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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2answers
440 views

How to tune a hamwhip-type mobile HF antenna?

I'm a new ham and would like to start working HF with my mobile (my only) rig, an FT-857d. I have a handful of antennas, all of the variety that has a fiberglass base, extended by a stainless steel ...
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1answer
81 views

Power handling of a simple VHF ground plane

The ARRL welcome pamphlet contains instructions on building a simple ground plane antenna and specifically comments on its use by handy-talkies. However, I wonder what the actual capability of this ...
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2answers
1k views

Optimising a small magnetic loop with 1:1 SWR but little radiation

I'm trying to build a small magnetic loop for 5W on at least 40m - 20m following ideas of G4ILO's wonder loop. For this, I'm using coax with a ~2mm copper core and ~1mm spacing to the braid (see 1st ...
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2answers
216 views

Type and name of this smartphone cellular antenna

Please identify the type and name of this antenna? It's a iPhone 6s cellular antenna. What material it's made of? Any reason for it's 'painted black'?
6
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3answers
1k views

Will coaxial cable degrade over time?

I have a 40' section of RG-8 that is about 35 years old. One end was terminated with a standard PL-259 and the other was soldered directly to an antenna. When I removed the connector from the one ...
2
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1answer
144 views

Choose the right dongle for NOAA images visualization with GnuRadio [closed]

I'm a newbie in such domain and I was reading some articles around the internet and what attracted me most is using the GnuRadio to see NOAA images using some cheap hardware. I looked further it ...
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3answers
3k views

How do I connect an antenna with coax output to my stereo?

I want to buy a radio antenna for my stereo in order to pick up a few farther-away stations clearly. The outputs from the antennae that I'm seeing are to coax cables, and the input to my stereo has 75 ...
2
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2answers
338 views

Loop Antenna - configuration?

Due to space limitations, I'm looking at loop antenna designs. I'm starting with receive only, but hope to eventually transmit. I've seen magnetic loops (single turn with a coupled loop) and I'm ...
2
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3answers
152 views

Can the tip of an antenna burn insulation/drywall?

In my house, I’ve got a mag mount antenna mounted on a piece of sheet metal on top of rubber and the tip of the antenna goes into my ceiling and possibly contacts or is near to home insulation. I was ...
0
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1answer
65 views

Will rewiring this antenna change the characteristics?

Speaking of the antenna in this question: What kind of 2 meter antenna is this? The connections are rusted and corroded so I'd like to rewire it. If I move the shield from where it is currently ...
5
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3answers
249 views

What kind of antenna connector is this?

I'm looking for antennas to attach to my CB radio. This one is a "rubber ducky" antenna. I'm not sure what the connector is, can anyone identify it for me? [edit] Here are some other pictures
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2answers
2k views

Choosing a wideband antenna design

On a previous question I asked about proper antenna design for wideband SDR receiver and ways to improve signal/noise ratio. Ideally the reciever has a range of 100kHz-2GHz. Keeping in mind is ...
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3answers
464 views

HF antenna design for high-altitude balloon

I'd like to put a WSPR or JT65-like transmitter on a high-altitude balloon, but lacking much experience with HF antennas, I don't quite know where to start. I'm thinking it will operate on 20 meters, ...
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3answers
1k views

Broadband antenna for SDR radio

I recently bought a very wideband SDR receiver (DX-Patrol MK4, declared covered frequencies are 100kHz-2GHz). I'm experimenting with antenna designs because unfortunately I live in an apartment ...
2
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1answer
277 views

What kind of antenna design is this?

I've found an old antenna that once came with an HP laptop with a TV (DVB-T?) card. I decided to see if I can use that antenna for something else, so I opened it up and found the following antenna ...
2
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1answer
632 views

How do I specify that wires are connected in 4NEC2?

I've been trying to get acquainted with the 4NEC2 antenna modeling program. Perhaps this is obvious, but it's not clear to me that wires with one end in the same place are connected. I'm attempting ...
2
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4answers
638 views

Can I install a Diamond X30A Antenna on a Balcony with a Metal Rail?

