Questions tagged [antenna]
Questions about the design, selection, building, testing, mounting, or properties of antennas. See also specific tags: [antenna-theory], [antenna-construction], [dipole], etc.
925
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The best antenna for use in a rotating environment
I'm trying to use a low power wifi connection to move about 20MB/sec of data between a instrument mounted on a rotating steel barrel about 20 inches in diameter and a stationary wifi unit. A low power ...
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2
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Will spray painting a J-pole impede functionality?
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.
...
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Utilising old CB Base Antena to 5g Antena
Is it possible to utilize an old CB Base Antenna (10 meters tall) as 5g Antenna to plug into the back of a 5g router that is currently only registering 4G? I have one on top of a single story unit ...
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Antenna from the roof / coax cable to Ham and Weather radios
Just want to make sure I don't need anything else (to prevent damage to the radios)
I have an antenna on my roof. It used to be used for TV but I switched back to cable.
Can I literally just use a ...
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How do these ceiling mount dome antennas work? Are these discone antennas or horn antennas?
The small cone is connected to the larger one. The coax center cable is terminated into the small cone and the coax shield into the larger outer cone.
The screenshots are from this video https://www....
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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'...
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Exposure to AN/FRD
Why are Wullenweber CDAAs obsolete?
My dad worked inside the FRD sites on various Navy duty stations and is suffering now from Parkinson's and dementia. Has anyone else heard or read of similar side ...
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How can an HT antenna be half wave?
There's a model of HT antenna for the GMRS band by Nagoya (NA-771G) that's specified as a half wave. How can that be? An end fed half wave antenna needs a 49:1 impedance transformer to match with ...
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Noise power with and without antenna
I have designed a receiver at 440 MHz with a 10 MHz signal bandwidth. I have measured the sensitivity of the receiver in a cabled setup (coax cable between transmit and receive) and that is about -93 ...
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Why does SWR of a dipole decrease the closer it is to the ground?
I experimented with a 20m dipole made of a 1:1 balun connected to 2x ~5-meter lengths of copper wire, running parallel to the ground (by "ground" I mean "pavement", not quite the ...
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Tips for getting a 2m dipole higher while out in the field
I want to start operating the 2m band while camping, but with my current setup, my antenna would be very close to the ground and ineffective. So I'm wondering, does anyone have tips for constructing ...
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Is 100m too long for hf feed wire?
I have room to erect a DX Commander, multi-band vertical, and to give it a good number of radials on a good clear site.
Problem is I would need to run about 80 - 100m of coax feed from operating ...
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93
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Why does my received power rise so much when I connect an antenna?
I am in early stages of making a narrow-band radio receiver (block diagram below). To give you an idea, I am using a simple CP-FSK based modulation scheme, and have achieved 5dB SNR with a Tx signal ...
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127
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What is this vertical antenna with radials pointing up
I work next to "Koninklijk Marine Kadettenkorps Afdeling Oostende" (Royal Marine Cadet Corps Ostend). They have an antenna that I've been wondering about for years now:
It is a vertical ...
2
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2
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HF vertical 1/4w antenna on a tin roof?
I would like to build a 1/4 ~ vertical antenna on my tin roof for a ground plane.
Does the angle of the roof matter?
Should the antenna be vertical, or perpendicular to the roof?
Would it be better ...
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95
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Off-center fed long wire antenna
I want to feed a horizontal wire antenna (approximately 150' long at 50' or more above the ground) for multi-band HF operation with an off-center (25-33%) feedline. The element wire will have no ...
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Is the noisy spectrum from 20MHz to 330 MHz normal?
I have recently been testing some VHF/UHF antennas for reception in my Lab, and have noted something I could not explain. Following are the spectrum plots captured on our R&S FSV spectrum analyzer,...
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Would a 3D-printed antenna case interfere with the antenna itself?
I primarily use a Baofeng for most of my contacts. I've got a pretty good antenna (14.5 inch whip), but when I have to pack it into any sort of bag, I'm always worried that it'll get bent. This has ...
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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 ...
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76
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TV Coax cable for QFH antenna
I'm new to this hobby and I'm trying to make me a QFH antenna for NOAA satelites myself. I would like to know if I can use AC15-380WH 4/8K TV coax cable with double ...
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Antenna Aperature for out-of-band frequencies
I am doing some calculations where I determine power at the input of Rx given some field strength at the antenna. I have a question about the antenna aperture:
...
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57
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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 ...
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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 ...
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How to assemble a DB8 antenna balun
I have an old (2009) Antenna Direct DB8 antenna that has never worked great. I would get good reception then poor reception and not due to atmospherics. I finally decided to take it down and inspect. ...
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Would two perpendicular dipoles work to avoid polarization mismatch?
What would happen if you made an antenna consisting of two perpendicular dipoles tuned for the same frequency and connected to the same feed line? Would this work to avoid polarization mismatch loss?
