Gentlemen: It is generally accepted that low gain receive antenna coax lead-ins, from Beverages to Flags, must be well shielded, balanced and choked, to prevent unwanted signals and noise from enteri
Sounds like it might be worth investigating. My initial reaction, however, is that there might be problems of an electrical/ mechanical nature. Unlike single insulated wires, which are easily twisted
I have seen rolls of "double barrel" coax at hamfests. It has two separate parallel inner conductors instead of one. Sort of like shielded twin lead. I forget the RG number, but it might be a better
separate Don & David & others, The single coax shield with twin center conductors would be excellent, if available. A multitude of problems now faced with the darn unbalanced feedlines would be solv
This stuff was extensively used in Wang computer and word processing networks during the 80s. I bet there are still spools of it out there someplace. I'd start with E-bay -- one trade name was Twinax
RG-22/U, RG-22A/U, RG-22B/U are the designators for the Twinax cable that looks like RG-213 (RG-8). It is 95 ohms impedance. Proper connectors are harder to find surplus than the coax--but can be bou
Thanks guys for all the advice & offers for cable. There is Belden 1808A, Twinax & several rip coax cables that will work. These are quite expensive compared to just using two RG-58's for the balance
I think I may have confused things by throwing the trade name "Twinax" into the equation. The stuff we used with Wang computers and WP gear was more like 2x RG59, 2 1/4 inch coaxial cables in one mol
Actually using fully balanced line won't fix any problem, the problems will remain and likely increase significantly. The problem with our antennas and feedlines are that they are never completely p
A little web searching has revealed much about the theory of how balanced, shielded cable would work to reduce common mode noise pickup. I also understand that a balun will be required at the shack e
-- Tom is right. Balanced line is not a "silver bullet" fix for feedline pickup. And he is right that it can make matters worse -- any added complexity introduces new opportunities for problems. To
Author: k3ky@erols.com (by way of Bill Tippett <btippett@alum.mit.edu>)
Date: Mon, 26 Aug 2002 16:29:42 -0400
Tom casts doubt on the value of converting from unbalanced to balanced feedline in real world situations. My suggestion: while you still have those trenches open, install *conduit*. Probably some lar
Good advice Gary, but moving the preamp will not affect the system unless the feedline loss is so high the noise floor is established by the preamp and not the antenna. By far the most common proble