SuperFox User Guide
Joe Taylor, K1JT — June 12, 2024

WSJT-X 2.7.0 includes SuperFox mode, a powerful new tool that helps DXpeditions to makedigital QSOs at very high rates. Rather than sending concurrent streams of up to five normal
FT8 signals, each 50 Hz wide, the SuperFox station transmits a full power constant-envelope
waveform, 1512 Hz wide, conveying signal reports or RR73 acknowledgments to as many as
nine different Hounds simultaneously. There is no signal-strength penalty for simultaneouslytransmitting to the maximum number of Hounds. Hounds chasing the DX station transmit
normal FT8 signals, as in the already familiar Fox and Hound mode. SuperFox QSOs arelogged as FT8 mode, and SuperFox will not make robotic QSOs. This brief guide to newfeatures assumes familiarity with old-style Fox and Hound operation, as described here:
https://wsjt.sourceforge.io/FT8_DXpedition_Mode.pdf.
SuperFox Operation requires the Fox operator to select Special operating activity, Fox,and SuperFox mode on the Settings  Advanced tab, and to enter a valid key as in thisexample:

The secret key is used to create a digital signature conveyed as part of the SuperFox messageand used at the receiving end to establish legitimacy of the signal. Authorized keys will beissued in advance for legitimate DXpeditions by the Northern California DX Foundation.
The SuperFox waveform extends from audio frequency 750 Hz upward to 2262 Hz. Standard
messages include up to 9 Hound callsigns: as many as four may receive numerical signal
reports to start a QSO, and the remainder receive RR73 to acknowledge that a QSO has been
logged. If you check the More CQs box (see below), any SuperFox message will also include
a CQ. Stand-alone CQ messages may include a free text message — perhaps someinstructions for calling stations — and free text may also accompany a message with up tofour Hound callsigns and either signal reports or RR73’s. To send a text message, click theFree Text button, enter your desired message (up to 26 characters), and check the Send msg
box as in this example. Use your own message, of course.

Hound Operation should begin by selecting Special operating activity, Hound, andSuperFox mode, on the Settings  Advanced tab:With this setup WSJT-X will decode SuperFox transmissions in even reception intervals (thosestarting at 00 and 30 seconds of a UTC minute) and normal FT8 signals in odd intervals.
Hounds may transmit anywhere in the audio frequency range specified by the SuperFox
station, up to a maximum range 200 to 5000 Hz. Note that Hounds are not forced to transmit
above 1000 Hz, and a Hound’s frequency is not automatically shifted after he is called bySuperFox. The entire QSO is conducted at the Hound’s original calling frequency. All parts of
decoded SuperFox messages will appear in the left (Band Activity) panel, and messages
addressed to you in the right (Rx Frequency) panel. The SuperFox decoder tests the digital
signature included in each message; if valid, the transmission will be marked “<FoxCall>verified” as shown in this screen shot:

In nearly all other ways, Hound operation is identical to that used for the old-style Fox andHound mode.
SuperFox features are available only in WSJT-X 2.7.0-rc5 and any later releases. The
Northern California DX Foundation (https://ncdxf.org) will be ready to accept SuperFox key
requests from DXpedition organizers by September 1, 2024.