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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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2 answers
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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 ...
dlowrey's user avatar
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0 answers
29 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. ...
Bill Smith's user avatar
1 vote
1 answer
40 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&...
KJ7LNW's user avatar
  • 759
1 vote
1 answer
51 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 ...
gschro's user avatar
  • 344
-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 ...
user98055's user avatar
0 votes
1 answer
58 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 ...
SRobertJames's user avatar
2 votes
1 answer
116 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 ...
Tony565's user avatar
  • 21
0 votes
3 answers
94 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 ...
user98055's user avatar
1 vote
0 answers
120 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 ...
Xingda Chen's user avatar
1 vote
3 answers
233 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 ...
Michael's user avatar
  • 13
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 ...
ah6pilot's user avatar
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 ...
Hristos's user avatar
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.
S54KZ's user avatar
  • 1
0 votes
1 answer
216 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 ...
bolson437's user avatar
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 ...
Alex Mac's user avatar
-5 votes
1 answer
218 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?
Francis Archibald's user avatar
3 votes
1 answer
369 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 ...
KJ7LNW's user avatar
  • 759
2 votes
3 answers
114 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 ...
enemra's user avatar
  • 69
3 votes
3 answers
374 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 ...
spl's user avatar
  • 265
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, ...
Jake Koenig's user avatar
3 votes
3 answers
373 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 ...
ralph vanhoek's user avatar
2 votes
2 answers
562 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 ...
Zane Lile's user avatar
3 votes
1 answer
250 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 ...
stighy's user avatar
  • 133
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 ...
Mot's user avatar
  • 61
2 votes
1 answer
172 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 ...
Duane's user avatar
  • 21
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
jake9wi's user avatar
  • 121
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 ...
john_ham_radio's user avatar
6 votes
3 answers
933 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 ...
Ben's user avatar
  • 163
3 votes
2 answers
179 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. ...
john_ham_radio's user avatar
3 votes
1 answer
244 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'...
Marcel Kopera's user avatar
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 ...
A Bit of Help's user avatar
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 ...
A Bit of Help's user avatar
0 votes
0 answers
77 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......
Eduardo Lucio's user avatar
0 votes
1 answer
523 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 ...
Eduardo Lucio's user avatar
1 vote
2 answers
65 views

Relation of Emitted Wave in Far Field Regions and Radiation Pattern with Antenna Design

As this post from electronics stack exchange suggested, EM wave emitted by the antenna tends to become spherical waves(plane wave with a local analysis) in the far field region regardless of the shape ...
Felix's user avatar
  • 111
0 votes
1 answer
421 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 ...
Mackdice35's user avatar
0 votes
3 answers
116 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 ...
Felix's user avatar
  • 111
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 ...
ALEX's user avatar
  • 21
3 votes
3 answers
161 views

Serial Inductors in Tuned Circuit - Elenco AM780K AM Radio Kit

I'm trying to understand a component of an AM radio kit that I have. (There is a document available here: https://www.elenco.com/wp-content/uploads/2017/10/AM-780K_REV-K-2.pdf describing the build ...
Jared's user avatar
  • 201
1 vote
2 answers
139 views

2M antenna considerations / options for back-country emergency use

I fly a small airplane over the Rocky Mountains and carry a handheld 2M band transceiver with the idea that it might help me get rescued in an emergency landing situation. We have pretty comprehensive ...
Toby Eggitt's user avatar
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 ...
Krishna Kanth's user avatar
0 votes
3 answers
519 views

SMA Connector Impedance

I am new to antennas, and am trying to create a monopole that connects to an SMA female to transmit a 2.4ghz wifi signal. I know that the antenna needs to be a multiple of 3.1cm in order to have the ...
Saveer Jain's user avatar
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 ...
Jim Archer's user avatar
4 votes
2 answers
532 views

Is Army surplus steel wire suitable for an antenna?

I have a whole spool of military communications steel wire that I've been thinking about using to string up a doublet. We used this stuff when I was in the 138th Signal Btn and let me tell you, it's ...
Dax's user avatar
  • 453
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 ...
chris cutting's user avatar
1 vote
1 answer
116 views

Centre pole construction for 20 metre half wave dipole

I am about to embark on the construction of an inverted V half wave dipole. It will possibly be multi-band but, for the moment, I want to build it for 20M. Because of the shape of my property, I would ...
jonel's user avatar
  • 11
1 vote
1 answer
267 views

Feedpoints for stacked antennas?

I'm considering building some stacked 70cm quad antennas (home brew / DIY build) -- and... I'm having a devil of a time trying to figure out how/where to feed these antennas. For a single home-brew ...
Alan T's user avatar
  • 11
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 ...
N4LEP's user avatar
  • 41
4 votes
2 answers
440 views

DIY Short Vertical Wire Loaded Antenna: Using 20 Ohm Resister to Widen Q

I've been working with Xnec2c to model a 40 meter vertical antenna I want to build for field QRP. This antenna is short at 25 feet and uses a 1:1 unun at the base with 4 radials. The model has the ...
wbg's user avatar
  • 301
3 votes
1 answer
520 views

Using threaded rod for VHF radials

I've been thinking about building a VHF antenna using stainless threaded rod for the ground plane's radials to mate with a hub I already have. My theory is that will make life easier than trying to ...
user3486184's user avatar
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