[TowerTalk] UL listed protector for ladder line

[Wes]

Although Tim does say "ladder line (open wire)", so I know what he means, I 
think there could be some confusion about this.  I could be wrong, but I think 
in the usual ham lexicon "ladder line" often is used for what I call "window 
line", i.e. polyethylene insulated twinlead with windows poked through the 
ribbon.  The loss characteristics of these two is quite different.  Window line 
used with elevated SWR can be very lossy.

Likewise, the loss in tuners is often dismissed as negligible, when it too is 
not.  Tim's Matchbox with air-wound inductors and air capacitors is very 
efficient, the average T-network with relay-switched toroid inductors and  
capacitors may not be. And then there are the baluns....

I wrote about this in a somewhat antiquated draft of a paper published in one of 
the ARRL Antenna Compendiums.  I don't maintain a personal website, but someone 
else thoughtfully posted it here: 
https://www.casa.co.nz/equipment/Aerials/Ladder-Line/LadderLines-7132619_9p.pdf

Wes  N7WS

On 6/16/2025 6:34 PM, Tim Duffy wrote:
> A couple of notes about using a 80 meter dipole (center fed 130 feet long) on multiple bands fed with ladder line (open wire).
> Using a good open wire tuner - results in a very low VSWR presented to the TX on all bands. Even a used Johnson Matchbox (my favorite) is affordable and with one wire antenna - you can cover 80 through 10 meters easily. Even though the Antenna feedpoint impedance is high, so the VSWR on the openwire line is high, it doesn’t matter - because the feedline loss is so small due to using ladder line. This is not the case for high VSWR on coax fed antennas that are used on multiple bands without traps or other techniques to keep the VSWR low.
>