I am using a Cobra Senior with 100' 450 ohm ladderline run into a 1:9 balun then into a tower antenna switch then into the shack. Running a kilowatt into the antenna. Routing the ladderline is a pain
Ladder line does not "radiate" if the current is well balanced. If your balun is good and your antenna is in "free space", that should be the case, but nothing is perfect. Regardless, you would not w
again, this is the Cobra Senior... googling it , it is found at http://www.k1jek.com/ there are 100 reviews at http://www.eham.net/reviews/detail/3798 it hears well, talks well and tunes everywhere t
It's either luck or maybe he would just have a much better signal if he didn't do that. There is no reason why that should work well. I get good signal reports out of Europe on 160m and my current b
In the case of the Cobra antennas the ladder line section is important to the operation of the antenna itself. They recommend if it is too long or difficult to route that you coil it outside and off
Ladderline does not radiate differential mode current (the power it carries from the transmitter to the antenna). Ladderline DOES radiate COMMON MODE current. So does coax. Common mode current is the
Just wondering out loud here.. If I put a twisted pair (unshielded) or ladder line through the center of a ferrite toroid, would it not choke the common mode currents? I can see this being somewhat i
the common mode currents? Twisted pair through a toroid. _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.c
Recall that common mode chokes work by adding a high resistive impedance in series with the common mode circuit. The primary problem is that there is a LOT of leakage flux from the differential field
Two issues. First, the aforementioned dissipation from leakage flux. Second, a significant discontinuity in the impedance of the line. A closely spaced pair is going to be on the order of 70-100 ohms
Jim, I've seen experimental data for a Guanella current balun, wound on a #43 material ferrite toroid with a bifilar winding, which shows the efficiency as 97% (0.12dB loss) when working into its des
I suppose you get trapped in the flux problem. A classic common mode choke relies on the differential mode flux from one conductor essentially cancelling the differential mode flux from the other, le
No, cancellation is cancellation. _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contest
Yes, but consider this.. A long bar of iron. One winding on one end, the other winding on the other. There's no net flux, but the flux has to travel through the core to actually be cancelled (whether
Recall also that the common-mode circuit for coaxial line is on a separate conductor from those carrying the differential-mode signal, creating a "three-wire" system in which the common-mode current
Think about where the magnetic flux is in a parallel wire line. It is MOSTLY between the two conductors, but it also leaks out around them. Now, wind that line around a core. Most points within the f
On the comments about balun heating/QRO, even for guanella current baluns with lower loss cores like Type 61 or 43: I like this topic, because I've been wrestling with that issue for a 6:1 or 9:1 imp
Unless the widget that's doing the affecting only "sees" the common mode signal. If you were "sufficiently" far away from the pair, the differential mode cancels. We do this all the time to filter ne
First of all, there is net flux due to leakage. In your case, the flux is highly nonuniform and so the bar midplane is the *only place* the fluxes are equal and opposite. Your example is intuitive,
Unfortunately, that's taking the macro view when what's happening is micro. AND, losses are sufficient that the magnetic circuit isn't very close to ideal. The model is better at low frequencies wher