- 1. [TowerTalk] Inverted L Question (score: 1)
- Author: DENNIS BRICKEY <n4dd@embarqmail.com>
- Date: Fri, 29 Aug 2008 16:58:06 -0400 (EDT)
- I realize this is not a tower question, but the antenna gurus hang out here. Hopefully some bandwidth can be tollerated for an antenna question. I am working on a 160 meter inverted L and having som
- /archives//html/Towertalk/2008-08/msg00617.html (8,013 bytes)
- 2. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: Joe - WDØM <joe@wd0m.com>
- Date: Fri, 29 Aug 2008 15:02:08 -0600
- If you can, move the bottom of the vertical section in/out from the base of the tower (assuming it's on one) to see if that change the SWR - does on mine. You may also want to try changing the horizo
- /archives//html/Towertalk/2008-08/msg00619.html (8,984 bytes)
- 3. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: Chris Adams <n4vi@comcast.net>
- Date: Fri, 29 Aug 2008 15:29:23 -0600
- Dennis, A few questions: 1. How much are you trimming/extending the vertical section? 2. Is your SWR meter designed to work with 75 ohm cable or 50 ohm cable? Changing the number of radials should ha
- /archives//html/Towertalk/2008-08/msg00621.html (9,173 bytes)
- 4. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: "Jim Brown" <jim@audiosystemsgroup.com>
- Date: Fri, 29 Aug 2008 14:38:40 -0700
- One big reason you're having trouble matching it is the 75 ohm coax. Replacing the hard line with RG8 will get you closer. The radiation resistance (Rr) of a quarter wave antenna is going to be somet
- /archives//html/Towertalk/2008-08/msg00622.html (8,639 bytes)
- 5. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: K4SAV <RadioIR@charter.net>
- Date: Fri, 29 Aug 2008 17:00:58 -0500
- The answer is probably in the data you didn't give us. If this was an L made from something like #12 wire held up by a tree, it would be a very good match for 50 ohm coax, so about 1.5 SWR for 75 ohm
- /archives//html/Towertalk/2008-08/msg00623.html (9,209 bytes)
- 6. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: Les Kalmus <w2lk@bk-lk.com>
- Date: Fri, 29 Aug 2008 22:25:27 -0400
- Dennis, I had the same problem with a similar configuration of inverted L. I measured the antenna at the base with an MFJ259B and used the readings as input to the matching formulas given by ON4UN, w
- /archives//html/Towertalk/2008-08/msg00643.html (10,000 bytes)
- 7. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: "N7mal" <n7mal@citlink.net>
- Date: Sat, 30 Aug 2008 01:12:38 -0800
- I have been reading all the answers to your questions. I have 2 questions. Firstly I have had 3 160 inverted L's at different locations. My questions for you are: Why 175 feet.?. Where does that come
- /archives//html/Towertalk/2008-08/msg00649.html (9,271 bytes)
- 8. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: Steve Hunt <steve@karinya.net>
- Date: Sat, 30 Aug 2008 09:59:16 +0100
- Is there another piece missing from this jigsaw - the length of the feedline? Taking Jim's figure for Rr of 35 Ohms, we get a VSWR of 2.1 in a 75 Ohm system. BUT if the feedline were an electrical qu
- /archives//html/Towertalk/2008-08/msg00650.html (9,987 bytes)
- 9. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: K4SAV <RadioIR@charter.net>
- Date: Sat, 30 Aug 2008 11:00:52 -0500
- Mal I'm not Dennis, but I think I can answer your questions. The 175 feet number comes from the length required to get the resistive part of the feedpoint impedance of the L close to 75 ohms. The cap
- /archives//html/Towertalk/2008-08/msg00656.html (9,824 bytes)
- 10. Re: [TowerTalk] Inverted L Question (score: 1)
- Author: Terry Conboy <n6ry@arrl.net>
- Date: Sat, 30 Aug 2008 09:38:13 -0700
- Thanks Dennis. All those instruments are calibrated for a 50 ohm system, so the SWR they indicate on a 75 ohm cable isn't too representative of the mismatch at the antenna feedpoint. For example, the
- /archives//html/Towertalk/2008-08/msg00657.html (10,404 bytes)
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