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Questions tagged [transmitter]

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Will a LPF filter on the transmitter prevent CW key clicks?

Reading about key clicks, it would seem that they are primarily caused by the fact that the square wave of turning the key on and off must, by definition, have higher frequency harmonics, which sound ...
SRobertJames's user avatar
0 votes
0 answers
71 views

Range of superheterodyne transmitters with low IF

As I understand it, the last mixer stage in a superheterodyne transmitter outputs the desired signal, an image of the signal, and the LO frequency. But a non-tunable RF filter is usually responsable ...
Green-Avocado's user avatar
2 votes
3 answers
395 views

How do radio jammers work?

I just want to prefix by saying I asked where to post this question on meta and no one was 100% sure but this seemed to be the most likely fit so please tell me if this is off topic and where I should ...
Ethan's user avatar
  • 129
0 votes
0 answers
74 views

Construction details for an HF Transceiver output power splitter

I have a requirement to feed two HF power amplifiers with one HF radio transceiver, maximum input power is about 400 W, is it possible for someone to post an answer with schematic and construction ...
Andrew's user avatar
  • 3,693
2 votes
0 answers
156 views

How to convert device with Monopole antenna to Directional/Dipole antenna?

I'm trying to increase the transmission range of a stationary wireless microphone toward its receiver by connecting a yagi antenna. Aside from the antenna sticking out of the top, I don't know where ...
user20377's user avatar
0 votes
1 answer
130 views

How to create FM Radio Mesh

What (devices transmitters, receivers and transceiver) do i need to create a fm radio mesh, instead of using a single transmitter with big antenna, i want to build fm transceiver mesh radio to cover ...
Hither Joe's user avatar
1 vote
0 answers
96 views

Problems with the Droitwich transmitter

Does anybody know what is up with the BBC transmitter at Droitwich in the UK, specifically the Radio 4 Longwave broadcast on 198kHz? It's been reporting intermittent faults for a while, and was off ...
user1211's user avatar
  • 129
3 votes
1 answer
117 views

Does ERP power depend on transmitter duty cycle?

I’m building a transmitter and I’m trying to stay under the ERP power limit of my country , which is 0.5 Watt at the frequency I’m working on . I was thinking about increasing the transmission range . ...
Alessandro Mini's user avatar
1 vote
1 answer
143 views

Would a transmitter similar to "The Thing" be legal on ham bands in the US?

The Thing was a listening device used by the Soviet Union to eavesdrop on US government officials. It was basically an AM transmitter if I understand correctly, but it required another transmitter on ...
Someone's user avatar
  • 604
2 votes
4 answers
1k views

Does an RF amplifier allow us to receive a signal from further away?

From my understanding a RF amplifier boosts the transmission power of your antenna, this will in turn give you a higher gain. However I've read that this only will give you a further "...
icyli2's user avatar
  • 71
0 votes
3 answers
137 views

How to transmit computer audio to a wireless microphone receiver? [closed]

I'm currently trying to broadcast my computer's audio output to a wireless microphone system receiver so that I can accompany my school's coming presentation with music. The frequency range is 480-598 ...
user21397's user avatar
6 votes
1 answer
179 views

How do businesses develop and test amateur radio products in the US if you cannot be paid for amateur radio use?

Certainly there are companies in the US (like Kenwood) that develop HAM products that transmit. For development and QA they would likely need to test the product outside of a Faraday cage. How can ...
KJ7LNW's user avatar
  • 775
2 votes
1 answer
216 views

Reasons for an antenna tuner at the transmitter other than transmitter protection?

An antenna tuner colocated with the transmitter may be required to prevent transmitting into an SWR higher than the allowed specification for the transmitter, or if the transmitter might overheat or &...
hotpaw2's user avatar
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1 vote
1 answer
99 views

multiple pcb trace antennas in the same design. Bad idea?

Since time is money and my PCB home making skills are not the sharpest, I would rather fit my PCB design with two unbalanced antennas (no balun, just impedance matching parts, for 315 / 433 MHz) for ...
kellogs's user avatar
  • 205
1 vote
0 answers
47 views

Is it beneficial to boost the transmit power from a transmitter past 2W around 2.4GHz?

I have a ready-made transmitter that outputs 2W of RF power at 2.4GHz carrier frequency (I'm trying to transmit TV using DVB-S2) into the antenna, and I was wondering if it made sense to add a power ...
user42875's user avatar
  • 151
-1 votes
1 answer
75 views

Acoustic Communication issues [closed]

[![I've attached schematic, I am connecting transducer directly to that header pins on receiver side. On transmitter side I am connecting op-Amp to boost voltage to +10v -10v.][1]][1]I am working on ...
Gaurang Solanki's user avatar
3 votes
1 answer
2k views

Implementing a BPSK and 4-FSK transmitters in GnuRadio (GRC) with USRP?

Currently trying to transmit a BPSK and a 4-FSK(MFSK) signal via GRC using USRP, I have two attempts at it but don't seem to be going anywhere. Still fairly new to GRC. For the BPSK, how will this ...
lceans's user avatar
  • 55
1 vote
2 answers
305 views

How many cars/devices can connect to a transmission from a 7 Watt FM transmitter

I currently own a 7 Watt Frequency Modulation (FM) transmitter that I purchased from eBay some years ago. We are planning a drive-in cinema setup where the transmitter will be placed 5 meters above ...
Manny265's user avatar
  • 113
1 vote
1 answer
371 views

Help getting use out of an old RC radio transmitter

I have an old "Walkera-RC 2.4ghz Radio Transmitter WK-2401" radio transmitter from an RC Helicopter. I want to use this transmitter with a receiver in order to transmit some sort of data ...
James McGreivy's user avatar
0 votes
2 answers
170 views

Repeater design using round robin transmitters to increase duty cycle?

