[Elecraft] RE: zip cord as antenna wire

[Darrell Bellerive]

Joe,

Way better to use 300 ohm twin-lead. The losses are substantially less.
The ARRL Antenna Book shows 300 Ohm tubular as having only about 0.55 dB
loss per 100 feet at 30 Mhz vs. 8 dB loss for 100 feet of zip cord. I'm
not sure what they mean by tubular, if this is the common TV feedline
stuff or not. TV type ladder line has losses of only 0.175 dB for 100
feet at 30 MHz.

Remember that in a multiband antenna the mismatch will vary from band to
band and the losses will increase with the mismatch. So the losses
specified above are for matched systems. Ladder line would be the best
choice followed by the TV 300 ohm twin-lead. From a practical
standpoint, for 28 feet, I'm not sure it would make a whole lot of
difference though.

Darrell VE7CLA K2 #1973


On Thu, 2004-03-25 at 07:24, Joe - aa4nn wrote:
> If zip cord or speaker wire is bad for a transmission line, what if I use
> 300 ohm tv lead as the transmission line to a 44 foot center fed dipole?  Is
> 300 ohm any better ?
> de Joe, aa4nn
>