A simple home brew FM ham radio repeater.
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JPEG Image - 2.22 MB - 09/21/2020 at 21:20
JPEG Image - 2.41 MB - 09/21/2020 at 21:20
i have managed to get the board programming. Now i just have to work out what issues i have in my firmware.
While trying to program the ESP32 I found a few big mistakes in my PCB. Firstly I forgot to route the Enable Pin. thankfully I can easily solder a wire to it. I also made another mistake with Pin 2. During programming Pin 2 has to be held low or floating. I had it pulled high and used as the PTT for the Input radio. Thankfully this is an easy fix on the current board of just cutting its trace.
I haven't found any additional issues and will be trying to get it working over the course of the week.
I have had this sitting on my USB for a while and just forgot to push it to github. https://github.com/wgaylord/ESP32-Repeater-Controller
It firsts initializes all the needed pins then both radio modules before registering two interrupt routines.
The interrupt routines are used for detecting when the RX radio gets a signal to trigger the TX radio.
The main loop does a check if its been on for too long. (Someone talking a long time with out unkeying) If this is the case it turns of the TX modules PTT. The next thing it does is the Identification. I will probably have to add some sort of delay to this but I will figure that out when I have to.
I will be trying to program the module over the next week.
I finally assembled the board.
I will be trying to program it over the next few weeks.
I am posting this as an update of whats going on.
I am going to attempt to assemble the PCBs this week end and hopefully program it shortly after. I also realized that I currently don't have a good enough 3.3v supply to actually run/program the repeater board once assembled. So I guess its time to design up a power supply board that can power the repeater and also the future Power Amplifier board.
I have also yet to fix the resistor issue on EasyEDA because I haven't assembled the PCB to know if it will actually be an issue or not.
The main PCB of the repeater consist of two SA818 modules and an ESP32. There is also a few passives on board for the ESP32 and also for linking the audio.
The board is currently at https://easyeda.com/chibill/fm-repeater , unfortunately I figured out too late that I need a few more passives on the audio lines to allow the ESP32 to monitor and also send into it. I will be fixing the PCB on EasyEDA soon but for my own boards I will just be bodging them in.
The SA818 modules will manage the PL tones as it has built in support for them. The ESP32 will manage actually the keying for the transmit side. This is to allow the ESP32 to cut out transmission after some amount of time.
Some may notice that the board has no filtering. This is because this is only the RX/TX board not the amp or filter. Plus this also allows this board to be used with the SA818 boards that support 2m or 70cm with out changing parts. You could even put one as a 70cm and the other as a 2m to make a cross band repeater.
I am going to work on assembling the board soon.
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