Questions tagged [transmitter]

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1answer
62 views

If i transmit on the same frequency using two separate transmitters joined together will they both add up in a reciever to produce a stronger signal?

If i were to use a passive transmit coupler to connect two transmitters of equal power output to the same antenna, and connect one microphone to both transmitters, and then transmit on both at the ...
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2answers
30 views

Required receiver for HX-1 (144.390 MHz) & NEO-6M GPS Module?

Context I'm launching a series of weather balloons as a capstone graduation project. Right now I am in the process of building the payload. I have been going over the different components of the ...
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4answers
92 views

Can I make signal transmitter without decoder?

I'm sorry if my title seems weird but I just started to learn about signal transmitting and I don't know where to start I'm searching about simple ways to make diy radio but I can't really ...
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3answers
91 views

Is there a way to split a frequency into channels?

Is there a way where I can take a single frequency and subdivide it into channels so theoretically I can transmit multiple voice channels on the other?
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0answers
54 views

Can I make a simple Tx/Rx antenna (Radio System) which will receive signal from BTS and broadcast/transmit it, and vice versa? [duplicate]

Consider a situation as below. I am stay in a farm field, which my house is 9.4km distance from the nearest and the only one BTS (Base Transceiver System), a cellular antenna for transmit and receive ...
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1answer
71 views

What happens when you directly couple the transmitter antenna to the receiver antenna?

I was wondering what happens when you directly electrically couple the transmitter antenna to the receiver antenna? Particularly I’d like to know what happens for FM radio broadcast. Since I don’t ...
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1answer
52 views

Unusual modulation

I've been writing a SciFi story, and it calls for something very unusual to happen. I'd like to check this idea for plausibility, but as I'm not a radio ham myself, I don't know if this already exists ...
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4answers
149 views

How is working on DC high voltages as in a tube radio different from 120VAC?

Suppose that I am familiar with the safety procedures for working on 20 A 120 VAC 60 Hz household lines. What should I be prepared for before working on high voltage DC circuits (say, 800 volts) as ...
2
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1answer
120 views

How does one know how a signal has been modulated

I am trying to intercept signals from a drone remote controller and decode them. Before I can do this I need to demodulate the signals. All I have is radio data from the transmitter's operating ...
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1answer
96 views

How hard to send files [duplicate]

How hard and expensive would it be to send a file from my house in London to a coastal area in Spain? It would most likely be software I want, so it must transfer perfectly, however if it is feasible ...
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2answers
97 views

Pi Matching circut for tube PA - what values?

I am working on my 80m and 40m CW transmitter and ran into a problem: I need to match the high impedance of PL504 to 50ohm coax, a Pi match seems to be the best, but I don't know how to calculate ...
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0answers
60 views

Parasitic inductance of relay contacts

I need to switch a bank of filters operating on bands from about 2MHz to 30MHz. The parasitic series inductance of the relay contact system will have an effect on the performance of my system. ...
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1answer
70 views

did static fry my uv5r?

I was hit with a big arc of static from a metal door frame. I was a little over a foot away. It stung pretty good, then my coworker told me I was transmitting. My baofeng uv5r will not stop ...
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2answers
206 views

Can I have a signal generator on while it's not connected?

The unit in question is an Elecraft XG3 test signal generator. It puts out anywhere from -107 dBm to 0 dBm. Is it safe to have these signal generators on and transmitting while not connected to ...
2
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2answers
191 views

How does keying a CW transmitter work?

In my handbook it talks about keying the transmitter to produce the dots and dashes. Does this mean that the operator is turning the transmitter on and off, or does this mean that the key is turning ...
2
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1answer
112 views

Where does this common spurious transmission come from? Is there a quality difference?

I decided to see what my ham transmissions look like on an SDR and was kind of shocked to see how much leaks out. The waterfall display is split between two handhelds during transmit. There are a ...
4
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1answer
122 views

Will I get cleaner keying by keying the oscillator, or interrupting the amplifier B+?

