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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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 ...
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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 ...
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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 ...
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1 vote
1 answer
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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 ...
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1 answer
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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 ...
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5 votes
3 answers
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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'...
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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.
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4 answers
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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. ...
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3 answers
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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 ...
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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 ?
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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 ...
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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 ...
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Turnstile antennas with a "single-point feed": what's the antenna theory behind this, and how do I build/model it?

The conventional turnstile antenna uses a 1/4wl phasing line between the crossed elements, to get the required phase shift. 4nec2 includes an example file, though, of a circularly-polarized Yagi using ...
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1 answer
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AM radio cross-talk / hearing strong station everywhere

I've built the M0AYF active loop antenna for my RTL-SDR, using BC847C for the amplifier transistors. There are a couple very strong AM stations here, usually playing music. What I'm noticing is that ...
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3 votes
1 answer
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Parameters needed to calculate inductor value to achieve proper phase delay?

I'm thinking about trying a coil in my collinear 5/8λ antenna, instead of the 3/8λ phasing delay line between the lower and upper elements pictured below. I figure that a coil with a certain ...
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2 votes
2 answers
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How bad is it to make dipole elements slightly helical?

I'm looking to make a dipole for 10 M. TX power won't be more than 10 W, likely less than 1 initially, but I would prefer that it be reasonably good performance for reception. EDIT: After a ...
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1 vote
2 answers
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Antenna Size limits at 2-30 MHz (10 m to 150 m wavelength)

I am interested to know what are the smallest antenna sizes that are efficient transmitters for skywave propagation/ham radio applications. Has anyone been able to design a transmit antenna to work in ...
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3 votes
1 answer
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Phasing stub length for colinear 5/8λ?

I've been designing a "Super J-Pole" for 10M in MMANA-GAL, but I'm designing it having two 5/8λ sections. However, I came across this picture: Various J-Poles types diagram indicating the ...
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2 votes
1 answer
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What kind of wire would be good for a 160m - 40m fan dipole?

I want to know the best copper wire or tinned copper wire for a fan dipole for 160, 75, 40 meters. It would be coax fed and I would like it to handle 1500 watts or more. I would like 65/30 strands of ...
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4 answers
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If I tie antenna wire in a knot, will there be damage to the wire?

I'm building HF kits 80m EFHW kit, and in the instructions it directs you to tie a knot in the antenna wire. I'm concerned of damage to the wire. I have found no source as of yet that indicates if ...
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3 votes
2 answers
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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 ...
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2 votes
1 answer
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What's the proper way to mount antenna mast to the side of a house?

I'd like to mount an antenna mast to the gable end of my house. I was planning for the mast to extend from ~10 feet above the roofline down to the ground. I've seen wall mounts specifically for masts, ...
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For a 5'X9'balcony up 12-18 ft I need a good short antenna for 40m USB. Openings ~5x 8 ft to west 5'X4ft to south w/3' metal balustrades

Is there a 2-3 meter long loaded dipole for the USB 40m ham band that I can use on a 2nd floor balcony?
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3 votes
1 answer
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How does the material of a fishing-pole mast affect antenna performance?

I'm a newly-licenced ham and currently starting out with HF. My home doesn't allow for a permanent setup. I can therefore only operate portable from parks and such, with limited TX power (my rig goes ...
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3 votes
5 answers
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How do VHF antennas compensate for change in frequency in Frequency Modulation?

I would like to understand how antennas specifically, compensate for variability in the frequency while receiving FM waves in VHF. The way FM works is that the receiver system - receiver and antenna ...
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Can I use inductive coupling to pass low power (< 50W) VHF transmit and receive through glass?

I want/need to put up an outside antenna, ideally without inviting lightning into the house. One idea that occurred to me was to use inductive coupling to pass signal through the glass of a window, ...
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Troubleshooting range on Lora Radio

I am using these Adafruit LoRa radio microcontrollers: M0 radio paired with these parts to make up the antenna system: antenna connector cable And for some reason I am unable to get much further than ...
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1 answer
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Recommendations for Antennas installation with Steep slopes

I have a property that I am trying to figure out the right antenna setup for. Transmission Goals North of this property is 900 miles to communicate 80M or 40M. Also want to communicate to another ...
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5 votes
2 answers
340 views

Can coax be run through the center of a radiating element without currents being induced on the coax shield?

I run a λ/2 vertical dipole for 20M that's fed to a 1.5:1 balun at its center with coax that is perpendicular to the dipole (parallel to the ground), for about 30 feet before it comes down to the ...
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3 votes
2 answers
398 views

What gauge of winding wire will be "invisible" but sturdy as an antenna?

I plan to build a receive-only longwire/Beverage antenna. The wire will be at least 40m/120' long and strewn at about 7m/21' above ground. Tried "regular" thin insulated wire but it was an ...
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Is there such thing as a center-fed longwire?

