Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

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1500 questions
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How do I renew my FCC amateur license?

I have a technician class license, and my license expires in March 2014. How do I renew my license? I received a notification in the mail from W5YI-VEC informing me that I could renew my license through them. They included a form that I can fill…
Ben Miller
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How does VHF/UHF propagate beyond the expected (radio) horizon?

I am not asking about the fairly well-known effect of the earth "appearing less curved to radio waves" that are otherwise still essentially line-of-sight, but a deeper arcanum: In the ARRL Antenna Book, 17th edition (1994) there is a discussion of…
natevw - AF7TB
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Could a weather balloon make a good antenna?

I can't afford a massive tower, but I can get a weather balloon. What kind of set up would work best to get the maximum efficiency out of altitude?
Muze
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Single or Dual Paddle Key?

I want to eventually use a CW paddle and built in keyer in my Yaesu FT-890. What are the merits of each style. Single or Dual Paddle. Does it make any difference if I start with say a dual paddle then later use a single paddle? Any disadvantages of…
jim
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Why isn't twisted pair used for feedlines?

My son was asking about some Ethernet cable (Cat 5 unshielded twisted pair), and since he recently passed his Technician exam and we both have "radio stuff" on our minds, I tried to make the analogy between coax transmission lines and the balanced…
natevw - AF7TB
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How to reduce RF in the shack when using vertical HF antenna (no radials)

What can be done to reduce RF in the shack (riding back along the coax) when using a vertical 10M antenna (without radials due to space constraints)? The antenna is an IMax-2000 at 32' elevation (20' over roof) with a 125' coax LMR-400, SWR is under…
Ron J. KD2EQS
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Confusion about SDR

I've just written code for the RTL2832 to receive and decode ADS-B packets (very cool!). I had some confusion about what is actually happening: Is the raw data coming from the USB dongle literally samples of the ~1090 MHz wave? Or is the carrier…
Nathan Wong
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Are hashes (such as md5) legal in the US

If I were to implement a remote computer control system using amateur radio, would using hashes (such as md5, sha-*, etc...) for authentication be permissible under the United States rules?
W8AWT
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What transfer rates are actually achievable using known digital modes?

I've found all sorts of info concerning digital modes, sound samples, spectrum samples, but nobody ever cites what speed a given digital mode can reach. Could anyone tell me more about that, or point me somewhere where I can find this kind of info,…
red-o-alf
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Why does AM have sidebands?

Why does AM have sidebands? Isn't the whole point of AM to broadcast on ONE frequency and ONLY change the amplitude? In the picture there is only ONE frequency and the amplitude changes, so why got AM sidebands? And why can't AM work without the…
Axel H.
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Is there a convention for SSB frequency selection?

I know that the amateur bands are not channelized. I know that anyone can pick an arbitrary frequency and they're not wrong, and you are not obligated to have a calibrated VFO. But if everyone picks frequencies at random during a period of heavy…
Kevin Reid AG6YO
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Should I ground my radio to the chassis or battery for a mobile install?

From what I've seen, there are generally two ways to power a mobile radio: Positive lead to battery, negative lead grounded to chassis Both positive and negative leads to battery I know that antennas should be grounded to the chassis, but what…
Ben
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While backpacking, is it worth mounting the antenna to the backpack frame (above my head)?

I am planning a trip with a large group in 6 weeks. We will be spread out in small groups on a trail in a mostly desert plateau landscape perhaps 5 miles apart, but mostly in a straight line. I'm new to amateur radio, but I have been studying and I…
NL - Apologize to Monica
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Does iron ore in the ground affect my signal?

Mineral content in the ground varies from one place to another. I've visited places where the ground & waters were an orange-red shade from the high iron content; not good for trees either. This post on eHam.net, seems to indicate there may be…
VU2NHW
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What would propagation look like on Mars?

If we could get a few HF stations on Mars, what would the propagation look like? Thought shamelessly copied from this blog.
PearsonArtPhoto
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