One of my goals as a new ham is to homebrew my own transmitter (using vacuum tubes, aka valves). Initially I'll stick with CW for the transmitter, though over time I might build an AM modulator or ...
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2answers
53 views

Simplest way to transmit beep 5-10km (3-6 miles) using FM? [closed]

I would like a simple device which enables me to transmit a beep every second or so on a chosen frequency. Is anyone aware of a product that can do this? If not, can anyone tell me what you would ...
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0answers
76 views

Can anybody identify an appropriate radio for this game? [closed]

Complete radio ignoramous here. I've been playing a game called The Blackout Club, and I'd quite like to make a 3D model of a radio set for it. The game is set around 2007 and, as in the picture ...
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1answer
55 views

Can radio waves be made to travel as or along a particle beam? [closed]

Can a laser be used as an antenna? Can a beam of any type extend transmission distance of an electromagnetic field? https://medium.com/starts-with-a-bang/this-is-why-the-2018-nobel-prize-in-...
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0answers
82 views

2GFSK 9600bps Transmitter and amplifier for 433 MHz

I'm looking for a reliable, however cheap solution for ground-space communication. I need at least 50W of transmitted power with 2GFSK modulation at 70cm band (433 MHz). Transmission will be done ...
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3answers
205 views

Long range communication with just 1W of power?

Is it possible, and how can I setup communication between stations 1000km apart from each other by using just 1W of transmission power? By communication, I mean: It can be text based It can be very ...
5
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1answer
222 views

How to create a simple 1296MHz transmitter?

I have asked this quesion on other sites, but want to try to repeat it here. Also I have asked question about multiplier, and this is a different question. I discovered a 1296MHz beacon in my city ...
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1answer
48 views

What circuit to use to multiply 434 MHz by two?

I wanted to make an experimental simple 1296 MHz transmitter to have fun with my sdr dongle. But after hours of googling I realised that there is no such thing as "simple 1296 MHz transmitter". Even ...
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2answers
267 views

Share wide band antenna with multiple transceivers

I'm trying to incorporate several transceivers on my board design; I need WiFi (2.4 GHz) SatCom (~1.6 GHz) RF (~900 MHz) and GNSS (~1.5 GHz). I need to combine them into one antenna. I found a wide ...
5
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3answers
374 views

Unlicensed TV broadcasting power limit (Band I)

I'm curious what is the legal limit for unlicensed TV signals being transmitted on the VHF Band I? This seems ill defined. The part 15 FM rules I am assuming don't apply here. And I don't think it ...
5
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1answer
987 views

How do PTT buttons work?

I'm really new to this, and I was wondering how the whole PTT system works? I have a headset with microphone, and a Baofeng UV-82 radio. I know the radio has its own PTT button, but is there any kind ...
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1answer
93 views

Is there any way in which elevation *does* affect medium frequency (AM radio) transmissions?

This is a followup to this question of mine. From reading the wiki article, I get that: Radio waves at MF wavelengths propagate via ground waves and reflection from the ionosphere ( called skywaves)...
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0answers
434 views

LimeSDR Mini + Raspberry Pi 3 B+ Transmission problem

I am new at this. I would like to transmit an audio signal cleanly using WBFM but I see two signal peaks occur around my fundamental frequency when I start transmitting. In this case I am using a ...
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1answer
91 views

Why would a nearby antenna cause intermittent transmission?

I'm having an issue with some handheld transmitters, and not sure if they're bad, or the newly-installed antenna is bad, or if this even makes sense. I've been using a handheld Icom aviation radio (...
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3answers
1k views

What does the spark-gap do in a spark-gap transmitter?

I read the Wikipedia article about spark-gap transmitters and I have to admit that I’m even more confused as to what the spark-gap actually did. The article references this simplified circuit ...
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4answers
1k views

How to tune an FM transmitter to a specific frequency?