I would like to build an FM repeater using a short stack of Kenwood TK-890H rigs adjusted to 70cm USA amateur band, but the model has a 100W rating with a duty cycle of only 20%. 20% isn't nearly ...
Jason W7DM's user avatar
2 votes
1 answer
192 views

Simple AM Radio Troubleshooting

I just got all the parts to make a simple AM transmitter from Scitoys. I followed the instructions from different websites and they still don't work. I don't know why it's not working. On my ...
Derpy's user avatar
  • 95
1 vote
2 answers
176 views

How should I go about finding the transmitter or antenna of a radio signal?

This site gets many questions about people trying to track down RFI, or interesting signals picked up on radios. Often the exact location of the transmitter or the antenna would be a valuable clue to ...
rclocher3's user avatar
  • 9,252
3 votes
2 answers
503 views

Why do repeater duplexers have notch cavities between transmitter and antenna?

Why are notch filters used on the transmit side of a repeater duplexer? The primary purpose of a duplexer is to keep the transmitter output out of the receiver input, since they both operate at the ...
AC0CW's user avatar
  • 51
3 votes
1 answer
155 views

Is this "floating" output single-ended or differential and against GND or VCC?

I'm looking at a simple FM transmitter output (see picture). It is from the collector of a transistor and it goes through a DC blocking capacitor before the antenna would be connected. The entire ...
pgibbons's user avatar
  • 444
2 votes
3 answers
696 views

FT-450D not transmitting with microphone

I've been using FT8 on my Yaesu FT-450D for quite some time. I decided to try to talk on phone frequencies and discovered neither one of my mics will transmit. My mics are the original hand mic and a ...
Lyndon's user avatar
  • 21
2 votes
3 answers
1k views

What replaces the T/R switch in modern transceiver

I have been watching and reading about the time when receiver/transmitter were separated and T/R switches were used. Current transceivers are still sharing a single antenna to transmit and receive. ...
ITChap's user avatar
  • 209
4 votes
2 answers
943 views

Reduction in transceiver power output into high SWR

How much do transceivers drop their output power, when the SWR is high? Most amateur solid state amplifiers or transceivers are (fully?) protected against high SWR, by a circuit which reduces the ...
tomnexus's user avatar
  • 11.5k
5 votes
2 answers
847 views

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 ...
user avatar
2 votes
1 answer
220 views

Can these in-band spurs from rpitx be eliminated somehow?

I'm putting together a 2m NBFM transmitter/receiver combo using rpitx and rtl-sdr. During testing my low-pass filter I discovered that rpitx is generating spurious signals within and around the band (...
user9103's user avatar
0 votes
1 answer
101 views

FT450D no cw tx unless ppt is held

FT450D in cw mode does not transmit unless PTT is actuated. "BK-IN" not in display despite pressing function followed by vox/store button.
Gordon Jackson's user avatar
0 votes
2 answers
203 views

sdr as watts and amps [closed]

Thanks to rclocher3 for helping edit more to English why closed so my struggle to get thought to English thank rclocher3 I round back too best I put in avuenue what I was asking why closed i tryed ...
kc0hwa's user avatar
  • 29
1 vote
0 answers
41 views

power limit on wireless FM microphone transmitters [duplicate]

I am building a "toy" radio station as a teaching tool for high school students to work with. I intend to use a small (short-range) wireless FM microphone module as the transmitter. What is the legal ...
niels nielsen's user avatar
0 votes
1 answer
474 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? [duplicate]

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 ...
Andrew's user avatar
  • 3,693
0 votes
2 answers
156 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 ...
R. Grondin's user avatar
0 votes
4 answers
162 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 ...
Mordecai's user avatar
  • 111
1 vote
3 answers
682 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?
Ben Madison KO4UXC's user avatar
0 votes
0 answers
93 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 ...
Sitorus's user avatar
  • 77
1 vote
1 answer
281 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 ...
elcojon's user avatar
  • 113
0 votes
1 answer
92 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 ...
BenRW's user avatar
  • 103
3 votes
4 answers
304 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 ...
Mike Waters's user avatar
  • 8,071
2 votes
1 answer
274 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 ...
Pizza Receptacle's user avatar
0 votes
1 answer
176 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 ...
John Smith's user avatar
4 votes
2 answers
412 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 ...
thegamebusterpl's user avatar
1 vote
0 answers
166 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. ...
Brian K1LI's user avatar
  • 7,878
4 votes
1 answer
233 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 ...
joe schneider's user avatar
5 votes
2 answers
273 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 ...
Paul's user avatar
  • 781
2 votes
2 answers
1k 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 ...
Ben Madison KO4UXC's user avatar
2 votes
1 answer
271 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 ...
RobC's user avatar
  • 123
4 votes
1 answer
512 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 ...
Zeiss Ikon's user avatar
  • 4,137
0 votes
2 answers
64 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 ...
user94416's user avatar