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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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0 votes
4 answers
104 views

Running antenna parallel to steel fence: antenna effects and neighborhood RFI

I am moving into a 55+ community, relatively small lots, single story frame and stucco homes in close proximity to neighbors. However, one edge of the lot is parallel to a golf course and has a steel ...
1 vote
1 answer
42 views

NEC2: Should I model a "tube" or just solid wire (GW) for an aluminum-tube-based antenna design?

I'm considering using this 1/4" aluminum tube to build a cross-yagi antenna in the 2m band. The tube dimensions are 1/4" OD x 1/8" ID x 1/16" Wall (.250" x .120" x .065&...
2 votes
1 answer
121 views

Insulated mounting pole section for vertical dipole?

I am considering improving my 2m vertical dipole by replacing the top section of mounting pole with non-conducting tube. Will this have a positive effect on gain? I am theorising that the downward ...
0 votes
0 answers
34 views

End Fed 160-10 meter Antenna

The antenna as shown here has a counterpoise, but I can't remember how long it is. Its shape is dictated by what trees and distance I have available. It tunes 160 meters ok with my auto tuner. ...
-1 votes
1 answer
427 views

How does nitinol shape memory wire work as an Antenna in 60 MHZ whip antenna?

I'm trying to make a body whip antenna for some friends of mine running at 60 Mhz at 10 W power. We are in the military, and we are trying to make an antenna that can be routed through our gear to ...
1 vote
1 answer
52 views

Any better alternatives to bullet connectors for connecting outdoor antenna wires?

I build antennas and sometimes have a need to repeatedly connect and disconnect wire antenna elements, such as loading coils and radials. It is especially the case for portable antennas. I have been ...
-1 votes
2 answers
60 views

Is the TAOGLAS PCB Antenna Too Long on Purpose?

I have been using a TAOGLAS 915MHz PCB antenna for my remote control. I'm about to redesign the PCB and wanted to try including my own PCB antenna on the board. For the 915MHz band, a quarter ...
0 votes
1 answer
59 views

Configuring an antenna for (short distance) ground wave propagation on 40 m?

I'd like to use 40 m for short distance (ground wave) QRP CW. My criteria for antenna selection is simple: Works short distance (ground wave) As simple as possible As small as possible Ideally, some ...
0 votes
3 answers
95 views

Formulae for monopole antenna inductance/capacitance

I am looking to make a wire antenna for a transceiver module I have. My target frequency is ~915MHz, and so with a quarter wavelength model I should be using an antenna of ~81mm. If I wanted to use a ...
2 votes
1 answer
118 views

Two different dipoles attached to three trees

I wish to erect two separate antennas, one 20 meter dipole and one 40 meter dipole. My property has 3 trees that are the correct distance apart from each other. They are oriented such that when the ...
3 votes
4 answers
1k views

Help designing a random wire antenna to work with my tuner

I recently picked up an Icom M802 marine HF radio that includes ham bands and an Icom AT-140 antenna tuner. I have a ham license, but have been away from HF for many years and have never used a random ...
1 vote
0 answers
121 views

End fed half-wave dipole only measured 5 ohms

This is a bit unusual but I am trying to diy a simple high impedance antenna running in 2.45GHz, for some explorations in ultra-narrow band applications in WiFi. And I have heard in ham radio ...
2 votes
1 answer
86 views

Tuning a coil shortened 1/2 wave dipole for 80 meters

I've built a shortened 1/2 wave dipole for 80 meters to fit my lot in town. 90 feet total length. Using the calculator at K7MEM.com I opted for a 36 ft. and 9 ft. section (45 ft. on each dide of the ...
1 vote
3 answers
243 views

450-ohm ladder line fact vs fiction

I am considering many possible doublet antenna scenarios for a multi-band antenna (80 meters to hopefully, 6 meters) customized to my specific home situation. Everything is a compromise. I will be ...
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 ...
0 votes
1 answer
1k views

Lightning Antennas 4 Element Quad Feed System Validity

I recently purchased a 4 element quad for 10 m from Lightning Antennas in USA. The antenna is designed to be mounted so the elements are diamond shaped. Notice in the picture how nice and straight the ...
0 votes
1 answer
103 views

Converting a 470-694Mhz TV antenna for 433Mhz reception

I'm working on a project which requires me to pick up LoRa signals that will be transmitted from a relatively low gain antenna. I've figured out that a large dipole would be idea for the receiver ...
2 votes
2 answers
237 views

What type of metal, length & diameter should i use to build a vertical antenna to listen to airband frequencies (118-137Mhz)?

