FT-8 New digital mode 8-FSK modulation

It’s still in beta testing, but FT8 — the latest digital bauble to capture the imagination of the Amateur Radio community — has been luring away many of those already using the popular JT65 “weak-signal” mode. FT8 is included in a beta release of WSJT-X, version 1.8.0-rc1. Among its biggest advantages is a shorter transmit-receive cycle, meaning quicker contacts. The notes for the “candidate” release say that FT8 offers “sensitivity down to –20 dB on the AWGN channel.” Contacts are four times faster than with JT65 or JT9, and an entire FT8 contact can take place in about 1 minute.

The new mode is named after its developers, Steven Franke, K9AN, and Joe Taylor, K1JT. The numeral designates the mode’s 8-frequency shift keying format. Tones are spaced at 6.25 Hz, and an FT8 signal occupies just 50 Hz. Unlike JT65 or JT9, transmit and receive cycles in FT8 each last about 15 seconds. Like JT65, FT8 requires accurate time synchronization. An auto-sequencing feature offers the option to respond automatically to the first decoded reply to your CQ.

“FT8 is an excellent mode for HF DXing and for situations like multi-hop Es on 6 meters, where deep QSB may make fast and reliable completion of QSOs desirable,” Taylor’s release notes assert.

The beta release came out just days before the July CQ VHF Contest and proved to be a boon to many operators who took advantage of FT8 on 6 meters. In a limited outing for the CQ VHF, Frank Donovan, W3LPL, made 22 FT8 contacts on 6 meters, “during which the FT8 software reported SNRs from my receiver below –10 dB (measured in a 2,500-Hz bandwidth). Some of the 22 QSOs may have been difficult to complete on CW.”

Enthusiasts will have to wait a little longer for Logbook of The World (LoTW) to accept FT8 contacts as FT8 contacts. Because FT8 is still in beta, it has not yet been added to the ADIF tables. Configuring TQSL to automatically map FT8 contacts to “DATA” will enable users to upload FT8 contacts now, and confirmations will be valid for DXCC Digital, VUCC, WAS Digital, and WPX Digital awards. A new TQSL configuration will be released once the new mode has been accepted to ADIF, which could happen within a week.

Important characteristics of FT8:

– T/R sequence length: 15 s
– Message length: 75 bits + 12-bit CRC
– FEC code: LDPC(174,87)
– Modulation: 8-FSK, keying rate = tone spacing = 5.86 Hz
– Waveform: Continuous phase, constant envelope
– Occupied bandwidth: 47 Hz
– Synchronization: three 7×7 Costas arrays (start, middle, end of Tx)
– Transmission duration: 79*2048/12000 = 13.48 s
– Decoding threshold: -20 dB (perhaps -24 dB with AP decoding, TBD)
– Operational behavior: similar to HF usage of JT9, JT65
– Multi-decoder: finds and decodes all FT8 signals in passband
– Auto-sequencing after manual start of QSO

*Comparison with slow modes JT9, JT65, QRA64:* FT8 is a few dB less
sensitive but allows completion of QSOs four times faster. Bandwidth is
greater than JT9, but about 1/4 of JT65A and less than 1/2 QRA64.

*Comparison with fast modes JT9E-H:* FT8 is significantly more
sensitive, has much smaller bandwidth, uses the vertical waterfall, and
offers multi-decoding over the full displayed passband.

*Still to come, not yet implemented:* We plan to implement signal
subtraction, two-pass decoding, and use of “a priori” (already known)
information as it accumulates during a QSO.

Three extra bits are available in the message payload, with uses yet to
be defined. We have in mind special message formats that might be used
in contests, and the like. Your considered suggestions for use of these
bits are very welcome!

K1JT, K9AN, and G4WJS have conducted on-the-air tests of FT8 with
excellent results. We’re now at a stage where tests under a wider range
of conditions are desirable. If you can build WSJT-X from source code
revision r7750 or later, and would like to help, please do so and report
your results to us! Pre-built installation packages will be made
available after further testing is completed.

FT-8 New digital mode 8-FSK modulation

Paul Leicester | MØFOX | Chesterfield UK | IO93HE | Icom IC-7300

SharkRF openSPOT DMR/FUSION/D-STAR hotspot

openSPOT is a standalone digital radio IP gateway / hotspot

Supports DMR (Brandmeister, DMRplus), D-Star (DCS, REF/DPlus, XRF/DExtra, XLX), System Fusion (FCS, YSFReflector) networks. More supported networks and features will be available with new firmware releases.

