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).
...
- 314
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 ...
- 628
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 ...
- 52.5k
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 ...
- 52.5k
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-...
- 161
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 ...
- 448
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 ...
- 61
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 ...
- 2,195
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 ...
- 17.4k
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 ...
- 13.2k
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 ...
- 18.6k
3
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'...
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 ...
- 412
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 ...
- 141
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 ...
- 52.5k
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 ...
- 17.4k
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 ...
- 21
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 ...
- 61
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 ...
- 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, ...
- 125
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 ...
- 121
2
votes
What frequencies should I listen to for packet radio?
145.010 was the "primary" packet frequency in the 90's
Lee N4TCW
- 21
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 ...
- 276
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 ...
- 7,469
2
votes
nrparms: SIOCADDRT: Inappropriate ioctl for device
Looking at the kernel code, I see four things that can make an "add node" ioctl on a netrom socket return -EINVAL:
The route has more than 8 digipeaters. ...
- 13.2k
1
vote
Accepted
Find the right COM to setup Winlink
If you're running under WINE, you can make the port whatever you want. You need to know the Linux device name (like /dev/ttys0 or /dev/ttyUSB or whatever) the TNC is plugged into on the computer. ...
- 959
1
vote
AX25 + Reed Solomon : Bit stuffing errors
I'm quite confused by your question. I suspect you are talking about a satellite which is using the FX.25 protocol (on Wikipedia), which is an extension of the original AX.25 protocol.
FX.25 is a ...
- 699
1
vote
Are packet BBS discussions archived anywhere?
Not unless individual operators did so.
When we ran the PBBS at the National Guard building at Fort Richardson we would often print out relevant messages during disaster situations. Sometimes ...
- 2,097
1
vote
LoRa radio transceiver for PtP mesh?
Let me stress the fact mentioned by @mike65535 again: Couple of hundred kbps is not what LoRa is designed for. It is more in the area of IEEE 802.15.4 (ZigBee etc.) even though you might have to ...
- 399
1
vote
Packet Radio at 100 miles
Take a look at this article. Radio communication via Near Vertical Incidence Skywave propagation: an overview. I'm not sure from my reading of the URL that the signals would make 100 miles. I ...
- 11
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