Nexus HamradioTools – one program for the entire ham radio station

Nexus je bezplatný softvér s otvoreným zdrojovým kódom napísaný v jazyku Rust, určený pre rádioamatérov, ktorí chcú prevádzkovať digitálne módy, SSB, CW, APRS, satellites and track wave propagation – all from a single window. Auto KD9TAW is licensed since 2021 and active since 2022. The program runs on Windows (x64), Linux (.deb and AppImage packages) and Raspberry Pi arm64. It is distributed under the license GNU GPL v3.

Why did KD9TAW create Nexus?

Typická rádioamatérska stanica bežala donedávna takto: jeden program dekódoval, ďalší zobrazoval mapu, tretí posielal upozornenia, štvrtý viedol log and piaty zobrazoval panadapter. Each had its own settings, its own copy of the log, and all competed for one COM port. KD9TAW, a technologist at heart, decided to rebuild this entire stack into one program. The result is Nexus – software that he uses for every delivery and in everyday operation. A by-product of this project are also the original TempoFast and TempoDeep protocols, which we write about below.

KD9TAW is not just a software developer: in April 2023, he DXpeditioned to KP2 (St. John) and VP2V (British Virgin Islands), where he made over 6,000 contacts in a few days from a coastal QTH, including SSB on 6m – the first such activity from VP2V in years. He also placed 1st in the state of Illinois and 10th in North America in the 2025 CQWW 160m DX, in only his second appearance in the contest. As of 2026, he has 11,274 contacts on QRZ and 285 confirmed DXCC entities.

Nexus Benefits

Základný argument je prostý: každý z úloh, ktoré Nexus zvláda, je bežne samostatný stiahnuteľný program. V Nexuse zdieľajú jeden rádioprijímač, jednu vrstvu CAT and jeden log. Keďže log je základom údajov, napríklad pre výpočet diplomov aj pre farebné zvýraznenie každého dekódovania, konzistencia nastáva automaticky – bez potreby synchronizovať viaceré kópie ADIF.

In addition to consolidation, Nexus offers two capabilities that cannot be built from multiple separate programs. First, VHF propagation is scored based on receivers near your location, not the global stream of skimmer spots. Each line in the list of needed stations shows who in your vicinity heard that station and when, so you know before you call that the route exists. Second, accessibility for operators with visual or hearing impairments – Nexus works with JAWS and NVDA screen readers without any switching, the keyboard controls all activity tables, and there is an announcement on receive and transmit.

Fifteen supported modes

The current version of Nexus supports fifteen operating modes, each in both transmit and receive.

How to start?

Inštalácia prebieha trojkrokovým sprievodcom. Nexus prečíta USB deskriptory, identifikuje rádio, spáruje zvukové zariadenie and ponúkne import existujúceho logu alebo začne s novým. Ak ešte nemáte rádio, APRS mapa, DX cluster and propagačný indikátor bežia na internetových feedoch samé. Winshield inštalátor v systéme Windows ešte nemá kód-signovací certifikát, preto SmartScreen zobrazí varovanie pri prvej inštalácii – treba zvoliť Ďalšie informácie and potom Predsa spustiť. SHA-256 každého artefaktu je uverejnený pri stiahnutí pre manuálne overenie.

Nexus funguje v dvoch režimoch: buď sám ovláda rádio cez CAT, alebo pracuje ako companion – pracuje s dekódovacím streamom z bežiaceho WSJT-X, JTDX alebo MSHV bez toho, aby prevzal riadenie rádia. Váš log prichádza importom ADIF and odchádza exportom ADIF; záloha sa robí automaticky pred každým načítaním.

FT8 and FT4 operation

The FT8 and FT4 sequencers are built on the behavior of WSJT-X, the keyboard shortcuts are the same, and the UDP protocol is byte-for-byte identical, so GridTracker, JTAlert, and your logger work exactly as they have before. The FT8/FT4 decoding layer is built from WSJT-X DSP resources (currently following upstream 3.0.2); on identical audio recordings, it achieves a threshold of −21.3 dB versus −20.7 dB for standard WSJT-X with no false decodes in pure noise.

Kokpit FT8/FT4 obsahuje vodopád, ktorý možno pozastaviť and prehrávať späť, tabuľku volaní zoradenú podľa hodnoty každej stanice pre váš log and pásmomú aktivitu s krajinou, správou signálu, vzdialenosťou and azimutom pri každom dekódovaní. Nexus si udržiava databázu z FCC licenčného súboru, vďaka čomu rozoznáva nový štát aj na CW, SSB and klasterových spotoch, ktoré neobsahujú grid.

SSB, CW and RTTY operation

The SSB and FM cockpit displays a live bandscope, TX metrics, six-slot voice keyer, repeater bounce, and CTCSS. On a native CI-V Icome or networked FlexRadio, this scope is the radio's own RF spectral range, not just the 3 kHz from the sound card. Nexus does not immediately display anything on the radio when opened - it will receive the radio in the same state you left it in, and only after active operator action will it change frequency or mode.

The CW cockpit transmits via CAT, serial DTR/RTS keyline, K1EL WinKeyer or sound card. The dominant feature is the decoding transcript, powered by the DeepCW neural network model, with a classic decoder as an automatic fallback. Macros can greet counterparties by name and send status. For RTTY, the Nexus handles AFSK from the sound card and true FSK via keyline with auto-sequencer for hands-free operation.

