Good questions. Although you asked them off-list, I'm answering on-list to prompt others to answer and to comment on-list, for my benefit as well as others'. As with, e.g., an automobile, several ind
I've seen fiberglass-reinforced Teflon(R) circuit boards (diel. constant about 2.2), about 0.031 inch thick, cold-flow. They were in a microwave receiving antenna, inside an unventilated translucent
No. To deliver the _same_power_ as a single coaxial line, two coaxial lines operating in "push-pull" deliver half the current at twice the voltage. At HF, virtually all of the loss is ohmic, and the
Sheesh. Let me try again. To deliver _twice_ the power as a single coaxial line, two coaxial lines operating in "push-pull" deliver the same current at twice the voltage. The same current and twice t
He _should_ have meant that the shields of the two coaxial cables were connected together, both at the antenna end and at the tuner end; at the tuner end, the shields of the two coaxial cables were a
I don't know the loss and power-handling capability of that stuff (for transmitting); but, in small-signal applications, shielded twisted pair is great. A few years ago I considered making 70 feet of
In a web search I found several manufacturers of hollow plastic balls, in a range of sizes. An attractive possibility would be cylindrical "plugs" an inch or two long, of polyethylene or polystyrene
1. Make a short, fat, low-inductance connection between the shield of the coaxial feedline and the metal of the garage roof at the feedpoint of the antenna. (Otherwise too much current will flow on t
Jim's comments are valid, and important. I regret that I did not qualify my reply to your question by making the same points. A short, low, vertical antenna will never work as well as a horizontal di
I think they like the texture/chewiness more than the smell/taste. Gray squirrels have chewed off the sheet lead flashing around my chimneys; and, last year chipmunks chewed completely through not ju
I covered my tower with color LCDs from junked laptop computers. I drive the LCDs with video signals from an array of LCD cameras, so the tower always looks like its background, day or night, cloudy
It's a jungle, or a minefield, out there. A whole lotta snake oil being peddled. OTOH, you'll find a lot of good reading at <http://www.cebik.com/> That's plenty of room. That's not too bad. Plenty o
Thanks for the pointer. I'm reading that thread now. To date, _has_ anyone (incl. you) tested any LP by means of the protocol that you have developed and used to test various tribanders? And, if so,
Has anyone here measured the ratio between the (undesired) common-mode current on the feedline from his transmitter to his antenna, and the (desired) difference-mode, in other words the transmission-
It's nice to hear that someone else thinks it's interesting. :-) I agree. I probably would not have done it myself, had I not been able to borrow the instruments. As you've probably guessed, I suspec
I agree. Because the impedance of a common-mode choke approaches zero as the frequency approaches zero, it tends to be difficult to achieve effective common-mode choking at low frequencies. Because t
Good question; thanks for asking. I'll answer in two parts because there are two distinct issues, relating respectively to the common mode and to the difference mode of transmission on an open-wire l
The effectiveness of this method depends critically on the impedance of the "ground" connection between the chokes. A low-impedance ground is difficult to get at higher frequencies. For a quantitativ
I agree. I've found _no_ measurements of actual field situations. That's why I asked whether anyone could point me to anything. So far, nothing. 73 de Chuck, W1HIS