I recently purchased RTL-SDR v3 dongle along with antenna kit. I used 60cm each length and built vertical dipole antenna with boom length of 58cm and listened to airband frequencies.The closest ...
0 votes
1 answer
61 views

Radials with centre-loading coil

Does a centre-loaded HF antenna need radials? If I put a loading coil 1,5-2m (5-6,5 feet) high, do I need to put radials out on the ground? Feed point would still be near the ground.
4 votes
2 answers
854 views

How to make a 1:2 UnUn

Does anyone have a drawing or instructions on how to make a 1:2 unun like the one in the picture below ? I searched this question on this site and on the internet with no luck.
6 votes
3 answers
2k views

Does an End-Fed Antenna need to be straight?

Typical yard and wondering if I can go out a window, to a tree, turn to another tree, turn to another tree simply trying to achieve the length required for 80m band? One video stated it doesn't need ...
3 votes
3 answers
864 views

How to make ELF-ULF antenna myself?

I want to check the EM pulse between 3HZ-3kHZ with N9041B UXA Signal Analyzer,it seemed the only antenna I can use is Aaronia MagnoTRACKER,but the price is not affordable. Then I plan to make ELF-ULF ...
0 votes
1 answer
218 views

Need help installing long wire antenna for shortwave reception

I have 70 feet of bare wire running from a tree up about 14 feet, sloping down to my house and then running at a 45 angle under my soffet and then down to where I'm hooking up to a 4:1 unum and ...
1 vote
1 answer
753 views

How to Construct a Dual Polarization Cubical Quad Antenna for 10 m?

I want to make a four element diamond quad for 28 MHz which can be switched between horizontal and vertical polarization. The spreaders would be made of fiberglass. The coax for the driven element has ...
2 votes
3 answers
115 views

Find the the geographical North for yagi setup

I am setting up a 435MHz cross polarized yagi antenna on Yaesu rotor (for both azimuth and elevation). The application is satellite tracking. The beamwidth of my antenna is 20 deg horizontal and ...
5 votes
3 answers
3k views

Does a receiving antenna need radials?

I am very new to radio and am using two 433MHz 1/4 wavelength monopole antennas to send and receive data. On the transmitting antenna I'm going to add radials (as it is the standard in my application)...
-5 votes
1 answer
220 views

Why are fibreglass type base antennas seemingly more susceptible to lightning strike? [closed]

Fibreglass antennas with the radiator inside are apparently more prone to lightning strikes. Is this true, and is there a scientific reason as to why?
3 votes
1 answer
372 views

What is the antenna design and gain for the WA1 U/V band antenna on the ISS?

My son KJ7NLL is working to contact the ISS using an antenna we built together, and we were wondering the approximate minimum transmission power to reach the ISS. If I understand correctly (and ...
3 votes
3 answers
375 views

Dipole antenna using current on outside of coax as intentional radiator?

Is there an antenna design somewhat like a coaxial dipole, where the coax ends in a quarter-wave radiator, but instead of an explicit coaxial radiator running back over the coax body, the outer ...
3 votes
3 answers
375 views

Advice on constructing half wave dipole with reduced velocity factor for site that is not quite big enough?

I want to construct an antenna competent on the 160m band, but I haven't got quite enough space, here's my thinking, please let me know if/what you agree/disagree with. I have a plot of land with ...
2 votes
1 answer
246 views

Portable indoor VHF antenna for SDR

I want to make / buy VHF antenna that can meet the requirements below: Portable (easy to install and transport). Indoor (I want to install the antenna at a windowsill). Low noise level, no (or not ...
2 votes
2 answers
208 views

Why does my 7 MHz antenna trap have an SWR of 8?

I made a 7 MHz antenna trap. On testing it the cut-off point was 6.687 MHz which is about right but the problem I've got is the SWR was an 8 and wouldn't go down to a resonant SWR. What have I done ...
2 votes
2 answers
567 views

Can I use different materials when building an antenna?

