RE: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
-Original Message- From: Repeater-Builder@yahoogroups.com [mailto:Repeater- [EMAIL PROTECTED] On Behalf Of George Henry Sent: Saturday, March 17, 2007 1:10 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline Visit Polyphaser's web site for excellent professional advice on lightning protection. DO NOT use a separate ground rod for your antenna if it will be any significant distance from the electrical mains ground for the house! You will induce ground loop currents which can be VERY high from a near-strike! All mains, telephone, cable TV, and lightning grounds should be bonded together at the same ground connection (usually the water main, in residential installations). (I did end up using a separate ground rod for my ham and satellite antennas, simply because the water main ground was not easily accessible, but my ground rod is within 2 feet of the water main entrance to the house) George, KA3HSW / WQGJ413 There is nothing wrong with using multiple ground rods, in fact 1 or 2 ground rods are in no way enough. A single point ground system does not mean that all equipment is tied to only one ground rod. A single point ground system is accomplished when all equipment lines including antenna cables, power lines, phone lines etc. all are tied to a common point BEFORE they go to the equipment. That common point is then tied to a multiple ground rod system including the tower ground system. All grounds need to be bonded together. Reading the polyphaser site is good advice. 73 Gary K4FMX
RE: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
At 3/16/2007 18:34, you wrote: Joe, Re the Diamond antenna: No, due to quality difference between it and a commercial-grade antenna. Consider a DB antenna. This isn't a comm. site installation, just someone's home. So unless money is of no consideration I'd stick with the Diamond. A commercial antenna having the same gain as the Diamond is going to be very heavy expensive, will offer no advantage in coverage from a low-level location. The UHF connector on your Diamond antenna can be a problem, but if you mate a silver-plated PL-259 to it you should be OK. Bob NO6B
RE: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
I cant see nay advantage in a commercial stick in those circumstance as long as a decent seal tape is correctly wrapped over any fitting or joins to avoid the wicking of H2o ( assuming the peformance is similar) From: [EMAIL PROTECTED] Reply-To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline Date: Sat, 17 Mar 2007 06:41:27 -0700 At 3/16/2007 18:34, you wrote: Joe, Re the Diamond antenna: No, due to quality difference between it and a commercial-grade antenna. Consider a DB antenna. This isn't a comm. site installation, just someone's home. So unless money is of no consideration I'd stick with the Diamond. A commercial antenna having the same gain as the Diamond is going to be very heavy expensive, will offer no advantage in coverage from a low-level location. The UHF connector on your Diamond antenna can be a problem, but if you mate a silver-plated PL-259 to it you should be OK. Bob NO6B _ Advertisement: yellow.com.au - Find what you need when you need it http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fadsfac%2Enet%2Flink%2Easp%3Fcc%3DPAS062%2E9345%2E0%26clk%3D1%26creativeID%3D57763_t=761839555_r=hotmail_email_taglines_1March07_m=EXT
Re: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
- Original Message - From: Mr John Lloyd [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Cc: John Lloyd [EMAIL PROTECTED] Sent: Saturday, March 17, 2007 10:33 AM Subject: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline 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. Visit Polyphaser's web site for excellent professional advice on lightning protection. DO NOT use a separate ground rod for your antenna if it will be any significant distance from the electrical mains ground for the house! You will induce ground loop currents which can be VERY high from a near-strike! All mains, telephone, cable TV, and lightning grounds should be bonded together at the same ground connection (usually the water main, in residential installations). (I did end up using a separate ground rod for my ham and satellite antennas, simply because the water main ground was not easily accessible, but my ground rod is within 2 feet of the water main entrance to the house) George, KA3HSW / WQGJ413
Re: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
At 3/16/2007 01:12 PM, you wrote: Gentlemen, Is LMR-400 a good coax to use for my 70cm repeater feedline. No. 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 No; the power sensing diode may generate IMD. 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? No. For a home-based repeater you probably want all the on-the-horizon gain you can get. Bob NO6B
Re: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
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? It is a wise move. I used about 75ft of LMR-400 to get my UHF machine on the air in a pinch. This install unfortunately became permanent. For a while the LMR is OK but after about a year or so in the weather you start getting duplex noise occasionaly in the machine. For a 130ft run Andrews LDF4-50A (1/2) or eqivalent is fine. If you want to spend the extra money LDF5-50A (7/8) is a lot thicker/stiffer but has about .8db of loss for 100ft @ 440MHz. 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? The RG-142 is OK for duplexer cabling. Only improvement here would be to go to RG-214. As far as equipment jumpers RG-214 would be the better bet especially for the TX side of the duplexer. 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. Bad Idea. The Daiwa is a nice meter, but is not exactly the best shielded device in the world. Especially with UHF SO-239 connectors on the back. Just adding more loss and another source of noise/desense in the cabinet. 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? The Diamond is fine in my book (prefer with N connector but whatever is available). If you want to go commercial grade, the RFS PD-1151 is the equivalent to the 510. Otherwise if you want to really look for the horizon with the most gain, the Andrew or RFS 22ft 10dbd verticals are really nice. 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. The 850 is better than a micor (not trying to start a holy war with this one guys) in the long run. It is new, synthesized, and best of all, new. Never had a problem with one before. Please let me know your thoughts and suggestions You got em'. Good luck, Andy - Bored stiff? Loosen up... Download and play hundreds of games for free on Yahoo! Games.
Re: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
Save yourself some grief and keep all LMR cable out of any of your repeater installation. Chuck WB2EDV - Original Message - From: kc7ght [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Friday, March 16, 2007 4:12 PM 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?
RE: [Repeater-Builder] Coax for cabinet and for feedline - other than hardline
Joe, Re the LMR-400 coax: No, due to dissimilar-metal issues. Use RG-142B/U or RG-400/U for in-cabinet wiring. Re the Daiwa: No, due to potential IMD and losses in the UHF (gasp!) connectors. Re the Diamond antenna: No, due to quality difference between it and a commercial-grade antenna. Consider a DB antenna. Re the Kenwood TKR-850 repeater: I consider the TKR-850 to be roughly equivalent to a Motorola GR-1225, meaning that they work very well as low-tier repeaters for non-demanding applications. If you want a current model repeater that is roughly equivalent to a MICOR, consider the Motorola MTR-2000 or a Kenwood TKR-840. The latter requires a separate PA. Before we leave the topic, would you please explain the problems you had with your MICORs? There are many pro-MICOR folks on this reflector who would like to know exactly what problems you have or had with those repeaters. Perhaps others can help you resolve those issues. Please give us that opportunity. 73, Eric Lemmon WB6FLY -Original Message- 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
