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1500 questions
4
votes
3 answers

Receive directionality of a sub-optimal Yagi

How do I build the best antenna for a given VHF frequency given that an optimal design is too large? I am trying to understand the properties of a directional antenna of sub-optimal design. All the discussions of directional antennas assume…
dwitten
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1 answer

How to bypass LNA for TX in UHF Antenna?

I want to work with amateur, low power, and/or pico satellites. I would like to use an Eggbeater or Turnstile antenna with my UHF 433 MHz radio, since those antennas are very cheap and easy to build and I don't have to care about yagi rotors. The…
vz0
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4
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3 answers

Bridging LAN over ~1-2km distance

A friend of mine and I live across a lake from each other, and recently we thought it'd be fun to try and connect our computers together somehow across that distance. Running cable from either side is expensive, difficult (no boat), and probably…
haze
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2 answers

Experiences on a 70 cm band shared with radiolocation service

I currently live in Brazil and our governmental regulatory agency (www.anatel.gov.br) has recently started a public consultation process regarding the allocation, in secondary nature, of part of the 70 cm band to the radiolocation service. Some of…
Rodrigo Magalhães
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1 answer

What does the APRS 'to'/destination address mean?

I'm looking at incoming packets. Here's the beginning of a few messages: KF7WXW-9>TU3RTW,WIDE1-1,WIDE2-1:`2D<.. KX5ONE-9>T5SRPV,WIDE1-1,WIDE2-1:`2E0.. KX5ONE-9>T5SRSV,WIDE1-1,WIDE2-1:`2E .. So, what to the Txxxxx labels mean? The APRS spec talks…
300D7309EF17
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What is "Meter" referencing in "60-Meter Band"?

I know that there are various bands referenced in meters (or cm). My question refers to what exactly the word "meter" is referring to when identifying the 5MHz band? I know that the 60-meter band is 5MHz, and considering that communications on that…
RedDogAlpha
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3 answers

Recommended 9:1 unun core type(s)

I would like to construct a 9:1 unun that connects my QRP transceiver to a random-wire antenna. The transceiver's antenna connection is an unbalanced BNC jack and the random-wire antenna is, well, a random wire. ;) I have several toroidal ferrite…
Will B - AF7EC
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3 answers

What should be in a one hour class about Radios in Boy Scouts

I have been tasked with teaching a one hour class to adults who lead Boy Scout troops about "Radios in Scouting". What should I teach them? Possible subjects include: Teaching the Radio Merit Badge Operating a Jamboree on the Air Use of radios on…
RobSartin
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1 answer

Why is 900MHz restricted in some areas in the US?

So I found these rules: (2) No amateur station shall transmit from those portions of Texas and New Mexico that are bounded by latitudes 31°41 ′ and 34°30 ′ North and longitudes 104°11 ′ and …
Skyler 440
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Low power long distance wireless data communication

I am looking for a communication solution with the following requirements: wireless unidirectional, point to point low power (li-ion battery powered, should operate at least one hour on the single charge) low baudrate data transfer (cca 40 - 80…
Martin Ždila
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4
votes
1 answer

Warbler vs SoundModem

I'm trying to decode a BPSK 1200 (with no success). In this endeavor I tried both SoundModem and Warbler. The scenario here is the following: Ettus receiver + HDSDR with speaker plugged into mic via an audio cable. Warbler and SoundModem both do the…
KcFnMi
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HackRF One — Expected 'hackrf_transfer -t' file format and its creation?

What file format does the HackRF One expect on the command line, using the -t option with hackrf_transfer? Also, how would I create or convert that format from a standard WAV file? I was expecting the following to transmit a 36 second wav…
M6JNY
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4
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Why there is no AFSK in FLDIGI

I was expecting to see an AFSK option in the Fldigi "Op Mode" menu (as there is one option for CW, i.e.), why isn't it there? Basically, I want to get the data send according to this.
KcFnMi
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4
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2 answers

Is this simple description of SSB correct?

I was recently asked to explain why a "carrier injection oscillator", or CIO is needed in an SSB receiver but not in a transmitter. This is the explanation I gave, and I would be grateful for comments on its validity. I find the usual diagrams…
Harry Weston
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What is my VE status?

I was an ARRL VE years ago. The info about ARRL VEs says that you remain a VE and the only way one will be dropped is loss of license. However, years ago to be a valid VE one would have to have a current date sticker on one's badge. Am I still a VE?…
Herb Robbins
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