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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What core material would offer the highest sensitivity in the design of an ELF/VLF handheld rod antenna?

I want to design an ELF/VLF handheld rod antenna. What rod material would offer the highest sensitivity at these low, low frequencies? Below 50 Hz.
Ron K5TDF's user avatar
0 votes
2 answers
50 views

Minmum spacing between two receive-only omidirectional antennas

I need to mount a VHF receive-only omni (166Mhz to be specific) and a UHF receive-only omni (434Mhz) on a pole and plan to use a T-bracket at the top to space the two antennas apart. How much distance ...
TvE's user avatar
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0 votes
2 answers
67 views

How is the length of an inverted V affected by being too close to the ground?

In the near future, I'm planning to build an indoor inverted V dipole. However, I won't be able to raise the ends significantly above the floor. I understand that this will adversely affect ...
Someone's user avatar
  • 604
1 vote
1 answer
61 views

Testing a magnet mount base antenna

My Comet M-24J 144/440 antenna doesn't seems to receive signals as well as it should. I seem to receive more transmissions on HT radios than the mag mount and micro mobile radio. I only have a Rig ...
Radio Rails's user avatar
0 votes
1 answer
44 views

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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0 votes
1 answer
84 views

RF Coax Termination Question

I am looking to terminate a line with the below characteristics and having a hard time locating an RF coax terminator. Can anyone help? I have an FPGA HW that is feeding multiple receivers. The input ...
Newb's user avatar
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8 votes
3 answers
2k views

Can larger antennas damage an HT radio?

Can adapting a larger antenna such as a Diamond X-50 or larger mag mount damage an HT radio? Would it overload the receiver?
Radio Rails's user avatar
2 votes
2 answers
100 views

Performance of 2M/440 Amateur magnet mount antenna with CB

As I suspect that most people reading know already that a "well behaved" CB antenna tends to be quite large. In the past I compromised on a "proper" antenna to reduce size by ...
MacGuffin's user avatar
  • 359
0 votes
1 answer
92 views

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
3 votes
2 answers
94 views

Automatic switching of RX antenna -- xcvr has only one antenna connection (SO-259)

I have a local noise problem that's pretty intractable, especially on low bands. I'd like to at least experiment with a loop-on-ground RX antenna -- I've got a 1/4 acre to play with. My IC-718 has ...
W1WFG's user avatar
  • 33
1 vote
4 answers
168 views

Connecting two sites in the Arctic and Antarctic with a HUGE equatorial repeater? (Science fiction story advice)

TLDR: With infinite resources but real technology (no satellites, and no other repeaters possible), how would you best connect two ideal sites in the Arctic and Antarctic with an ideal, well-equipped ...
Tris - 2E1OAT's user avatar
1 vote
2 answers
111 views

Amateur radio antennas cause static on a cell phone call

My neighbor is a Class 8 truck driver and he recently put up what appears to be a large antenna outside of his house. I assume it is an antenna for radio - sorry, I am not technical and I just moved ...
Gretchen's user avatar
1 vote
0 answers
51 views

Whats the best way to orient these antennas of a wireless mic receiver?

The exact model that I have is this - https://ahujaradios.com/Document/349-AWM-495V2_OM.pdf I wonder if both the antennas are on different frequencies as mentioned in the picture above, since no ...
Mavin's user avatar
  • 43
0 votes
1 answer
141 views

Circular polarization

I'm installing my first beam antenna. I have 2 connection points, one for vertical and 1 for horizontal. So far. I have not found a lot of information which would be better. To run them separately or ...
David Hamilton's user avatar
0 votes
2 answers
115 views

Can mobile phones be used to intercept signal in 4-8 GHz frequency range?

I am trying to understand which is the radio frequency band of signals that can be intercepted using a regular mobile phone. In particular, I want to know if the 4-8 GHz frequency range is accessible ...
Radu M.'s user avatar
  • 103
3 votes
0 answers
106 views

Tuning an L-band dish for receiving GOES signals

I've encountered some challenges with my ground station intended for receiving images from GOES satellites, and I'm seeking your expertise to troubleshoot the issue. Here are the system specifications:...
Moses Browne Mwakyanjala's user avatar
-3 votes
2 answers
147 views

What frequencies can a GNSS (Global Navigation Satellite System) antenna pick up?

Am sure that a GNSS antenna can pick up other frequencies than GNSS ones, so is there anyone who tested that theory?
user avatar
3 votes
1 answer
344 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
  • 723
1 vote
1 answer
87 views

How do you decide on number of turns for twisted gamma match?

I'm looking at a 40MHz short transmitting loop (STL) with 6 rectangular loops: I need to fit within some design parameters and this gives the good radiation that I need in the near field. If I want to ...
Tunneller's user avatar
  • 111
0 votes
1 answer
126 views

Why are the signals that my antenna is receiving weak? [closed]

I recently bought the EFHW antenna kit from ARRL, put it together, and set it up. But, my received signals were not clear enough to hear clearly. Is the problem specific to the antenna from ARRL, my ...
o'o's user avatar
  • 111
2 votes
1 answer
187 views

Operation of an off-center fed vertical for 10 meters

I am looking for a smallish omni-directional 10 meter antenna for installation in my attic. I notice that MFJ sells one called MFJ-1790. They call it an off-center fed vertical, and it has two ...
gschro's user avatar
  • 157
2 votes
4 answers
174 views

Wave bounce inside a resonant antenna

Let's assume we have a transmitter, a feed line, and a standing wave antenna (dipole, etc.). The transmitter is matched with the feed line, and the feed line is matched with the antenna, which is why ...
elgroovy's user avatar
1 vote
1 answer
170 views

When should I switch antenna inputs on the Yaesu FT-897D?

