New answers tagged

-1

Skyler, don't believe the myths which over stress and over complicate the importance of the type of metal used for the elements of a yagi antenna for instance. For all the common types of suitable metal available with which to make an antenna, excluding for very high powered transmitters, in reality it makes little if no noticeable difference which metal ...


0

I think that Brian's answer is very helpful. In this case the tapped inductors do the matching, and the inductor resonates the circuit to remove the net inductance. (The same thing could be done with tapped capacitors and an inductor replacing the capacitor.) This does not assume or require any flux linkage between L1 and L2. If L1 and L2 were windings of an ...


5

It is a 2-meter halo antenna as built by Mike Fedler N6TWW: the image appears to have been lifted from his page describing the build. It's 40" in circumference, and the boom length (slightly more than the diameter) is 14.5" long. It's tuned for 144.25 MHz. The name "halo" comes from a combination of the antenna's appearance and an abbreviation for half wave ...


1

Don't believe the many myths in circulation concerning which wire to use for an antenna. Most of the myths over complicate this very simple subject. In reality, it doesn't make much if any difference what type of wire you use, so long as it's strong enough to hold it's own weight and isn't too thin, you should be ok. I've used copper, stranded, solid, ...


3

That is a horizontally polarized omnidirectional halo antenna. The relationship between the diameter and length (λ/2) is simply diameter÷π. Some halos have a series capacitor to the right (where the picture is cut off). Others are open. Pictures from Google search. They were in common use on automobiles back when 6 and 2 meter AM was popular in the 50s ...


1

There are two properties you care about for antenna wire: 1) Will it conduct well 2) Can it support its own weight. Due to skin effect, cost, conductivity, etc., the best material for conduction is copper. The best material to support its own weight is steel. You can use a large gauge (say, 14-12) of copper wire which will work. For short wires that won'...


0

The antenna on this page seems doable and does not appear to require soldering.


1

Often they are the same antenna electrically. What sets them apart are aesthetics, material and price (unfortunately) as well as other factors. For example, I have a "genuine" antenna purchased from manufacturer-authorized distributor and a "counterfeit" antenna purchased online. I am unable to distinguish performance between the two in a blind comparison ...


1

Antenna performance is not dependent on service or modulation type (waveform). As long as your waveform is inside resonant frequency and bandwidth, the antenna will perform as constructed.


2

If you are interested in space communications (EME and satellites) even small losses are important since losses have room temperature. The sky as well as a good preamp should be well below 100K while losses are about 3 times warmer which makes them 3 times more destructive. When one designs a yagi one can trade between gain/pattern and element losses. The ...


2

The NEC4.2 analysis below compares the intrinsic fields/gains of the same monopole for the definitions and conditions shown in that graphic. Note that the monopole having a 10 Ω path connecting it to the ground plane does not display zero gain in the horizontal plane, then gradually rising to more positive values for greater elevation angles above the ...


2

Now I'm using the software 4nec2 (with wine) with the description from DL6GL. With this software you can generate the .out files. I hope to succeed.


2

Some friends of mine and I launched a balloon a couple of years ago. We used an antenna based on the design shown here: http://www.trackuino.org/2010/04/trash-digging-at-its-finest-111-swr-vhf.html Unfortunately, the links are rotting. That page still exists, but the linked photos don't, nor the original reference they used. But the latter was captured by ...


1

A quarter length antenna needs a ground plane, correct. Or at least large conducting plane. The radiation pattern of dipole antenna is just the double (like mirrored) as a quarter length antenna. The RC planes usually have two dipole antennas, that are positioned 90 degrees with respect to each other, so it can cover almost any angle. But for a baloon, ...


-1

Cut down your ground plane radials or counterpoise.


2

Yes, you need a 6:1 balun to feed a folded dipole. It might be a good idea to measure the real impedance of the antenna before making or buying a balun though. The real impedance can be anywhere between 200 and 300 Ohm depending on the exact shape of the antenna, the height of the mast, etc. If you are going to feed an antenna using a coax cable you should ...


2

Is it a "miracle antenna" that will work in any band when tuned with a suitable balanced tuner? No more than a regular dipole. A dipole of an appropriate length, fed by ladder line to reduce the standing wave losses (often called a "doublet") can be pretty close to a miraculous all-band antenna with a little care, a little luck, and a big tuner. A "folded ...


4

Does a folded dipole really have "wider bandwidth"? Some sources say "yes" because that's what the textbooks say, others say "no", based on their real wold experience A little more, yes, mostly just because they are thicker than a simple dipole. The same increase in bandwidth could be achieved by making an ordinary dipole out of sections of ladder line with ...


0

Recently Kevin Loughin, KB9RLW made a few videos about folded dipoles and how they perform comparing to regular dipoles. I believe these videos will answer all your questions.


4

Anyone know of any uses for the cabling The cabling in cellular sites is usually relatively high-quality relatively high-power (for the microwave frequencies 4G uses). If this is actually 4G, Verizon (I think) uses 1900 MHz, 1700 MHz and maybe 700 MHz; it's possible the antenna is multi-band and supports all three, and they'd definitely use cable that ...


1

Location and Height The manual seems to suggest that it would be better mounted outside on a mast. Grounding The manual (page 14) implies that no separate ground wire is necessary. Choke decoupling An Isotron antenna generally should not have any type of choke balun at the feedpoint, even though the feedline carries some common-mode current (and ...


1

CW 4ever. On 80 Meters, not much difference between 15 or 20 feet AGL. The resulting near-vertical radiation would be good for communications around your region. Experience will show beyond what distance the antenna can't reach. When you're done with net business, you can get a couple of thousand additional miles by going on 7 MHz and up. My first ...


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