PicoAPRS V4 LoRa 70cm Transceiver

The world's smallest APRS transceiver gets even better! With version 4, the small radio comes of age!

The 70 cm LoRa APRS function enables long ranges at low output power. The transceiver can not only be used as APRS tracker and receiver for APRS data, but also as LoRa RX-iGate! In contrast to the VHF version, the voice radio function is omitted.

The display has become larger and more colorful! With 240x240 pixels incoming APRS packets like position messages, APRS messages (similar to SMS) and status messages are displayed. For position messages, the distance and compass direction to the station is also displayed. The last heard stations incl. distance and compass direction as well as received messages are stored and can be retrieved via the menu.

The GPS coordinates received via the built-in GPS receiver can be displayed and thus the PicoAPRS can also be used as a GPS tracker, e.g. for geocaching. If desired, the own position can be permanently stored in the device, for example if no GPS position can be determined. The permanently stored position is then only used to display the distance and compass direction of received stations. A speedometer display is also available. The units of the speed display can be changed between km/h, mph and knots.

Operation is made even easier than on the predecessor via the joystick keys on the front. The five buttons make it easy to control the menu and make all settings, even without a computer. In the delivery state, the device is almost completely pre-configured. All that needs to be done is to save the callsign, and then you can get started right away.

The included rechargeable battery enables an output power of approx. 0.4 watts (26 dBm). The transmitting power of the LoRa version can be adjusted in 1 dB steps from 16 dBm (approx. 40 milliwatts) to 30 dBm. However, the actual output power is limited to approx. 26 dBm (0.4 Watt) due to the battery voltage.

With the built-in and replaceable 850mAh LiIon battery, the device can be operated up to 10 hours [1] depending on the configuration. The same battery is used as in the predecessor V3. The battery is charged via a modern USB-C port in the PicoAPRS V4. What is new is that the socket is mounted on the side. This allows the little all-rounder to stand safely on the table while it is being charged. Of course, radio operation is also possible during charging.

The LoRa variant is more economical than the VHF variant.

The receiver requires significantly less energy.

As a result, the runtime is significantly longer than the VHF variant for comparable use.

The PicoAPRS can also replace a pager (POCSAG). Unlike a pager, the device also sends back an acknowledgement of receipt. This lets the sender know whether his message has arrived or not. Messages can be sent directly from the PicoAPRS.

The "Follow" function can be useful e.g. when skiing with a partner. There you can press FOLLOW at the callsign of your partner and now you can always see how far and in which direction your partner is located. When new position messages are received, the display is updated automatically. Or you can use the function when you are on vacation with several people, or when you drive together with several cars to the same destination.

With a size of only about 33 mm x 66 mm x 25 mm, the PicoAPRS V4 is similar in size to a matchbox. At the same time, the device (without antenna) weighs just about 60 grams! Ideal to have the device always with you, e.g. while hiking, biking, motorcycling, skiing, on a boat or in the air.

The PicoAPRS was developed by Taner Schenker (DB1NTO).

[1] Depending among other things on how often the position data should be sent, whether APRS packets should also be received, whether the GPS receiver may be switched off automatically when not in use and how often the display can be switched off.

[2] The PicoAPRS V4 supports BT 'Classic' as well as (since version 8 from Feb. 2023) 'Bluetooth Low Energy (BLE)'. This allows Apple IPhone devices to connect to the APRS interface.

Menu items (will be further developed if necessary):

• Device off
• SOS function
• APRS settings
• GPS
• Last heard
• Bluetooth on/off
• Wifi
• Weather messages
• Radio settings
• Messages

The PicoAPRS is delivered fully assembled. No charger or antenna is included with the unit. Due to the standard USB-C connector, the charger of a newer cell phone can be used for charging. Alternatively, the device can be charged with any USB charger or at the USB port of a PC.

Any antenna with an SMA connector can be used as an antenna. The tiny device naturally tempts to use a tiny antenna as well, but of course small antennas also have a comparatively poor efficiency, and we only have 1W transmit power after all. An external antenna should definitely be used in the vehicle, for example a magnetic base antenna.

But this is not the end of the development of the PicoAPRS. For the future, the developer DB1NTO plans other variants, for example with receivers for long, medium and short wave.