Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g. TV or radio) waves. -Wikipedia

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Data transmission in ocean

What is the greatest depth where we can communicate with the submarine over the sonar system in ocean? Also, how can we calculate how much data can be transmitted using this method?
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1answer
50 views

Does an antenna work inside a plastic box

I need to put two antennas for GSM and GPS communication on my PCB. My final product will be embedded in a user-friendly plastic box with buttons, leds and switches. I have not choosed yet which type ...
2
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1answer
280 views

What is an antenna amplifier ? How does it add gain?

I don't know what exactly does antenna amplifier mean. Is it possible to increase the gain of a Tx antenna ? Where do I connect the antenna amplifier to it ? If, for example, the Tx has a power of 20 ...
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0answers
51 views

Can a PC sound card (realtek) be used to transmit radio signals

If I were to use software such as PureData to generate a 20 KHz sine wave and perform AM on the wave, played it out the line-out on the right channel, with the ground and the left channel sent to a ...
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0answers
38 views

Easy-to-use Antennas for beginners

I am designing an embedded system with a GPS and a GSM modules both from the u-blox company. I need external antennas for my GSM and GPS modules. From what I see when I looked for antenna integration ...
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0answers
29 views

Arduino Broadband Peak Frequency Detector

I'm hoping to build a peak frequency detector, but am wondering whether I'm going to need more than just a couple of antennas. I'd like to be able to detect between 5Hz and 5GHz. So one question is, ...
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1answer
30 views

Working of resonance phenomenon

How does actually the resonance phenomenon help to receive AM signals in a receiver?
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2answers
133 views

Where does radiated power come from?

I've had electromagnetism classes back in uni, but I'm having a hard time linking them with that matter: Take a car antenna -which I assume is simply a wire, coiled or not-, and apply a voltage ...
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3answers
143 views

How should I test a coaxial cable?

I'm a ham radio operator, but haven't been very active on HF bands for a while. I have an inverted-V antenna and a long run (approximately 25m) of coax that runs from my upstairs "shack" down the ...
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0answers
39 views

How to increase the read range of an active NFC tag?

I want to read a NFC tag at a distance of 1m from my NFC enabled smartphone. Is it possible to do so by enhancing the antenna of the NFC tag (not the one on the phone). Size of the NFC tag is not an ...
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1answer
48 views

Two different length antennas can cause problems?

I am using two 443 MHz transceivers (FY-605 transceiver) with both having different antenna lengths. One antenna is around 12cm long and the other antenna is around 17cm long. Will this cause ...
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1answer
46 views

Relationship of antenna size to gain and directivity

This question is derived from certain answers I received for a previous question I posted. Case : Let's say I have two GSM antennas of the exact same shape, design and material. The only difference ...
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1answer
36 views

Gain vs. Directivity and effect of animal body to Antennas

My design works in a foresty area inside a collar of an elephant. These areas have at least -110dBm GSM strength (accurate ref. map linked) but, usually higher as I live in a small country where GSM ...
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1answer
62 views

How does a receiving antenna generate current/voltage?

I have see on many websites people explaining how antennas radiates energy. But I am failed to find an explanation on how a receiver (i.e. receiving antenna) generates current/voltage? Can anyone ...
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3answers
63 views

Waterproofing a GPS antena

I need to use this GPS antenna on a model boat. As a result of placement, it will be submerged periodically (though I don't expect it to work while submerged), and damp often. What can I encase it in ...
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0answers
67 views

433MHz quarter-wave length antenna: Longer is better?

I am trying to conduct an RF project using some cheap modules: link here My problem is that even though most blogs and Google searches for these modules use a quarter-wave length antenna (roughly ...
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1answer
47 views

How does the impedance that voltage “sees” while traveling down a tranmission line affect how the current move down the line?

