Has anyone tried powering KrakenSDR+Raspberry via PoE? I have found an interesting guide that mentions this approach, but I have reasonable doubts that it will work properly, primarily because of the extra noise the PoE injector and splitter may create. Also, I still remember when the device was freezing, stucking in the calibration loop, undetectable, etc. when it was used with power supplies different from the original RaspberryPi-ones. Will this approach work? This is a page from this guide, and also links to the PoE devices the author recommends using
PoE will work, I have tested it before. But yes it is noisy, it adds noise spikes all across the spectrum if you don’t take any steps to mitigate.
The ways I found to mitigate was to do the following:
Use a PoE splitter that comes in a metal enclosure. The only one with a metal enclosure I found was manufactured by Rak.
Ground the Pi 4 / Orange Pi 5, PoE splitter and KrakenSDR to the same metal sheet via the mounting screws. The Pi4 mounts are actually not grounded, so you’ll need to solder on a grounding strap from a ground point on the Pi4. The Orange Pi 5 is a lot better because the mounts are grounded.
Put everything in a sealed metal enclosure so that the antennas don’t pick up any POE noise, and make sure the metal sheet is grounded to the enclosure via several screws.
Is this the one? PoE Splitter Raspberry Pi | DC Jack 12V Type-C 5V PoE Splitter – RAKwireless Store
So the splitter’s 6A is enough to power Raspberry/Orange Pi and KrakenSDR, right? I am double-checking because I already had power-related software issues when data on the SD card became corrupt randomly on frequency change or just powering on, and only switching to the original RPi power supplies helped with this recurring issue.
Could you please share your recommendations on the PoE injector as well, if there are any?
What level of noise mitigation can be achieved with such measures (from your experience)? No noise spikes at all, or just a reduced level?
I have also had the desire and been working towards getting a stationary setup at home.
To minimize cabling, I decided to put the Kraken SDR and Raspberry Pi in a box just below the antenna array. Here is a Visio drawing of the components inside the box:
I found this DC to USB adapter that will make the DC cabling inside the box easier, but I am concerned if it will provide enough current for each device:
Carl, I like your comments about grounding all the components.
Gary
Yep that’s the one. The 6A spec is definitely enough. 3A MAX for the Pi 4 (in reality about 2A is the highest I’ve seen), and 2.2A for the Kraken
I’m just using the corresponding RAK injector. But any other similar one should work fine too.
I was able to go from almost full scale noise spikes to only having a few at certain VHF frequencies and most under ~5-10dB. Not perfect, but usable especially when an antenna is connected and real signals drown out most of the noise.
I have built a Kraken stack using Pi4 and the kraken SDR. Each device has each own independent PoE supply. This means that the Kraken SDR is power supplied by a PoE injector and a PoE splitter (the network is not connected). The PoE splitter is 5V and 2A and it connected to Kraken using the USB C power supply port. However, I have observed that the Kraken device sometimes is not enumerated (using lsub) and the problem remains until I disconnect everything (not just cutting the power supply). This is a bit odd. Does somebody has similar experience? Could somehow the PoE creates problems to Kraken and set it to something like safe mode or whatever?
There’s no safe mode in the Kraken. Not sure what could be causing that with PoE specifically. It should not care about the power source as long as there is enough current.
Unless perhaps the POE supply is unstable at powerup? Can you measure the power up voltage on a scope and look for dropouts?