I am planning to organise a simple fox hunt, a family event. This includes building a transmitter. I am currently considering the following schematics: https://maker.pro/education/diy-fm-transmitter ...
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1answer
118 views

Parts for a 915 MHz low power transmitter

I'm interested in doing some experimentation with custom modulation in the 915 ISM band. Off-the-shelf radio modules use specific known modulations (FSK, QAM, etc.) so those won't work for my ...
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3answers
286 views

Weird Harmonic Issue on Raspberry PI FM Transmitter

So I talked to my neighbor about my Raspberry PI, harmonics and his emergency radio. He told me to fire it up, as we saw the FCC sticker on it, meaning it is in compliance with Part 15. I started my ...
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1answer
70 views

Are there receivers and transmitters that can be tuned to multiple frequencies at once? [closed]

What kind of hardware/circuitry would be needed for a device to be able to transmit and receive over a range of frequencies at once?
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1answer
876 views

Ettus B210 USRP Is it possible to transmit on both Tx Ports either with same or different application?

Just getting up to speed on the ettus B210 - basically the same as the B200 but with two Rf boards. I am testing using gnuradio-companion. I have setup a very simple transmitter consisting of: ...
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2answers
553 views

Is my low-power VHF transmitter dangerous?

I use a Raspberry Pi for transmitting FM on 107.9 Mhz. It uses square waves and has a power of approx 0.085 Watts, but just to be safe: If I have a 1 watt transmitter approximately 1 metre away from ...
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2answers
863 views

How to transmit images and video through a hurricane?

Background You're in the path of a hurricane, and the eye just passed over your head. There is no electricity (apart from your own generator or battery), there is no mobile network and there is ...
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2answers
161 views

Is using a DDS chip directly a viable way to transmit 2FSK and PSK on HF?

I'm thinking of building an HF transmitter for data (AX.25 or PSK31). Rather than using an IF stage, I'm thinking of generating the RF frequencies (or phases) directly with a Direct Digital Synthesis ...
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2answers
85 views

Is there an advantage with having a DC bias for a FM radio transmission?

I'm studying FM radio transmissions at the moment. I'm using an NTX2B transmitter to experiment naturally assumed I'd use 0V for False/No signal and 3V for True. However, a lot of articles that I ...
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3answers
115 views

Is there a risk of interference between a 403 MHz and a 433 MHz Radio?

I hope the question is not too stupid, as I am very new to Radio. According to my logic, the obvious answer is no. However I believe to have read somewhere that interference may be a problem when the ...
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3answers
839 views

What is the output impedance of a typical solid state ham transmitter?

I've often heard that the output impedance is 50Ω, and the load impedance should be matched to that and also 50Ω. While the reasons for the load impedance to be 50Ω are clear, is the output impedance ...
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2answers
2k views

How far does a watt equal in range in the FM band?

How many watts would be needed to cover a 10 mile radius with good sound for music on the 88-108 MHz FM broadcast band? I am an amateur and for fun only.
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1answer
247 views

Would I be able to legally operate this FM transmitter without a license in Canada?

I've been looking into FM transmitters, and I've found one that I think I may use. The transmitter is based off of the KT0803L integrated circuit (http://radio-z.ucoz.lv/kt_0803/KT0803L_V1.3.pdf). The ...
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1answer
144 views

Signal booster with transistor

How can I make a simple signal booster without introducing too much noise? My first thought was to just feed the signal into transistor base (capable of 4GHz) through a 1K resistor. I could get a 1.2W ...
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1answer
345 views

Detecting the listeners

I wonder, if a broadcasting radiostation can detect, how many receivers are tuned on it, and if it possible - how exactly this detection is happening? Thanks.
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1answer
65 views

How does inductive coupling between transmitter amplifier stages reduce harmonics

In some notes on transmitters I have found the statement that "inductive coupling between transmitter amplifier stages reduces the generation of harmonics", with no further explanation. Can anyone ...
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1answer
132 views

is fm transmitters legal in japan

I was wondering what the laws are in Japan concerning FM Transmitters. I recently purchased one of eBay (http://www.ebay.com/itm/401047827071) I don't have a license or anything so I would like to ...
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4answers
8k views

How To Join Packet Radio BBS

I'm a complete newbie here, and on the Southeast Coast of the USA. I don't even own a ham radio yet. Some preppers and I got to talking about a dystopian time of Internet collapse where shortwave ...
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1answer
178 views

Is it possible to generate rf by directly programming a pc parallel port?

From what info I've found, it seems a pc parport has a max speed of ~2meg /sec ? So transmission on medium wave, to ~160 meters should be possible ? With antenna than possibly a small wire, I ...