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8

Coverage maps are a thing that is notoriously difficult to do right. There are some very complex programs (Radio Mobile is the one I know the most about) which can generate coverage maps if you're prepared to wade through the technical details and the quirks of the software. Unfortunately it's not as easy as drawing a circle of a certain size around each ...


8

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 tried it. http://www.ka2ddo.org/ka2ddo/YAAC.html


8

APRS is a data transmission protocol and is independent of the underlying connection details. So there is no required modulation for the protocol. That said, the common implementation of APRS is FM modulated 1200 baud AFSK in the 2m band. Several major vendors like Yaesu and Kenwood support the protocol with built in functionality for APRS. There have ...


8

There's a few parts: §97.109 Station control. (d) When a station is being automatically controlled, the control operator need not be at the control point. Only stations specifically designated elsewhere in this part may be automatically controlled. Automatic control must cease upon notification by a District Director that the station is transmitting ...


8

So you want to broadcast your location using backpack-portable equipment from deep in a narrow valley hundreds of miles from civilization. I'll assume that you would also like the ability to get a message out when necessary. These are very demanding requirements. I don't think that there is any inexpensive, 100% reliable way to do what you seem to want, ...


8

This is answered somewhat in this question already, and the answer is no. And I will add some passages about the broadcasting part. To quote the relevant rule §97.113: §97.113 Prohibited transmissions. (a) No amateur station shall transmit: (1) Communications specifically prohibited elsewhere in this part; (2) Communications for hire or for ...


7

Most of the common disadvantages for Baofengs et al have to do with usability (e.g. poor user interface, odd squelch performance). The actual reception and transmission power is just fine. The majority of the disadvantages are negated when working with APRS, since it's the APRS modem interacting with the radio rather than a human being. The main thing you'd ...


7

There is no rule specific to APRS; the relevant regulations do not care about what mode, protocol, etc. you are using. From §97.113: §97.113 Prohibited transmissions. (a) No amateur station shall transmit: Communications specifically prohibited elsewhere in this part; Communications for hire or for material compensation, direct or ...


6

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 around the world, run by a large team of volunteer server operators. APRS-IS requires the use of the passcode number for logging in and sending data to the APRS-IS ...


6

I don't know Europe's regulations, but in the US under the FCC's jurisdiction, the onus is on the station operator to prevent unauthorized transmissions. An unlicensed individual using APRS on the internet wouldn't be violating any regulation, but the station operator who allows her station to make prohibited transmissions via the internet would be. ...


5

Actually, current specifications encourage or require digipeaters to add their callsigns to the WIDEn-N path, since including callsigns greatly helps in finding and fixing all sorts of network issues (look for "traceable" in the page). WIDE1-1 is often replaced by the callsign of a dumb digipeater, WIDE2-1 is usually prepended by the callsign of a digipeater....


5

My reading suggests that the advantage of AFSK is that the audio signal can be fed to any radio mike input. But if we ignore that, and assume a transmitter where the frequency can be controlled directly, can this be done? Yes, and it is sometimes done for APRS on HF. (This is still "to the mike input", but the radio is doing SSB instead of FM.) From the ...


5

AFSK sent over a FM radio is very different to FSK, as explained in my blog post FM over FSK: FSK over FM is not FSK when you look at the over the air waveform. The spectrum is no longer two tones bouncing back and forth. Assuming you have a FSK modulator that takes 0's and 1's as input, then you will not be able to generate the same signal as AFSK over ...


5

Two relevant facts about APRS: APRS stations are not obligated to get their location from GPS. And in practice, many fixed stations have manually entered locations. It is possible to transmit an explicitly coarse location (removing digits from the right). I do not think that this can be a coarse location because I cannot reproduce that center of lake point ...


5

I've put together something that is conceptually similar to @user3486184's comment, but without actually using chroot. I'm taking advantage of SystemD to manage both direwolf and the subsequent kissattach command necessary to activate an ax.25 interface. I created the following Systemd template unit and installed it into /etc/systemd/system/direwolf@....


