Super-regenerative vs Superheterodyne

Cheap receivers like the XY-MK-5V / MX-RM-5V are super-regenerative: simple, but broad and noisy. Superheterodyne receivers (RXB6, SRX882, WL101) use a crystal-locked local oscillator, giving much better sensitivity, selectivity and range for a small premium.

One-way vs Transceiver

ASK TX/RX pairs only send data in one direction, with no acknowledgement. If you need replies, retries or addressing, pick a transceiver: HC-12 (UART), CC1101 (SPI) or SX1278 LoRa (SPI).

Sensitivity & Antenna

Receiver sensitivity (in dBm, more negative is better) and the antenna decide your range more than anything else. A 17.3cm straight wire or a tuned helical/SMA antenna can multiply range several times over a bare pad.

Supply Voltage & Logic

FS1000A runs from 3-12V and more voltage means more power, while XY-MK-5V wants 5V. CC1101 and SX1278 are 3.3V-only parts and are not 5V tolerant, so use level shifting with a 5V Arduino.

Library Support

RadioHead, VirtualWire and rc-switch cover ASK modules; HC-12 needs only Serial; SmartRC-CC1101 and ELECHOUSE drivers cover CC1101; Sandeep Mistry’s LoRa and RadioLib cover SX1278. Good library support saves hours.

The QIACHIP WL101 + WL102 kit is another superheterodyne pair from a brand that actually specialises in 433MHz remote modules. The WL102 transmitter is rated at more than 11 dBm and the WL101 receiver is a crystal-locked superhet with far better noise immunity than an XY-MK-5V. The boards are tiny, which makes them ideal for battery sensor nodes and compact enclosures. Check the voltage notes on the listing and your board before powering from 5V, since these are low-voltage-oriented parts.

Already own a drawer of FS1000A transmitters? Swap the XY-MK-5V receiver for an RXB6 and range often jumps dramatically. The RXB6 is a superheterodyne receiver with sensitivity quoted up to -116 dBm, a 3-5.5V supply range that suits both 5V Arduinos and 3.3V ESP32s, and a clean data output that makes decoding weather stations, doorbells and remote sockets with rc-switch or rtl_433-style sketches far more reliable. It is receive-only, so pair it with any ASK transmitter.

The QIACHIP RX480E + TX118SA kit does the encoding for you. The RX480E is a superheterodyne receiver with an onboard EV1527 learning-code decoder and four digital outputs, so a button press on the TX118SA simply drives a pin high: no RF library, no timing code. It supports momentary, toggle and interlock modes, learns commercial EV1527 remotes, and works with Arduino, ESP32 and Raspberry Pi GPIO or directly with a relay driver. Ideal for gate openers, lights, and panic buttons.

The HC-12 turns the 433MHz band into a transparent wireless serial cable. Wire TX/RX to any UART, and bytes written on one side come out of the other: no packet library needed. Under the hood a Silicon Labs SI4438/SI4463 transceiver gives true two-way communication, 100 selectable channels, adjustable power up to 20 dBm and a default range of about 1 km in open air. AT commands set baud rate, channel and power. It is the easiest upgrade when you outgrow one-way ASK and want bidirectional telemetry.

The TI CC1101 is the Swiss-army knife of Sub-GHz radio and the chip inside many popular RF gadgets. It is a programmable transceiver that speaks ASK/OOK and FSK/GFSK, so with the SmartRC-CC1101 or ELECHOUSE library on an ESP32 you can both transmit and receive rc-switch codes, capture and replay signals, read FSK sensors and build packet networks. This board includes an SMA antenna matched for 433MHz. It is a 3.3V-only part, so use level shifting with a 5V Arduino.

When metres become kilometres, move to LoRa. The Ai-Thinker Ra-02 uses Semtech’s SX1278, whose spread-spectrum modulation can decode signals well below the noise floor for multi-kilometre links at low data rates. It also supports FSK and OOK, runs from 3.3V over SPI, and is supported by the Arduino LoRa library and RadioLib. Note the 2mm-pitch castellated pads and IPEX antenna connector: you will want an adapter board and a proper 433MHz antenna. For deeper coverage, see our dedicated LoRa buying guide.

Want the best simple TX/RX link?

Get the STX882 + SRX882 kit: superhet receiver plus a strong transmitter, antennas included.

Learning RF on a budget?

Start with the HiLetgo FS1000A + XY-MK-5V (MX-RM-5V) five-pack and follow any tutorial.

Decoding weather stations or remotes?

Use an RXB6 superhet receiver with rc-switch or RadioHead for much better reception.

Building a wireless switch?

The QIACHIP RX480E + TX118SA kit gives 4 channels with no RF code at all.

Need two-way serial data?

Drop in an HC-12 pair and use Serial.print() as if it were a cable.

Going kilometres?

Pick the Ra-02 SX1278 LoRa module, or the CC1101 if you need ASK and FSK flexibility.

What is the difference between FS1000A, XY-MK-5V and MX-RM-5V?

The FS1000A (also marked XY-FST or MX-FS-03V) is the small square 433MHz ASK transmitter. The XY-MK-5V is the long, thin super-regenerative receiver that is sold in the same kit, and MX-RM-5V and MX-05V are simply other factory markings of that same receiver design. They are pin- and code-compatible: the transmitter has DATA, VCC and GND, and the receiver has VCC, two DATA pins (tied together) and GND. Any tutorial for one works for the others.

How can I increase the range of my 433MHz modules?

Add an antenna first: a straight 17.3cm solid wire (a quarter wavelength at 433MHz) soldered to the ANT pad of both boards, or a coiled/SMA antenna. Next, run the FS1000A transmitter at a higher voltage (up to 12V) and swap the super-regenerative XY-MK-5V for a superheterodyne receiver such as the RXB6 or SRX882. Lower the data rate in RadioHead (for example 1000-2000 bps), keep antennas vertical and away from metal, and avoid noisy switching regulators near the receiver.

Can I use 433MHz modules with ESP32 or Raspberry Pi?

Yes. The FS1000A and RXB6 work well with 3.3V logic, and the RadioHead RH_ASK driver and rc-switch both support ESP32. If you power an XY-MK-5V receiver from 5V, its data output swings to 5V, so add a voltage divider before an ESP32 or Pi GPIO pin. The CC1101 and SX1278 are native 3.3V parts, which makes them a natural fit for ESP32 and Raspberry Pi; they must not be connected to 5V signals without level shifting.

Do I need a library, or can I send data with Serial?

For bare ASK modules, use a library. A super-regenerative receiver outputs random noise when nothing is transmitting, and ASK needs a balanced, preamble-framed signal, so feeding UART data directly gives garbage. RadioHead (RH_ASK) and VirtualWire add framing and checksums for data; rc-switch handles the fixed codes used by remote sockets. The HC-12 is the exception: it has its own microcontroller, so you really can use Serial.write() on one side and Serial.read() on the other.

Is it legal to use 433MHz modules?

In most countries 433.05-434.79MHz is a licence-exempt band for short-range devices, but each region sets limits on transmit power, duty cycle and permitted uses. In the US, FCC Part 15 rules restrict continuous data use around 433MHz, while Europe allows 10 mW ERP with duty-cycle limits. Modules like the HC-12 and Ra-02 can transmit up to 20 dBm, which may be above local limits, so set power as low as your link allows and check your national regulator’s rules before deploying a product.