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.
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Chaining multiple coaxial adapters
I want to connect an RTL-SDR dongle that has an MCX Female antenna port to an N-Type Male antenna feedline. I know there are thousands of pigtails and adapters for every possible need, seemingly ...
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Follow Up on a previous question- Transmit antenna on HF band
I had asked a question in a previous segment and the link is provided below
Antenna Size limits at 2-30 MHz (10 m to 150 m wavelength)
I think i have some more clarity on the question I wanted to ask. ...
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Does an antenna pick up signals of all frequencies or only its resonant frequency?
I heard that an antenna picks up signals of all frequencies, and then these signals are filtered by a circuit using an inductor and capacitor, and that this is how a radio is tuned.
However, I also ...
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What is the differece between a large loop antenna and a small loop antenna in terms of their response to an electromagnetic wave?
There is something that I don't get. I read that a small loop antenna (also called magnetic loop) responds more to the magnetic field than a large loop antenna does. I was wondering why this is the ...
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How does a Large Loop Antenna work physically?
I am learning about loop antennas at the moment. I read that the response of a small loop Antenna is proportional to the rate of change of magnetic flux through the loop which causes a uniform current ...
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Can an 80 meter band dipole work in a basement?
I don't have an HOA, but I don't: a. have the space outside for an 80 meter dipole, nor: b. does my wife want visible antennas on the outside of the house.
So I've been in the mode of finding an ...
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Does an RF amplifier allow us to receive a signal from further away?
From my understanding a RF amplifier boosts the transmission power of your antenna, this will in turn give you a higher gain.
However I've read that this only will give you a further "...
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Power rating of a selfmade air coil
A colleague was winding an air coil himself. It's a 110µH coil with 200 windings for an 80m antenna, intended to be used on a 600 W transceiver. He used a copper lacquer wire with 0.6mm diameter. ...
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VHF Balancing, necessary? Methods?
This is a question about power dissipated due to radiation and ohmic heating caused by common mode current in the coaxial shielding, specifically at VHF frequencies.
When a balanced antenna (such as a ...
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SMA 3.5mm to Baofeng or similar radio
My friend just got a 2006 Chevy Calorado and it came installed with an 3.5mm SMA cable running from the roof to under the dash. It was a park ranger vehicle so it would make sense that they needed a ...
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Can you think of any reason my NanoVNA says my antenna has 1.2 SWR while my radio says it has off the scale SWR?
My radio is an mcHF kit that I just finished soldering up. It receives fine, but when I went to transmit it's giving off the scale SWR. I rechecked my antenna with my NanoVNA, and it shows 1.2 SWR at ...
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Hanging a dipole from a tree not code compliant?
I just got off the phone with my town's electrical inspector (in Massachusetts), and he informed me that you are not allowed to hang anything electrical from "vegetation". He said if I did ...
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How to transmit computer audio to a wireless microphone receiver? [closed]
I'm currently trying to broadcast my computer's audio output to a wireless microphone system receiver so that I can accompany my school's coming presentation with music. The frequency range is 480-598 ...
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Whip/stub antenna sorting with SA using VSWR
I have an assortment of whip antennas for various RX & HT devices such as a 2M/70cm FT740, a Uniden race scanner 29-54Mhz/108-174Mhz/406-470Mhz/806-956Mhz, a similar Realistic Pro-32 scanner and ...
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Can I use my CB mobile antenna with a 10 meter radio also?
I have a mobile mounted CB antenna that has an SWR of 1.5 on channel 20. Is it possible to use it with a 10 meter radio? I do not have enough room on my car for an additional antenna, so if it is ...
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Antenna options for a small urban garden
I've narrowed down my antenna options to fit a small urban garden. It's tough, space is tight and a neighbour three doors down reports everything I do to the council so I'm routinely inspected for ...
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Is it ok to use a length of wire as an RX only antenna to test my new radio?
I have almost finished building my first shortwave transceiver kit (mcHF). Remarkably it's fired up and not gone up in a puff of smoke. The kit still needs some finishing off and I need to decide on ...
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Why ferrite-core transformers are wideband while air-core are not?
While experimenting with end-fed antennas I've made two 1:49 transformers.
The first one has an air core, as shown in the article by John, M0UKD. This transformer doesn't even work as a transformer ...
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Coupling Capacitor of an Antenna
I have a simple question about general meaning & importance
of the coupling capacitor in following part of
a simple receiver circuit:
Is it true that the proper reason why this
coupling capacitor ...
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Can I use a car antenna intended for 2m/70cm on a 868mhz Lora device?
I have a Lora radio device that runs at 868mhz, it came with a tiny stubby antenna.
I want to use the device out and about so wanted to know if it will be OK connected to a magnetic/car antenna I got ...
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High electrical noise only when coax shield is connected
I'm trying to understand a noise issue on my Yaesu FT-891. I have very high 60 hz electric buzz on most bands with 40 and 15M being the worse at about S9+. My antenna is a MyAntennas 66ft EFHW fed ...
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Are there any active ham satellites orbiting that use the 5cm band?
I see that 5cm is available for satcom in amateur radio. Are there any active satellites for that?
If so, what satellites and are their TLE's available?
