I have been trying to troubleshoot an issue I have been having since I decided to move my ProStick closer to my antenna but using a powered USB extension cable.
I have been doing some reading around the web about SDRs in general and there might be an issue with there not being enough power getting to the ProStick.
At the moment the powered USB extension is directly attached to the Pi and drawing power from that, in addition the ProStick is getting its power off the extender.
Everything is still functioning, however my message rate is way down. Is it possible that the ProStick is having a sort of brown out?
I do have some stuff on the way to inject power at the ProStick end but this is a few weeks away.
I had a similar issue after switching to a 30’ usb cable to eliminate 30’ of antenna cable. Message rates dropped. It turned out that without the signal loss from that long antenna cable the prostick was being over-saturated. I needed to add a filter between the antenna and the prostick. Later discovered that I could get the best message rate by removing the filter and manually adjusting the gain setting down.
The pi is powering my prostick fine over the 30’ usb cable with no external power added.
What sort of message rate are you getting out your way? Mine doesn’t seem that high compared to some regions in the world, nowhere near as much traffic down here
I’m in central USA. Not near major airports, but some of the busiest cross-country routes pass through my range. At peak times I’m tracking over 200 planes and 1200 message/second.
I didn’t mean to suggest that your receiver is being over-loaded by the number of messages. It could just be interference from strong radio signals on other frequencies preventing the receiver from distinguishing the ADSB messages out of the noise. Also, with the gain on the prostick cranked up all the way (as it is by default) the messages from nearby planes can be so strong that they can’t be decoded or they hide weaker signals. When this is happening CPU utilization will go up, but number of messages goes down.
There are several message threads on this board concerning the FA filter, and adjusting the amplifier gain, if you haven’t already seen those. My take-away from all of it is that every installation is different so there is no magic answer that is optimal for everywhere. Tweaking for maximum range will probably reduce the message count or the number aircraft, and tweaking for message rate will probably cut maximum range. Those are hints rather than rules and may also depend on where you are located and all the details of your installation.
No issues Was just curious what numbers you are getting, I often hear about saturation, I just don’t see that many aircraft down this way so don’t think it will be an issue.
I am going to sort power out first to eliminate that from the equation, there is enough doubt there for me to do something (having power on the mast will be handy).
Then will try the different filter/no filter options gains etc…
I don’t think you were over saturating your Pi with messages, but you may have been oversaturating the radio and needed to turn your gain down. The filter really won’t help if you’re in a quite RF environment, so that was probably a good move.
I have been using a 20m long powered USB extension for over 2 years now and it works perfectly. Silver RTL-SDR dongle is plugged into flightaware bandpass filter and they both are sitting right at the 9 element CoCo antenna. Coverage range is over 200 NM in all directions
Was just curious what numbers you are getting, I often hear about saturation, I just don’t see that many aircraft down this way so don’t think it will be an issue.