Mare & Gal Electronics

This is small module for splitting 1 signal to 4 receivers. It is part of the multiband SDR receiver, but it can be used standalone for any similar application.

In past I assembled small SDR receiver based on Raspberry Pi and SDR USB dongle based on software developed by PA3FWM. The problem was with limited usability by multiple clients connected to the Raspberry pi at the same time. The old SDR was retired and put aside for few years.

Then András Retzler ha7ilm developed (and stopped developing) OpenWebRx, which was the base for now regulry maintained and further developed OpenWebRx.de.

I recently built homelab server based on “proper” server infrastructure with plenty of RAM and lots of processing cores. I decided to setup OpenWebRx in one linux virtual machine with raspberry pi only as remote receivers serving single user (server itself).

Yaesu FT-991A Frontend has nasty hidden fault. It is not normal from €1000 radio to stop working just because you use it in a pileup situation or when your close OM is beaming toward you with QRO.

New, out-of-the box radio receive performance of the FT-991(A) was normal, but after other station(s) had transmitted at a higher power levels, the FT-991(A) receiver failed. The failure mode was as follows:

• Receiver operation is normal when the Attenuator feature is disabled.
• Receiver operation fails (no receive and a very quiet noise-floor) when the Attenuator feature is enabled.
• IPO operation enables the Attenuator and results in the same receiver failure mentioned immediately above.

Same issues are reported elsewhere:

• Yaesu FT-991A Receiver Front End Failure
• FT991 frontend gone bye bye
• FT 991 A deaf in IPO mode, receives normally in AMP modes in HF bands

Patient with exactly the same simptoms got to the operation table in my lab today. The owner is OM S52W, very successfull contester and member of the famous contest club.

There are many flight tracking services around the web and most of them are based on ADS-B receivers placed by individuals. Few months ago I put together simple GP antenna, RTL-SDR and installed Pi-Aware software. It fed data to FlightAware. Soon after one of my mod-school friends asked if I could do the same for FLightRadar24. After some search I found this github repo: Balena ADS-B Multi-Service Flight Tracker. I had good experience with balena (for LoRa gateways) and followed the really excellent step-by-step instructons. Below are some details about my installation of this Multi-Service Flight Tracker.

The plane tracker is now feeding online (with short outages) since August 2019.

Here are links:

https://flightaware.com/adsb/stats/user/s54mtb

https://www.flightradar24.com/account/feed-stats/?id=24076

https://planefinder.net/coverage/receiver/102325

I bought used outdoor WiFi access point for couple of coffees. At first I wanted to use only the housing for conversion of the TTN Indoor gateway to outdoor gateway. But after some testing and factory reset of the AP I found out it is working and could be configured as stand-alone WiFi MIMO AP. Usually such APs require infrastructure, or at least some management server.

This is short tutorial how to send data from sensor connected to The Things Network via LoRaWAN to Weather Underground. I will use Scidrom air quality sensor whic I developed for students in local school. Just a quick reminder the “AQ” sensor detects PM10, PM2,5 particles, air pressure, temperature and humidity and solar radiation in visible in UV spectrum. More details are available in older post.

“Special offer” came out for 5GHz antenna. It was posted on Polish web store Interprojekt, where I sometimes buy some equipment for long range WiFi point-to-point links.

The antenna came well packed in carton with additional box for the feed. The grids were separated with paper to avoid scratches during transport.

Here are instructions for outdoor UV index and ambient light sensor.

The solar radiation shield is a low cost DIY device to protect temperature, relative humidity and other sensors from the weather, while shielding them from the sun for highest accuracy. Provided here are instructions and files. It require some CNC machinig, but then it could be assembled in minutes. It is made from plant pot saucers.

Two PCBs from earlier projects were used in this project:

1. LoRa breakout board
2. Sensor PCB with Si7013 humidity sensor from multisensor LoRa project
3. … and particle sensor.

Finished particle sensor in housing, ready for the TTN

Continue reading ‘Particle Sensor with LoRa’ »