FT2 fast digital mode

The world of amateur radio has undergone a digital renaissance in the last decade. Since Joe Taylor (K1JT) introduced the protocol to the world FT8, sa rádioamatérske pásma zmenili na nepoznanie. Pre niekoho je to „automatizovaná nuda“, pre iného fascinujúci spôsob, ako nadviazať spojenie s druhým koncom sveta aj s anténou z kusu drôtu a výkonom pár wattov. Avšak technologický vývoj sa nezastavil pri FT8 ani pri rýchlejšom FT4. Na scénu prichádza FT2, projekt, ktorý sľubuje priniesť novú úroveň efektivity a rýchlosti do sveta slabých signálov.

If you are looking for an answer to the question of whether we need another digital mode, you will find the answer on the project's homepage FT2.it. Let's dive into the details of this protocol that is ambitiously knocking on the doors of our amateur radio stations.

The evolution of digital communication: Why was FT2 created?

To understand the significance of FT2, we must look at its predecessors. FT8 has become a global standard due to its ability to decode signals deep below the noise level (down to -21 dB). Jeho nevýhodou je však časová náročnosť – jeden cyklus trvá 15 sekúnd, čo znamená, že kompletné spojenie (QSO) trvá minimálne minútu. FT4 tento čas skrátilo na 7,5 sekundy, čím sa stalo vhodnejším pre contesty, no na úkor mierneho zníženia citlivosti.

FT2 (Future Technology 2 / Fast Transmission 2) fills the gap that radio amateurs felt especially during variable propagation conditions. It arose from the need for a protocol that is:

1. Rýchlejší ako FT8: In order to take advantage of short 'openings' of the band (e.g., during Sporadic-E or meteor scatter).

2. Robustnejší ako FT4: To maintain a high probability of successful decoding even with an unstable signal.

3. Moderný a otvorený: Using the latest algorithms for error correction.

The technical heart of the FT2 protocol

FT2 is not just a 'repainted' FT8. It is a standalone protocol with a different packet structure and modulation scheme. Unlike older modes that relied on fixed time windows inherited from legacy. WSJT-X, FT2 experiments with flexibility.

Modulation and bandwidth

FT2 využíva viacstavovú frekvenčnú manipuláciu MFSK (Multi-Frequency Shift Keying). Like its predecessors, FT2 also aims for the narrowest bandwidth possible to fit as many stations as possible into one audio channel (usually 3 kHz) at the same time.

The basic philosophy of FT2 lies in optimizing the transmission of information. While FT8 transmits 77-bit messages in 15-second blocks, FT2 optimizes the protocol overhead to achieve a similar informational value in a fraction of the time.

Error correction (FEC) and LDPC codes

Kľúčom k úspechu FT2 je implementácia pokročilých kódov LDPC (Low-Density Parity-Check). These codes are a mathematical marvel of modern communication. They allow the receiver to reconstruct a damaged message even if part of the signal was completely lost due to fading or impulse noise.

The formula for calculating the sensitivity limit in decibels in relation to bandwidth $B$ and information rate $R$ is key for FT2 developers:

By optimizing the SNR (Signal-to-Noise) ratio, FT2 achieves a balance where the signal remains readable even at speeds that older modes could not withstand.

Software and implementation: What will you find at ft2.it?

The FT2 project, primarily backed by an Italian radio amateur IU8LMC, nie je len teoretický koncept. Na oficiálnom webe je k dispozícii softvér, ktorý umožňuje rádioamatérom začať pracovať v tomto móde takmer okamžite.

User interface

If you are used to WSJT-X or JTDX, you will feel at home in the FT2 environment. The software offers:

• Vodopád (Waterfall): Visual representation of activity in the band.

• Automatické sekvencovanie: The software automatically responds to calls, exchanges reports, and ends the connection with the message '73'.

• CAT ovládanie: Full integration with most modern transceivers for automatic frequency tuning.

Cycle speed

One of the most interesting parameters of FT2 is its 6,25-sekundový cyklus. To je o viac ako polovicu menej ako pri FT8. V praxi to znamená, že celé spojenie môžete dokončiť za približne 25 až 30 sekúnd. Pre kontestového operátora je to obrovský skok v efektivite (QSO per hour).

Practical use: When to reach for FT2?

FT2 is not designed to completely replace FT8 on HF bands during a normal day when conditions are stable. Its strength is shown in specific scenarios:

1. VHF and UHF operation

Na pásmach 6m, 2m a vyšších sú podmienky šírenia často prchavé. Pri šírení typu Sporadic-E the signal can pop up for 10 seconds and then disappear. In such a window, FT8 is too slow – by the time you finish the first sequence, the other station may no longer be 'in hearing'. FT2, thanks to its short cycle, maximizes the chance of successfully completing the connection.

2. Satellite communication

Pri práci cez nízkoletiace satelity (LEO) dochádza k výraznému Dopplerovmu javu a rýchlym zmenám v polarizácii signálu. Rýchlosť FT2 umožňuje operátorom nadviazať viac spojení počas jedného preletu satelitu nad ich horizontom.

3. Expeditions and 'Pile-ups'

When a rare DX station activates an island in the Pacific, thousands of people try to make contact at once. FT2 allows for faster 'processing' of stations, reducing frustration in the pile-up and increasing the chances for lower power stations.

Controversy and future: Fragmentation or progress?

Like every new mode, FT2 faces criticism from the conservative part of the community. A common argument is fragmentácia pásiem. Ak polovica digitálnych operátorov zostane na FT8 a druhá prejde na FT2, nájsť partnera na spojenie bude ťažšie.

Amateur radio is about experimenting. If we were afraid of fragmentation, we would all still be transmitting only in telegraphy (CW). FT2 brings new dynamics to the ether. The challenge for the future is the integration of FT2 directly into major software packages like WSJT-X, which would ensure its mass adoption.

Open source

A big plus of the project on FT2.it is its openness. Developers from around the world can review algorithms, suggest improvements, and port code to various platforms (including low-power microcomputers like Raspberry Pi).

Conclusion: Should you install FT2?

FT2 je jasným dôkazom toho, že rádioamatérske inovácie neumreli. Je to mód pre tých, ktorí chcú byť na čele technologického pokroku. Ponúka rýchlosť, ktorú si vyžaduje moderný digitálny svet, pri zachovaní citlivosti, ktorú potrebujeme pre prácu so slabými signálmi.

If you are tired of waiting 15 seconds for each line in the decoder and want to experience amateur radio connection in 'real time', FT2 is the way for you. Download the software, set your audio levels, and become part of the community that defines what amateur radio broadcasting will look like in 2026 and beyond.