Cable TV wire for antenna
- Thread starter offfor4
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N_Jay
Guest
offfor4 said:
The wire YES, (it is probably RG-6 or Equal.)
The wire as it is installed, probably NOT, unless you know it is a strait run and not connected to anything else.
TeRayCodA
Member
offfor4 said:
Is what going to be a good antenna? Just the coax ? No.
Or,are you thinking about using an outdoor TV antenna?
As for the PC interference,you may have to choose a different location with the scanner.
RG-6 works great for scanner reception.
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I just ran RG-6 (DishTV coax) to my attic. As it stands it does NOT work as an antenna. I'm playing with connections and I am new to this but I believe the coax is shielded and will not act as an antenna. I think you can make one end of it into an antenna but as it stands I don't think plain sheilded cable will do anything.
Just cut back 19" of the insulation leaving the center conductor exposed at the end in the attic and you will have a perfect VHF 1/4 and 3/4 on UHF. Be sure to leave the 19" verticle and in the highest spot in the attic for maximum performance.
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N_Jay
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ve3nsv said:
You can leave the insulation on, just take the shield off.
Of course what you really want to do is fold the shield wires back so they hang down, like a very limp ground plane.
You would be surprised how well this works.
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N_Jay
Guest
fuzzymoto said:
Transmission line DOES not work as an antenna. That is the whole point. :roll: :roll:
What you are trying to do is the RF equivalent of using an extension cord as a light bulb. :evil:
Al42
Member
Or peel the shield back over the cable, so you have outer shield, outer insulation, inner shield, inner insulation, center conductor. Cut off about 22" of outer (black) insulation, then trim the shield to 18" after you're done peeling it back over the cable.N_Jay said:
It's called a coaxial or bazooka antenna and it's a lot easier to mount and handle than a ground plane, but it works at least as well. It's just twice as high, but most attics are more than 36" high, so that shouldn't be a problem.
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N_Jay
Guest
A lot of RG-6 is foil shielded so that is really hard, but it is the right way to do it for good braided coax.
kc4jgc
Member
offfor4 said:
It can work. Bear in mind that tv coax is 75 ohms. Scanners and antennas are generally 50 ohms. What you'll need is something on both ends to compensate for the impedence mismatch between antenna and cable and then between cable and scanner.
My advice would be to buy a new 50 ohm coax, then have that fished inside the walls to an outlet placed near your scanner.
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N_Jay
Guest
kc4jgc said:
This has been hashed out MANY times.
The mismatch loss from using 75 ohm cable on a 50 ohm receiver system is usually not much worse than the loss of some other commonly used 50 ohm cables.
A wide band antenna system is not a constant impedance so matching to 50 ohms is not a perfect match. It is VERY likely that the antenna may be as good or better a match to 75 ohms at many frequencies.
Go ahead and use the RG-6 untill you can afford an air dielectric or very low loss 50 ohm cable.
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