The Yaesu FT-897D has two antenna ports: "HF/50 MHz" and "144/430 MHz". The manual states: The "HF/50 MHz ANT" jack is used for HF and 50 MHz, while the "144/430 ...
user3486184's user avatar
  • 1,902
2 votes
2 answers
377 views

Understanding how antenna mismatch can damage a transmitter

I know it's important to tune an antenna to the same impedance as the transmitter for maximum power transfer. But I've read that if you don't do so, you not only get less radiated power, but you can ...
SRobertJames's user avatar
3 votes
1 answer
164 views

Impedance of linear loaded 1/4 wave element

I am in the process of planning a multiband vertical antenna and have a few questions I would be grateful for any advice on. So I plan to have 1/4 wave elements for bands 20-10m with a common ...
owen81's user avatar
  • 31
1 vote
1 answer
140 views

Distance between Yagi antennas for 3500 MHz 5G

I have a lowcostmobile Rad5G-Ultra that I've been used for years with my LTE router. Now I have to use this couple of antennas for 5G through a ZTE MC801a (3500 MHz). Please, can you tell me the ...
Netsurfer's user avatar
2 votes
2 answers
119 views

Long Distance antenna feedline for UHF/2.5GHz signal

I'm building a boat towed underwater platform. This underwater platform has a single board computer with a remote wifi antenna connection via a u.fl connector. I'm experimenting around with a way to ...
leeprevost's user avatar
2 votes
0 answers
76 views

trying to get a passive AM bar antenna to work

I pulled a nice big external AM ferrite bar antenna off a working stereo. 5.5" long. it has 4 wires coming off of it. red must be the main wire, because checking that with an LCR meter connected ...
Fyodor's user avatar
  • 31
3 votes
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
  • 245
4 votes
2 answers
304 views

Antenna tuning confusion - help!

In a recent discussion with a fellow ham about where to use a RigExpert antenna analyzer for tuning an antenna for minimum SWR, we couldn't decide if "antenna only" or "feedline+antenna ...
K4JUL's user avatar
  • 41
2 votes
0 answers
123 views

Receiving a lot of noise with RTL-SDR and SDR# for GOMX-1

Hi im new to SDR and having issues setting up SDR#. I'm trying to receive from GOMX-1 on 437.25 MHz for a project. My set up is the dongle, a LNA and a self built helical antenna for that frequency's ...
Rob's user avatar
  • 21
1 vote
1 answer
124 views

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
2 votes
1 answer
172 views

Impedance of Yagi boom model in NEC

When modelling a Yagi in NEC the radiation pattern is essentially identical whether a conductive boom is included or not, see pictures below. An explanation says this is a limitation of the method of ...
butterflypea's user avatar
3 votes
4 answers
495 views

Using UV5R HTs. Will i lose receiving range by attaching coaxial cable to put my antenna remotely as well as higher?

Using beofeng UV5R HTs. Changed antennas to retevis whips. Will adding coaxial cable to HT & antenna for height reduce or increase reception. As i'm in a valley. I receive only. As i'm still ...
Snowy's user avatar
  • 61
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
377 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
2 votes
1 answer
472 views

What are these extra wires coming out of my ferrite rod antenna

From my understanding a ferrite rod antenna is simply a length of wire wrapped around a ferrite rod. A wire will sticks out of each side of the rod, one is ground and one is the main receiver. I ...
Dan's user avatar
  • 311
1 vote
1 answer
970 views

How to wire simple homemade long antenna for 100KHz+ on RTL-SDR

I have a rather beginner question, hope that's okay. I use my Quansheng to listen over 50 MHz, and I have heard that one can hack the firmware to go down to 18 MHz, but I really want to listen to the ...
spl's user avatar
  • 245
2 votes
3 answers
483 views

Monopole antenna with no ground connection

I have a SDR device and have a question about using a monopole antenna with them, but the question could be applied to any device which uses an antenna. SDR comes prepacked with a monopole antenna ...
Dan's user avatar
  • 311
1 vote
1 answer
206 views

Creating a single feed wearable wire antenna

When I was deployed, our commo guys gave us wire antennas we could thread through our body armor (through the MOLLE loops). These antennas were just lengths of 50Ω coax that had the insulation ...
Jesse Knott's user avatar
2 votes
1 answer
128 views

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
  • 21
4 votes
1 answer
543 views

60kHz WWVB receiver help

I have built a large ferrite loopstick antenna based off this video. I live in Washington state and am trying to receive and decode WWVB. I can get my antenna to resonate at 60kHz with ~700 pF of ...
Max686's user avatar
  • 41
6 votes
2 answers
1k views

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
1 vote
1 answer
127 views

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 ...
user3842718's user avatar
3 votes
2 answers
159 views

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
-1 votes
1 answer
83 views

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 ...
Murtaza Younis's user avatar
2 votes
1 answer
197 views

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 ...
vnat's user avatar
  • 21
3 votes
1 answer
213 views

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....
Mavin's user avatar
  • 43
3 votes
1 answer
230 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
0 votes
2 answers
81 views

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 ...
Monique's user avatar

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