now lol. >Thanks! > > > > > > > > > > > > > >Yahoo! Groups Links > > > > > > > > > > >Yahoo! Photos >Ring in the New Year with ><http://us.rd.yahoo.com/mail_us/taglines/photos/*http://pa.yahoo.com/*http://us.rd.yahoo.com/mail_us/taglines/photos/evt=38087/*http://pg.photos.yahoo.com/ph//page?.file=calendar_splash.html&.dir=>Photo > >Calendars. Add photos, events, holidays, whatever. > > > > > > > >---------- >YAHOO! GROUPS LINKS > * Visit your group > "<http://groups.yahoo.com/group/Repeater-Builder>Repeater-Builder" on the web. > * > * To unsubscribe from this group, send an email to: > * > <javascript:parent.ComposeTo('[EMAIL PROTECTED]');>[EMAIL PROTECTED] > > * > * Your use of Yahoo! Groups is subject to the > <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service. > > > >---------- > > > > > > > > > >---------- >YAHOO! GROUPS LINKS > * Visit your group > "<http://groups.yahoo.com/group/Repeater-Builder>Repeater-Builder" on the web. > * > * To unsubscribe from this group, send an email to: > * > <mailto:[EMAIL PROTECTED]>[EMAIL PROTECTED] > > * > * Your use of Yahoo! Groups is subject to the > <http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service. > > > >---------- 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/
