Topband: What length for twisted pair two directional beverage

[Tom Rauch]

Another benefit of using twisted pair wire or WD-1A is the 
lower Velocity Factor (VF) of the wire: a physically short 
antenna “looks” electrically much longer. Using a VF of 58% 
for example, a 311 foot long twisted pair antenna is 
electrically the same length as a 537 foot single wire (one 
wavelength) antenna on 160 meters.

So if I were to use the .58 velocity factor on a 440' single 
wire 80M beverage, I should expect to get the same 
performance from a 255' twisted pair beverage.  Am I 
understanding this correctly?  Or is there some downside 
that I'm not accounting for?>>>

The statement is absolutely incorrect Brent.

The velocity factor of the wire in a transmission line mode 
has nothing at all to do with the electrical length of the 
antenna.

Only the common mode currents in the wires, where the 
currents are parallel, can act as an antenna. Those currents 
are unaffected by the differential (across) slowing caused 
by the majority of insulation being something other than 
air. So a 300 foot long antenna made from .66VF coax or 
twisted cable acts exactly like a single conductor Beverage 
of the same outer insulation and diameter.

There is no advantage for receiving.

73 Tom