Hello to all, In the ARRL antenna handbook they show where you can use two coax lines as a balanced line. Only the center conductors of the Coax are used. The article covers the new impedance of the
The losses of the dual coax will be comparable to that of a single coax run. For lower frequencies, the ohmic losses dominate (skin effect, predominantly) over the dielectric loss (at least until you
The dual coax setup will have no more loss appreciably than the twin lead. It essiencially becomes shielded twin lead. Remember that the shield from the 2 coaxes is NOT connected at the antenna end.
i don't think so. there is still the conductor there and the dielectric is between them. you can't get rid of the capacitance between them, nor can you get rid of the losses in that capacitor. i wou
Hi Boys, Anyone of you actually used coax in this configuration? I have. Fed a 40m loop, tri-band Quad, mono-band beam and 160m dipole. The loops were fed with the shields tied together at the antenn
I agree with K1TTT's comments, below.. comments interspersed.. Jim, W6RMK -- Original Message -- From: <k1ttt@arrl.net> To: <towertalk@contesting.com> Sent: Tuesday, July 29, 2003 6:30 AM Subject: Re
Actually, it depends on whether or not you connect the shields together at both ends. If you don't connect the shields together at both ends, then current can be capacitively coupled from the center
Mike is exactly right... Looking at loss as a dB/foot for the coax, you divide the power into two pieces of coax, so the absolute loss (in watts) will be half in each piece of coax, but you've got tw
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
Now I am really confused.. enough of the facile quick stuff.. time for the rigorous analysis.. stay tuned, but more facile analysis below But half the power flows through each line, no? and, half the
Don't feel bad, Jim. I went to bed last night thinking that it was 1/2 the loss, but when my head hit the pillow I started to imagine two separate generators (one driving each coax with 1/2 the total
Hello, In the early nineties, I installed a fairly equilateral, 75 meter delta loop utilizing the paralleled and taped coaxial feedlines described. The loop was fed with 2 each RG-62 lines (93 ohm co
What is really meant by, '.. tied together ... but not connected... '? Also, if you twin lead is, say 600 ohm 6in apart do the centres of the coax have to be 6 inches apart ? Chris opr VE7HCB
I am wondering what the impedance would be if two RG8X coax cables are right alongside each other... this would be easy to fabricate... either some tape or heat shrink every few feet would make a cle
Once the signal is "inside" the coax, it matters not how far apart they are. The impedances are determined by the coax. However, from a spurious currents carried on the outside of the shield standpoi
100 ohms.. 2 * 50 (or 104 if RG-8X is 52 ohms.. it's probably not controlled that well anyway) They actually make coax "zip cord". I don't recall the number, and it might be more expensive than 2 RG-
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
If signal pickup is the criterion, why not use shielded twisted pair such as the RG-22 series. We used it at Coast Guard LORAN stations to minimize pickup of the megawatt LORAN signal on the receivin