I live in an apartment with a metal rail patio very similar to the attached photo. I want to put a Diamond X30A on the patio but the radials will be about a foot below the top rail. Will this work, or ...
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1answer
64 views

Receiving medium - low frequency CPU signal

I'm trying to listen to the CPU freq's my PC produces (kinda similar to what was done here: https://github.com/fulldecent/system-bus-radio) I do see a clear signal that comes from the CPU (I know ...
2
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3answers
408 views

SWR, overall, is too high

This is a sort of follow-on question from my tuners in series question. The problem I am ultimately trying to solve is this: I am using a manufactured end-fed, half-wave 40m antenna. The ...
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4answers
669 views

CB Ground Plane on fiberglass RV

The CB ground plane on my 43' fiberglass motorhome stinks. Has never worked correctly. If I install a piece of sheetmetal around the antenna on the roof would that help the ground plane at all? A flat ...
5
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3answers
517 views

Tiger Tail + capacitive coupling… what's the interaction?

I've been working on a 2m setup for hiking. My goal is to have the best possible antenna that can be used while walking, and that won't get damaged if I walk under a low branch or some other forest ...
2
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1answer
193 views

75Ω Wire FM antenna

I was recently given an older, but really nice broadcast FM receiver (88-108Mhz) by neighbor, but I am confused by the antenna connector and labeling. for the FM antenna connection, there are two ...
2
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5answers
867 views

What kind of 2 meter antenna is this?

At first glance this appears to be a simple ground plane but there is far more going on. The ham who built this back in the '80s is now SK and I can't find anything else like this anywhere. The ...
2
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2answers
362 views

Satelite dish modified for Wi-Fi (Signal Elevation Question)

I am doing a project where I will be re-purposing an old TV satellite dish as a directional Wi-Fi antenna. The dish is circular in shape, not oval. The dish has an arm coming from the bottom that ...
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3answers
802 views

Can I test a base station CB radio with a magnetic mobile antenna?

I am looking at a base station and want to test it before purchasing can I use a magnetic mobile antenna to see if it transmits and receives without damaging it?
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1answer
379 views

What is pinout for headphone FM radio antenna?

My Android phone (as many others) have FM radio receiver on-board. But apparently, it has no internal VHF antenna at all, since there is no signal at all w/o headphones plugged in and sound quality ...
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3answers
247 views

Is cheap Chinese coax wire ok to use as an antenna?

So I've been following this guide on how to build an antenna for a High altitude balloon: link In the guide they say to use RG174 wire, which is why I bough some cheap RG174 wire off Ebay. I guessed ...
3
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2answers
698 views

Does a receiving antenna need radials?

I am very new to radio and am using two 433MHz 1/4 wavelength monopole antennas to send and receive data. On the transmitting antenna I'm going to add radials (as it is the standard in my application)...
4
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1answer
1k views

What frequency to set trap on?

I plan to build trapped multiband dipole so I read lots of documentation I found. There is one thing that confuses me: various authors recommend setting resonant trap frequency differently: some say ...
2
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1answer
192 views

Yaesu FTM-3200dr Antenna

I am looking to upgrade my station soon by buying a Yaesu FTM-3200dr mobile 2m radio. I am limited on funds for radio and I don't want to get the wrong type of antenna connector and wast a bunch of ...
2
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1answer
591 views

What material is best to design a dipole antenna working at VHF frequency? [duplicate]

I need to design an antenna using the tool FEKO. The antenna is supposed to work in VHF frequency and has a gain of around 2.2 dB. What is the best material to use and what are the specifications of ...
3
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3answers
636 views

What is the point of high gain antenna with respect to the maximum EIRP

OFCOM states that the maximum EIRP within the UK for 2.4 GHz is 100mW. Simply put, what is the point in being able to buy 2.4 GHz high gain antennas which can say do 24dBi, which already puts the ...
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1answer
152 views

Transition Point Between Fan and Cage Dipoles

A fan dipole is a dipole with multiple active elements, either for different frequencies or different directions (see turnstile antenna) while a cage dipole emulates a larger conductive by having ...
1
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1answer
459 views

Why Coaxial Collinear Antenna Gives Strange Graph of Frequency Sweep vs SWR?