Supports cross modem modes. Talk with your C4FM radio on DMR, and with your DMR radio on System Fusion networks!
Very easy to use, works without a computer. No additional hardware required, works out of the box. All accessories included.
Web interface for configuration and monitoring.
HTTP, UDP/TCP API support.
Custom 2FSK/4FSK RF protocol support with TDMA.

USB powered, low energy consumption, 20mW RF output.
Create your own private radio network using our open source server application.
Runs fully embedded software written in pure C, running on an embedded real time operating system. No Linux, bulky Windows software or failing SD cards!

Paul Leicester | MØFOX | Chesterfield UK | IO93HE | Icom IC-7300

DMR UK Core talk groups

There will be several changes to talk groups affecting

TG8, TG2350, TG2351, TG2352, TG2353, UK Wide & Direct Dial
As of the 28th December 2015 the new Talkgroup structure has now been implemented. However the new regional groups will not be linked to TG8

This is to allow users time to update their code plugs and test them on the new talk groups

Talk groups TG8, TG2350, TG2351, TG2352, TG2353 & Direct Dial
are still available, but will be switched off on 31st January 2016


Despite the talk group restructuring having been completed, there could be some “fine tuning” to be done over the next month (and beyond) as Keepers can request additions and removals. We will keep posting updates on the relevant pages on this site as well as via the Facebook page and Twitter. Also via our weekly newsletter


An update from the c-Bridge Admins

** As of 09/01/2016 the process mentioned below has now been completed and hold-off timers are now operational on all wide area talkgroups **

As promised we have started adding hold-off timers to the wide area talkgroups on Timeslot 1. This has already been implemented on the new regional 8xx groups on Slot 2.

‘Wide Area’ means TG1, TG2, TG13 and TG235. As has always been the case these 4 talkgroups will still normally be heard on all repeaters. Users can continue to use them as they always have.

If a repeater user makes a transmission on one of the user activated talkgroups (TG80, TG81, TG113, TG123, TG119, TG129) or local TG9 then the 4 wide area talkgroups will be turned off on that repeater for 10 minutes (5 minutes for TG9). This will allow a user activated or local QSO without the risk of being interrupted by the wide area groups.

The wide area talkgroups remain active and usable on all repeaters not involved in the user activated QSO. Any of the wide area talkgroups can be reconnected immediately without having to wait for the timer to expire by keying up on that talkgroup.

A similar scheme will be implemented on the slot 1 special talkgroups such as 803. TG1 and TG235 are currently working as above. TG2 and TG13 will follow shortly



Repeaters will be assigned a “home” region which is always on and is based on the repeater location. Secondary regions are available as a User Activated option. The reasons for the change include (1) it allows linking of repeaters with coverage in multiple regions (2) allows for qso’s to continue should a user go into the next region subject to availability on the next repeater (3) allowing the split of regions such as SE England which has grown to big for TG8













These groups will change talk group number – their function remains the same – their new TG number basically puts them within a “regional” block

The repeater listing will show “current special links” and “revised special links”

TG803 – Replaces TG2352 (GB7AK, GB7EP, GB7EX, GB7HR, GB7IK, GB7LO, GB7NS & GB7SE)

TG821 – Replaces TG2350 (GB7HM, GB7FW & GB7LP)

TG822 – Replaces TG2353 (GB7BR, GB7CA & GB7PN)

TG841 – New Talkgroup (GB7DS & GB7MK)

TG862 – No change to this talk group (GB7HS, GB7HX, GB7LE, GB7MR & GB7TD – M62 MOTORWAY)

TG871 – Replaces TG2351 (GB7HM & GB7PN)


To help with nation wide QSO’s especially as direct dial is suited for one to one QSO’s, two UK Wide User Activated talk groups are being implemented.

TG80 – UK Wide User Activated 1

TG81 – UK Wide User Activated 2


All direct dials will be removed from the network as part of the change and the UK Only User Activated Talk Groups can be used in it’s place.


The c-Bridge admins are working to add “hold off timers” which will assist users of these talk groups to hold on to the talk groups by inhibiting the other talk groups from taking the slot if the User Activated Talk Group is in use on a repeaters. This will be a new function that will be worked on to make using the UA talk groups easier for all.

