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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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
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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
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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
144 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
343 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
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2 votes
3 answers
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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
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3 answers
315 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
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1 vote
1 answer
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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
329 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
365 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
209 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
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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
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2 votes
1 answer
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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
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2 votes
1 answer
164 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
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2 answers
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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
794 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
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2 answers
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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
229 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
192 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
201 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
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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
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1 answer
341 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
63 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
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1 answer
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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
107 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
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2 votes
1 answer
228 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
151 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
119 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
213 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
434 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
947 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
436 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
191 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
112 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
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1 vote
1 answer
208 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
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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
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4 votes
2 answers
390 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
460 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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0 votes
3 answers
732 views

ELF antenna receiver build instructions?

I built a vlf receiver in the nineties but good grief, that's a long time ago and have looked very little at receivers since. I'm interested in frequencies from 12 - 18 Hz. Looking at the following ...
SeanJ's user avatar
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2 votes
2 answers
648 views

How do I rewire a simple a.m. loop antenna that became unwound?

This antenna has been around for decades and the design is as basic as can be. Somehow the antenna I'd been using, became unwound. The total length of the wire is 4.9ft. I need to know the proper ...
user11471's user avatar
1 vote
2 answers
247 views

Is a 94' dipole antenna fed directly by coax useful for any particular known purpose?

I'm trying to figure out an old handmade antenna I picked up at a swap meet a few years back. It is a dipole (or "doublet"?) that is both made of coax but also fed by a length of built in ...
natevw - AF7TB's user avatar
2 votes
1 answer
536 views

RG-174 vs RG58 for winding toroid

I'm building a balun for a fan dipole, and this chart suggests 9 turns of RG-58 on two FT240-31 cores will give good performance over the frequency range of interest. However, I don't feel confident ...
RoadieRich AE8RL's user avatar
3 votes
1 answer
130 views

Ferrite choice for fan dipole

I am intending to build a two element fan dipole for 80 and 20m. How should I go about choosing a ferrite toroid and number of windings for the balun, to operate effectively over such a range of ...
RoadieRich AE8RL's user avatar
5 votes
3 answers
1k views

What kind of soldering iron is best for PL-259 (UHF) connectors?

What do you use to solder connectors onto bulk coax cable? Soldering the UHF connector to the coax shield on a PL-259 is described as requiring a bit of "experience and skill" in Dave Casler'...
Dax's user avatar
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4 votes
2 answers
726 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.
Andrew's user avatar
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3 votes
4 answers
2k views

Issues with high SWR on HF Kits EFHW 49:1 UnUn kit

I recently tried assembling a EFHW kit, and some problems came up in testing. I believe this is the kit; I bought it through ARRL: HF Kits website. This is my first time making an UnUn and EFHW kit. ...
nerdenator's user avatar
1 vote
3 answers
168 views

Can ferrite rod antenna be made out of the choke?

I'm reading the instructions on preparing the ferrite rod antenna. If I understand it correctly it is matter of building an LC circuit. My question is: Can the ferrite rod antenna be built using a ...
Hieronim's user avatar
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1 vote
1 answer
371 views

What is the best way to allow for SWR adjustment for a cubical quad?

The driven element of a multi-element cubical quad is usually made of wire, and there is no adjust for SWR. How can adjustable SWR be provided for such an antenna ? Can a gamma match be used ?
Andrew's user avatar
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1 vote
1 answer
671 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 ...
Andrew's user avatar
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1 vote
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 ...
Andrew's user avatar
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