13 votes
Accepted

Resort FM radio station

I believe you have encountered a Part 15 radio station. United States Code of Federal Regulations, Title 47, Part 15 (47 CFR 15) covers such things as garage door openers and the like. As such, ...
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  • 2,031
8 votes
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Linux APRS client

Xastir is most likely what you want. http://xastir.org/index.php/Major_Features#SUPPORTED_TNC.27s:_DARN_NEAR_EVERYTHING.21 YACC - Yet Another APRS Client is also a newer choice. I have not personally ...
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  • 330
8 votes
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FT8 callsign/maidenhead compression encoding

You can find the code in packjt77.f90. Callsign encoding (for "standard" callsigns that don't require hashing) is in function pack28. A quick summary: ...
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  • 9,275
8 votes
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Calculating satellite passes without an internet tracker?

The simplest might be to use an app. On Android, Heavens Above, a product of the 25-year-old website of the same name, stores the orbital elements of the satellites of interest, and does the pass ...
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  • 8,225
7 votes

Do aprs.fi and APRS-IS use the same credentials?

The aprs.fi passwords can not be used when logging in to the APRS-IS servers. aprs.fi and APRS-IS are two different things. The APRS-IS network consists of roughly a hundred servers distributed ...
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  • 2,341
7 votes
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Decoding the Morse code

If you would like to decode Morse code with an existing program: My personal recommendation is Fldigi, which is a software modem that runs on most major operating systems, including Windows and Linux....
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  • 842
7 votes
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What does exclamation mark mean in FT8 CQ calls in WSJT?

That is something that is activated by "Show DXCC entity and worked before status" (selectable on the "Settings" > "General tab"). From the manual: When this option is checked WSJT-X appends some ...
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5 votes

What protocol or API does WebSDR use to stream audio?

The "HTML5"-compatible (not using Java applets) audio interface for WebSDR uses audio samples streamed over a WebSocket connection — this can be seen from the JS client files it downloads. However, ...
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  • 23.1k
5 votes
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How to read ID-51A GPS logger data

This is standard NMEA data format. The GPS is configured to provide the following NMEA strings: GPGGA, Essential fix data, time, location, quality of fix, altitude GPGSA, Dilution of precision and ...
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  • 11.9k
5 votes
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Open Source Library for Digital Mode

What you describe is Software Defined Radio! Hurray! So, everyone having read my answers knows: I'm a GNU Radio fanboy. GNU Radio has to be understood as the Free&Open-Source LEGO of Software-...
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5 votes

AX.25 on macOS (aside from APRS)

Xastir isn't bad at all but I recently encountered something called YAAC (Yet Another APRS Client). On it's site it states the following: YAAC can be used as a stand-alone APRS client, an APRS RF-...
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  • 161
5 votes
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What dot means in JTDX FT8 received messages?

Found on the JTDX groups.io (link won't work without login, unfortunately): sybmol • - this operator loaded his log into LoTW symbol ° - this operator loaded his log into LoTW and this is Hint ...
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  • 9,275
5 votes
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Is there a way to get FreeDV output level to follow the input audio amplitude?

It seems that FreeDV encodes the input audio signal in both the frequency and time domains, which means that the output signal amplitude doesn't follow the input signal amplitude, but rather the ...
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4 votes

Do aprs.fi and APRS-IS use the same credentials?

To get a passcode for the APRS-IS on APRSdroid you do not necessarily have to contact the APRSdroid Developer team. You can use any one of several APRS-IS passcode generators available on the web as ...
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  • 1,246
4 votes
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Is there an audio feature for Gpredict?

I just wrote you one. One of the things Gpredict can do is control antenna rotators (via the hamlib driver library). In this case, you're the rotator, but hamlib can't handle that (as far as I know), ...
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  • 23.1k
4 votes
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What rig should I start with when trying to get hands-on experience with Fldigi?

Nearly any SSB HF rig will do. You need some way to get audio out of the receiver and into your computer, and out of your computer and into the transmitter. Most modern transceivers provide some kind ...
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4 votes

HT programming software alternative to Chirp and RT-Systems

How about the software made by Baofeng for the UV-5R? http://www.miklor.com/uv5r/UV5R-Software.php I have used it and works fine when you figure out how to put it into English mode. The instructions ...
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  • 41
4 votes

Linux APRS client

You could use Aprx or Direwolf and configure the client as a Receive-only iGate. You can then assist in sending some directly received data to APRS-IS (the Internet side of APRS) and see the data ...
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  • 1,064
4 votes
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Line of sight from geographic/map data?

I've used this one several times. added: Go to the graphic under: Surface Elevation Tool. Scroll (zoom out to speed things up) OR use the search to get to your geographic area. Search somewhat ...
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  • 1,013
4 votes

Problem with sample rate

512 samples should take 256 microseconds, so your times look about right. The exact time it takes to execute those lines of code will depend on the rest of what your computer is busy with. And it's ...
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  • 8,225
4 votes

Problem with sample rate

The RTL-SDR interfaces to your computer via USB. The USB interface and driver will buffer the data and send it to your software at the requested sample rate on average (baring underflow due to ...
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  • 12.5k
3 votes

Is there any PC remote control software for the Baofeng UV-5RE Plus?

No the UV-5R does have a programming cable but it does not do any more that retrieve/store information to the radio. It is possible to build a small device that will listen to the audio output of the ...
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3 votes

Command-line satellite tracking software

Predict is the option that comes to mind. It is console based (no GUI), and provides a server mode where you can request data via UDP messages to a running predict server. It uses hamlib for rotor ...
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  • 1,099
3 votes

How can I send a voice message from my PC to HT radios?

All you need to do this is the following components: A radio to transmit the message. It doesn't have to be the same model as the HTs you want to receive the signal. In fact, it might be overall ...
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  • 23.1k
3 votes

Tytera MD-380 software (DMR radio software) not working on Windows 10

I had the exact same issue on the MD390 and it took some very frustrating attempts to make it work. Turns out its just that the software is just doesn't have an intuitive UI. Hopefully this will help ...
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3 votes

4NEC2 - Radiat-eff. vs. Radiat-power

I just did a bit of tinkering with 4NEC2 and I've got an answer. The Input power is the power generated by the source, and ignores all losses. It might also be called "Total power". The "Radiat-...
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  • 1,814
3 votes

4NEC2 - Radiat-eff. vs. Radiat-power

I'm a NEC2 user, never used 4NEC2, but I think it's the same engine underneath. The radiated efficiency is low because either: - a lot of power is absorbed by the ground, or - you have a structure ...
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  • 8,225
3 votes
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Can one modify footprints in Gpredict?

The footprint calculated by gpredict (and other satellite tracking software) is the area from which the satellite appears above de horizon (or, equivalently, the patch of earth seen from the satellite)...
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  • 1,099
3 votes

WSJT-X V2: How to identify stations already logged?

Set your "New Call" to one color and your "CQ in message" to a different color. My new call CQs are green and my "CQ in message" are light red. The light red indicates that I have worked the station ...
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3 votes
Accepted

ax.25 error shown in direwolf. Fails on channel 8, then 2, then works

This is issue #42 on Direwolf's GitHub page. https://github.com/wb2osz/direwolf/issues/42 To work around it, put the interface into CRC mode "none" with a command like this: ...
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