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).

I broke the original housing for GoPro Session (the smallest GoPro). Then I designed more bulky one, suitable for 3D printing.

Here is the OnShape project.

and 3D printed part…

Please send email for STL files.

Final version with holder for quick release gooseneck:

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 developed simple cable tester. The complete project is in my GitHUB repository:

https://github.com/s54mtb/cabletester

This is simple cable testing tool for checking your cables (e.g. ethernet patch cables or house installation). Complete tester consists of two modules and tested cable. Master (left) module is on the left. It is connected to the power supply (battery or wall adapter). Slave (right) is passive and has only LEDs.

I recently found interesting project https://www.telraam.net/ It’s an open source project where a Raspberry Pi with camera counts traffic passing by (pedestrians, bicycles, cars and other heavy vehicles). The device is (as stated by authorts) “mounted on the inside of an upper-floor window with a view over the street. To send the traffic count data straight to the central database, the device needs a continuous Wi-Fi connection to the internet.”
I placed one in my home on the window and it started counting some day after installation.

Next I wanted to install one in my remote location, where I have internet for other IoT purposes. There is no “upper-floor window”, which means I should place my raspberry and camera outside. Here is how I did it…

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.