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Working with the WIFI module
The Arctic Tracker lab model has a main microcontroller unit (Teensy 3) and a ESP-12 WIFI module. Now, can we connect the tracker to a PC or to the internet (using WIFI) and can we make a web interface to configure the tracker? Yes, it seems like we can. It can connect to the internet,…
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Assembling and testing the tracker lab model
The picture above shows the PCB for the Arctic Tracker with most parts mounted. It was straightforward to solder the parts on the board, except the Teensy. It can be tricky since it need to have 37 pins soldered on it first, and these should either be soldered onto the PCB either directly or a…
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The quest for open software for the ADF4351
It seems the ADF4350/ADF4351 is a versatile little RF synthesizer, ranging from low VHF to well into the microwave spectrum. The are quite a few articles describing projects using the ADF4350 or ADF4351, and a few that publish firmware files for diverse MCUs that can control the synthesizer, but no I haven’t been able to locate…
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Designing a lab model
The Arctic Tracker project is not dead (yet). The idea is to develop a tracker device with traits like these: It is modular, it can be assembled mainly from existing modules. Should be fairly easy to assemble. It has plenty of computing room and is open source. It can be a platform for hacking and…
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Receiving APRS packets
Receiving and decoding of APRS packets is now implemented and it seems to work. It is more tricky than sending packets but there are a fair amount of examples to look at. For instance the BeRTOS TNC implementation. Ok, here is how it is done: First, the audio signal from the receiver is fed to…
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Transmitting APRS packets
APRS packet transmission is now tested and it works. It is clear that the SA818 radio module is not usable for this project. The time it takes to key up the transmitter and get a decent modulation running is far too long. In addition it seems to vary and it seems like there is some…
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Linking Yaesu DR-1X repeaters without expensive hardware
My club has two DR-1X repeaters on the same site. One is on 2 meters, the other on 70 cm. We wanted to link the repeaters together so they would behave as one when needed. There are several complete solutions for this already on the market, and more on the way. Two alternatives we looked at…
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Interfacing the DR-1X Repeater
The documentation for the Yaesu DR-1X repeater has a number of shortcomings. This post will describe my findings so that others may hopefully benefit from my research. In our current application we are interfacing two of these repeaters, each connected to a separate USB sound interface and RS-232 serial port for squelch and PTT signaling. In…
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Using the DAC
Can we use the 12 bit DAC of the Teensy 3.1 to generate AFSK (Audio Frequency Shift Keying) signals? Lets try. First, we try to generate sine waves with frequencies of 1200 or 2200 Hz. If we could quickly toggle between those two frequencies, it would support generating AFSK. The idea is to use a…
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Hacking the radio module
It works. I connected the SA818 module to the Teensy 3.1 and wrote some code to control it. I tested that I could turn it on, set the frequency and engage the PTT from software, and yes, it it transmits on the selected frequency. The serial port is connected to the third serial port of…