David, the simple way to determine the voltage at the top of your top loaded vertical is to take the antenna current at the loading coil and multiply it by the loading coil reactance. This gives the
David, the relay will work but you don't necessarily need one. The antenna should cover 160 and 80 meters as is. To bring it into resonance on 80 meters a bit of length adjustment might be in order.
The noise figure of an amplifier tells us the input referred noise in a 1 Hz noise bandwidth. A 0 dB Noise Figure (NF) tells us the amp input noise is -174 dBm. Convert the noise power of the amp out
Art, since it happens when it is not raining or damp we can discard the moisture 'evidence.' It certainly sounds like the core is simply heating. When it reaches its curie temperature the relative pe
Dennis, that is a good question. As you say there are two ways that coaxial cable shield current is induced. Directly when the shield forms the third leg of a 'tripole' antenna, and when current is c
The 130 foot dipole puts great demands on the 4:1 balun. Even if the balun does a good job of the 4:1 transformation the coax will still see a VSWR above 10:1 on every band. The loop, if one waveleng
6' spacing for a 14 MHz 2-ele Yagi-Uda is short and I think the forward gain is 4 dBd. I can run a NEC simulation if you'd like. The TH3 should be about 1 dB better on this band. I don't think there
As can be seen by the fine data supplied, a horizontal loop and a horizontal dipole have about the same take-off-angle. Dave WX7G _______________________________________________ Antennaware mailing l
Paul, yes building a 'real' open line t-line in NEC works quite well. If you want to measure the characteristic impedance make is 45 deg long and measure the reactive portion of the input impedance.
A two band vertical can be built without a trap. The 80 meters vertical is full sized. On top of that sits a coil and a top hat for 160 meters. For proper decoupling the coil (inductance) needs to be
Gary, The Battlecreek is a good antenna. However, It looks like a lot of work though to get the tubing lengths correct before and after the 40 meter trap as well as to tune the 160 meter wire. Here i
Or I should say Art we can write an article or we can all participate. I wrote an article on a 38' 160 meter vertical some years back for AntenneX. Since then I've written 25 or 30 articles for Anten
Shon, The radials can be installed on the ground to several inches under the ground. I would run 30 or more radials 50' or longer. That is three 500' rolls of THHN wire. In the directions where you d
Rudimentary? It depends on what you are modeling. Modeling of future weather patterns, yes that might be called rudimentary. Modeling of semiconductor devices. Not rudimentary. Design, build in silic
Design via modeling, test, and compare is what I do for a living. I do this for my antennas. I don't model, and not test, and not compare. I then write articles about my antennas. 25 or 30, maybe mor
Joe, I model short and full size verticals, build them and they work as modeled. For the top loading inductance I leave about 10% of the loading inductance at the base to account for modeling errors
It sounds like a problem with your receiver. The test is to substitute a different antenna and see if the problem follows the antenna or the transceiver. Dave WX7G ___________________________________
To model this in EZNEC I put the source in the lowest current segment. The ground loss R can be in the next segment. The shunt inductor is olaced in the lowest segment as a load with *Ext Conn* set t
The balun should be a current balun. And it should use two separate cores to obtain the highest common-mode impedance. _______________________________________________ Antennaware mailing list Antenna
Gedas, you are correct. The reported resistive part of the input impedance is the short dipole is the radiation resistance. Dave KH6AQ, formerly WX7G _______________________________________________ A