I want to make a longwire/Beverage receive antenna that will work on a wide range of bands (80-10m or wider). I've got a place where I can put a wire of at least 50m/150'. The only problem is — the ...
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Generally speaking what might one expect from a J-pole based on PVC covered in tinned braid? [closed]

Would the skin effect provide benefits or would capacitance/inductance cause problems?
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3 votes
2 answers
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Antenna traps - problem with frequency change

I built a two-band antenna (20 and 40m) with traps. I made the traps as a parallel LC circuit on the AL7 toroidal core (3 MHz - 40 MHz), I also used a 1KV ceramic capacitor. I've tuned everything up ...
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2 votes
1 answer
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What might a "split-ring on a printed-circuit board" antenna for 144 MHz on a downward-looking Space Shuttle window look like? How big would it be?

This excellent answer to First Ham Radio contact from space; what frequency, what kind of antenna, and how did they route the coax out the window? in Space Exploration SE contains the block-quoted ...
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2 votes
2 answers
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Hang wire antenna on TV antenna?

I have a TV antenna on the top of my house that I don't use. It is the highest point around so I would like to hang a wire antenna (for HF) on it. Is an inactive antenna going to cause any ...
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1 vote
1 answer
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Unable to tune 20m vertical with trio of Hustler resonators on top

I just built a homebrew antenna that consists of a full-length quarter-wave vertical sized for 20m, with a "top hat" consisting of a Hustler VP-1 and trio of Hustler mobile resonators (RM-...
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2 votes
2 answers
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antenna element with "doubled up" nested aluminum rods for added stiffness

I'm building a full-size quarter-wave 20m vertical antenna (approx. 18 feet long, plus a trio of Hustler mobile resonators at the top to add 30, 40, and 80 meters). To make the top 12-14 feet stiff ...
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6 votes
3 answers
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Antenna options

I am considering a new ham station in a relatively urban environment on the South coast of England, and would like like some ideas / feedback on antenna options. Aim is to get reasonable performance ...
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3 votes
0 answers
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have an unwanted radio tower [closed]

I have a 190 foot tall am/fm radio tower I need to take down. Taking it down with big enough crane and manlifts and a torque crew will be quite expensive. It is a guyed lattice tower that if ...
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3 votes
3 answers
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If a sealed, non-airtight pipe is used as antenna element, how big of a problem is condensate trapped inside?

I'm building a vertical antenna. The lowest portion of its element consists of 3/4" type M copper pipe, with end caps that will be soldered on and 3/8-24 screws poking through at both ends (so ...
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2 votes
0 answers
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Biconical antennas - bandwidth and installation

I am posting this question (and its related question) here because of the unique expertise that Ham Radio Operators have as it relates to antennas. I'm a newish Ham and really appreciate your help ...
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1 vote
2 answers
539 views

Trying to identify and understand this antenna design - ground independent dual band vertical

This is the insides of a common dual band antenna 2m/70cm, made by diamond or nagoya. its generally labelled as: 1/2 wave radialless (144MHz), 2 x 5/8 wave radialless (430MHz) Its meant to be ground ...
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2 votes
3 answers
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Constructing a ground level antenna array to monitor radio frequencies using SDR

New to this community and also a newish Ham. Hello everyone. This question could easily have been posted under 'Astronomy', but I thought I would start here since Hams tend to be quite knowledgeable ...
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4 votes
3 answers
191 views

High-Z RF amplifier for magloop RX vs Q-factor

I've noticed that increasing load on magloop reduces it's Q-factor, it becomes less selective. Traditional way to approach this is reducing size of pickup loop, or alternatively, using transformer. ...
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4 votes
5 answers
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Is spacing of fan dipoles necessary?

Is spacing of parallel dipoles necessary. Could they be banded together and then trimmed or is there some consideration, other than tuning, requiring separation. I was considering a fan dipole. I ...
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0 votes
1 answer
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I have a 433MHz LoRa Dipole antenna mounted on a rocket. I am looking for a suitable Antenna to receive data from this. Any Suggestions?

The idea was to send GPS data from the rocket to the ground station at 433 MHz using a Lo Ra transmitter - mainly to help locate it once it lands and also to provide in-flight telemetry. I have a ...
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6 votes
2 answers
107 views

How is phone cable with iron called?

In in Russia I saw a phone cable called "field cable" (провод полевой П-274-М). It is a loosely twisted pair with some iron strains added alongside with copper ones. I tried to lookup ...
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2 answers
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Loop Antenna Construction

I have a loop antenna. When I connect the probe from my oscilloscope, does the probe also act as an antenna? If so, how should I fix that? I read about feeding technique, but I still do not ...
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4 votes
3 answers
258 views

Electromagnetic signal from spark gap

I am a power electrical engineer college student, and I have a project to make an antenna for magnetic direction finding. My main topic is to detect lightning strikes, but its to hard due to ...
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3 votes
2 answers
367 views

horizontal EFHW antenna attached to gutter

I'm brainstorming methods of mounting an EFHW. Unfortunately, I have no trees, so I'm considering a horizontal gutter mount which would afford me about 70 feet. Is this workable or should I consider a ...
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