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 > >> > >> > >> > >
