Oguz, TA2STO in Türkiye has developed a new mode called LongChat to allow radio amateurs to communicate with each other.
It's described as follows... "LongChat is a low-power (QRP) / low bitrate text chat software application over ham radios connected to a PC. Chirp symbols with an audio bandwidth of 2400 Hz (300-2700 Hz) are generated on the PC side for encoding the messages. Baseband audio signal is then transferred from PC to ham radio for modulation at the selected mode. SSB, FM and other types of modulation modes can be used. Forward error correction codes are used to correct messaging errors
Current version is tested on ICOM-7300 and YAESU FT991A radios. Other radios are supported but not tested yet. Future improved versions will support higher data rates or lower S/N ratios.
Since the software is continually improved and data structures may have changed, newest version needs to be used for compatibility with all users. To ensure this, software will remind you to download and use the latest version when a new version is ready.
Specifications Usable data rate (net user data) is 7 ASCII characters per second at -12 dB signal to noise ratio. Eb/No (Energy per Bit to the Spectral Noise Density) is 5 db Measurement of received message SNR. Measurement of chirp frequency shift in SSB mode. You may download the software, user manual and brochure at the link below. https://drive.google.com/drive/folders/1NQwbeoHE3vPLORGN1krpSNHHI9brhDJh?usp=sharing "
As of late 2024, this is all very new and I'm sure a lot of people will have questions as to how good is it? Will it be better than modes like JS8Call? And more critically, will it get a critical mass of users to make it worthwhile?
I'd suggest that at the moment, it should be seen as something of interest to those who like to experiment with digital modes on the HF bands and want to experiment to see how it compares to other modes.
It also seems to be a 'work in progress' project but remember that the software for this mode is free and is being developed by one person. It'll be interesting to see how it develops.
TA2STO released the following video about it...
Update from TA2STO - 1st Dec 2024:
- Hi, I am the author of LongChat chirp mode. I started it a few years ago as a project for low power sensor applications. Then I wanted to try it as an experimental digital ham mode.
-LongChat is an encoder/ decoder. In general it should work on all modulations LSB, USB, FM, AM etc.
- I usually work with USB at lower band edges and LSB at upper band edge. It is easy to miss it when changing the modes. I guess I relied on IC7300 to disable transmission at band edges. IC 7300 does allow that though. I had no specific reason for using LSB. It works both on USB and LSB.
- I am preparing a new video to compare the power efficiencies of digital modes. I will post it when ready
- Newest version is 1.3.00 . Setup manual, version info and other things are also in the link above.
- LongChat is experimental and supports a number of radios. Untested radios are marked with * as the first character
- I am not an experience radio ham in operations and regulations. Maybe experienced radio hams can designate frequencies and protocols for test purposes.
- Since the signal is way below the noise level (-13 db) , there is yet no equivalent of a waterfall display like FT8, JS8 etc. This makes it harder to see the activity.
- You can view the waterfall in FT8 because it's minimum SNR is -4 db. and bandwidth is 50 hz . People quote -21 db as the SNR for FT8. This is the referred SNR if the bandwidth were to be widened to 2500 Hz. My next video will clarify these issues.
- Since there are no designated frequencies for LongChat, it is difficult to find some one for QSO
-There is also a criticism of LongChat not being open source . LongChat code has some new algorithms with IP value. If I open the source code to radio hams, people and companies with commercial interest will also have a free access. But I totally respect and mostly agree with the open source advocators.
- In short, LongChat is an experimental mode. My effort is to bring the SNR of LongChat to the limit dictated by the Shannon channel capacity theorem and make it the most power efficient mode.
- If people want to experiment with it, I am ready to support. I am not the best person to decide on the designated QSO frequencies, LSB or USB selection, protocols etc. If some of you want to do that , or perhaps open a group here or on google groups i.o, I would be happy to get involved.
Addendum: Matt, M0DQW released the following video which shows LongChat in operation...