Other operating modes

APRS decodes and displays on a map with real station symbols and a detailed map showing distance, azimuth and path via digipeaters. When a 2m radio is not connected, the status bar clearly indicates this. Nexus connects to APRS-IS as a read-only network feed and can optionally operate a receiving IGate - internet traffic is never sent back to the air as this would mean unwanted keying of the radio without operator intervention.

For satellite operations, Nexus displays flyby plans, polar plots, Doppler correction and true 3D orbits with circular coverage footprints, while the Rotator automatically tracks the satellite path throughout the flyby. SSTV covers all fifteen modes with a live waterfall that becomes the image itself upon reception.

DX and diplomas in Nexus

Log je zdrojom pravdy pre jadro programu. DXCC, Challenge, Honor Roll, WAS, WAZ, per-band VUCC and IOTA sa počítajú offline z vlastného logu bez potreby účtu and bez uploadu. Potvrdenia si zachovávajú zdroj: eQSL alebo QRZ match sa zobrazí ako potvrdené, ale nikdy sa nezaráta do DXCC alebo WAS, pretože tieto diplomy to neakceptujú. Súčty teda vydržia skutočné žiadosti o diplomy.

DXpedičný kalendár zobrazuje každú operáciu ako farebnú lištu cez dni, kedy je v éteri, s pásmami od najnižšieho a modelovaným najlepším oknom. Nexus sleduje POTA a SOTA activator spots with the NEW PARK flag, one-click hunting and import of visited parks. The promotion uses the native ITU-R P.533 port – the same type of prediction engine as VOACAP – and scores openings based on receivers close to your QTH, not the global firehose.

Tempo protocols: TempoFast and TempoDeep

Nexus includes two original weak signal waveforms. TempoFast is a coherent 4-CPM mode on a 4-second conversation cycle with incremental HARQ redundancy – a failed frame is not discarded because retransmissions add new parity bits that are turbo-combined together into a longer, lower-rate code. No other amateur text mode accumulates redundancy like this. TempoDeep makes a different compromise: it trades speed for an incoherent 8-FSK tier on a 15-second cycle that remains functional even when the signal fluctuates.

Both protocols have closed real RF links in the air: the first TempoFast connection of two stations (KD9TAW and N9UM, 6 m band) was completed on July 26, 2026. However, all sensitivity thresholds are currently the results of bench simulations, not measured values ​​from real bands.

TempoFast sacrifices about 6 dB of sensitivity over FT8 per attempt, but instead delivers a cycle time four times faster than FT8 and a HARQ path in which redundancy accumulates across retransmissions. No other amateur text mode does this.

Other tools: Weak Signal Sleuth and MSHV Auto DX Chaser

Weak Signal Sleuth

Weak Signal Sleuth is a desktop early warning system for VHF band openings. Its primary function is to notify the operator the moment the 6m band opens in his local area. The 50MHz "magic band" comes alive without warning - a Sporadic-E cloud can light up the band for a few minutes and disappear before the operator even looks at the radio. Sleuth monitors spot networks and triggers an alert immediately when the area begins to open.

Sekundárne sleduje otvorenia na pásme 2 m (troposférické and ES otvorenia) aj meteor scatter na VHF. Funguje na báze real-time spotov z PSKReporteru and DX klastra cez Telnet, zobrazuje geografickú mapu otvárajúcich sa trás and obsahuje jednoduchý ML model, ktorý odhaduje pravdepodobnosť otvorenia na základe počtu spotov, unikátnych staníc, obojsmerných trás, geografického rozptylu and dennej doby. Nástroj je napísaný v Rust/TypeScript (Tauri v2 + React), distribuovaný ako natívny Windows .exe and je open source.

MSHV Auto DX Chaser

The MSHV Auto DX Chaser turns an FT8/FT4 station running under MSHV from LZ2HV into an intelligent DX chaser with a "listen first, then call" philosophy. It never calls CQ - it only responds to stations that it has decoded locally and evaluated as worthy of attention. It is intended exclusively for busy operation when the operator is at the station as a control operator.

Chaser čerpá spoty zo štyroch zdrojov (lokálne dekódovania, Reverse beacon Network, PSKReporter and päť DX klastrov paralelne) and skóruje každú stanicu v rolujúcej pamäti posledných 2 minút. Nová krajina DXCC získava 10 000 bodov (× až 5× násobič Most Wanted z Club Log), nový pásmový slot 1 000 bodov, nový lokátorový štvorec 500 bodov. V ATNO Chase Mode prejaví neobmedzenú vytrvalosť pri úplne nových entitách, kým stanica nevymizne z dekódovaní na minútu. Nástroj je napísaný v C++, distribuovaný ako Windows binárka and zdrojový kód je k dispozícii pod GPL v3 na SourceForge.

Conclusion

Who is Nexus for?

• DX operators
• FT8 users
• satellite operator
• radio amateurs using multiple programs at once

Nexus prináša na rádioamatérsku scénu originálny prístup: namiesto sady koordinovaných, ale oddelených programov ponúka jediný, modulárne navrhnutý Software, v ktorom jeden log poháňa všetky potrebné funkcie. Pre DX manov je zaujímavý najmä lokálne skórovanou propagáciou a offline výpočtom diplomov; pre digitálnych operátorov paritou s WSJT-X ekosystémom a experimentálnymi Tempo módmi; pre všeobecnú prevádzku konsolidáciou CAT vrstvy. Nexus je zadarmo, open source a aktívne rozvíjaný. Stiahnutie, zdrojový kód aj Discord komunita sú dostupné na hamradiotools.io.