Ian, Since RG-223 is double-shielded cable and is similar in construction to RG-400, it will be fine- provided you are using the connectors specifically made for RG-223 which has a larger OD than RG-400. Please don't even think about using LMR-400, 9913F, or any foil/braid cable because of their tendency to generate noise.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of kerincom Sent: Sunday, June 27, 2010 8:28 AM To: [email protected] Subject: RE: [Repeater-Builder] Coax shielding Jumpers between the TX ,rx and diplexer are rg223u .I thought of using rg223u for the link radio to its antenna because it is only aprox 2-3meters long but I felt I should try lmr400 because of the 100% shielding and the link radio is just a standard radio that works in either rx or TX mode and not in duplex mode Thank You, Ian Wells, Kerinvale Comaudio, 3A Murchison Street,Biloela.4715 Ph 0749922449 or 0409159932 or 0749922574 www.kerinvalecomaudio.com.au <http://www.kerinvalecomaudio.com.au/> -------Original Message------- From: Eric Lemmon <mailto:[email protected]> Date: 6/28/2010 1:24:37 AM To: [email protected] <mailto:[email protected]> Subject: RE: [Repeater-Builder] Coax shielding Ian, RG-213 coax can definitely contribute to desense, as can cheap connectors and adapters. I suggest making up new jumpers using double-shielded coax such as RG-400 or RG-214, and fit these jumpers with high-quality, crimp-on connectors of the correct type on each end so that no adapters or barrels are needed. Don't use LMR400 or similar foil-and-braid cable, as that will add entirely new problems to the mix. If changing the jumpers still leaves some desense, then try increasing the spacing between the link and main antennas- lowering the link antenna should be the first step. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> [mailto:[email protected] <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of kerincom Sent: Sunday, June 27, 2010 7:51 AM To: [email protected] <mailto:mail%3DRepeater-Builder%40yahoogroups.com> Subject: [Repeater-Builder] Coax shielding Hi guys .I am just wanted to confirm a question on coax shielding . With 2-10 watts transmitting through rg213u could rf be escaping that could cause desensitization to other radios .The repeater I have setup uses 9 meters of heliax from the main diplexer to ant and rg213u from the link radio to its antenna . I am finding I am getting problems with the link transmission interfering with the repeater rx The link antenna is a yagi 3 meters above the ground and the main repeater antenna is 6 meters above it .I am currently trying band pass cavity on the receiver rx or band pass/band reject diplexer with some success but I am wondering if the rf escaping from the cable is causing problems inside the repeater shed even at a low wattage .I am definitely changing the rg213u to either rg223u or lmr400 as it is only on the link radio and shouldn't have any effect on the repeater's operation .Has anyone else had the same sort of problem where the rf energy leaks out of the cable in the shed and causes problems to the repeater and they had to upgrade the link cable to 100% coverage cable Thank You, Ian Wells, Kerinvale Comaudio, 3A Murchison Street,Biloela.4715 Ph 0749922449 or 0409159932 or 0749922574 www.kerinvalecomaudio.com.au <http://www.kerinvalecomaudio.com.au <http://www.kerinvalecomaudio.com.au> >
