Amateur Radio Stack Exchange
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1500 questions
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1 answer

How do I legally use a Baofeng UV-5R radio for communication?

I'm new to radios. Only ever used them for squad communication in airsoft. I have two Baofeng UV-5R handhelds and would like to use them this week to communicate on a family camping trip with no cell service. I wanted to know how to do this legally…
Rwstahl12
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Using Direwolf with multiple radios?

I'd like to play around with ax.25 connections. It seems that if I have more than one radio (operating on different frequencies) that I would want to have multiple ax.25 interfaces. Direwolf creates a /tmp/kisstnc symlink to the KISS pty device,…
larsks
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"Coaxial capacitors in line” in E4E04?

I've been studying the U.S. license examination question pools. For the most part, it is reasonably obvious what the questions and answers mean even when I am not yet able to come up with the answers on my own. However, the correct answer to this…
Kevin Reid AG6YO
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SNR measurement for a BPSK/QPSK signal

I have created a software (gnuradio) that performs modulation/demodulation and supports a number of modulation schemes and error correcting codes. I'm in the process of evaluating the BER vs SNR for this software by using a secondary…
Moses Browne Mwakyanjala
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4 answers

Why does not a bigger antenna receive more power?

According to http://www.antenna-theory.com/basics/aperture.php, the power received by an antenna depends on the power density of the incoming wave, the wave length (which I consider to be fixed) and the antenna gain. So if I want to receive more…
Giovanni Mascellani
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Are old USA amateur radio licenses in the public FCC database?

My old man worked in avionics for 30+ years and taught me nearly everything I know about radios, like how a superheterodyne receiver works, how the ionosphere refracts signals, etc. He grew up only a half hour away from the ARRL headquarters, and…
durette
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3 answers

What does a first-time operator need to know when looking for a DIY kit?

When I was growing up, I lived about three blocks from a Heathkit, and envied every device on the shelves. Now that I'm older, am teaching myself electronics and have a background in film and television broadcasting, I think I'm coming down with the…
dwwilson66
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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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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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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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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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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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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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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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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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