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1500 questions
11
votes
3 answers
Where can I find the official definition of ITU Zones?
I've been looking around for a spot that has the official definition of what the various ITU Zones are, but can't find one. What is the official definition? I'm hoping for more than just a map, unless said map is VERY detailed and can be downloaded…
PearsonArtPhoto
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11
votes
1 answer
Why is dynamic range relevant for an SDR?
Sometimes I see dynamic range mentioned as a figure of merit for an SDR. For example, I know that the bits per sample used by the analog to digital converter can affect the dynamic range.
Why do I care about dynamic range? What happens when I don't…
Phil Frost - W8II
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11
votes
3 answers
When is APRS use considered commercial?
I've heard that APRS is only allowed for non-commercial use. I was thinking of a building a weather station that uploads data via APRS (so far, non-commercial). If I then include data from that weather station on a website with advertisements, is it…
Anssssss
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11
votes
4 answers
How do GPS receivers communicate with satellites?
I have a Technical Amateur Radio license so I know the basics of wavelengths. What I'm researching is how GPS works.
From what I've read, there are frequencies such as L1, L2, and L5 uses in GPS between the receiver and the satellite. These operate…
john_ham_radio
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11
votes
4 answers
How do I find out what bands are open?
Say the deck is stacked.
I'm out in the country with an all-band QRP home-brew rig, and an active antenna. Or say ship-wrecked and marooned on that desert island. The battery only has enough juice for say 1-min Tx, and 30-min Rx. The Sun is at the…
VU2NHW
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11
votes
2 answers
How to determine if my antenna is an effective radiator?
So I build an antenna, tune it with the SWR and make it look great for a 50 ohm load.
That does not determine if it is good at getting a signal out or not, it could just be a 50 ohm dummy load.
With my completed home-brew antenna, what is the best…
Skyler 440
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11
votes
5 answers
Why do operators mention the band when calling CQ on phone?
I'm a new-ish ham, licenced for about one year now.
Within that year I've heard a lot of CQ calls from other hams on phone (both HF and VHF), and it seems that a large portion of hams routinely mentions the band being called on within the call…
Ivan R2AZR
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11
votes
5 answers
Is it illegal to key up and not identify?
So, I key up on a repeater to see if it works, or to see what cool courtesy tone they are using. I don't do anything else. Is it illegal or bad ham radio etiquette to just key up for a second, key down, and not do anything else?
Where: USA, CO,…
Skyler 440
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11
votes
1 answer
Fastest Speed allowed for CW FM repeater ID in USA
What is the fastest legal WPM I can use for my repeater's Morse code identification?
I am in the USA.
Skyler 440
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11
votes
6 answers
What is a Gamma match in the context of the driven element of a Yagi antenna?
How (and why) does a Gamma match work, when used on the driven element of a Yagi antenna? As shown here:
(source: http://www.iw5edi.com/ham-radio/?2-element-yagi-for-10-meters-band,49)
The article describes a 10 meter Yagi where the driven element…
Ron J. KD2EQS
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11
votes
1 answer
How to combine two 50 Ω antennas such that they appear as one 50 Ω load?
I'm looking for a simple way to impedance match an array of two 50 Ω antennas so that when they are combined they appear as one 50 Ω load.
Assume that both antennas are identically constructed, are in phase with one another, and have the same VSWR…
Ben
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11
votes
1 answer
What is a CQ contest and what is the proper way to respond to a CQ contest call?
As I listen, I often hear stations calling "CQ contest". When I hear stations respond, they seem to do so with a specific set of information. I recognize the call sign and a signal report but there are often other pieces of information that seem to…
ghendricks
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11
votes
3 answers
AIS and RTL-SDR Dongles
I am looking for an Windows-based AIS Decoder for RTL Dongles. Currently, there is a solution available using GNU Radio and SDR# but it is complicated to set up and keep running.
ADSB has a dedicated solution called RTL1090 that connects directly to…
Mark Cupitt
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11
votes
1 answer
How does a "chip antenna" work?
How does a tiny surface-mount "chip antenna" for the 2.x thru 5.x GHz frequency bands work? What allows such a tiny item to radiate or receive RF with some amount of efficiency? What allows a chip antenna's radiation pattern to be (somewhat?)…
hotpaw2
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11
votes
5 answers
Non-traceable radio emitters
There are various techniques for locating a radio emitter. But what are some methods to make this really difficult? There is usually a patch to every vulnerability, at least from the world where I come from.