I'm thinking about building a 3-element beam using EMT for some parts and then steel tubing at each end to get the length of element I need. EMT will give the antenna more back bone but still give me ...
1 vote
1 answer
135 views

Combining antennas

Is it possible to combine 2 antennas, each being half the length of a normal antenna for a given band. To be connected to 1 mobile radio. Giving you 2 shorter antennas rather than 1 long antenna, ...
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" ...
4 votes
2 answers
3k views

Putting up a tower on my residential property

I live in upstate South Carolina. I contacted the city and the person who answered the phone call said it would be a new structure and can't be higher the the house on the property. I looked at the ...
3 votes
1 answer
253 views

How to passive amplify signal from outside to inside?

I have a house in the mountains, with very thick walls (they are old-fashioned houses). Outside the balcony, I get the full 4g signal, while just inside, I get almost nothing. I would simply use 2 ...
0 votes
1 answer
527 views

LTE (4G) - Is two (or multiple) antennas better than one?

I have two antennas. A "multiband" (1710~2170 Mhz, 22 dBi)... ...and a "fullband" (700~2600 MHz, 15dBi)... Taking into account that my modem (router) is "fullband" and ...
6 votes
3 answers
938 views

Is a boom important to a Yagi?

I am trying to make a yagi for a 900M. The tinkering starts causally with some 1.2mm welding wire (cut to size based on K7MEM yagi calculator, direct soldering, no special matching as suggested on ...
2 votes
1 answer
174 views

Converting an FM Antenna to a 2m/70cm Transmitting Antenna

I have a 2006 Honda Goldwing 1800 with an extra FM antenna that I would like to convert to a 2m (or 2m/70cm) transmitting antenna. Changing the connector to a PL-259 seems to be the easy part and I ...
2 votes
1 answer
182 views

Spacing Between Antenna Ends and Mast

How do I determine the amount of space needed between the end of a wire antenna and the mast? Edit: End-Fed Antenna Steel pipe one each end
1 vote
2 answers
198 views

What antenna is in this cylindrical vertical omni

Recently, I have received an antenna from one of the Chinese manufacturers and they haven't disclosed the detailed specification. Below is the picture of my antenna (please ignore the specification in ...
6 votes
2 answers
1k views

Why don't J-Poles need to be grounded?

I'm building my first J-Pole and the different projects and articles I read about differ slightly but one commonility is a J-Pole does not need to be grounded. Why is that? I read that it is optional ...
3 votes
2 answers
180 views

Will spray painting a J-pole impede functionality? [duplicate]

I'm building a J-pole antenna like the one specified here: https://www.sysjolt.com/2022/building-a-j-pole As you can see it's made of copper pipe and I'd like to camouflage the antennae a little bit. ...
3 votes
1 answer
249 views

Connection for Moxon antenna (blank space)

I just printed a Moxon Antenna and want to wire it. The Antenna wiring has a blank space and I'm not sure how to wire this place. From picture bellow I got that I need to connect a coax shield to top'...
3 votes
3 answers
611 views

Magnetic loop antenna : loops vs selectivity

I've built 2-turn magnetic loop RX antenna using 5 meters of 6.5mm copper tube. I was able to tune it with a variable air-spaced capacitor in the range of 1.8-10Mhz, but I noticed that as tuning ...
1 vote
1 answer
239 views

How to splice a 12 gauge, stranded wire to a ladder-line stranded wire?

I am building a zs6bkw dipole using a ladder-lock. For mechanical strength, I am looping the 12 gauge wire, as in the image below, and swaging it. The next step is to join the thick antenna wire to ...
3 votes
2 answers
255 views

What kind of crimp part is used for stress relief on dipole?

I like the way that the person provides stress relief for the dipole antenna wire in the following image. However, I cannot figure out what kind of crimp "device" they are using for making ...
0 votes
0 answers
78 views

LTE (4G) - Which external/outdoor antenna type is the best?

I've seen several antenna types out there, but I can't know for sure which model is the best for external/outdoor LTE (4G) use. I have to say that I don't understand anything about LTE (4G) antennas......
0 votes
3 answers
117 views

How does the waveform of electromagnetic wave affect the design of an antenna?

This is a question I thought about when trying to understand a design of an antenna. For different kind of waveform of electromagnetic wave propagating through space, how does one modify an antenna ...

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