M5Stack Cap CC1101 vs Hydra RF: Tri-Band NFC Cap or Dedicated Dual Radio?

PINGEQUA Lab · Cardputer ADV cap comparison · 11 min read · Updated 2026-09-02

M5Stack’s new Cap CC1101 puts 315, 433, 868 and 915 MHz plus NFC on one Cardputer cap. PINGEQUA Hydra RF keeps a dedicated Sub-GHz front end for one regional band and adds an nRF24L01+ 2.4 GHz radio for Bruce. They plug into the same Cardputer ADV header. They are not the same product.

Cap CC1101 vs Hydra RF at a glance

Same Cardputer ADV header, different jobs

M5Stack now sells an official wireless cap named Cap CC1101 (SKU U219). The documentation describes it as a Sub-1 GHz RF plus NFC expansion for Cardputer-Adv and CardputerZero, with applications listed as wireless remote control, access-control identification, device communication and IoT prototyping. Software listed on that page is Arduino and UiFlow2. (M5Stack Cap CC1101 documentation, read 2026-09-02)

PINGEQUA Hydra RF is a dual-radio cap for Cardputer ADV only: a Texas Instruments CC1101 whose matching network and antenna are built for one Sub-GHz band, plus an nRF24L01+ 2.4 GHz radio with PA/LNA. Bruce selects the active transceiver. A hardware mutual-exclusion circuit isolates the other radio. It is not an NFC reader, not a LoRa/Meshtastic cap, and not a CardputerZero accessory.

If you landed here because M5Stack announced Cap CC1101 and you already own a Cardputer ADV, the useful question is not “which board lists more megahertz.” It is “which second function do you actually need, and do you want one compromised Sub-GHz path or one dedicated one?”

Looking for LoRa or Meshtastic instead? That is a third product — M5Stack Cap LoRa-1262 — covered separately in M5Stack LoRa Cap vs Hydra RF. SX1262 is not CC1101.

Spec comparison: Cap CC1101 vs Hydra RF

That last row is intentional. Official Cap CC1101 publishes a sensitivity and a range test. Hydra RF does not. This article does not invent a Hydra dBm number, and it does not claim a longer range.

Tri-band switching is not four RF front ends

The CC1101 silicon can be programmed across 300–348 MHz, 387–464 MHz and 779–928 MHz. That is a chip capability, not a board capability. (Texas Instruments CC1101)

TI’s own CC11xx filter-balun note treats the matching network as band-specific. It publishes separate 315 MHz, 433 MHz and 868/915 MHz reference designs, and it gives 868/915 MHz an optimum load of Z = 86.5 + j43 Ω looking from the chip toward the antenna. You do not get four independent, fully optimized radios by writing four frequencies into a register. (TI Design Note DN017 / SWRA168, document dated April 2023)

Cap CC1101 is honest about the topology it actually uses. The RF section is one CC1101. Dual SP3T switches and a multi-band matching circuit multiplex 315, 433 and 868/915 MHz onto one RP-SMA connector. The box includes three different rubber antennas. Changing band is a switch setting plus, in practice, an antenna swap.

That design is a convenience product: one cap, several ISM labels, official Arduino and NFC. It is not the same as shipping three separately matched Sub-GHz boards. SP3T insertion loss, a shared matching network and a single connector are the cost of that convenience. How many dB that costs on a given band is a lab measurement. We have not published a side-by-side VNA or range test against Cap CC1101, so this page stops at the circuit fact.

The tell: 868 MHz and 915 MHz share one path

If you only remember one hardware detail from the official document, remember the RF switch table.

Source: M5Stack Cap CC1101 documentation, RF Switch Control Truth Table, read 2026-09-02.

868 MHz and 915 MHz are not two switched front ends. They are one switch position. The included “868 MHz” rubber antenna is specified for both 868 MHz and 915 MHz. EU/UK SRD work and US/Canada/Australia ISM work are being asked to share matching and a single whip.

Hydra RF splits those jobs on purpose:

GPIO is shared. The CC1101 matching network, antenna and operating frequency are not. A 433 MHz 424 cannot become a 915 MHz 924 in Bruce, POSEIDON, or any other firmware. That is the same physics the official cap admits when it refuses to give 868 and 915 separate switch codes. Full band logic: Hydra RF 424 vs 824 vs 924.

NFC versus nRF24: the second radio decides the job

Cap CC1101’s second chip is an ST25R3916 NFC front end at 13.56 MHz. Reader/writer mode covers NFC-A/B (ISO14443A/B), NFC-F (FeliCa) and NFC-V (ISO15693). Card emulation covers NFC-A and NFC-F. If your Cardputer work is access-control identification or tag prototyping, that is a real official feature Hydra RF does not have.

