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Message |
    
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 218
Registered: 9-2004
| | Posted on Thursday, June 07, 2007 - 10:05 pm: | 
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Does anyone know where I can get some 75 ohm ribbon line ? I would like to build a Turnstile antenna and I need 75 ohm ribbon line to complete this antenna project?
Bob CEF451/VE1CZ
Moderator Note!
Go to www.google.com and do a search for: 75 ohm ribbon line
Robert L. Spicer The days of radio are just beginning!
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Bruce
Senior Member
Username: Bruce
Post Number: 4467
Registered: 9-2003
| | Posted on Thursday, June 07, 2007 - 10:29 pm: |
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For what Band ?
I have used them on 2 meters they work well but mine used common 300 ohm not 75 into a stub match. Also the BIG WHEELS are a modded turnstyle that used one feed and a hair pin match.
On 6 since 66
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Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 220
Registered: 9-2004
| | Posted on Friday, June 08, 2007 - 9:06 am: |
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Tnx for the reply Bruce, its going to be for 10/11 meters , I need something with some what of an omni directional pattern with horizontal polarization.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
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Tech237
Moderator
Username: Tech237
Post Number: 803
Registered: 4-2004
| | Posted on Friday, June 08, 2007 - 9:14 am: |
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Actually Bruce, the last turnstyle I built called for 75 Ohm coax as the phasing harness and that was for 2m satellite work. I even recall that the one built for a bunny antenna (circa '72) used RG-59 too.
I have never seen a design for a turnstyle that required 300 ribbon, do you have a file of that you could email me??
Simon
Tech237
KD7IEB
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Bruce
Senior Member
Username: Bruce
Post Number: 4468
Registered: 9-2003
| | Posted on Friday, June 08, 2007 - 9:18 am: |
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At one time they made 72 ohm twinline
here is a thought use 4 CB antennas and lakeview mounts Mount them them at a 90 deg angle and phase them with coax.
On 6 since 66
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Bruce
Senior Member
Username: Bruce
Post Number: 4469
Registered: 9-2003
| | Posted on Friday, June 08, 2007 - 11:40 am: |
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The one I built used crossed folded dipoles same as the old TV antennas ( 300 ohms ) it came out of a old VHF manual from the early 60s
IF you want to build a good omni for 2 meters go with squailos I use stacked ones My last pair suvived the hurricanes.
On 6 since 66
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Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 221
Registered: 9-2004
| | Posted on Friday, June 08, 2007 - 12:33 pm: |
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I suppose I could get away with 75 ohm coaxial cable but this might skew the pattern.I believe that the twin lead helps to maintain a more symmetrical pattern, but I guess that it won't matter if the pattern is a bit off, it's only for a bit of skip and to keep down some of the local noise.
Bob CEF451/VE1CZ
Robert L. Spicer The days of radio are just beginning!
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Tech237
Moderator
Username: Tech237
Post Number: 805
Registered: 4-2004
| | Posted on Friday, June 08, 2007 - 6:48 pm: |
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Not really as the coax also acts as as balun too and a turnstyle is basically omnidirectional anyway, although not completely circular.
Try it - it can't do any harm, just remember the different velocity factor.
Simon
Tech237
KD7IEB
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