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Discussion Starter · #1 ·
I'm considering putting an antenna for HDTV reception in my attic but my HDTV is in a finished basement. Running antenna cable will be almost impossible. However, I currently have a couple of Cat 5e cable runs between the two areas. Can I use this cable to run the signal between the antenna and the HDTV receiver? Can anyone help?


Thanks in advance,


Alex
 

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I am not famliar with Cat 5e cable, but if the impedance is 75 ohms, and i shielded, I think it may.

Bill
 

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Cat 5e is ethernet networking cable(or office phone system cable). I don't think it can carry the antenna signal, but i'm no expert.

Dug
 

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Sorry, CAT5e won't work, at least not real well.


It's unshielded twisted pair, balanced cable, intended for data transmission. Characteristics impedance is 135 ohms, I believe. So at your antenna, you'd need a 300 ohm-balanced-to-135-ohm-balanced transformer, and then a 135-ohm-balanced-to-75-ohm-unbalanced transformer at the receiver. I don't think these are off-the-shelf items, certainly not at consumer price points.


But aside from that, CAT5e is only specified for up to about 100 MHz, about the FM radio band. Above thiat, attenuation increases rapidly. Even the guys I know looking at "exotic" applications for CAT5e aren't trying to push it above 400 MHz. The UHF band, where most DTV stations are, starts above this. So unless you're in a very strong signla location, the signal would be very weak by the time it got to the receiver.


Getting this to work would be an exercise in electrical engineering: matching the impedances, proper level of preamplification to compensate for cable loss (if possible), etc. In other words, definitely a "kids, don't try this at home" deal.


On the other hand, running a cable in finished walls is rarely impossible. A good remodelling electrician can work wonders with the specialized tools they have, like those 4 ft long flexible drill bits they use for drilling inside wall cavities.
 

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Those CAT5 to BNC converter units are only for baseband video signals (composite video) not for high frequency VHF/UHF RF signals for an antenna connection. CAT5 will attenuate UHF way too much. You need to use RG6 coax cable for wiring to an antenna.
 

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Discussion Starter · #7 ·
Thank you all so much for your input. It looks like the CAT5 is not going to be an option-at least not yet. Each one of the bedrooms on the second floor is wired for cable TV and like the two CAT5 runs they terminate in the basement. I was hoping to get away with using the CAT5, but I guess I'll use one of those lines.


Again, many thanks,


Alex
 

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Thanks Don, I can quit wondering if it was feasable. Alex, you may be able to use an existing cat5 cable to pull an RG-6 and a replacement cat5 through.
 

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Just another thought. I just installed my old DirecTV receiver in the bedroom and needed to get from there to the dish. My antenna guy suggested running it under the roof eave and around the house to the front porch and under the front eaves, then over about a 12" stretch of open roof to the outside wall of the bedroom and then via a hole into a wall disconnect. Excellent job and you can't tell it is there.

Bill
 

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Quote:
Originally posted by greywolf
Thanks Don, I can quit wondering if it was feasable. Alex, you may be able to use an existing cat5 cable to pull an RG-6 and a replacement cat5 through.
Highly unlikely you'll be able to do this unless the cat5 was pulled after the walls were up. If the house was pre-wired, the cables are almost certainly stapled to the studs.
 

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Quote:
Originally posted by BenBroder
Highly unlikely you'll be able to do this unless the cat5 was pulled after the walls were up. If the house was pre-wired, the cables are almost certainly stapled to the studs.
Unless they are in conduit. He'll know if it's possible as soon as he gives it a slight pull. If it doesn't move easily it's no go.
 
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