CC-3 dot NET

Paul Leicester | MØFOX | Chesterfield UK | IO93HE | Icom IC-7300



As most of you will know, we have been making various mutterings for many months now regarding the need to reorganise the current “TG8” regional talk group structure. To a great extent, this has been a victim of its own success, but it has shortcomings – some of which we have attempted to paper over with the invention and implementation of the “direct dial” talk groups.

With the rapid (and continuing) expansion of the network it is time for a fresh look at what we might do going forwards; this paper is intended to be the cornerstone of an open discussion regarding how the regional talk groups would be best organised . This is NOT a “done deal”, nor a fait accompli. Please feel free to share thoughts and observations and to ask questions…….

Paul Leicester | MØFOX | Chesterfield UK | IO93HE | Icom IC-7300

TAPR Packet Radio

Packet radio has been around since the mid-1960’s, but was first seen on the amateur bands in 1978 through research done in Montreal, Canada in 1978, the first transmission occurring on May 31st. This was followed by the Vancouver Amateur Digital Communication Group (VADCG) development of a Terminal Node Controller (TNC), also known as the VADCG board, in 1980. This was then followed by TAPR (Tucson Amateur Packet Radio) with the creation of the TNC-1 in 1982 and then the TNC-2 in ’84-’85. In 1985, the packet radio revolution ignited when TAPR sold over a thousand TNC-2 kits. The TNC-2 was what was needed to make this mode, that a few experimenters were playing with, into something that every amateur could enjoy. From its humble beginnings, where it was good luck to have more than three packet operators in the same city, packet radio now has thousands of amateurs using it daily, various manufacturers making and selling TNCs (terminal Node Controllers), and over a hundred thousand TNCs having been sold to date. What growth! No other mode of amateur radio has seen such explosive growth!

Like the title says, ‘Why Packet Radio ?’ Like any mode in the amateur service, it provides a group of amateurs with a way of having fun and meeting one of our primary aims, ‘improving the radio art.’ Packet radio was a new mode in the early 80’s that many of the outstanding amateur experimenters worked on and developed. The result, ten years later, is something that provides a lot of different operating opportunities. No longer is it just packet radio, but now it is bulletin board systems, DX Clusters, chat bridges, networking, emergency communications, satellite operations and much more. But what are these ? and is one of these, something that you want to do? How do you know? Let’s start off with a basic question.

What is packet radio? The good thing about packet radio is that you don’t really have to know a lot about how it works or find it necessary to memorize a whole new set of technical terms. Find a friend who is using packet, buy your TNC (terminal node controller), hook up your unit, and then ask for help. The nice thing these days is that almost every town has someone on packet radio who can help. A basic TNC allows your computer to use your radio to talk to another computer, thus combining two popular hobbies Q computers and radios. The cost of the TNC is going to depend on what you want to do. The question that you should ask before ‘What TNC do I want?’ is ‘Why do I want to invest in new equipment?’ Let’s spend the rest of the article talking a little about the most popular uses of packet radio. After you read this, find someone locally on packet and ask for a demonstration. Since amateur packet radio is different in every fifty mile radius, then what I can do here in Austin, Texas is going to be different from what you can do where you are. Find out what you are going to do before spending your money, unless you want to blaze a new trail of services in your area.

Packet Bulletin Board Systems (BBS): Most cities have one or more packet Bulletin Board Systems, or BBS for short. BBSs do two main things: send and receive personal messages for their local users (like yourself) and send and receive messages or bulletins intended for people locally or around the world. Since the BBS is part of a national system of other BBSs, it has the ability to pass information or messages to any other BBS in the US or the world. This allows you to send messages to friends locally, to someone located in the next state, or to someone on the other side of the world. The second thing that BBSs do is pass local and national bulletins, which are messages intended to be read by everyone. In this way, amateurs can read the latest messages about the ARRL, AMSAT, TAPR, propagation, DX, and other bulletins on varied topics. Message passing is the primary purpose of a BBS system, but BBSs can also support callbook programs, help references, Internet access, and more. Operators of BBS systems are a good place to start when you first get on the air. Because of the service they provide, they have to know how packet is working in the local area.

