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1500 questions
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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14
votes
4 answers
What does the addition of a shield to a small loop accomplish?
A small shielded loop is an antenna with a loop of wire, smaller than 1/10th of a wavelength in diameter, also surrounded by a shield. Often, they are constructed from coax. There is a gap in the shield somewhere. Feedpoint arrangements differ among…
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
5 answers
How can I add amplitude modulation to this transmitter?
I recently built this circuit, and could hear a nice full quieting signal on my short-wave radio with a 7.2 megahertz crystal for the 40 meter band.
What is the simplest way I could Amplitude Modulate this signal with a microphone or computer output…
Skyler 440
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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
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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
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
1 answer
Why does the audio on my FM transceiver cut out every 5.5 seconds?
Specifically, my Icom ID-4100a.
What's interesting, is that this happens in MR and VFO modes... but NOT when using the built-in WX stations. For example listening to WX-01 (162.550 MHz), no problem. Listening to 162.550 via VFO and I get the…
webmarc
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14
votes
3 answers
Are Baofeng radios illegal in the U.S?
Having a low price budget, my search for my first ham radio to buy has led me towards Baofeng. A quick Google search on baofeng showed a lot of results that said that certain model baofeng handhelds are illegal in the US. Is that true?
hopefulhacker-Reinstate Monica
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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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