Hydra RF’s second chip is an nRF24L01+ on 2.4 GHz, with PA/LNA, on the same SPI header as the CC1101. That is the radio Bruce’s nRF tools actually speak — spectrum, scanner, and authorized nRF24-family research. Cap CC1101 does not include nRF24. ESP32 Wi-Fi/Bluetooth on the Cardputer is not a substitute for that transceiver.

This is why a “CC1101 cap” search now returns two different products. One is Sub-GHz plus NFC for M5Stack’s Arduino/UiFlow stack. The other is Sub-GHz plus nRF24 for Bruce. Other third-party caps advertise tri-band CC1101 plus nRF24 on one board; they still put multiple Sub-GHz bands on one matching path. If you want nRF24 and a dedicated Sub-GHz front end, that is the Hydra RF series, not the official NFC cap.

Arduino and UiFlow versus Bruce

Official Cap CC1101 software, as listed by M5Stack, is:

• Arduino quick start, with RadioLib for CC1101 and M5Unit-NFC for ST25R3916
• UiFlow2 Cap CC1101 documentation

Bruce is not on that list. Bruce can talk to a CC1101 over SPI when the pin map and the board’s real matching band line up — that is how Hydra RF is used — but we have not verified SKU U219 inside Bruce. Do not read this page as “Cap CC1101 is Bruce-ready” or as “Cap CC1101 cannot run Bruce.” Treat it as an official Arduino/UiFlow/NFC cap until M5Stack or Bruce documents otherwise.

Hydra RF is documented end to end for Bruce: GPIO map, brucePins.conf, frequency per SKU, and a browser flasher that writes the Hydra pin file so you are not hand-editing LittleFS and SD copies. Setup: Cardputer ADV Hydra RF setup. What the CC1101 menus actually teach: CC1101 + Bruce on Cardputer ADV.

Which cap should you buy?

Buy M5Stack Cap CC1101 when:

• You want official Arduino or UiFlow examples, not a Bruce RF lab.
• NFC read/write or card emulation is part of the project.
• You need 315 MHz hardware and a 315 MHz antenna in the box.
• The host is CardputerZero, or you want one official cap that also lists Zero.
• You want Grove on the cap and you accept swapping Sub-GHz antennas.

Buy Hydra RF when:

• The host is Cardputer ADV and the firmware is Bruce (or another stack that already maps Hydra GPIO).
• You need nRF24 2.4 GHz as well as Sub-GHz — one cap, two radios, no extra board.
• You want the CC1101 matching network and antenna built for your band, not a switched 315/433/868/915 compromise.
• You do not want to unscrew an RP-SMA whip every time you move between Sub-GHz and 2.4 GHz.

Buy neither of these if you want LoRa or GNSS. That is Cap LoRa-1262. Hydra RF is not a Meshtastic radio.

Still matching ADV versus original Cardputer, or choosing among PINGEQUA SKUs? Use the existing buying guide rather than this comparison: Best RF module for M5Stack Cardputer.

Pick the Hydra RF band. Software cannot retune it.

Once you know you want Hydra RF, the remaining decision is regional hardware:

1. Hydra RF 424 — CC1101 433 MHz + nRF24 2.4 GHz. The default Sub-GHz pick for many consumer-device bands where 433 MHz use is permitted.
2. Hydra RF 824 — CC1101 868 MHz + nRF24 2.4 GHz. The EU/UK-oriented SKU. Confirm the live product page before ordering; this article does not attach a checkout URL for 824.
3. Hydra RF 924 — CC1101 915 MHz + nRF24 2.4 GHz. The US/Canada/Australia-oriented SKU.

Flash Bruce from the browser, let the flasher write the Hydra pins, then set RF → Frequency to 433.00, 868.35 or 915.00 to match the board you actually bought. Wrong SKU is scrap. That is a hardware sentence, not a scare line.

FAQ

Primary sources, verified 2026-09-02: M5Stack Cap CC1101 documentation (SKU U219) · TI CC1101 product page · TI DN017 / SWRA168 (April 2023) · RadioLib · M5Unit-NFC · Hydra RF 424 · Hydra RF 924 · Hydra RF hardware documentation · Cardputer Bruce flasher. PINGEQUA is independent and is not affiliated with M5Stack, Texas Instruments, STMicroelectronics, Nordic Semiconductor or the Bruce project.

For education, authorized research and interoperability testing only. The host device is not included. Attach the correct antenna before transmitting. Use only frequencies, power levels, duty cycles and protocols permitted where you are; hardware capability is not a license. Sub-GHz and 2.4 GHz operation may fall under FCC Part 15 / SDoC / FCC ID in the United States and ETSI EN 300 220 / CEPT 70-03 in the EU/UK — verify the rules that apply to your finished setup. Interference and unauthorized interception are illegal in many jurisdictions. “M5Stack,” “Cardputer,” “Cap CC1101,” “CC1101,” “nRF24L01+,” “ST25R3916” and “Bruce” are used for identification and compatibility.