4

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 appear on sites like www.aprs.fi You will need a password to be able to log to aprsis but this is trivial once you have a callsign and google for aprs password ...


4

Some of the cheap HTs, which were designed for voice, key up the transmitter quite slowly, and the transmitter also stays on for quite a while after the PTT is released. At least my older Puxings behave this way - they require a long txdelay in the tracker (delay from PTT down to the start of data transmission), and there's also a long "tail" after the data. ...


4

When two packets are transmitted simultaneously on the APRS frequency in a local area, it is unlikely that either will be understood. As the packet density in an area increases, the chances that two packets will be transmitted simultaneously increases. This issue is compounded by the presence of digipeaters which can unintentionally flood an area with ...


4

According to the way things work for simple AX.25 packets, the part after ">" is the destination address. However, the APRS specification commonly repurposes fields, with the goal being to keep the packet as small as possible. The destination field is like that: most APRS packets are broadcast rather than sent to a specific station, so when an APRS packet ...


4

What you are referring to is known as "Third Party Communications". Here is the blurb from the FCC on third party communications: Section 97.115 of the Commission's Rules, 47 C.F.R. §97.115, authorizes an amateur station regulated by the FCC to transmit a message from its control operator (first party) to another amateur station control operator (...


4

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 web based or Windows based applications . Just enter your callsign, press enter and a APRSIS passcode will appear with which you can login to the APRS-IS in ...


4

Apart from matured and highly reliable commercial satellite-based services, WSPR can be another 'DIY/experimental' alternative for broadcasting your location from wilderness. See examples for balloon, photo and ocean floater, photo. WSPR is an very low speed mode with 2x to 3x dB SNR advantage over many other digi-modes. Range of a few hundreds to a few ...


4

If the devices are fixed to transmit on amateur APRS frequencies, then you most likely cannot legally use them for business purposes, because that type of use is not allowed on the amateur bands — regardless of the design of the transmitter, the mode, or your license status. Individual countries have different regulations, but there is international ...


4

When you send something to APRS, even via Internet, it eventually may end up retransmitted on ham radio frequencies. Thus, you are not allowed to use the system if you do not have valid amateur radio license. APRS network requires you to identify using ham radio call sign which you have only if you have valid license.


4

You may be able to operate the device without consideration of your amateur radio status. CFR 47 Part 15.231 permits the low power use of 433 MHz without a license provided certain transmission repetition rates and maximum field strength rates are met. 433 MHz is commonly used by non-licensed home weather stations under part 15 provisions. If you need to ...


4

Here are the fundamentals of improving VHF antennas from what you've got: "Rubber ducky" (loading coil shortened) antennas are less efficient and more frequency-selective than un-shortened antennas. Choose an antenna which is a straight length of wire. (The exact length is not critical for receiving as long as it's in the neighborhood; you may get ...


3

If you're OK with using a smart phone instead of a regular GPS, you can use: APRSdroid with a Bluetooth TNC for an Android phone PocketPacket with an audio level converter you make yourself with an iOS device.


3

The APRS system and protocol itself doesn't track iGate type or frequency. There is a list of active iGates, but there is no frequency information for them, or for the packets they receive. Further no one appears to maintain a database of such stations. However those that have used it indicate that the coverage is good enough that you really don't need to ...


3

You're right, to make a properly working digipeater, you'll need to put both of the radios/TNCs in KISS mode, and use aprsdigi (or, my favourite, aprx), as a digipeater. But I don't think they can output both KISS and NMEA at the same time. For NMEA, you'll then need some other software to receive APRS packets, decode them and output NMEA. That's not very ...


3

The actual answer is a bit complicated and depends on a lot of things. In general, the answer is no, with exceptions, but the number of exceptions can be large, due to bilateral or multilateral agreements. In Europe, one of the most popular treaties is the CEPT recommendation T/R 61-01. Read the actual file for details, but in general, if you're within the ...


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