This is an ideal application for a common mode choke on the feedline snug up to the antenna feedpoint. As a starting point, follow the guidelines in the Choke Cookbook below. http://audiosystemsgroup
I've always hated these connectors, and the ones that Mouser sells have the added "feature" of melting quite easily while taking solder quite poorly. As a result, it's really tough to solder reliably
A better way of saying what I think you mean is that the laws of physics, biology, etc. are not established by agreement of those who study them. Rather, our UNDERSTANDING of those principles evolves
Let's clarify what we're talking about. If we make a change in the loudness of a sound sitting FAR above the level of other sounds, 1 dB is approximately the change that most people will just hear. B
I assume that 60 degrees is EU from your QTH, and also the direction of the mountain. Aiming your antenna away from the mountain won't get RF around the mountain to EU, it will simply throw less at i
The stress on the balun is due to IMBALANCE in your antenna, NOT due to SWR. See my tutorial on baluns. http://audiosystemsgroup.com/RFI-Ham.pdf Tom Rauch, W8JI, has also written about this. Jim Brow
This would be true of a transformer balun, but not a choke balun. And most dipole baluns are choke baluns. Jim _______________________________________________ ________________________________________
Yes Yes, the core of transformer balun carries the full transmitted power, while the core of a choke balun carries only the common mode current. Jim _______________________________________________ __
assist W8JI has correctly identified the issues with respect to elevated and ground mounting. It's highly dependent on clutter around the antenna, losses in the ground system, the operating frequency
For use on 20-10 meters, wind four turns of the coax through a stack of 7 FT-240 cores made of #31 or #43 material. It is VERY important that you spread the turns as widely as possible to minimize th
I'll bet that the vertical on the metal roof works just fine! Have you tried transmitting through it? Your mistake is thinking that SWR and impedance defines how well the antenna works. WRONG! A vert
You are mistaken. Twisting does NOT reduce capacitance. But twisting is a VERY good thing for rejecting noise pickup, RF pickup, and radiation to/from the signal pair. ALL control wiring associated w
Hmmm. Twisting WILL, of course, increase the LENGTH of the conductors a bit, which will increase the capacitance by that proportion. But the question is, HOW MUCH does it increase? I recently untwis
At the risk of sounding like a broken record, I will point you to the tutorial on my website, supplemented by subsequent measurements of some coaxial chokes. http://audiosystemsgroup.com/RFI-Ham.pdf
It's an optical illusion. There are only five curves -- the traces cross each other. I went back to the Quattro spreadsheet to confirm it. :) Hi Frank, Thanks for the questions. Lots of things have t
Probably for the same reason that it isn't in genreal use in ham radio -- few hams (including me) know about it or know that it is available at low cost. I see no reason why it wouldn't be a good cho
Anything is possible, of course, but coax would have to be pretty awful for enough field from the differential signal to cause significant heating. You can convince yourself of this by winding some c
It has been observed (by N6BV and others) that in most coax, losses are primarily IsquaredR below about 500 MHz, and primarily in the dielectric above that frequency. Obviously, that's a broad genera
A much better way is to add one or two good common mode chokes (some turns around some ferrite cores) to the feedline. See the tutorial on my website. http://audiosystemsgroup.com/RFI-Ham.pdf Study t
I haven't been following this thread up to now, but I'm beginning to see a possible clue to your problems. All I know about StepIR's that they are mostly made of non-conductive structure, and use mot