300 ohm flat antenna wire - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 8 Old 05-20-2019, 10:19 AM - Thread Starter
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Question 300 ohm flat antenna wire

Does anyone know where I can get large quantities of the old flat 300 ohm antenna twin lead wire? In need 1000s of feet for making low band VHF dipole antennas to hand out to views that cant get ch4. id prefer clear but anything is better than nothing. it is nowhere to be found anymore! Thanks in advance for any leads on finding it.
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post #2 of 8 Old 05-20-2019, 12:06 PM
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Got a quick hit on Amazon, though it's not the clear type.

Sounds like a lot of work to make an antenna they're still going to need a combiner to connect unless you expect them to disconnect their existing antenna whenever they want to watch 4. Unless you're in a market where that's the only station. . Given the labor, it actually might be better to invest in cheap rabbit ears you can attach a station logo sticker to.

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post #3 of 8 Old 05-20-2019, 12:07 PM
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Quote:
Originally Posted by Mark Pindler View Post
Does anyone know where I can get large quantities of the old flat 300 ohm antenna twin lead wire? In need 1000s of feet for making low band VHF dipole antennas to hand out to views that cant get ch4. id prefer clear but anything is better than nothing. it is nowhere to be found anymore! Thanks in advance for any leads on finding it.
Mark
https://www.frys.com/product/5231757

https://www.elliottelectronicsupply....d-300-ohm.html

Good luck at making your antennas.
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post #4 of 8 Old 05-20-2019, 12:24 PM
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$.50 a foot seems more expensive than the Fry's link above - but you could try The Wire Man if all else fails. https://thewireman.com/antennap.html#balanced

I've not bought TV antenna wire from him, but I've bought plenty of balanced ladder line for ham radio antennas. You can email him if you can't find what you want on the site. Honest folks.
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post #5 of 8 Old 05-21-2019, 10:19 AM - Thread Starter
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I cant find a set of rabbit ears that can get ch4, they are all too short. The repack moved us from ch42 to ch4 and killed our viewership! The dipole antenna I made gets the whole spectrum so its all they need. Frys is 10 cents a foot but only 100 foot lengths so i get an uneven number out of each piece. The others are four times the price so even with the waste Frys is cheaper. They are all black and id love clear but that looks like its out of the question. Such is life!
Thanks for the response.
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post #6 of 8 Old 05-21-2019, 11:08 AM
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Quote:
Originally Posted by Mark Pindler View Post
I cant find a set of rabbit ears that can get ch4, they are all too short.
I use one of these in my attic and get channels 2, 6 and 12 combined with a CM4228. Works fine.
https://www.ebay.com/itm/Antenna-Rab...cAAOSwzKVcxhrM
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post #7 of 8 Old 05-21-2019, 06:01 PM
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Ewwww....that R-S Plastic Twinlead looks like it has been deteriorating on the shelf for many Decades, getting ever more brittle with age....

Some specific Belden Part Numbers you might want to search for....and Summary of various Velocity Factor specs:
https://www.avsforum.com/forum/25-hd...l#post33718577

The specific Velocity Factor should be used in the fol. Folded Dipole Length Calculator, instead of the presumed VF=0.95 [impossibly HIGH] value:
http://users.wfu.edu/matthews/misc/dipole.html

Newer and much less expensive 300-ohm Ladder Line [more modern construction with intermittent "air holes" in the Plastic Insulation to reduce Loss when wet....similar to more commonly used 450-ohm Ladder Line]:
https://www.dxengineering.com/search...rder=Ascending
Ladder Line Velocity Factor VF=0.88 when calculating Length for Ch4 [66-72 MHz].

Using my 4nec2 Folded Dipole Model for the (skinner) Ladder-Line, the "best" Electrical Length 81.75-in [Same SWR at 66 and 72 MHz].
Which means "best" Physical Length = 81.75 * VF = 71.94-in or about 72-in.


Last edited by holl_ands; 05-21-2019 at 07:00 PM.
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post #8 of 8 Old 05-21-2019, 06:21 PM
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For those locations a DIY Ch4 Folded Dipole is inadequate, you might want to keep the following DIY Folding Ch3-6 Hourglass-Loop in your car, which could be laid out on four pieces of Cardboard [Each - 42-in H x 35-in W] held together with Duct Tape, which when folded would fit in your car/truck. Unfold for use [Total = 84-in H x 70-in W]. Permanent install [perhaps hidden behind some curtains] could be any flat piece of cardboard or foam-board or Masonite, or plywood....or a PVC Frame with Cross-Member in middle to mount the Balun at the Central Feedpoint...of course located on wall that more or less allows Antenna to "point" in desired direction....and fortunately Beamwidth is fairly wide:
https://imageevent.com/holl_ands/loo...lassloopnorefl

Ch3-6 Raw Gain = 3.8 to 5.4 dBi and SWR Under 2.7.


Last edited by holl_ands; 05-21-2019 at 07:10 PM.
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