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Questions tagged [antenna-construction]

Materials and methods for building antennas, and design of supporting (non-conductive) structures. For design of antennas themselves, use [antenna-theory] instead.

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Minimum thickness of whip antenna

I'm looking at designing a communication system using very low power transmitter (0.1 W) and operating in the 400 Mhz range. For my uses I think a quarter wave whip antenna would work well, so I've ...
FraserOfSmeg's user avatar
8 votes
2 answers
976 views

Simulating two antennas (transmitter and receiver) using 4nec2 tool

I am trying to find near field mutual coupling affects between two antennas - one being transmitter and other being receiver. The receing antenna is fed with very little voltage (I think, if I don't ...
Shiva Mudide's user avatar
2 votes
1 answer
2k views

Is it possible to determine if I'm adjusting gamma match in correct direction with an SWR meter and if yes, how?

I've recently obtained a Quad Loop antenna for 2 m and 70 cm that's fed through gamma match, as shown in the picture: The shorter metal bars are connected to the hot side of the BNC, while the longer ...
AndrejaKo's user avatar
  • 2,893
6 votes
2 answers
5k views

Tuning/trimming a ground plane antenna

I've built a ground plane antenna with a 19.5" vertical and 4 20" radials. Currently, at 147.135 MHz my SWR is 3:1, clearly not ideal (and even bad for the transmitter!). I'm reluctant to start ...
David Hoelzer's user avatar
  • 1,052
4 votes
2 answers
4k views

Ideal antenna type for FM 2 meters?

Clearly, building a Yagi tuned for 2 meters will likely have the best directional performance. Putting that aside, I'm trying to get information on what antenna type will have the best overall ...
David Hoelzer's user avatar
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5 votes
2 answers
2k views

Dipole versus ungrounded end fed for HF RX

I've built a 2 meter ground plane antenna that works pretty well for RX and has a decent SWR on 2 meters with my Alinco. However, I'm experimenting with SDR quite a bit and would really like to build ...
David Hoelzer's user avatar
  • 1,052
3 votes
1 answer
272 views

Rhombic Polarization Question, provided radiation maps

I am trying to engineer my first antenna to get on the air. I need to hit a repeater 50 miles away at a lower elevation than me so that I can use its IRLP nodes. Would this mean I am looking for low ...
Zeke Legge's user avatar
4 votes
2 answers
1k views

Cross Yagi Antenna Design

What will be the effect if I add the insulation between elements and metallic boom of the cross yagi antenna (where elements from outside of the boom, instead of through boom) and in this case boom ...
0x47-sci-tech's user avatar
-1 votes
2 answers
440 views

Choosing a type of array antenna

I want to design a steerable beam array antenna which has 15 dBi directivity using uniform fed infinitesimal dipole elements at 1GHz frequency occupying physical aperture. Considering that phases of ...
user4621's user avatar
3 votes
3 answers
688 views

WIFI Antenna Design

I have designed a dual band WIFI antenna (2.4-2.5GHz and 5.1-5.7GHz). In 2.4GHz it's completely omnidirectional but with negative gain and in 5.6GHz it's somehow directional but with very good ...
user4621's user avatar
3 votes
1 answer
3k views

How to build the smallest directional antenna (ISM band)?

What kinds of configurations should I try when trying to make the physically smallest 2.4 GHz (ISM band) antenna that is significantly directional front-to-back. "Smallest" meaning in in cm maximum ...
hotpaw2's user avatar
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2 votes
1 answer
198 views

Ferrite Rod Price Differences

We are trying to make a VLF geophysics device for our graduate project and we need two ferrite rod antennas (desired length is 6"). Searching on the internet, we have found two ferrite rod suppliers. ...
ecabuk's user avatar
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4 votes
2 answers
2k views

Where does one find high-voltage variable capacitors and inductors for RF? [closed]

I'm looking to start building various antenna tuning circuits, but I'm limited by my parts inventory. I have pots and mag wire for winding inductors and a nice spectrum of fixed-value capacitors, but ...
wolak's user avatar
  • 141
3 votes
2 answers
639 views

70cm antenna for an apartment

I have a blind friend who can't put anything outside, and is restricted to antennas near the window in his apartment. Luckily he lives closer to the top, which helps with range a little bit. He has a ...
Skyler 440's user avatar
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2 votes
1 answer
700 views

Vertical dipole as a mobile antenna counterpoise?

