Amateur Radio Stack Exchange
Amateur Radio Stack Exchange

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1500 questions
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3 answers

What skills will I learn from contesting?

I got into Amateur Radio for emergency preparation and to allow me to expand my electronics hobby. My needs are being met, but I'm wondering if I'm missing out on increasing my skills by avoiding contesting which, in and of itself, doesn't…
Adam Davis
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Does Coax Limit the Maximum SWR a Transmitter 'Sees'?

A recent discussion about SWR led to the assertion that a length of coax cable will ultimately limit the SWR to which the transmitter will be exposed. By experimenting with an SWR calculation tool like TLDetails, there appears to be a basis for this…
Glenn W9IQ
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What was the origin of the Morse code abbreviations "hi" and "es"?

In Morse code, hams use "hi" to indicate a laugh, and "es" to mean "and". Where did these abbreviations come from? Both being all dots, they are short and easy to send and easy to recognize, but why these particular abbreviations? For example, we…
Michael Geary
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1 answer

How can I do direct digital synthesis of a 630m WSPR signal?

I want to do direct digital synthesis of a 630m band WSPR signal. Specifically I'd like to use an Atmega 328 chip running at 20 MHz to produce such a signal. I will use standard phase accumulator algorithm which I believe I can get to run in less…
Eric Urban
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10
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2 answers

Multiple simultaneous tunings with SDR

I just found out about WebSDR, and I was wondering how is it possible that many listeners listen and tune to different stations simultaneously. Which components/technologies allow this, and how does this roughly work?
Cobe
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10
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2 answers

Why is this requirement in 60m in the US?

According to the FCC, if you are using an antenna other than a dipole, in 60 meters, you must keep a record of the transmission and gain of the antenna. I don't remember seeing any other requirement of log keeping. Why does this one exist? What's…
Pablo Fernandez
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3 answers

Why are germanium diodes specified in amateur radio designs?

It's somewhat common to find a schematic that calls for a germanium diode in amateur radio contexts. For example: This is a QSK circuit from the Fldigi manual. And yet, purchasing a germanium diode is a relatively difficult task. For example,…
Phil Frost - W8II
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10
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4 answers

What sources of power are useful in emergency situations?

Situations that call for emergency operating usually have some hams working in field conditions. Relying on the mains grid could be problematic. A lead-acid battery would probably be heavy to lug around should the operator need to relocate in a…
VU2NHW
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10
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1 answer

What is a waterfall display?

High-end transceivers apparently come equipped with a water-fall display - something to do with improved spectrum visibility. This is supposed to lead to potentially higher QSO count and rate. What is a waterfall display?
VU2NHW
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2 answers

Buddipole model comparison

Can anyone give me some insight into the different Buddipole models available? They look pretty similar to me except for the sizes. What would make you choose one over the other?
s3c
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3 answers

Using MIMO in Amateur Radio?

MIMO, Multiple Input, Multiple Output, is used widely in commercial data transmission. 802.11n and LTE devices use it to increase throughput, link reliability, and channel usage without increasing transmission power or using more bandwidth. While…
Adam Davis
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2 answers

APRS digi path for ISS digipeater?

So when I try to work the ISS digipeater, what should I set the digi path to be? My setup is a 5 W HT with a 2 m yagi connected to my phone with APRSDroid. I've tried the past few nights with ARISS R0ISS and WIDE2-2 and none seem to get picked up…
JW03
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3 answers

Stealth HF station setup advice

I need some advice on setting up my first HF station in a somewhat restricted townhouse community. If I had a detached house with a backyard I’d probably already have everything setup. But with this townhouse I keep second guessing what to…
ifletch
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10
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3 answers

Does modulation affect propagation?

Does the modulation scheme, whether OOK, SSB, AM, FM, a digital mode, etc, affect the propagation of a signal?
Adam Davis
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10
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5 answers

Can a Baofeng UV-5R Display Both Name and Frequency Simultaneously?

The Baofeng UV-5R style radios have a 2 line display that can display the Name, Frequency, OR Number of the selected memory location for each of 2 memory locations. Is it possible to display the Name AND Frequency using both lines for just one…
Lance
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