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1500 questions
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
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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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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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14
votes
4 answers
Is is possible to operate D-Star from a software-defined radio?
What is preventing a software-defined radio from transmitting the D-Star protocol?
Paul V
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14
votes
8 answers
Why are Wullenweber CDAAs obsolete?
Wullenweber circularly-disposed antenna arrays (CDAAs) are large HF direction-finding antennas, sometimes colloquially referred to as "elephant cages", that were popular in the Cold War. They allowed the bearing of an incoming signal to be located…
rclocher3
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14
votes
5 answers
How to operate IEEE 802.11 WiFi AP within the amateur radio service?
How can I properly use my ham radio license to operate an IEEE 802.11 WiFi access point within the US amateur radio service, rather than the US "part 15" regulations for unlicensed transmissions?
David Anastasio
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14
votes
4 answers
How can RF exposure hurt you?
In studying for the exam, one question came up about RF Exposure.
G0A
07
What effect does transmitter duty cycle have when evaluating RF exposure?
My understanding of Radio is that it is non ionizing electromagnetic radiation. How can RF be…
spuder
- 271
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14
votes
3 answers
Is there a KML or similar file that shows all of the CQ Zones?
I'm wanting to view the CQ Zones in Google Earth, and I understand that a KML file will allow me to do so. Is there a place where I can get a KML file that shows all of the CQ Zones?
PearsonArtPhoto
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14
votes
3 answers
What is the effect of using different number of radials with ground plane antenna
I'm new to electronics and telecommunication at all, I having trouble with understanding the difference between 2, 3 and 4 radials, as I've searched online I've learned that I can use only 1 radial(and it makes sense) but when using 2, 3 or 4 its to…
Aviel Fedida
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14
votes
2 answers
When is RF grounding necessary, and when is it not?
I've seen many installations, particularly at field day and also in second-floor installations, where RF grounding is ignored entirely. What are the drawbacks to this and when is it absolutely essential to have RF grounding?
Bill - K5WL
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14
votes
3 answers
Why do concurrent FM signals not mix together?
Generally when I hear two conflicting signals they do not mix together, but rather one dominates then the other. This phenomenon can be observed on FM broadcast station when driving out of range from one station into the range of another. During the…
Dan
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14
votes
4 answers
Calling a friend on simplex
Can someone please help clarify. I have tried searching all over, but almost all of the examples you find online and in books are for calling CQ on HF. I am new to ham radio, and recently got a few of my buddies licensed as well. I am confused over…
Atomiklan
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14
votes
1 answer
How would a time-difference-of-arrival receiver with two antennas know which side the signal is from?
An easy TDOA design by Byonics was published with the following schematic:
It appears that the antennas are switched at a rate of 640Hz, which allows a 640Hz tone to be heard in the radio when the antennas are not in phase. When the antennas are…
Adam Davis
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