can I use 75 ohm coax ??
can I use 75 ohm coax ??
Hello All could I use 75ohm coax for my feed line for my 2 meter Jpole Antenna? A friend gave my 50 plus ffet of brand new Belden 9116 coax its 75 ohm, and R11 Shielded.
75
Sure,, why not. I understand loss on the 75 ohm will be less but potentially
a mismatch.
Well 50 ohm might well be a mis-match also. The only guaranteed 50 ohms is the radio.
I think on a J-=pole you adjust the feed line at the antenna for a match so you can adjust the "whole system" for best match and go for it.
So in any antenna system you have to balance what you may loose in db
in a mis-match , with the 'lack of loss' in db of better quality cable.(losse per foot)..
Its all one big compromise.
Just slap it up and use it. What is the difference in reality. Will you be able to communicate 5 miles farther with on or the other ,, or maybe 50 feet,
or 50 miles. Its all a big guess except when compared to another antenna. .
Can you hit the repeaters you want to with the setup?
Can you work a mobile simplex 35 miles away, but not 36..
It has to have some limit.. It will be as good as it will be and work from there.
No one (I hope) will tell you you can talk 35.78 miles with 50 ohm cable
and only 34.69 miles with 75 ohm. Nothings that precise.
Do some calculations on line loss and mis-match loss and then take a wild guess on cost effectiveness , close your eyes and take a stab at one or the other.
Don
a mismatch.
Well 50 ohm might well be a mis-match also. The only guaranteed 50 ohms is the radio.
I think on a J-=pole you adjust the feed line at the antenna for a match so you can adjust the "whole system" for best match and go for it.
So in any antenna system you have to balance what you may loose in db
in a mis-match , with the 'lack of loss' in db of better quality cable.(losse per foot)..
Its all one big compromise.
Just slap it up and use it. What is the difference in reality. Will you be able to communicate 5 miles farther with on or the other ,, or maybe 50 feet,
or 50 miles. Its all a big guess except when compared to another antenna. .
Can you hit the repeaters you want to with the setup?
Can you work a mobile simplex 35 miles away, but not 36..
It has to have some limit.. It will be as good as it will be and work from there.
No one (I hope) will tell you you can talk 35.78 miles with 50 ohm cable
and only 34.69 miles with 75 ohm. Nothings that precise.
Do some calculations on line loss and mis-match loss and then take a wild guess on cost effectiveness , close your eyes and take a stab at one or the other.
Don