Questions tagged [frequency]

Use this tag for questions about which frequencies to use or not use in certain locations/situations.

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44
votes
5answers
4k views

How do I report an emergency using ham radio?

If I'm in the wilderness with ham equipment but no phone signal, how would I report an emergency? Is there a particular frequency I would use, a particular protocol or suchlike?
7
votes
2answers
794 views

Why do some DX listen on a different frequency than they transmit on?

I've heard some DX indicate "CQ up 5" for instance, indicating that they are listening on a different frequency than they are transmitting on. What are the reasons one might want to do that?
9
votes
4answers
32k views

What is the difference between channel & frequency & band in RF?

I am reading about wireless networks basics. I found three terms I cannot find exact definition for: channel, frequency band, frequency. Can anyone give exact definitions for them?
5
votes
3answers
3k views

What frequencies am I not allowed to use north of line A in the USA?

What frequencies can I not use if I live north of line A in the USA?
3
votes
2answers
330 views

What are the technical reasons that there are no frequency modulated transmissions on the long- and medium wave?

Why are there no frequency modulated broadcasts on the long/medium/short wave, but only on VHF? I'm sure there are many historical and political reasons (long/medium/short wave were already in use for ...
3
votes
2answers
8k views

Can a Baofeng UV-5R+ be used on FRS, GMRS, and MURS?

Is this secure if I was talking to another Baofeng UV-5R+?
7
votes
5answers
506 views

Why do Hams refer to bands by wavelength and not frequency?

I've noticed while reading literature and websites geared towards and written by amateurs and ham radio enthiuasts that frequency bands are commonly referred to by wavelength. In professional ...
7
votes
1answer
672 views

Why are there no amateur allocations in the LF and VLF spectrum?

Amateur radio enthusiasts have slices of spectrum at every magnitude of spectrum MF and above, but in the US none are below MF. Why are there no spectrum allocations below 160M?
5
votes
1answer
155 views

What are these continuous sine wave tones I keep hearing?

I'm messing around on WebSDR and by just scanning through I sometimes come across these continuous tones in USB. One in particular was 28.800 MHz USB. I've picked them up on nearly every WebSDR unit ...
4
votes
3answers
190 views

What are these antennas used for?

I noticed this antenna park in Heidmoosstrasse, Switzerland. What is it used for?
3
votes
1answer
353 views

How can I tell the frequency without an oscilloscope, or frequency counter?

Just going through the RF oscillator listed on SM0VPO's web-site. I replaced C1 by a reverse biased 6A8, and used an E-core transformer pulled out of a Compact Fluorescent Lamp instead of an inductor ...