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11 votes
Accepted

Why does the FCC put restrictions on symbol rates?

That's a good question---and one that is heavily under debate currently. The FCC originally limited symbol rates as a way of limiting bandwidth for data modes indirectly (it made sense at the time). ...
ruhnet's user avatar
  • 314
11 votes

How To Join Packet Radio BBS

A summary of requirements: Licensing: Technician - very minimal requirements Equipment: Transceiver, Terminal Node Controller and terminal Transceiver - traditionally a VHF/UHF FM radio Terminal ...
JSH's user avatar
  • 590
7 votes
Accepted

Using Direwolf with multiple radios?

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 ...
larsks's user avatar
  • 608
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-...
Tmanok's user avatar
  • 161
5 votes

Packet Radio at 100 miles

If by "packet radio" you mean the common AX.25 kind used by APRS for example, you can probably forget about it. Otherwise you'll need to use HF, and also find an appropriate mode since there's nothing ...
Phil Frost - W8II's user avatar
5 votes
Accepted

If the data port on a Yaesu FT-7800R only communicates FM signals, why does the manual mention the port having a bit rate?

The data port does not carry FM signals: it carries demodulated audio. The radio performs FM demodulation and de-emphasis, and the output is heard on the speaker and is also present on the 1200 baud ...
Phil Frost - W8II's user avatar
5 votes
Accepted

Can APRS and other AX.25 packet-based systems (ie. a BBS) use the same frequency?

APRS typically uses a fixed frequency (e.g. 144.39MHz in the US), and shared by all APRS users. So yes, it would be frowned upon to also run a BBS on that frequency as it would interfere with everyone ...
User5754448's user avatar
4 votes

How To Join Packet Radio BBS

A Technician Class license or better is required. What equipment you need very much depends on the solution or solutions you pursue. There exist well-baked schemes for creating relatively long ...
Tadd KA2DEW's user avatar
4 votes
Accepted

Using a Baofeng UV-5R V2+ as a Portable Packet Radio

As far as I know, none of that series "speaks" APRS by itself, so you'd need your external controller to generated the AFSK tones. Whilst it's possible to generate AFSK at such low rates with an ...
Marcus Müller's user avatar
4 votes

Are there any Alternatives to Packet Radio for sending digital data?

In absence of a clear indication of what Amateur Radio band is being targeted here, an answer for the 13 cm band: You can use 802.11g/OFDM with a 20MHz bandwidth on 2400-2450 MHz Amateur band. You ...
Edwin van Mierlo's user avatar
4 votes
Accepted

How do I write a modem for DireWolf?

Actually, direwolf already supports higher data rates since 2017; it will use the G3RUH modem for a speed of 9600 or higher. As shipped it can be configured up to 40000 bps. But it's a mistake to ...
hobbs - KC2G's user avatar
  • 12.5k
3 votes
Accepted

Is packet radio possible on Baofeng UV-5R and similar HTs?

In the end I used 'amodem' ( see https://github.com/romanz/amodem ). After a few calibration steps, I could get decent I/O rates - considering the nature of the medium. Compression of archives is ...
user400344's user avatar
3 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

The easiest way now is to get the Btech APRS-K2 Cable: it allows you to receive and send audio to the radio with a single cable. You can use it with the aprs.fi app or with a variety of software from ...
caleb's user avatar
  • 141
3 votes

How To Join Packet Radio BBS

I think you're barking up the wrong tree preparing for the possible dystopian future. If the internet is unavailable, short-term or long-term, generally the need is to communicate as widely as ...
rclocher3's user avatar
  • 9,242
3 votes

Raspberry Pi with TNC-Pi - How to Connect to BBS

Assuming that you have: correctly connected your Baofeng to the TNC installed the AX25-tools and AX25-apps configured /etc/ax25/axports with your call and the baud rate attached the serial port to ...
Glenn W9IQ's user avatar
  • 18.6k
3 votes
Accepted

How does AMPR work over IPIP tunnels?

FYI, I'm writing this as someone experienced with Linux IP routing, but only superficially familiar with AMPRNet. All of the routing appears to happen through ordinary Linux facilities which can be ...
Phil Frost - W8II's user avatar
3 votes
Accepted

Automatic identification system (AIS) on aprs.fi - Long Rx -> Tx distances

There's large AIS observer networks (think MaritimeTraffic.com and consorts), and chances are that Edinburgh station just feeds data from the internet into the system. Furthermore, theres official and ...
Marcus Müller's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

Sure it's possible. You'll need some sort of Terminal Node Controller (TNC), either one implemented in hardware or software, plus a set of cables that plug into the 2.5 mm / 3.5 mm TRS ports. If ...
rclocher3's user avatar
  • 9,242
2 votes

What frequencies should I listen to for packet radio?

145.010 was the "primary" packet frequency in the 90's Lee N4TCW
Lee N4TCW's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I built a homebrew interface that uses a small USB soundcard with mic and ear 1/8" jacks. Each of those drives a 600:600 ohm transformer. On the radio side, the transformers drive the mic and ear ...
Dave Telling's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I recommend against using the modern inexpensive HT radios for packet, especially if you are buying the equipment on purpose for that application. You'd be much better off with 30-year-old used ham ...
Tadd KA2DEW's user avatar
2 votes

What issues can I expect when using Bluetooth for packet radio?

Sounds a lot easier to reverse-engineer the Hand Controller Interface, especially since that comes with a handy RJ45 connector, which would make it cheap to build an adapter that allows you to poke ...
Marcus Müller's user avatar
2 votes

Is packet radio possible on Baofeng UV-5R and similar HTs?

I was able to get a Baofeng HT working with packet, but had to adjust a number of menu items. (The tricky one that is poorly understood is Squelch Tail Elminate or STE.) My suggestion, assuming you'...
Rob McNicholas's user avatar
2 votes

V/U Packet Rate Limits

There are two questions in the General exam dealing with bandwidth in the VHF and UHF bands (G1C09 and G1C11). Both of these questions are dealing with the regulatory, not technical, limits of data ...
Glenn W9IQ's user avatar
  • 18.6k
2 votes

Cannot establish AX.25 connection to RMS gateway

Is it possible that my VOX has a hang time that's causing me to loose the initial response to my call? Yes, that is definitely possible. You want the lowest possible VOX threshold and, if possible, ...
anarcat's user avatar
  • 125
2 votes

LoRa radio transceiver for PtP mesh?

Ham LoRa does seem to exist, although I haven't seen any mention of it around the Boston MA area. I think to make best use of LoRa on Ham frequencies, one could use the European version that works in ...
cmm's user avatar
  • 276
2 votes

LoRa radio transceiver for PtP mesh?

A few comments on amateur LoRa: As others have pointed out, the datarate is measured in tens of bytes per second. Not thousands... Forget about file transfer! LoRa is spread-spectrum and therefore ...
W2CAM's user avatar
  • 121
2 votes
Accepted

How do you open ax.25 ports?

Listen tcp 0.0.0.0:5000 bind address already in use. This sounds like a somewhat generic error, not necessarily related to your AX.25 software itself but certainly a bummer to encounter it while ...
natevw - AF7TB's user avatar

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