Hi Dave, Mutual coupling is what happened. The antennas couple power through the air from one antenna to another. Because of the phase delay in space, and because of the delay line that is NOT shifti
Conference," basic I'll vote for that. The correct grade of Locktite (the softer for breakable bonds) will accomplish everything than needs to be accomplished, and be faster and easier. 73 Tom -- FA
As Ian says, the new Handbooks have a much better handle on phasing. Unfortunately, the wording is a bit unclear unless you already understand what is going on. At least in the sections I have read.
Hi Dick, I haven't seen the Comtek, so I can't comment on it except to say many people are very happy with it. I have no idea what they do, but it obviously works. Speaking of typical phased antenna
Hi Eric, This is gone so deep into your specific antenna, my points to the people considering an HF J-pole are probably missed. My points are.. 1.) It is easy to "mess up" a J-pole, because it is a *
Bill probably spends a lot of time listening to weak DX. the Which goes back to my point, directivity is more important than gain for receiving at HF. For transmitting, a clean pattern with minimum s
Hi Scott, come desired antenna or At HF or lower, directivity of the antenna (which does NOT consider efficiency, just the sinX/X patterns) and NULL depth improve receiving capabilities. Gain has not
I just strip off the jacket for an inch, and lay a 1/2 inch wide copper foil along the braid with two flying (free) ends. I tightly wrap the shield to the foil with a single flat layer of thin CLEAN
When the diameter of an antenna changes, stuff happens. When the diameter at the feedpoint is thin and the outer ends large, bandwidth increases and the antenna has a nice current distribution. Thin
Hi Bill, If you use resonant elevated radials, and only a few radials, grounding to the building can actually HURT your signal. Expect about 4 to 8 dB less signal with a small elevated system when co
Hi All, Who makes slip rings for towers? I want to rotate a 55G tower. I know about RTS, and have a catalog. Are there any other vendors? 73 Tom -- FAQ on WWW: http://www.contesting.com/towertalkfaq.
Hi Mike, Absolutely. Gain actually goes up as spacing is made wider, up to about .65 wl spacing. No change in phase is needed, assuming you are using the array broadside (it will fire in the same dir
I agree with Dave's suggestion!! If you spend time with a Smith chart and various input impedances you'll see multiple SWR dips all over the place as you trim a mismatched system. You might wind up w
Hi Pete, The suggestion... You ask: only Definitely not. If the far end is open, the measured Z becomes maximum at multiples of 1/2 wl (not minimum). Maximum Z measurements are more subject to instru
coming from (even harmonic multiples of the basic half wave length, in this case corresponding to 1.808 mHz). 5.401 mHz must then be the 3/2 WL point, correct? This would be consistant with the othe
Immeasurable without of lab instruments. In the hundredths of a dB. switching I assume you have a RCS-8V. In that case, the loss is Immeasurable without lab instruments. In the hundredths of dB. Eve
Dick, I've not read the AEA manual, but it should warn you about the method used to measure able loss. That loss method is dependent on cable Zo. With connectors and relays in line, you will have imp
Hi Bob, The AEA unit, like the MFJ unit, measures SWR to determine loss. Return loss is easily determined by any instrument that measures SWR, and transmission loss is 1/2 of return loss when the far
filters. noise I effect. I think marketing and folklore has us all convinced stubs are lossless. Just like lumped components, ALL stubs have loss. Coaxial cable stubs can be particularly lossy. They
Hi Jim While that can be true, it isn't a "rule". Bandwidth is determined by more than losses. Measuring BW to determine efficiency can be very misleading. For example, my highest efficiency 160 mete