4 and 8 Watt WiFi bi-directional amplifiers are designed for about 10-20 dBm input power. They listening in their input for a relatively strong signal to decide whether turn over to TX state from RX state (and changing over RF switches). Doing this simply rectifying the inrush RF power and leading that into an amplifier Read more about Modifying EDUP EP-AB007 4W bi-directional Wifi amplifier for OA-100 Es’hail satellite operation, non-stop TX mode[…]
Setup:– WSPR transmitter: QRP Labs U3S kit at 2m mode WSPR, using GPS calibration (later might trying OCXO option)– 2m BPF– Morfeus converter – a Minicircuits ZX60-43-S+ RF amplifier block (single stage) – 2.4 GHz BPF– 5 turn LHCP helical and 1m parabolic dish– Virtual Audio Cable SW tool for routing web sdr audio to Read more about Celebrating successful Es’hail 2 / QO-100 GEO HAM satellite WSPR transmission using only 4 milliwatts[…]
As indicated by ham users the schematic is low quality in the PDF article released by TAPR. Here sharing a better quality picture, hopefully that helps.
Here is list of commands how to install and configure a standalone wspr receiver on Raspberry Pi using an RTL-SDR V3 dongle for wspr reception and reporting. Running this since a year on the roof with great success! Can be run in RPi 1-2-3 even zero.
Hi, As may many of you seen on RTL-SDR blog the RPITX V2 is out there We made several measurements booth on 434 MHz and 144 MHz and looks like the first still has difficulties while the second (144 MHz) is exceptionally clean, even with PA (1W) and almost no filtering. 434 MHz strange spuriouses Read more about RPITX V2 measurement plots[…]
An excellent and clever solution using a SoC ISM radio as 2m APRS transceiver: FeatherHAB: 2-gram High Altitude Balloon Tracker
Didn’t find an elegant compact solutions out there. I’m using only the GPIO pins, no need to route the audio jack output back to the PCB like existing solutions. Also using an on board amplifier which supplied from RPi 5V. Built a few prototypes yet and working nice 🙂 Enjoy! https://github.com/rfsparkling/RPi_Speaker https://www.reddit.com/r/RASPBERRY_PI_PROJECTS/comments/55hk5k/rpi_speaker_an_open_source_fully_integrated/
Remote Spectrum Monitoring Drone from RTL-SDR, RPi, 4G internet using OpenWebRX Can be used as an improvised “virtual antenna tower” for example in emergency situations, ham radio activities or experimenting. Possibly words cheapest aerial spectrum monitoring tool as of today. You can see APRS and ham radio FM repeaters in the spectrum plot of the Read more about Remote Spectrum Monitoring Drone from RTL-SDR, RPi, 4G internet using OpenWebRX[…]