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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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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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Narrow bandstop filter not requiring ground connection in SMD package
I’m designing an antenna that I’ll implement on a printed circuit board. The antenna will be working on both sides of 900 MHz, so it’s not exactly for ham use. I’m planning to use a bandstop filter in ...
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Could my HF antenna cause problems to these other antennas on the roof? [duplicate]
I am planning to purchase a property soon in an apartment block on the top floor. I am very very keen to install a HF multiband Yagi antenna on the rooftop.
I notice some small cell towers and a ...
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Using Decoupling Stubs to Allow a Vertical Yagi to be Mounted on a Metal Pole
A while a go i asked a couple of questions on this site about mounting a vertical yagi antenna on a metal pole. One of the answers given to the first question talks about using decoupling stubs to ...
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What is the signal of a receptor antenna irradiated with a plane wave?
Let's say there is a reception antenna connected to a detection system with a coax, and a transmitter sends a plane wave. What happens is that the antenna gets a certain power, following the [...
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How much attenuation (dB) from a balun is expected?
I'm building a dipole antenna for 433 MHz, first one ever. I will have to use a ferrite bead to balance the feed. How many decibels of attenuation should I expect from the ferrite bead?
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Do these look like amateur radio antennas?
I am planning to move into a new apartment, and of course would like to install a HF antenna there, on the roof if possible.
Today I noticed a small Yagi antenna on the roof of the building , more ...
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Fractal antenna shapes that work for you? [closed]
I just answered this question, and I wanted to know if any particular shape has been found to be successful for anyone.
There seems to be a lot of research on IEEE that indicates that there should be ...
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What steps to take to secure for G2 geomagnetic storm?
So I see NASA has issued a geomagnetic storm watch for a possible G2-level storm on the 11th. I’m at about 53 degrees north geomagnetic latitude.
Is this something I need to care about equipment-wise? ...
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Why half-wave dipole is the most efficient one in comparison to other electrical lengths of that antenna?
I have a problem on the understanding of a half-wavelength antenna. Namely, why is the half-wave antenna has a highest power emission. Considering Far Field factor F($\theta$), which is known from the ...
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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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How the ELF-VLF background noise spectrum looks like?
In the ELF-VLF frequency band,some background noise like Schumann resonances shows in the spectrum analyzer as peaks.
I want to have a overview look of the background noise of ELF-VLF frequency band,...
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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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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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Calculating SWR for a dipole
I have a dipole wire antenna that is tuned to 14.0 MHz so that it has an SWR there of nearly 1:1. Is there a mathematical formula by which I can compute the expected SWR for other frequencies? I would,...
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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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Why is the total radiated power of array calculated by sum of square of excitation coefficients different from the result by integral of power pattern
Consider an array with same isotropic antennas, $P_{ele}^n$ is the input power of the nth antenna. As I consider antenna radiation efficiency = 1, the $P_{ele}^n$ is also the radiated power of the nth ...
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Will a HF beam antenna on rooftop building interfere with other antennas there
I am moving into an apartment on the top floor of a building and I intend to install a HF beam antenna for 20 to 10 meters, on the rooftop of the building.
I notice that there are already some ...
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Mounting a hex beam on top of a high urban building
I am moving into a new apartment in the city soon which is on the 24th and last floor of an apartment building. I will have access to the roof of the building also.
I'm still trying to understand ...
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Common-mode choke (CMC) hurting my SWR. Live with it? Drop the choke?
I have been using a Par EndFedz Mk2 Trail Friendly 40/20/10 though using the matchbox from an EndFedz EF-QUAD (with Vibroplex’s blessing) so I could transmit at more than 25W. On all three bands I ...
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Is tuning at all useful for an antenna that is already resonant?
Say you have a resonant antenna that also has a tuner. Does this help at all? Can your antenna be "fine tuned" ?
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multiple pcb trace antennas in the same design. Bad idea?
Since time is money and my PCB home making skills are not the sharpest, I would rather fit my PCB design with two unbalanced antennas (no balun, just impedance matching parts, for 315 / 433 MHz) for ...
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Mounting a vertical antenna on a fiberglass mast
I have a multiband SE-X80 HF vertical antenna which works ok from 20 meters to 10 meters with a tuner. It is attached to the railings of my apartment balcony at the moment. This is the antenna : https:...
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Broadband dipole with no standing waves?
If a diode or directional coupler is fitted at the outer ends of the elements of a dipole, would this stop current reflected from the ends and so result in no standing wave on the antenna ? It can't ...
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Does antenna Q cause distortion?
Everyone knows that a 1/2 λ dipole has on the elements a standing wave the voltage and current of which are a bit less than 90° out of phase with each other, and the departure of this phase difference ...
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Why do ham radio operators say that a full wave dipole isn't resonant?
Every reputable antenna book that I've read says that dipole antennas are resonant at integer multiples of a half wave length.
Wikipedia describes resonance as:
the phenomenon of increased amplitude ...
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Sealing connection between mobile antenna and mount
I've got a brass mount installed on my car which has a 3/8-24 socket. All the antennas I'm looking at seem to have stainless steel connectors. Is packing the connection between antenna and mount with ...
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