Antenna Analyzer gives a understandable results for a Quad Antenna (photos 1, 2 & 3), but gives strange results for Coaxial Collinear Antenna (photo 4) Photo 1 of 4: Test setup for Quad Antenna ...
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2answers
684 views

Optimal antenna orientation for High altitude balloon?

(First of all, I hope this is the right subform, please correct me if I'm wrong) I am using a 433 Mhz LoRa Radio to communicate with a high altitude balloon and am using an antenna like in this guide ...
2
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2answers
1k views

What is the purpose of having multiple bays for a bowtie antenna?

What would be the difference between a two-bay antenna designed like this: and a four-bay antenna designed like this: Assuming that everything about these two antennas are identical aside from the ...
2
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2answers
175 views

Reciprocity for loopstick antennas?

What is the reason a small loop-stick antenna ( typically used for AM reception) does not have reciprocal characteristics for both reception and transmission. ( AM reception works great on those ...
2
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3answers
455 views

Packet Radio at 100 miles [closed]

I am wanting to assemble a Packet Radio solution that will allow for packet radio transmission with a range of about 100 miles or better. I am not sure what band to use, what radio to use, what ...
5
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2answers
1k views

What ways are there to extend an antenna?

I am using an arduino micro controller with a LoRa radio module to communicate. The shield has 2 ways of connecting an antenna: either a SMA jack or a hole for soldering. Now my problem is this: I ...
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2answers
159 views

Amplified antenna & typical boombox radio

Can an amplified antenna be connected to a typical boombox radio with a telescoping antenna without damaging the radio?
3
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3answers
894 views

What do you connect antenna Radials to?

I am trying to communicate between two arduino microcontrollers using radio. For this purpose I am building a whip antenna with 4 ¼ wave radials. I've done a bit of reading and have got most of it, ...
2
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2answers
947 views

Field Strength calculations with known antennas

I can receive a calibrated decibel milliwatt signal level from the output of any antenna at a given frequency. With a given antenna gain (dbi) in the direction I want to receive the signal (...
2
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2answers
273 views

baofeng UV-5RA has issues with j-pole

I have a baofeng UV-5RA which doesn't seem to receive properly with my j-pole antenna. my dad's radio (same model, different firmware) receives without a problem, so it's a radio issue. if I go into ...
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4answers
1k views

Good Hidden Antenna For 2m

I would like to have an antenna outside for 2 meter VHF use but I do not want it to be expensive and I won't be allowed to put it up if it stands out too much. Does anyone know a good antenna to buy ...
3
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3answers
231 views

How do you keep your vehicle clean with a mobile antenna?

I want to add a V/U antenna to my truck, but my wife started asking about weather proofing and car washes and I had no answer. How do you keep your vehicle clean after installing a new antenna, and ...
2
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2answers
289 views

dual band j-pole creates connectivity problems when connected all the way

I recently made a "deseret j-pole" dual band antenna for basic 2m and 70cm transmitting and receiving use. I have it on a large metal tube behind my house, connected through a 50 ohm pl-259 cable, and ...
6
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1answer
408 views

What kind of antenna is this?

This was found among some old ham stuff and is believed to have been used on 2 meters. The vertical elements are 17 1/2" long and the connector on the bottom is a standard SO-239. Antenna (left) and ...
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2answers
1k views

How to best connect an FM transmitting GPIO pin to an antenna?

I'm trying to use a RaspberryPi3 as a FM transmitter, using pifm and/or PiFmRds to send audio in 88-108 MHz band. The RPi can then use the GPIO-4 pin to transmit between ...
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1answer
1k views

My Baofeng radio won't recieve but transmit does not work when I hold the MONI button [closed]

My radio won't receive. Help? It literally went dead and I still have the rubber duck antenna
3
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1answer
355 views

Using an HF antenna for VHF scanning

Are there any disadvantages (or advantages) to using a long-wire HF antenna for wide-band VHF reception? Or would feedline losses make that useless compared to a ground level ducky or short whip? (...