Maybe a dumb question, but...

[LoTech]

I remember back when I was young that we used open ladder line run about 2500 feet to the top of the mountain behind my house to pick up our "local" VHF channels about 75 miles away. With all of the research I've done recently this shouldn't have been possible. Today I stumbled upon why it may have been... According to several ham radio sites, open ladder line has much less loss than even the best coax. Some of the loss numbers per hundred feet I found were:

RG6 Coax - 5.9 dB@400MHz
RG59 Coax - 7.3 dB@400MHz
Window Line - 0.81 dB@400 MHz
Open Ladder Line - 0.53 dB @ 400 MHz.

On VHF low it says the loss for open ladder line is only about .25-.3 dB/100 ft. That would mean a 1000 foot run for low VHF would only lose about 3 dB, and UHF would only lose about 5 to 8 dB.

I realize that these are ideal numbers at best, but are these numbers even close to correct??? If so, why aren't more people still using ladder line or window line?

[GroundUrMast]

Those numbers sound right...

Coax is preferred these days because it is able to be mounted directly to metal objects like masts or towers. Coax shielding is excellent at keeping the signal inside separate from the signals and noise outside. With coax, I can drill a 3/8" hole, pass the coax through, caulk it, and I'm on to stapling down the rest of the run.. With paired lines, I could have have dozens of standoffs and through-wall tubes to install.

Unshielded paired wire must be supported every so many inches or feet to keep it from coming close to materials that would affect its' characteristic impedance. Also, unshielded paired line is more prone to act as an unintended antenna, receiving or radiating signals that should not have been. The signal loss per unit length increases more rapidly with increased frequency as well.

Paired lines have their place, look at any of the 2, 4 and 8 bay panel antennas for example; You will see the elements connected to the feed point via paired line. This is to match the impedance of the individual antenna elements with as little loss as possible. As you have already mentioned, HAMs are probably using more ladder line these days than any other single group, given it's power handling and low loss in the HF bands.

[John Candle]

Yes open line can still be used. As GUM stated there is much more interference in the air now days. However Yes it can still be used. Many years ago most of the Tv transmissions were in the VHF low band of 2 thru 6 that has much less loss per foot then VHF high 7 thru 13 and UHF 14 thru 69. And like you recall was used to bring the signal from the top of a hill/mountain that is blocking reception down in to a valley many feet away , 1000 feet , 2000 feet , 3000 feet. As you see from the old pictures the ladder line is supported on poles high up off the ground so as to keep the wires away from animals and vegetation is cut away from the path of the line so the branches do not take down the line. And no ladder line can not be buried in the ground. Rhombic antennas were often used as receiving antennas on the mountain top. The main reason that open transmission line and other ways of electronic transmission are not used now days is because ( and I will try and be nice ) because people now days are , spoiled rotten , stupid , lame brain , idiot , a** holes. They expect ever thing to be handed to them with a tiny little antenna or no antenna. As examples , many people have insane dislike for Tv antennas Tv transmission towers , cell phone towers and other forms of electronic transmission. They like there cell phones but do not want to see the towers that make cell phones possible. They like there Tv but do not want to get it for free with a Tv antenna , they would rather pay for cable or satellite. Do not be fooled by what antenna haters say , the truth is they are plain nuts.