It is well known that the voltage sees different impedances while traveling down a tramission line, and this impedance is a function of the intrinsic impedance of the line Zo and tangent of wave ...
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1answer
114 views

Length of a 40MHz antenna

A few days ago I had the brilliant idea of replacing the ugly antenna of a 40MHz car remote control with an extendable one. Now the range decreased from 50 meters to 3-4m. I don't know exactly what I ...
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2answers
62 views

What is actually transformed in quarter wave transformer?

I'm reviewing some stuff on quarter wave transformer for a transmission line but since I have not had any experienced in handling these type of stuff, I am struggling to understand this concept ...
5
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1answer
247 views

Antenna Design for specific directions

I am designing an antenna for a device and was hoping to gain some insight in the correct design direction for the antenna. The Idea: A receiver & antenna that fits in a 6" diameter by 3" deep ...
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0answers
49 views

Material that Degrade GPS Signal Reception

Between clear tempered glass (see through,thick & very strong) Vs. coloured plastic material, which would result in more degradation of GPS signals if used to make a box? The box contains a ...
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1answer
46 views

Important Parameters to Check while Chosing a GSM/GPRS Antenna [duplicate]

what technical parameters decide the performance of a GSM/GPRS antenna? (excluding power consumption and size) I have found out several antennas that have 3dBi gain. And I want to chose between them. ...
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0answers
53 views

Mobile Phone GSM Antennae Used | What are the Latest Types?

What is the best antenna type mobile phones are incorporating nowadays for GSM/GPRS connectivity? Is it PCB etched antennas or anther? I want to know this because mobile phones have the same ...
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0answers
43 views

Is 3dBi PCB etched GSM/GPRS Antenna Possible?

Is it possible to design a GSM/GPRS antenna that has a gain of 3dBi? if not, what is the maximum gain possible with a PCB GSM/GPRS etched antenna? I'm thinking of a PCB sized 11cm long and 5cm width. ...
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1answer
42 views

Impedance line matching and component value matching

I have the following circuit for the SIM900's antenna connection, using the A10393 antenna from digikey: In closer look: First of all my knowledge on RF design is not great. My questions now are ...
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1answer
56 views

Connecting dipole antenna for transmission

I have a small FM transmitter on a breakout, the antenna is a single connection. It came with a thin blue wire for this purpose; below it spirals up and out the top of the photo. This works fine ...
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1answer
70 views

How to reduce objects/hands impact on PCB antenna efficiency

I am trying to learn about planar inverted F antennas creation and have designed two different designs for two different frequencies with success. One seems pretty much unaffected by the proximity of ...
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1answer
70 views

Is it possible to extend the reach of a pn532 NFC/RFID shield?

I am working off an Arduino UNO with an AdaFruit pn532 NFC/RFID shield. The goal is to have a shoe box, with a false bottom. Under that false bottom would be my prototype, which hopes to be able to ...
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0answers
52 views

RFID reading / sniffing demonstration at a live-event

In the context of a live-event, we want to demonstrate how easy it is for someone with the right equipment to sniff RFID devices, including clear-text information. Our idea is to hide a RFID reader ...
0
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1answer
58 views

What components do I need to connect a phone to my device via Bluetooth?

I have a phone I want to connect to a docking station I am making, via Bluetooth for as cheap as possible. As I understand the situation, all I need is something that can pick up a bluetooth signal ...
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1answer
72 views

Determine the working frequency band of unknown RFID chip

I have a passive RFID chip from which I would like to scan the ID. I have a standard USB RFID Reader, but this doesnt print out anything. This reader scans the 120–150 kHz range, so the chip must ...
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1answer
48 views

Passive RFID transponder timing system

I'm looking to build a timing system base on passive RFID transponder. This is how I see it : An antenna to "question" the tag An antenna to receive tag unique ID A tag with unique ID I would like ...
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1answer
54 views

Radio direction finding - dependence on source signal type

I want to make a robot that can track the direction of the transmitter that is controlling it, for example to aim a camera at the transmitter. The robot vehicle will be controlled by a 2.4ghz ...
8
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1answer
165 views