I have a NMO mount antenna- 1/2 wave on 2 meters. I am going to stick it on top of a PVC pipe which is 5 feet tall. Since this is a bicycle mobile antenna, I do not have the option of large radials ...
Skyler 440's user avatar
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3 votes
1 answer
606 views

Trap dipole tuning up on the wrong band

I'm building a trap dipole for the high HF bands, 10 / 12 / 15 / 17. So far what I've got in the air is: The 10 meter section (4.92 meters, 16.14 feet, resonant at 29Mhz) The 10 meter traps (...
Turingrad's user avatar
5 votes
1 answer
2k views

Connect Printed Yagi-Uda Dipole Array with Balun to coaxial cable correctly

I am making the Printed Yagi-Uda Dipole Array with Balun (that is the full name). I used Antenna Magus to calculate dimensions. I am not sure how to properly connect it to coaxial cable. Here is what ...
Triak's user avatar
  • 153
10 votes
1 answer
7k views

How to design a rubber ducky antenna

I am attempting to design an antenna for a 162.4 MHz omni receive only application and am confident it is going to be difficult if not impossible. I have very tight specs on space(6" diameter by 3" ...
Josh Cox's user avatar
  • 241
3 votes
1 answer
2k views

Dual-band yagi on single beam: element positioning

I'm planning to build the WA5JVB Cheap LEO Yagi, which is basically a 2M and a 70cm yagi on the same beam for handheld or tripod use. I'm thinking to do a 3-element 2M and a 5-element 70cm design, ...
David KF4MDV's user avatar
13 votes
5 answers
11k views

Is an antenna analyzer necessary for building antennas?

I'd like to try my hand at building a few antennas for VHF/UHF use. I'm going to be going approximately from established designs, but obviously the final result will require some tuning. I don't ...
David KF4MDV's user avatar
6 votes
3 answers
10k views

What is the velocity factor of a wire?

This is Belden 9223. It is a 50-ohm coaxial cable, velocity factor 0.56 This is Belden 8524. It is a 22 AWG hookup wire. No velocity factor in the datasheet. Why does the coax datasheet have a ...
Phil Frost - W8II's user avatar
12 votes
3 answers
14k views

Protect rig from static charge on antenna

How can I continuously discharge static from my end-fed antenna? My Electraft K2/100's autotuner (schematics) has an SWR bridge using two 1N5711 pin diodes. These diodes get blown if any static ...
Wayne Conrad KF7QGA's user avatar
4 votes
2 answers
370 views

Recommendations for starting out with HF for an amateur

I'm a beginner who's nearly half a year from receiving my ham license in India. I want to start with HF radio and wish to build my own rig. Currently I have looked and multiple designs using the ...
Parth Sane's user avatar
2 votes
3 answers
2k views

How to shorten the length 50 ohm characteritic impedance antenna cable

I have two 50 ohm characteristic impedance cables of which I need to shorten their length to compact my design. (put everything in to a box) The cables I need to shorten are the GPS & GSM antenna ...
Denis's user avatar
  • 702
4 votes
2 answers
256 views

Antenna Design for specific directions

I am designing an antenna for a device and was hoping to gain some insight in the correct design direction for the antenna. The Idea: A receiver & antenna that fits in a 6" diameter by 3" deep ...
Josh Cox's user avatar
  • 241
11 votes
2 answers
771 views

How to determine if my antenna is an effective radiator?

So I build an antenna, tune it with the SWR and make it look great for a 50 ohm load. That does not determine if it is good at getting a signal out or not, it could just be a 50 ohm dummy load. ...
Skyler 440's user avatar
  • 7,620
6 votes
4 answers
879 views

Weather-proofing antenna connections

Here's a problem: you buy a fancy new vertical for a fair bit of coin, but there's no coax connector on the thing. There are just screw terminals. You need to attach coax to it, but in such a way ...
Phil Frost - W8II's user avatar
11 votes
1 answer
3k views

How to combine two 50 Ω antennas such that they appear as one 50 Ω load?

I'm looking for a simple way to impedance match an array of two 50 Ω antennas so that when they are combined they appear as one 50 Ω load. Assume that both antennas are identically constructed, are ...
Ben's user avatar
  • 347
9 votes
2 answers
455 views

Is steel or aluminum structurally a better material for catenaries?

I understand that steel is not a good material for antenna wire, but let's consider that I'm using the wire for purely structural support, or I am cladding it with copper to address the RF ...
Phil Frost - W8II's user avatar
6 votes
4 answers
5k views

Can an HF antenna be put inside a tree?

There are some trees around with branchy tops that seem wider than half of 10M, maybe even half of 20M, and above the nearby rooftops. Can a wire dipole or a vertical be mounted inside a tree? If so,...
hotpaw2's user avatar
  • 13.5k
6 votes
2 answers
6k views

Is copper-clad steel a good material for wire antennas?

There are some people selling steel wire plated with copper for making wire antennas. Perhaps the most well-known brand of this product, Copperweld, makes at least two kinds of copper-clad wire, ...
Phil Frost - W8II's user avatar
36 votes
4 answers
57k views

Effect of different metals for antenna elements

Other than rust, corrosion, and other reactions with air that would make the use of a metal unfavorable, how do different metals affect the performance? Let's give Yagi an example: Let's say I use 4 ...
Skyler 440's user avatar
  • 7,620
6 votes
1 answer
8k views

Noise bridge use in antenna construction?

