Finally got my spare parts for the Raspberry Pi PoE hat and put the ADSB receiver back online. It took DHL Express almost 6 days for the customs clearance, was the last time I used this carrier. UPS is way more efficient on that.
I used the outage for an upgrade to the Mode-S Beast receiver. The performance of the neat little thing is astonishing! Compared to RTL-SDR dongle the ADSB message rate is 3 times higher, I see 40-50 more aircrafts, tracks per hour increased by 300-400, range increased by around 70km and CPU usage is down to 2-3%. That’s with the G7RQG antenna, connected by a short coax cable (<1m).
My dump1090-fa fork now supports the Mode-S Beast directly via USB. See Github for details.
Today, a thunderstorm passing overhead just killed, or better grilled, my ADSB receiver. There was no direct lightning strike but for some reason the DC-DC converter on the PoE hat stopped working and shows a short on the 48V input. The Raspberry Pi and everything else on the 5V side is working just fine. The PoE hat is powered by a 48V switching supply off the 220V mains. That is also still working fine, probably because of its output short circuit protection.
On the PoE hat the DC-DC converter is a Silvertel AG9805-M, ordered some new from http://www.semiconductorstore.com. $8/piece is a good deal compared to the price for the PoE hat or replacement converters supplied by other manufacturers.
I will stock some spares just in case that happens again. But then I need to investigate why that thing breaks.
Today I tried my G7RGQ antenna together with a NooElec NESDR Smart stick connected to the ADSB Raspberry Pi. I put the antenna and the stick on the roof and had it running for a while. To my surprise the performance was not as expected. I needed the same a gain setting to archive results comparable to my QFH antenna with 6m coax to the receiver. Again, I removed 6m of coax, around 6dB attenuation, but results were ain’t better. Took everything down again and disassembled the setup for testing.
After successfully testing of my G7RGQ antenna here my built details:
In red the dimensions I ended up with.
With above dimensions the antenna is tuned to about -22dB return loss at 1090MHz when placed inside the PVC tube.
I took the opportunity for some experiments with gain settings in dump1090-fa while testing a new built antenna for the ADSB receiver. I compared my previously built QFH antenna to a G7RGQ omni directional antenna that I built last week. Second object of test was a 10m active USB cable (from Amazon).
1090MHz QFH on the left. G7RGQ omni on the right.