Thanks for the correction Bob. I think it was still a little early for me when I typed that email.
Corey N3FE On Mon, 31 Aug 2009 10:14:58 -0700, n...@no6b.com wrote: > At 8/31/2009 09:03, you wrote: > > > >>Good Morning/Afternoon Jim! >> >>Not sure about the Antenna, I know Randy's (HJC) is working great! Any >>type of double shielded coax/feedline anywhere in the system will cause >>problems. As the temp inside or outside changes it can cause the shield >>to rub together and make a lot of noise on the repeater. Even if it is >>used inside on the duplexers... > > This is incorrect. Silver-plated double-shielded coax is practically the > standard for duplex interconnects. Non silver-plated braided coax will > generate noise, whether it's double shielded or not, due to the eventual > oxidation of the copper & resulting poor intra-braid contact. > >> I had mentioned to the person you are referring to that I may be able >> to find some 1/2" hardline but he thought it may be to weighted for what >> he is doing... > > This would be a good choice for the duplexer-antenna feed, with RG-214 > jumpers between the hardline & duplexer/antenna. > > Bob NO6B > > >>Corey N3FE >> >>On Mon, 31 Aug 2009 11:46:36 -0400, "Chuck Kelsey" >>wrote: >> > Sounds like maybe a bad antenna. Don't use the foil/braid cable >> > anywhere in >> > >> > a repeater system. >> > >> > Chuck >> > WB2EDV >> > >> > >> > >> > ----- Original Message ----- >> > From: "ka2ajh" >> > To: >> > Sent: Monday, August 31, 2009 9:33 AM >> > Subject: [Repeater-Builder] Tram 1481 Dual Band UHF/VHF Antenna >> > >> > >> >> Hi Guys, >> >> We spent most of yesterday working on a UHF Mastr II Exec. Repeater, >> >> we >> >> are using a TRAM 1481 Dual Band Antenna on. This is the high gain 8.3 >> >> dB >> >> VHF/11.7 UHF. The system uses UHF Repeater, VHF Simplex, and IRLP. The >> >> antenna works very poorly on UHF and much better on VHF. The SWR is >> >> about >> >> >> >> 3-1 on both frequencies. The antenna is not DC Ground and there is no >> >> shorted connectors. Lack of help prevented us from taking the antenna >> >> down >> >> and apart at this time. We ran tests by putting the antenna on a >> >> portable >> >> >> >> and working a fixed base and again the VHF pinned the meter and the >> >> UHF >> >> was weak, only a couple of S units better than the portable rubber >> >> duck. >> >> Has anyone had a similar problem. I understand that the antenna is a >> >> compromise and not as good as a single band folded dipole for example, >> >> but >> >> several of us have these and they work great except for this one. I am >> >> thinking there are enough Tram 1481 out there and someone may have had >> >> the >> >> same problem. >> >> Also there has been many posts about the LMR400 used in repeater >> >> service. >> >> >> >> It is my understanding that the foil type should NEVER be used between >> >> duplexers, from the TX, RX to the Duplexers, but I am not sure about >> >> between the duplexer and the antenna. Comments please! >> >> My friend has the LM400 on the repeater mentioned above and I know it >> >> is >> >> NOT the present problem as even on simplex the antenna performance on >> >> 440 >> >> >> >> very poor. >> >> >> >> Thanks again an advance for your experiences and thoughts. >> >> >> >> 73 JIM KA2AJH >> >> >> >> >> >> >> >> ------------------------------------ >> >> >> >> >> >> >> >> Yahoo! Groups Links >> >> >> >> >> >> >> >>
