New answers tagged antenna-construction
3
That is possible with this constraint: the coupling factor between the indoor and outdoor inductor needs to be high. Otherwise the losses will be high. For limited frequency range there is an option to use resonant circuits on both sides. At the cost of bandwidth reduction there is an almost lossfree solution possible.
This is without the effect of losses in ...
0
For your required distance of 10-20 ft, you might consider first testing a dummy load.
An antenna approaching any kind of efficiency will be larger than the space you're looking to cover.
And any antenna that is portable will closely approximate a dummy load... So try a few wire wound resistors and see what happens.
Will be interesting to see what your ...
5
That is a great idea. In fact antennas of this design are quite common, and you probably have a much smaller antenna of similar construction on your Wi-Fi router:
Effectively, the lower dipole element, which is a tube, forms a "bazooka" or "sleeve" balun. See also W8JI's description of sleeve baluns. I'll let you follow the links for ...
0
If a feedline isn't centered in a balanced antenna's near field, it can couple into the EM near field, pick up induced currents, and thus distort the pattern.
If you feed the feedline into a quarter wave length pipe segment of a half wave dipole, the end exit of that pipe will be a very high voltage node at resonance that can capacitively couple to the feed ...
-1
An electrically resonant circuit or object would be very difficult or extremely large at those low frequencies (possibly county, country, or planet sized).
But mechanically resonant generation of a 1 Hz alternating EM field might be easy.
You can accelerate either a charged object, or a magnet in some cyclic or periodic fashion. Note that according to ...
5
The wavelength at 1 Hz is several times greater than the circumference of the Earth. At these frequencies, one arguably can't even have an "antenna" for terrestrial communication, since any two such antennas would be so close together they would be more like two plates of a capacitor or two windings of an inductor than an antenna.
1 Hz isn't even ...
1
If you are using copper wire, 14 gauge is about as small as you want to get. Be aware, however, that if you hang a long copper wire that thin, it will stretch. This is not a big deal as long as you don't care about its length for antenna purposes.
If you use something like copper clad steel, you can go as low as 16 or 18 gauge and it will still support its ...
3
First check your local regulations. Some specify the minimum gauge for wire antennas. For example NEC Article 810 specifies a minimum of 14 AWG for wire receive antennas. For temporary antennas such a POTA activation using a smaller gauge would be acceptable. I've also know hams to ignore the local regulations. If transmitting check that is can handle the ...
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