Hi Steve, The best antenna is one that makes the user happy, no matter how it really works. With a few misused terms that sound official, like "critical coupling" or "radiation resistance", an antenn
Hi Jim, <snip> This did go on for a while before. The problem is complex. While inductance is lower, resistance is higher from non-uniform current distribution (as in a flat conductor) for a given su
Hi Bill, This is an unimportant point for results, but something that always "bugs" me. RF transformers and cores get hot because of flux density and high loss tangent in the material, they usually r
Hi Bill, I don't understand what any particular sequence of beads would do, since they are all in series without shunting components to "sap off" current. RF is just like low frequency circuits so fa
Hi Bill, I wonder about that also. Roy Lewallen and a bunch more besides me would sure like to see one do that first hand!!! I have had beads in closed areas do that when hung vertically, the upper b
Hi Mike, Yes, that would be the most direct path for common mode current return...since the open end of the coax is the source. 73 Tom -- FAQ on WWW: http://www.contesting.com/towertalkfaq.html Submi
I have to agree with those who say the transmitter most likely is not at fault with a TV on CATV. Normal signal levels are generally far above 0 dBmv at the set terminals. Harmonics from any rig are
Hi Ted, Keep in mind the bandwidth of the cable, where it acts like an exact 1/2 wl section, goes down as the length of the cable increases. Because of that, you want to "TUNE" the cable on 28 MHz. A
Hi Jim, You are "in a pickle". You have a complex problem, and it is an area where there is almost no data. One thing is for sure, elevated radials are critical systems. They radiate and couple quite
Hi Pete, Yes The picture gets more complex with real-world antennas and Yes it does, but it also gets unpredictable. SWR bandwidth might get better, worse, or stay the same. Center frequencies might
Hi Ted, With 112 feet, you won't have a half wave on 160. A length about that long would be OK for the other bands. Just be sure the VF is what you think it is, because a very slight error can totall
Hi Con, To: <towertalk@contesting.com> purely If the transformer is perfect, the impedance is changed by the turns ratio formulas you gave. With a 100 ohm R and 100 X load through a perfect 4:1 trans
designed usual instrument for Use a small 12 volt light bulb Con. Run your rig into a dummy load, through a T connector (or use the W8JI method of splicing in, it works just as well below two meters
Hi Bill, Why use the return loss feature, instead of the more accurate reactance mode? Or are you cutting the stubs as a "package deal" into an absolutely perfect test load and pruning for a repeat o
-- To: <towertalk@contesting.com> attention to the lengths. I just thought I would accept the raise in SWR because it should only be about 1.5 : 1 increase. The SWR on the 75 ohm line is only 1.5 : 1
is the should and Not me. Zero is a pretty extreme case! Zero failures is a good goal for nuclear bomb detonators, but not my stuff! I balance cost with life, performance, and ease of installation.
See my reply on the CATV line! The SWR on the 75 ohm line might be 1.5:1, but the SWR presented to a 50 ohm system at the end of the 75 ohm line can be the square of the mismatch at the input end of
Hi Brian, top of about cost What is high power? What frequency range? The RCS-8V is a pretty darned good value. While rated at 5 kW...it will handle 10 kW into 50 ohms if you replace the connectors w
Good point Roy! Concrete is a lousy conductor. If you are depending on a ground connection through concrete, you are in deep deep trouble. I've seen a tower pier explode after someone removed ground