Joe, You will be better off if you stay away from the LMR400 type of coax due to the braid can rub against the shield (dissimilar metals) and create noise in your repeater system.
Yes, I would replace your coax run with Heliax cable which is sometimes called hard line. I use Andrew LDF4-50A 1/2" Heliax on VHF runs up to 150 Ft and I use LDF5-50A 7/8" Heliax on UHF runs over 75 Ft. Make sure you install grounding kits on each Heliax cable before entering your home for lightning protection. Connect this to a good copper lightning rod earth ground. I use RG-142B/U for most of my in cabinet connections and more recently have switched to installing Andrew FSJ1-50 1/4" heliax inside in the cabinet on UHF because of its lower loss. I would not use the Diawa wattmeter permanently on the output of the duplexer. Use a Bird 43 with N connectors and the proper slug. When not using the meter, turn the slug 90 degrees so that the meter is grounded and protected from lightning strikes. I use high quality commercial antennas because most of my repeaters are located at high elevation sites that demand the best antennas due to the extremes of weather conditions. I would recommend the DB408 antenna for UHF. I have several of them in Amateur service. I would recommend the Sinclair or DB antennas. The Diamond antenna would be ok for your home location. I have a UHF repeater at my home and I use the Diamond X50 antenna on my tower at 60 Ft and it works well. I feed it with 75 Ft of 1/2" Heliax cable. That is the only place I use a Diamond antenna. For all outside coax connections, make sure you use butyl rubber and good 3M type 88 tape to seal them up to keep moisture out. I also use Micor stations at my repeater sites. I have one on 2Mtrs at an 11,000 Ft site near Salt Lake. It has been in operation there since it was installed back in 1973. Yes, I have had to maintain it over the years and rebuilt the PA a few times but it has provided many years of trouble free operation! I am curious what problems you have had with yours? I also use the Kenwood TKR-750 and TKR-850 repeaters at some sites and they both work fine too. I have had years of trouble free service with them. I mainly use the GE Mastr II stations at all my sites. I have had very good results with these radios. Most of my repeaters are linked together so when you key one up, they all key up together. Thanks, John Lloyd, K7JL Intermountain Intertie http://utahvhfs.org/snowlink.html From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of kc7ght Sent: Friday, March 16, 2007 1:13 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline Gentlemen, Is LMR-400 a good coax to use for my 70cm repeater feedline. My feedline is 130 feet long and located at my house. Should I really go to hardline and replace my LMR-400 feedline? If so what diameter? Will it really be worth the cost and trouble to run it through my attic and into my house? Your article indicates that some LMR-nnn coax are OK for cabinet connections. Is LMR-400 Ultraflex a good choice for cabinet connections? I am using RG-142B/U now for my duplexer connections (an Angle Linear custom made duplexer, bandpass cavities, and preamp). Should I use RG-142/B/U for my (30 inch long) Tx to duplexer run also? I would like to keep my new Daiwa CN-801 (UHF connectors) SWR Power meter in the Tx line permanently. Is this a good idea? It is comforting to see the power and SWR at a glance. I am using a Diamond X510MA (17 feet long with a UHF connector) dual band antenna at 65 feet high. Should I be using a different antenna for my repeat operation? If so, what antenna? Is the Kenwood TKR-850 repeater a good unit. I just ordered one to replace my Micors. I have nursed my two Micors for the last year, and just gave up on them. One problem after another on both units. Please let me know your thoughts and suggestions Thank you. Joe KC7GHT ____________________________________________________________________________________ The fish are biting. Get more visitors on your site using Yahoo! Search Marketing. http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
