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1500 questions
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2 answers

Propagation effects of noctilucent clouds

I know auroras are a propagation mode, but I was wondering with the recent outburst of noctilucent clouds (as reported on www.space.com) brings with it any interesting propagation modes, either on HF or VHF/UHF?
Duston
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3 answers

Is Field Day a contest?

Is the ARRL Field Day a contest, or is it not a contest? Kindly explain the reasoning behind your answer. A non-ham could not tell the difference.
Mike Waters
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What does "THREE ALPHA in Virginia" mean?

I'm listening to the 40m band during Field Day and I keep hearing things like "You are THREE ALPHA in Virginia," or "do you hold me ONE ALPHA in Eastern Pennsylvania?", or "you are TWO ALPHA Maine." I have no idea what they're talking about, can…
SandPiper
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1 answer

How do Field Day participants protect from lightning?

I'm planning to attend Field Day this weekend, and the forecast calls for thunderstorms. I can picture a serious issue with a bunch of temporary antennas set up in an open area when a thunderstorm sweeps through. This seems to have the potential…
Zeiss Ikon
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2 answers

Multiband vertical antenna not working as expected

I built a vertical out of a 5M aluminium pipe. It tunes fine (and wide!) on 20M. I decided to add a loading coil to operate it on 40M, and it also worked fine, albeit not so wide. While I was at it, I extended the coil for operation on 80M as well.…
hjf
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6
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2 answers

Is there any practical advantage to a parabolic reflector over a high-gain beam antenna?

I've been looking at options for a high-gain directional antenna recently, and I've noted that there are commercially available parabolic antennae for the shorter bands -- specifically 70 cm, with an antenna that probably doubles as a UHF OTA…
Zeiss Ikon
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6
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2 answers

Preventing CW key clicks

What are "key clicks"? How much does the rise time or bandwidth of a CW signal need to be limited to prevent other QSOs on adjacent frequencies from being annoyed by "key clicks"? Is there a legal limit regarding this (in the U.S.)? How do…
hotpaw2
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Pros/cons of the PL259/SO239 connector (M type)?

What are the pros/cons of the PL259/SO239 connector (M type), and why is it used preferentially on civilian rigs vs military?
Timtech
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6
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4 answers

Can an HF antenna be put inside a tree?

There are some trees around with branchy tops that seem wider than half of 10M, maybe even half of 20M, and above the nearby rooftops. Can a wire dipole or a vertical be mounted inside a tree? If so, what kind of problems might such an antenna…
hotpaw2
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Is copper-clad steel a good material for wire antennas?

There are some people selling steel wire plated with copper for making wire antennas. Perhaps the most well-known brand of this product, Copperweld, makes at least two kinds of copper-clad wire, copper-clad steel (CCS), and copper-clad aluminum…
Phil Frost - W8II
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6
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Noise bridge use in antenna construction?

How does a noise bridge work? And how can a noise bridge be useful in building, testing, and/or tuning an antenna?
hotpaw2
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2 answers

Low parts count CW HF receiver?

I'd like to be able to provide my kids with the opportunity to build something a little better than a passive crystal set, but still very, very simple in terms of individual electronic parts count. It seems to me that a CW receiver should be the…
Adam Davis
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5 answers

Are QRP transceivers only meant for CW communication?

I was just thinking about making a QRP transceiver, but are they only used for CW (Morse code) communication? If it is so, can I modify a QRP for two way audio communication?
Sumithran
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6
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1 answer

What is homebrew?

My question is the title itself: what is homebrew (or home brewing)? And how do homebrews differ from ordinary ham radios?
Sumithran
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Effective Area of Dipole Array

I'm trying to design a low frequency dipole interferometer antenna array. I am realizing how little I know about radio antennae. I'm confused by the concept of effective area $A_e$ and how it applies to arrays. I haven't been able to get a clear…
Spuds
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