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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72 views

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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0answers
44 views

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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2answers
96 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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3answers
86 views

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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3answers
70 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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4answers
130 views

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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1answer
46 views

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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2answers
89 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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2answers
137 views

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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3answers
211 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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2answers
114 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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2answers
105 views

Magnetic loop antenna: Which side of conductor is the current due to skin effect?

Contemplating a big magnetic loop antenna. Would a wide copper strip be better than a tube with the same conducting surface? Where will all the current be due to the skin effect? Would a flat ring be ...
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1answer
98 views

Antenna Mast near EFHW Inverted L

I have an EFHW 40-10 in inverted L configuration on a fiberglass mast. I'd like to put an aluminum push-up mast nearby for a 6 meter antenna. How close can I get to the EFHW with the push-up mast? ...
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1answer
34 views

How to calculate of shielded loop antenna correction factor without extra antenna measurements

A lot of article about 60 cm shielded loop antennas and how to measure antenna factor using antennas with already known antenna factor. But for example if I have one shielded loop antenna (...
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3answers
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Recommendation for hobbyist flight computer radio antenna

I'm a CS college student working on the flight computer of my Rocketry Club's rocket. My flight computer has a 915MHz radio transceiver, and it needs to transmit data to my computer with another radio ...
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1answer
88 views

Substitute a car roof with radials?

I have a K40 Plus CB antenna, which is supposed to be attached to a car roof for the ground plane. However, I would like to set this up as a base antenna. Could I instead attach the ground to separate ...
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2answers
90 views

How many turns of wire inside 60 cm shielded loop antenna (9kHz - 30 MHz). How can I find this number without destroying the antenna?

Lots of information about shielded loop antennas is available on the internet. However, antenna manufacturers do not indicate the number of turns. How can I find the number of turns of a manufactured ...
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1answer
59 views

60cm 9 kHz 30 MHz Shielded loop antenna behavior as a transmitting antenna

I know how shielded loop antenna work as a receiver antenna. (How behave electric and magnetic field). But I can not understand how shielded loop antenna works as a transmitter. Will it produce only ...
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3answers
96 views

Yagi Antenna - Elements Length

I am currently modeling a yagi antenna using Matlab and after I optimized the antenna, it gave me a director length shorter than the exciter itself (even if the optimization gave me a good gain). From ...
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84 views

How to stabilize an antenna

I have an antenna on a building. It is made of steel and is about 10ft long. It wobbles a bit in high winds. It is not going to do a Tacoma Narrows but it is a bit annoying. Can I tie stainless steel ...
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2answers
191 views

Is the Boom Strictly Necessary in a Vertical Dipole?

I'm planning to build a vertical dipole for 4m and a club member pointed out that my design needs to allow for a boom that should be at least a 1/4 wave long. Why does a vertical dipole need a boom ...
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2answers
173 views

Heat-shrink as dielectric for bazooka balun?

I'm intending to make a sleeve balun (aka bazooka) for 2m, but rather than keep the lossy coax jacket as a dielectric (I have some RG58), was considering to remove it and replace it with heat shrink ...
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0answers
89 views

what frequencies is this antenna cut for?

I just bought a magnet-mount whip antenna at a garage sale. It has no brand markings anywhere on it. it is 32" long overall but is broken up into three segments by what appear to be two small ...
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57 views

Omni 144 MHz antenna

I plan to build omni antenna. My goal all about better gain versus a 1/4 wave antenna. I am curious about radial position of the legendary ARX2B Ringo Ranger. Why is the position in below feed point? ...
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97 views

Built a 2 meter 5 element Yagi

Straight dipoles. I can't get the Yagi to tune. I have tried the 4:1 Balun method with coax but not able to tune. With the straight unbalanced input to the dipole I get a 1:1 swr on about 129 MHz ...
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1answer
97 views

Pondering variations on the vertical bazooka antenna

I've seen these antennas built out of coax that are called a bazooka vertical. It's a kind of 1/4 wave vertical, or perhaps a 1/2 wave dipole. Constructing such an antenna is to roll back the outer ...
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1answer
197 views

440MHz collinear dipole array - suitable coax?

friends! Finally found my next antenna project..a collinear dipole array for the 70cm US ham band. The general idea: (image courtesy https://link.springer.com/referenceworkentry/10.1007%2F978-981-...
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1answer
56 views

What is the maximum antenna cable length allowed in GNSS application?

I am beginner in designing GNSS receiver design and facing concern while testing the high precision GNSS survey.I am using GNSS survey grade antenna for my GNSS receiver application testing, the ...
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3answers
305 views

Ground-Plane radial sizing, is there such thing as too long?