How does a noise bridge work? And how can a noise bridge be useful in building, testing, and/or tuning an antenna?
hotpaw2's user avatar
  • 13.5k
1 vote
1 answer
5k views

Homebrew 2 meter Yagi construction

Here is what I have • A Baofeng Uv-82 transceiver • A 1/2 inch 10 foot PVC pipe • 3 1/4 inch x 36 inch Aluminum rods • 2 1/4 inch x 48 inch Steel rods (I know they'll rust, it's just temporary to ...
Skyler 440's user avatar
  • 7,620
7 votes
1 answer
1k views

How does aluminum siding on a house affect an inverted-vee antenna next to it?

My two-storey house is wood with alumninum siding. I had wanted to install an inverted-vee antenna with its midpoint hanging from the eave, and endpoints near the ground, but this would place the ...
Cyberherbalist's user avatar
20 votes
2 answers
15k views

How to detect common-mode currents or “RF in the shack”?

Let's say we already know that if your antenna is not suitably constructed or connected then you can get current on the shield of your coaxial feed line which will flow through the shielding/grounding ...
Kevin Reid AG6YO's user avatar
  • 24.7k
8 votes
1 answer
5k views

What's an appropriate core material for a loopstick antenna?

A loopstick antenna, if you don't know, is a coil of many turns around a high permeability core. They are frequently encountered in AM receivers and look like this: This particular example is ...
Phil Frost - W8II's user avatar
6 votes
4 answers
8k views

Does oxidation of the antenna elements have any impact on the signal quality of the station?

So I'm still QRT; apart from a brown-out on the rig, the support on the inverted-vee toppled over in high winds. Thanks to the topple-over I discovered the conductors (SWG 16 bare copper) had ...
VU2NHW's user avatar
  • 2,834
5 votes
5 answers
7k views

What type of solder is best suited for radio and electronic use?

Many types of solder are available today, such as acid-core, silver, rosin-core and aluminum solder. What kind should I use for building antennas and radio equipment? Why? From test question: T7D08
JC Hulce's user avatar
  • 901
6 votes
1 answer
1k views

Are there easier ways to make traps than coax and plastic pipe?

I recently built an antenna for my attic inspired by http://degood.org/coaxtrap/. I found making the coax traps very time consuming and frustrating to tune. I got to thinking about 3D printers, and ...
K9KRB's user avatar
  • 642
9 votes
2 answers
4k views

What is the largest gauge (thinnest diametre) wire I may use as an antenna?

A follow-up to Good wire for wire antenna? I'm QRT at present - thanks to fooling around with just a couple of diodes and PVC capacitors instead of a well-regulated supply. The antenna I used earlier ...
VU2NHW's user avatar
  • 2,834
5 votes
4 answers
1k views

Is string trimmer line suitable for supporting antennas?

In searching for suitable materials for a wire antenna, I found a few mentions of using string trimmer line to hold up each end of the antenna. This would be a nice option as it is readily available ...
W5VO's user avatar
  • 1,921
9 votes
3 answers
24k views

How would I modify a satellite dish to transmit and/or receive to a Baofeng UV-5r plus? ( A handheld transceiver) If it's possible

I have an old satellite dish just lying around and was wondering how to hook it up to my baofeng uv-5r plus.
Sudo_Cats's user avatar
8 votes
1 answer
1k views

Do I need a SWR meter for a basic 2 meter antenna?

I have a 5 watt 2 meter handheld transceiver and want to build a helmet with an antenna, microphone (with VOX enabled) and earpiece for the radio. For the antenna part, I just want to do something ...
Skyler 440's user avatar
  • 7,620
8 votes
3 answers
2k views

Will anodizing or powder coating or wetcoating (painting) antenna elements affect performance?

I want to put up a small tower and beam on my roof, but I don’t want the aluminum to “stick out” and want it to be unnoticeable as possible. I would think black anodizing would be the best solution ...
NT1K's user avatar
  • 81
10 votes
1 answer
1k views

Can I have multiple inverted-vee antenna fed by a single coax?

A friend who recently received his call is planning to setup an inverted-vee for 40/20m bands. Our take is the signal will take the path of least impedance into the correct length antenna wire. ...
VU2NHW's user avatar
  • 2,834
0 votes
1 answer
123 views

Can wood be used to build 6m quad? [closed]

Could I use wood to build 6m quad? If not, what material(s) would be better/more useful?
Timtech's user avatar
  • 2,336
21 votes
5 answers
78k views

Good wire for wire antenna?

What properties should I look for in a good wire for building a wire antenna? Could anyone recommend something specific for me?
Timtech's user avatar
  • 2,336
2 votes
5 answers
2k views

Metal for antenna construction?

What do I need to consider when choosing metal for an antenna? How do I determine what thickness to use?
Timtech's user avatar
  • 2,336
15 votes
1 answer
9k views

What is the purpose of a balun and a unun in a feed line?

I have never understood how a balun or a unun works and under which situation I need to use either of them in an antenna feed line.
Dinesh Cyanam's user avatar

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