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1500 questions
16
votes
3 answers
Why do we not use AM and FM at the same time to transmit more information?
Amplitude modulation uses the modulation of the amplitude of a carrier wave to transmit data while leaving the carrier frequency constant, and in the case of FM it's just the other way round.
Why is a modulation of the frequency in an AM signal not…
DK2AX
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16
votes
5 answers
Can a licensed ham use or modify CB equipment to work the 10 Meter Amateur bands?
Can a licensed ham use or modify CB equipment to work the 10 Meter Amateur bands? If so, are there any advantages/disadvantages to this?
Timtech
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16
votes
2 answers
How does one read a ferrite datasheet?
Datasheets for ferrite materials are usually filled with incomprehensible graphs with greek letters. For example, Fair-Rite's 73 material:
What's a $\mu'_s$ and a $\mu''_s$? What do these numbers represent, and how can I use them in amateur radio?…
Phil Frost - W8II
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15
votes
4 answers
FCC tracking of unlicensed FRS/GMRS transmissions
If a transceiver such as the BaoFeng UV-5R is used to transmit over FRS/GMRS frequencies (unlicensed), it is illegal in the United States due to FCC regulations that state that the power must be <0.5W and that the radio must not have a detachable…
J. Taylor
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15
votes
3 answers
Why does SSB have the hollow voice sound?
When I listen to SSB, it has the very familiar tunnel-voice sound. What properties make it sound like this? With a Carrier and an extra sideband as AM, I don't hear the tunnel-effect at all. Is there special equipment to get rid of the effect?
Skyler 440
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15
votes
3 answers
What does Ham mean?
Amateur radio operators are always referred to as Hams, it's basically the most common term for the hobby, at least around here. Where does the term come from? I heard that it's an acronym for something, is that true?
Dan KD2EE
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15
votes
4 answers
Are there federal laws (US) protecting antenna installation?
Are there any federal laws or FCC guidelines that allow ham radio operators to install antennas?
I live in an apartment building in a large city that bans outdoor antennas. I recall reading that the FCC protected the installation of satellite…
Brad
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15
votes
4 answers
What should I consider when choosing a coaxial cable?
Given a middling-power rig (up to 100 W) requiring a 50 Ω antenna, a few options for the coaxial cable with a 50 Ω impedance are
RG-174
RG-58A/U
RG-8
RG-213
Apart from cost, what factors are relevant in deciding which coaxial cable to use?
VU2NHW
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15
votes
2 answers
If I install a G5RV in my attic how could I be certain there are not harmful levels of RF in the shack, or my kids bedroom?
I assume that anyone who has a G5RV or G5RV junior in their attic has done so with ceramic spacers, and has zigzag or dog-leg installations, or otherwise has contorted the antenna to fit up there.
My worry is how can I satisfy my own and my XYL…
Warren VE3WPX
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15
votes
3 answers
What is a linear RF amplifier?
Most of the RF amplifiers advertised, and most of the questions about amplifiers, are "linear" amplifiers.
What is a linear amplifier, and what other common amplifier type(s) exist that requires people to say "linear" every time they talk about RF…
Adam Davis
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15
votes
1 answer
What is the purpose of a balun and a unun in a feed line?
I have never understood how a balun or a unun works and under which situation I need to use either of them in an antenna feed line.
Dinesh Cyanam
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15
votes
11 answers
Is Morse code a digital, binary mode?
At first glance Morse code looks like a digital mode - there are dits and dahs, two values which contain the information of the transmission. Alternatively, at any point in time there either is a signal, or there isn't.
Morse code follows the…
DK2AX
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15
votes
3 answers
WWV, WWVH, and WWVL may be shut down. Are there any alternatives?
The US government is proposing to shut down the NIST standard time and frequency stations WWV, WWVH, and WWVB in Colorado and Hawaii.
If that actually happens, are there any free or inexpensive alternative frequency standards available so that we…
Mike Waters
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15
votes
2 answers
50 Ohm coaxial cable vs 450 Ohm or 600 Ohm ladder or window line?
What are the relative advantages and disadvantages of using 50 Ohm coaxial cable as opposed to 450 Ohm or 600 Ohm ladder or window line?
Timtech
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14
votes
5 answers
How does a folded dipole work?
A folded dipole is like an ordinary dipole, but with the ends extended and folded back, until they meet. Although it looks like a loop, I'm told it behaves similarly to a dipole.
How does this thing work? If I could see the voltages and currents in…
Phil Frost - W8II
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