Talk:Twin-lead

message: I don't think the color vs. black and white distinction is relevant.  A balanced line directly from the antenna to the TV is actually superior to a connection requiring a balun, as the balun has some loss, and the coax is (in general) more lossy than the twin-lead line.  However, if the line has to pass through a wall that has a lot of rebar or other metal, it will interfere with the twin-lead, and coax is better.  Also, the old screw type antenna connections are notoriously loose and have poor connections.  Coax connectors are a bit more robust and smaller (i.e., easier to install on the assembly line) and so would probably shave a few cents off manufacturing cost, as well as be more maintainable for the consumer, and so would be more likely on a modern mass market TV.  -ssd 04:42, 3 January 2006 (UTC)

message: This stuff became more or less obsolete in the 1960s in the UK, not recently. Since then it has occasionally been seen on FM rabbits ear antennas, but not often.
Tabby (talk) 12:21, 1 March 2008 (UTC)
thread_title: Date

message: I am very suprised to see this stuff described as better than coaxial. Twin-lead seems to have been about as "useful" and "reliable" as using an old wire coathanger as an antenna. Long lengths of twin-lead seems to work great as an antenna, meaning it sucks up interference from all directions to such a degree that the yagi on the roof becomes drowned out in the noise.
I tend to assume people used it back in the 1950s, only because they could not afford the better coaxial system. I know that the old coaxial was usually huge, about a half-inch wide, and very stiff.
Is there an equivelant form of twin-lead that is very low-loss, and as well-shielded against interference as coaxial?
DMahalko (talk) 06:23, 22 February 2009 (UTC)
thread_title:  Shielded twin-lead? 

message: I think that the page on Ladder Line (http://en.wikipedia.org/wiki/Twin-lead) should be merged into / redirected to this page, which is more general and more complete.  However, I don't know how to do the banner at the top of the ladder line page proposing same. 70.232.79.15 (talk) 01:46, 31 March 2010 (UTC)
replies: text: Done. - LuckyLouie (talk) 01:54, 31 March 2010 (UTC)
thread_title: Merge

message: The table at the end of the article can't be correct.  75 ohm and 300 ohm lines would not have the same loss and these values differ from the few sources I checked.  I will research various authorities and see if I can come up with some more reliable values.  I appreciate any comments from any and all.  JNRSTANLEY (talk) 18:47, 18 July 2013 (UTC)
replies: text: Not sure what you mean by VF values. If you mean the phase velocities (0.8c and 0.71c), then these depend on the thickness and dielectric constant of the insulation on the wires. The capacitances likewise depend on the details of the dielectric. If the capacitances and phase velocities are consistent, then we should have C = 1 / (Z vphase) in each case (so Z = 300 Ω, vphase = 0.8c => C = 11.1188 pF/m). In any case, since the details of the dielectric sheaths are not given, then these values are -like the losses- somewhat meaningless. To be fair, the section is headed typical values, so it doesn't make any claims that the data has any particular significance. However, I reckon your objection is valid and so the table should go. I shall delete it. --catslash (talk) 23:41, 18 July 2013 (UTC)
replies: text: Yes, VF is the same as phase velocity.  And you are quite right, it also depends on the thickness and type of insulation.  300 ohm open wire lines can have a VF near .95.  Better to delete for now. Thanks.JNRSTANLEY (talk) 12:04, 19 July 2013 (UTC)
thread_title:  Table of loss at the end of the article is not very helpful