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1500 questions
12
votes
2 answers
What is a "roofing filter"?
What are roofing filters? Are there different kinds of things that are called roofing filter? Why would a circuit or component be called a roofing filter instead of just a IF bandpass filter? Why is the word “roofing” used? (as it seems to have…
hotpaw2
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12
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3 answers
Share antenna between receiver and transceiver?
I recently put up a fan dipole for 80/40/20/10. I'm looking for a way to share this antenna with a receive-only SDR and my shack transceiver. Obviously I can just switch this antenna between the two manually, but I was hoping there was a way to have…
s3c
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12
votes
4 answers
Can a ham license be used for a job?
If you get a ham license, can you, later on, get a job with that license, or at least display it on a resume? Or are there further licenses after ham radio licenses?
hopefulhacker-Reinstate Monica
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12
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3 answers
What is the decimal in Morse Code?
The ITU's International Morse Code recommendation ITU-R M.1677-1 specifies a "Full stop (period)" as ".−.−.−", however it falls short of specifying a decimal point. Even the examples, though they illustrate fractional numbers, don't show decimal…
Amin Shah Gilani
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12
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1 answer
Dominant speeds of Morse Communications
5 wpm is easy to learn and better than nothing in emergency.
Speed Morse Coding is fine for "sport competition"
I am trying to find out which is the typical speed for what I call "conversation" and define it with the following questions:
Are there…
03525
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12
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1 answer
Who funds amateur radio satellites?
I am currently studying for my Technician Exam and I am amazed at the sheer number of amateur radio satellites in orbit. Knowing how expensive it is to launch something into space, and assuming there is very little return on investment concerning…
Dave G
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12
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5 answers
What is the definition of DX?
I always believed that DX meant out of one’s own country, and in the continental US that can be pretty far. However, tooling around on the bands I’ll often hear people calling DX inside the US receive responses from others also inside the US.…
Adam Davis
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12
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2 answers
Why say "break" and "over" on walkie-talkies instead of an automatic chirp?
My understanding of why movie characters say "break" and "over" during radio conversations is based on this answer, which says that people using half-duplex devices often will want to let others on the channel interrupt them with something more…
Ryan
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12
votes
4 answers
Capacitive hats on wire dipoles?
Capacitive hats seem to be advertised as an option for mobile vertical antennas. One mentioned advantage is the they can widen the SWR bandwidth, making the antenna easier to tune.
What might be the effect of using capacitive hats, not on a mobile…
hotpaw2
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12
votes
2 answers
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?
Adam Davis
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12
votes
7 answers
Can I transmit anything inside a Faraday cage?
Can I perform any transmission regardless of my license as long as I'm inside an RF sealed enclosure, such that no RF will be detectable from my transmissions off my property?
I imagine the answer is yes, but I'd like to be sure I understand.
Adam Davis
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12
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3 answers
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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votes
3 answers
Why can't I hear myself from a second radio when bouncing off a repeater?
I am a relatively new ham, and haven't joined any club yet or participated in any nets. I have, however, hit a repeater just to know I can do it. I was told my sound was scratchy (no surprise there) but I want to hear how bad it is. I tried…
Bernem-KG7NUB
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12
votes
3 answers
What is the best practice when tuning an antenna on air?
I have a magnetic loop antenna that takes a long time to tune and of course, while tuning it, I need to be transmitting.
What is the best procedure for tuning on air? I understand I need to check the frequency and identify myself before…
David VK2VXK
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12
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2 answers
What are the (US) rules about unlicensed low-power transmissions?
It is common wisdom that transmissions of any sort (perhaps unidentified, encrypted, in the FM broadcast band, etc.) are permitted if they are sufficiently low power.
Where are the FCC regulations which permit this, or where can I find a…
Kevin Reid AG6YO
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