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How can cross-polarization loss be determined given the angle between two antennas?
This question addresses the case where two antennas are exactly 90° cross-polarized, but not other angles.
How can I determine the theoretical, and estimate the actual, attenuation from cross-...
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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 ...
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93
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How to create FM Radio Mesh
What (devices transmitters, receivers and transceiver) do i need to create a fm radio mesh, instead of using a single transmitter with big antenna, i want to build fm transceiver mesh radio to cover ...
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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 ...
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Why did the International Telecommunications Union denote CY for Canada?
CGP Grey recently released a video on the history of airport acronyms, e.g., LAX. He briefly said that you may wonder why codes for Canada started with Y and formerly CY, and that it traced its ...
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miniature parabolic antenna
I have to build a 2.4ghz wifi antenna with one SMA feedpoint. The rules are that it must fit inside a 15cm cube shaped box. For testing, the antenna will be pointed at a laptop that is moved to ...
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HF Vertical antenna with no radial and loading coil but only ATU for 80m to 10m in a boat
I am new to HF antenna designs. I want to build an antenna for my fishing boat. My question is - if I use an ATU (like the ATU-100) and a 10m aluminium pipe as an antenna and fix it with a mast, will ...
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Antenna array's relative phase changes at each measurement trail
I am using an Rx antenna array (4 antennas), and a TX transmitter. Without changing my location of both transmitter and receiver as well as modifying my array geometry, I am measuring different phase ...
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What is the best way to ground a whip antenna in a hotel room?
We have a 102" CB whip antenna cut for 10 meters. We're staying in a hotel and trying to figure out the best way to ground this antenna. Right now we're using a pile of wires on the floor, but we'...
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What's the best long-range antenna for a Baofeng V2N? [closed]
I'm just getting into Amateur Radio, and bought a Baofeng BF-F9 V2N. The antenna's range is about 7-8 miles, but I live in an area where Ham radio isn't very common. Does anybody have recommendations ...
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Calculating a real antenna gain from electric field strength?
Could someone please tell me if it is possible to measure the antenna gain simply by placing a field strength meter at a selected distance to my antenna, knowing the power applied to the antenna. ...
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Diamond X50 and X300 pipe mounting bolt thread
I have a Diamond X50 and X300 that are both now missing the pipe mounting bolt (Part #07004 in the drawing.) None of the bolts in my coffee can full fit, either way too big or way too small. An ...
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Hi SWR with End Fed HF Wire 9:1 UNUN
Good Day
I understand every antenna set up is different, so I'm looking for advice on what I could change to alter my findings.
The set up is new including the EFHFW - 20 which was bought off the ...
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Testing a balun in isolation
Consider a microwave RF source going to an unbalanced coaxial cable, then using a 1:1 balun to feed a dipole/Yagi style antenna. How can I test this 1:1 balun in isolation, independent of the type of ...
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How to build the best bang for yhe buck uhf vhf antenna or should i just buy one [closed]
Help with antenna build what makes up a great antenna what can I use for elements and would a dush network dish be good reflector and how to wire the elements like the copper to one side and the ...
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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 ...
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What frequency ranges are most common for Amateur radio astronomy and why are most parabolic antennas tuned to such high frequencies?
What frequency ranges are most common for amateur radio astronomy?
I am mostly interested in radios for the purpose of astronomy. In general I was expecting that the lower frequencies would be more ...
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seeking links info for design and theory of handheld VHF UHF antennas
I've been looking but so far nothing.
Even design software with templates for monopoles, end feds
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What balance (radials or counterpoise) do I need for a vertical hamstick as a stealth antenna?
I'm just getting back into operating after a long break. I'm currently in a ground-floor apartment of an old four-plex and I'm trying to set up a stealth-like antenna for HF. I decided on the Shark ...
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What is the wavelength of 144.52 0MHz frequency?
Problem
What is the wavelength of 144.520 MHz frequency?
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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 ...
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Antenna reciprocity how does an antenna increase receiving range?
According to Wikipedia antennas are reciprocal unless they're constructed of nonreciprocal materials.
There are a multitude of mathematical formulas which unfortunately I'm unable to understand due to ...
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153
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Do I need an antenna tuner for new mobile antenna
I am looking to buy my first mobile antenna, for use with a 2m/70cm HT in the car. The HT needs 50 Ω impedence.
I was looking at this antenna, but another ham told me that I need 1/4 wave or 5/8 wave ...
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Using old vehicle through glass cell antenna
My old (2001) Seville had a cell phone with antenna mounted on the rear glass. The coax connects inside the glass, with signal passing through the glass to the whip mounting plate.
I'm wondering if I ...
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How can I inject an oscillator output into the RF input to my radio?
I have a Bodnar GPS disciplined oscillator, and I would like to inject its output into the antenna input to my HF rig. This will allow me to compare the frequency of received unknown signals to the ...
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