As explained in the November issue of “QST” (page 66) the ARRL examined the use of ladder-line and did some rudimentary testing of this cable in dry vs wet conditions.They had test gear to measure the SWR and other concerns. At the end of the testing they reported that beyond a simple re-adjustment of the tuner they used not much in the form of variations occurred.
Unfortunately, their tests were not complete.
This weekend, the Bexar Operators Group will do some “real life” testing of ladder-line and the implications of getting the dry line saturated to prove that the ARRL’s final assumptions are “all wet”! Having done some experimentation 20 years ago using ladder-line as a feed cable, W2IK came up with some very different findings.
The Bexar Operators Group will re-create W2IK’s experiments to show that the ARRL’s findings are incorrect and offer alternatives when using ladder-line in amateur radio communications.
The testing is scheduled to take place on Sunday, November 15th at 1 PM at JOHN JAMES PARK off of Rittiman Road near RT 35 (note change). Interested parties are encouraged to attend. You might find the tests interesting. The results, with photos, will be published here at a later date.
November 10th, 2009 at 6:25 AM
Bob,
I’m sure you mean”Window” or “Twinlead” lines, as “Ladder” line is usually open-wire with spacers. Either one provides low loss when feeding a mismatch,as on my 80M. loop fed with 2M SSB signals. All bands 160-2M with one antenna. Can’t do that wid coax. HI.
I’ve not had to re-tune the loop in rain, but have to with ice coating.
AD5HR
Jon
November 11th, 2009 at 9:05 AM
Hi Jon!
We will be testing the 450 ohm “ladder line” as pictured in the post. Up in NY this is what we call ladder line or “web line” . The type with the two runs of line offset by spacers we call “open wire line”. The ARRL uses the term “ladder line” or “window line” to discribe both. The difference is the impedence.
Please feel free to join us in our testing. You are quite correct about ice coating. I’ve even had my ladder line hum to my cw transmissions whe it was covered with ice! 73 es gud dxing. Bob W2IK