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1500 questions
6
votes
1 answer
What prevents automation in contests?
It seems that using a CW skimmer with an SDR one could fully automate a contest station, and even handle multiple contacts simultaneously in the case of pile-ups.
Has this been done or discussed before?
What rules are common that would prevent this…
Adam Davis
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6
votes
1 answer
Optically clear RF shielding?
Is there a material suitable for use as RF shielding that would allow at least 50% light transmission in the visible range? Thinking about a sensitive light receiver.
Adam Davis
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6
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2 answers
During a radio contest, how do I determine if a station is "too faint" to be worth trying to contact?
Suppose I hear a station during a contest that is an eligible contact, but not necessarily a multiplier (worth points, but only a nominal amount of points). This station is relatively faint, (maybe 2-3 S-units above the noise floor) but…
W5VO
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6
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2 answers
I was told to check the cluster. What does that mean and how do I do that?
A comment on this question says to "check the cluster". What does it mean to "check the cluster"? I'm guessing it's a website. I did an internet search and http://www.hamcluster.net/Map.aspx seems to be limited to DX.
YetAnotherRandomUser
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6
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2 answers
What should I put in a "Go box", "Go bag", or "go kit" for emergency communications?
If I wanted to build a mostly-portable-but-still-comprehensive kit to use in emergencies, either my own, or simulated ones through ARES or RACES, what should I put in the kit? I'd prefer responses to be generic (see below), though I won't complain…
YetAnotherRandomUser
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6
votes
1 answer
Two antennas on different sides of a building
I live in the 4th floor of a building with one side facing south and the other north. I am able to use my 2M mobile base transceiver with a mobile magnet mount antenna placed just outside the window. I get fairly decent coverage of areas on one side…
4G1BGS Larry
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6
votes
2 answers
Advantages of IQ generation at Mixer Stage or within FPGA for SDRs
I draw two possible architectures for Software Defined Radios below.
In the first architecture, I,Q signals are generated at the mixer stage and two ADCs are required. The FPGA down-samples the samples from ADCs and forwards them the USB PHY.…
Denis
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6
votes
1 answer
USA/callsigns: Why is California region 6? And the midwest in regions 7-9?
I don't quite understand the regional callsign system for the USA. At first it seems to make sense with CT, MA, ME, NH, RI, and VT being region 1 and then going west NJ and NY are region 2, and then DC, DE, MD, PA for region 3.
But why does it end…
RoboKaren
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6
votes
1 answer
Baofeng UV 9R Handheld programming
I have a Baofeng UV 9R Handheld that I just recently bought and received in the mail brand new, however as much as I like this handheld device I am maxed out with frustration as far as manual programming of this device is concerned. Does anyone have…
Sebastian Masters
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6
votes
3 answers
Alinco DJ-500T handheld radio will not transmit, why?
Shows the word OFF on screen when PTT is pressed. In settings "TX" is set to on, what am I missing?
The manual is no use due to poor translation and general incompleteness.
Kevin
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6
votes
3 answers
Practical differences between switching and linear power supplies?
Power supplies for ham radio equipment (and other equipment of course) seem to come in two flavours: switching and linear. The switching gear tends to be cheaper and smaller as well as more efficient.
My understanding is that switching supplies…
Jim MacKenzie VE5EV
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6
votes
3 answers
Why are 2m and 70cm the common frequencies on HTs?
Why do most HTs have 2m and 70cm as the two bands? Is it just out of history or tradition, licensing restrictions, or is there something in the transceiver or antenna design that would make these the two obvious frequency bands of choice?
RoboKaren
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6
votes
2 answers
Is CW necessary to be competitive in most ARRL contests?
The ARRL hosts many contests throughout the year, and maintains a leaderboard of sorts to encourage competition.
Is it possible to rank on any of the leaderboards without knowing or using morse code?
Adam Davis
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6
votes
1 answer
What is "Billion Code" for garage door openers from around 1996?
I've been trying to "hack" my garage door using an SDR (LimeSDR) for a high school physics project, and I have run into a snag.
When I look at the signal and demodulate it using ASK in Ultimate Radio Hacker (URH), I seem to be getting a signal that…
Ben Newhall
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6
votes
3 answers
Why do we distinguish between balanced and unbalanced?
I hear all the time, "you need a balun between your balanced dipole and unbalanced coax to stop the common-mode current" when it seems the proper advice is "you need something to stop common-mode current (full stop)." Sure, attaching a balanced…
Dominick Pastore
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