Keyboard-to-Keyboard: Like other amateur modes (SSB, FM, etc), packet radio can be used to talk to other amateurs directly. Amateurs can talk to each other simultaneously using their keyboards when they can directly communicate with each other. With the use of networks (see a little later), amateurs can talk at a distance beyond the reach of their own stations by using the network. Keyboard-to-keyboard communications is one of the least frequent methods of packet communications, because amateurs are rarely on packet at the same time. Many packet operators send electronic mail using either personal mailboxes or a local BBS. In this way, messages are read when the amateur is on the air. Another limitation to direct keyboard-to-keyboard packet is that you can only talk to one packet station at a time Q no easy way to hold round-table discussions like on a voice repeater. Some areas support chat or conference bridges, which allow for more than one amateur to talk to each other Q much like a voice repeater. If a chat is supported over a network, then you can talk to someone as far away as the network reaches.

DX Packet Cluster: Many cities have DX (foreign amateur) spotting nodes or networks. HF (High-Frequency) operators connect to their local DX Packet Cluster in order to receive reports on the latest DX. This type of packet came about from those interested in ‘chasing’ DX. Many amateurs like to frequent the HF bands looking for rare international operators to contact. A DX Cluster allows many HF operators to be connected over packet radio at the same time while operating HF and hunting for DX. When someone finds a DX station, they send a packet message to the DX Cluster, which then sends the information to all other packet operators using the DX Cluster. In this way, you have several stations monitoring the band, looking for DX. Often an amateur will ‘spot’ (hear) a DX station and then distribute the DX report almost instantly. DX Clusters allow everyone to operate many more hard to find DX stations in one evening than was possible operating by oneself. Some amateurs have been known to attain enough contacts to qualify for DXCC in a matter of weeks. One point though, if your HF station is not a ‘big-gun’, then it is sometimes best to operate the DX station before posting your spot for others to find. There is a good chance that a pile-up will occur as soon as you make your spot to the DX Cluster and then you will not be able to work the DX station that you found!

RACES/ARES/NTS and Emergency Communications: Packet radio is being used in many emergency services. Whether packet is used to pass a message accurately and in large quantities or to handle messages passed by the National Traffic System, it can provide an important function like any other amateur mode when used correctly. A new application called APRS combines GPS (Global Positioning Satellites) with packet radio to allow a master station to plot on their computer the location of all other stations in the field. The purpose is to coordinate the exact position of weather spotters or searchers, without having to waste radio time informing the control station of their locations. Recently, amateurs in Oklahoma have been distributing Doppler Radar images via the packet network. The small weather image file takes but a few minutes to retrieve and display. This helps those amateurs outside of the local ATV coverage to get an accurate weather picture from the Doppler Radar.

Networking: Since amateurs use radios to transmit their data, their range of communications is limited to approximately line of sight. An average packet station talks in a radius of about 10-30 miles. Packet Networks allow amateurs to widen the area of communications past their line of sight, by having a series of packet stations linked by radio, that can be used to get their packet messages to where ever the network goes. Much like the telephone system, networks provide long distance service outside the local area. There are a number of amateur networks which allow amateurs to travel from one area to another. Network types include: Net/Rom, TCP/IP, TexNet, G8BPQ, ROSE, KaNodes, and many more. These networks are typically built by a local or regional group that allows packet operators to get outside of their area. Amateurs get hooked on building and maintaining such networks, just like some amateurs operate DX or handle emergency communications. The type of network you use locally will depend on your area. Much depends on the network philosophy the local group has chosen when developing their network.

Satellite Communications: Many of the amateur radio satellites in orbit contain computer systems that provide packet capability. Most packet satellites provide BBS-like functions for messages to be passed to anywhere in the world within 24 hours. Several contain CCD cameras, which allow amateurs to download images of the earth and some allow users to retrieve data from the onboard experiments. Most satellites use AX.25 with special software developed for satellite communications. DOVE, Digital Orbit Voice Encoder, can be received with any normal VHF/FM 2-meter packet station, but most of the packet satellites use SSB and require more complex equipment in order to operate them. Just something else to spend your amateur dollars on.

Conclusion: These are just some of the things you can do with packet radio. Once you find something that you can do with packet radio, then you have a reason to purchase the equipment necessary to get on the air. A good place to start is to find a friend who uses packet and go visit. See what your local area has to offer. As already stated, packet radio changes every 50-miles. What is being done where I operate is probably slightly different than what you can do where you live.

TAPR Packet Radio