| Author |
Message |
    
Charliebrown
Member
Username: Charliebrown
Post Number: 59
Registered: 10-2002
| | Posted on Monday, March 15, 2010 - 7:13 am: | 
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TECH 237,Could you tell me how many turns it would take on rg 213 coax to balance 75 ohm tv hard line cable to 50 ohms. If you would it could save me some time and trouble. For now I have it balanced with 100 feet of 213 coax at the radio and at the antenna. I could be wrong but I think coaxal coils could be a little better. What do you think? |
Tech237
Moderator
Username: Tech237
Post Number: 1316
Registered: 4-2004
| | Posted on Monday, March 15, 2010 - 1:38 pm: |
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A coax coil wont really balance a feed line, what it will do is reduce the chances of RF on the outside of the coax. What I usually use, to do that is 3-4 turns around 6" diameter.
The difference between running 75 ohm coax and 50 ohm coax between a radio and antenna is so small I dont bother to try and match it. If everything else is good the worst case is an SWR of 1.5:1.
If I read your post correctly, what you're seeing as a balancing effect is more likely signal loss in the cable length
Tech237
N7AUS
God only made some many perfect head, on the rest he put hair.
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Charliebrown
Member
Username: Charliebrown
Post Number: 60
Registered: 10-2002
| | Posted on Monday, March 15, 2010 - 2:26 pm: |
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TECH237, You are correct. In using the length of coax of 100 feet at the radio and the antenna it shows about a 1 to a1.1 swr. The swr is the other reason I had asked. I was thinking in using the coils I could get rid of 200 feet of rg 213 coax (FOR LESS POWER LOSS) and keep the same 1 to 1.1 swr. I know that all I am fooling is the meters because it is not truely balanced. So with 6 to 8 turns in the coils at the radio and antenna do you think this would do the trick???? |
Tech237
Moderator
Username: Tech237
Post Number: 1317
Registered: 4-2004
| | Posted on Tuesday, March 16, 2010 - 3:07 pm: |
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IT^ should go pretty close...
Tech237
N7AUS
God only made some many perfect head, on the rest he put hair.
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