I'm just trying to make sure I understand the theory correctly. I have some triband VHF/UHF/800MHz antennas, I need to mount on a tower so I plan on using a "mobile to base" conversion kit. ...
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1answer
60 views

Lightning protection for a vent stack antenna

I've seen ham radio antennas that slide over a vent stack. The usually way to connect them to the transceiver is to lay the feedline across the roof. However, the manufacturer provides instructions ...
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2answers
137 views

How to match transmitter to Beverage antenna

Beverage antenna consist of pair of transmission lines - one being the "antenna proper", the other ground. The antenna is being fed via open feed line ( approximately 450 Ohms ) - one side ...
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2answers
245 views

Antenna Basics - Open/Short Circuit & Half-Duplex/Full-Duplex

I am beginner in the Antenna theory and I have a few basic questions. Please help me to clarify my understandings related to the basics which I have read. And this question has 3 basic questions. ...
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5answers
618 views

Significance of 1/4 wavelength with respect to antennas

I am a new to the radio design field. My question is, 'What is so significant about 1/4 wavelength with respect to antennas.' From the information I have gathered from various sources, it is my ...
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3answers
134 views

Need antenna for mobile mag-mount LPFM broadcast 88.3 MHz

I am doing some temporary FM broadcasting for car events such as COVID-safe car parades and drive-in movies. The terrain is horrible, urban areas with lots of buildings. The cars snake around a city, ...
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6answers
4k views

Can you use a satellite dish for a ham radio antenna?

Can I use a satellite dish as a ham radio antenna? I was thinking that because there are two unused, working satellite dishes that have all appropriate wires attached conveniently to the roof of my ...
2
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2answers
222 views

Yagi: split or solid driven element?

Short question: What are the advantages and disadvantages of using gamma (solid element) or beta (split element) matching a yagi? Long question: A while ago I built a coil loaded yagi for the 20M ...
2
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2answers
236 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 ...
4
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1answer
124 views

Commercial Loopstick Antenna Manufacturers?

I am an electrical engineer working on a product that needs a loopstick antenna. I had thought that AM radios were so commoditized that I'd be able to find an off-the-shelf vendor. However the closest ...
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5answers
150 views

2.45GHz: constructing a horn of *thin* steel, what are good ways to join the edges (at least one joint along corner?)

TL/DR: How does someone make a good horn antenna system without using expensively made parts? Welding thin steel for this is not something even pro welders can do (it's a specialty app.) What are DIY ...
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3answers
175 views

Can I build a guanella balun using single strand wire instead of coax?

I am trying to homebrew a cobweb antenna and need some help understanding the guanella balun used as described here: http://www.karinya.net/g3txq/cobweb/ This author used RG316 coax around the ...
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3answers
457 views

High Altitude Balloon Antenna Design

I'm designing a weather balloon with a club at college. We want to build the antenna from scratch to learn more about antennas but are at a loss as to which antenna design would actually work for high ...
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2answers
95 views

Does RF go through thin corrosion better than DC?

I might have a bit of a problem with my groundplane, but I am unsure. I am using a ground screen instead of radials. The problem is the ground screen is made of galvanized metal, but I can see that a ...
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4answers
117 views

Which 10 m antenna will give the most rejection in one direction for received signals which are vertically polarized?

I want to null out a particular direction so that i can't receive some vertically polarized interference on 10 m coming from that direction. Which 10 m antenna will give the most rejection in one ...
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1answer
237 views

Will painting a 4 element 10 m yagi using conductive paint onto the side of a building work?

Will painting a 4 element yagi using conductive paint onto the side of a building work?
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1answer
86 views

Is there a suitable alternative to using a metal pole to mount a vertical yagi apart from wood and fiber glass?

Does anyone know if a non-metallic pole approx. 4 m long is available that i can use to mount a vertical 10 m 4 element yagi ? that is not wood, PVC or fiber glass as these are either too heavy or not ...
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2answers
68 views

Will ferrite rings around a metal pole hide it in an RF sense from my vertical 10 m Yagi?

If i mount my vertical 10 m 4 element yagi directly on a metal pole so that the pole is between the elements and so messes up the radiation pattern and input impedance, if i put lots of type 43 ...
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1answer
212 views

When I am told that a dipole must have a determined length, does that include the space between both elements?

I am trying to build an antenna for receiving NOAA satellites and I need to build two 137,5MHz dipoles. When I enter the frequency and width of the wires in a calculator, I obtain that $λ/2=1.09\,\...
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3answers
1k views

Can I build a Yagi antenna for my Baofeng UV-5R?

I would like to build a Yagi antenna for my Baofeng UV-5R, but I'm a total newbie when it comes to amateur radios. The antenna will be for UHF and shouldn't be too long (like 1.5 meters max). So my ...
3
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1answer
132 views

UHF cubical quad VNA analysis interpretation

I've designed a two element UHF cubical quad. It was designed to resonate at 385 Mhz. I used 0.1mm thick and 1cm wide copper tape instead of wire to lower the antenna Q. I used PVC electrical conduit ...
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0answers
84 views

How do I Construct a Simple FM Antenna?

I recently bought a cheap stereo amplifier with built in FM receiver from Amazon at the first link below. Testing it out today I found the FM reception to be sub-par. All of my local stations that I ...

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