Antenna matching network topology

In tuning an antenna, there are multiple possible topologies that will take it to the middle of the smith chart. Some differences that I can see between them are: Component ESR (losses). Effect ...
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1answer
41 views

Effect of antenna position indoor and influence of multipath

for my current project I do research regarding indoor-localization and I try to use the RSSI from my wifi to calculate the distance between smartphone and access point. I heared that: ) this ...
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2answers
110 views

Impedance matching with unknown load

I somewhat know the answer to this question but just want to clarify. In order to design the impedance matching, I will need to know the load impedance and the source impedance to begin with. ...
3
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1answer
87 views

What exactly is (Horn) Antenna Gain

I was doing an experiment for finding the radiation pattern of Pyramidal Horn Antennas at RF frequencies(as part of my course curriculum). There I came across the Friis Transmission Equation What ...
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2answers
110 views

How can I turn pulsating DC (square wave) from a 555 IC timer into an ac square wave?

I am trying to create build a morse code transmitter. I know that morse code is sent at 500 KHZ so I set my 555 to spit out pulsating DC in a square wave with 9 volt peaks. But I am unsure wether ...
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4answers
65 views

GPS Antenna Selector: How to electronically select one antenna from multiple available antennas?

I want to connect multiple GPS antennas to a single GPS module and select one of them based on some logic. Basically, I want the module to receive signals from only the selected antenna. Is there an ...
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1answer
99 views

How to install an embedded GPS patch antenna

How should I install an embedded GPS antenna? Here is the antenna in question: http://www.robotshop.com/ca/en/seeedstudio-embedded-gps-antenna-for-gps-bee.html It has a 9 cm cable. My project ...
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1answer
97 views

Antenna Diversity: two Yagi antennas to the Rx and Rx/Tx u.fl-male points on the wifi-NIC?

I looked at the BCM4312 file - available as as doc or a pdf - and it says: BCM4312 has 2 radio chains, one is a dedicated Rx chain, the other is shared by TX and > RX chain using an RF switch ...
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2answers
94 views

RF Energy Harvesting Project

I am presently working on an energy harvesting system using RF signals. I have read some of the other posts made on this topic and have learnt quite a few things. However, I have some questions that I ...
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0answers
73 views

What kind of antenna is this?

The product page for this antenna supplies meager information. Do any of you RF gurus have a guess what kind of antenna this is as well as any other insight or reference radiation patterns?
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2answers
43 views

Multi-antenna extension for NFC

Like many, I am new to this. I am working on a project that would require a short read range over a covered space, like a person's body or table top. Could I make an extended antenna from my smart ...
3
votes
2answers
228 views

AM and FM reception with the same antenna

I'm designing a radio with the Si4735 chip to use in a car, and I want to use the existing FM antenna for both FM and AM reception. I'm not sure how to go about this, exactly. How would I go about ...
0
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1answer
91 views

Improving reception of 318MHZ remote control

We have a gate opener with keyfob-type RF remote transmitters that operate at 318MHZ. The range from inside the car is about 75 feet -- less than we'd like due to the time taken by the gate ...
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1answer
80 views

Separate antenna for radio transmitter and receiver

I am building a HAM radio. Do I need a separate antenna for transmitter and receiver? I will be using 20m band and voice communication (No Morse code). My primary requirement is that I should be able ...
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2answers
62 views

What are evanescent fields?

I am not able to understand what is the origin of the evanescent field, how do they interact and what is the physics behind it.
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2answers
105 views

SNR vs Signal Strength for digital throughput

I'm trying to compare two antennas, A and B for WiFi. A is showing: Signal Strength of -77dBm, but SNR of 9dB. B is showing: ...
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2answers
275 views

What is the difference between peak-power, average power and true RMS power in RF measurement?

What difference between peak-power, average power and true RMS power in RF measurement? I have read a peak-power measurement can calculate average power measurement also. Does any of these needs ...