Amateur Radio Stack Exchange
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Questions tagged [transmitter]

92 questions
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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 radio might be an important factor of survival. This…
Radio1
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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 diagram: So it seems to me (and correct me where I’m…
RoboKaren
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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…
Alexander Churanov
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7
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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 slow. It's okay if I receive a small message in…
Akshit Mehra
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2 answers

Preventing CW key clicks

What are "key clicks"? How much does the rise time or bandwidth of a CW signal need to be limited to prevent other QSOs on adjacent frequencies from being annoyed by "key clicks"? Is there a legal limit regarding this (in the U.S.)? How do…
hotpaw2
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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 of PTT button that could be attached to it via…
Jack. D
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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 obviously no internet availability. But you do have a…
not2qubit
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How to calculate power transmitted by monopoles?

I only studied monopole in sending mode or receiving mode alone but never in both modes together, I have this question which says: Two vertical λ/4 monopoles are parallel to each other with 20 meters separation between them at 5 GHz. The first…
user17194
5
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2 answers

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 anything, or should they always be connected to a 50…
user3191449
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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 that I can receive with SDR and got inspired by this…
Hose Dias
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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 band antenna that can handle the 700 MHz to 5…
Jedi Engineer
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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 can be illegal at all power levels because even old…
Synaps3
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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 chip. The chip I'm thinking of is the Analog…
watkipet
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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 really 50Ω and if so why? If it isn't 50Ω, what…
Phil Frost - W8II
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Low power long distance wireless data communication

I am looking for a communication solution with the following requirements: wireless unidirectional, point to point low power (li-ion battery powered, should operate at least one hour on the single charge) low baudrate data transfer (cca 40 - 80…
Martin Ždila
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