Some people have reported almost no reception with the FA ProStick+ due to interference from FM or TV or mobile towers.
If the interference is above a certain threshold, it seems that the LNA overloads and useful reception becomes impossible.
Either add a filter in front, or just continue using your current setup.
The LNA is located before the filter. So if it starts to overload you just lose your signal at that point.
Also a filter only attenuates, so it can be useful to use a 2nd filter for strong interference.
Is your dipole cut for 1090MHz or another frequency?
The RTL-SDR does not have a preamp built in.
The Prostick plus has a 20dB preamp before the filter.
I run a Prostick Plus here and I need additional filtering to prevent the internal preamp overloading and reducing performance in exactly the way you have seen.
@LawrenceHill Yes, homemade dipole for 1090. On RTL-SDR has good performance, seen more than 90nm. What is strange is the RSSI seems to stop about -17 or -18db while RTL-SDR goes lower. I will try to add a FM filter in front of it to introduce a small loss. @wiedehopf no idea about the components. The blue stick has a warranty sticker on it and because is not mine I don’t want to open it.
@abcd567 I have materials ordered for a collinear from RG213. A spider was on plan but won’t be that soon.
Now I added a FM filter in front (from RTL-SDR) and tried gains of 20.7 22.9 25.4. At 25.4 I lost the plane around 20nm away so I need more tests. But for the time being I had ADSB messages with location with lower RSSI, which is a step ahead.
I changed antenna with a previously known working CoCo which is more selective (based on scan results). Same result overall.
For the moment I have nothing more to change, hopefully soon I will make another CoCo based on a thick coaxial.
But for the moment the conclusion is … waste of time.
Either this particular example is bad or there is something wrong which I can’t figure out.
A bit later edit: the blue stick cannot decode nothing below RSSI -18, while most of the messages are mode S. RTL-SDR goes below -30 (seen -33.9) and same messages from the same plane are ADSB.
I found that the voltage at the stick input sometimes was below 4.4. Changed the power supply, now I get some proper ADSB messages decoded, but only from less than 20nm away which is weird. Gain was 29.7
I am working on a collinear antenna made out of RG214 with VF of 0.66 to see if that changes something. Should have a narrow bandwidth.
Probably high RF issues - overloading the receiver. (Nearby cell sites etc) Locate the discussion topic “Do I need a filter” and consider some of the testing suggested there to see what may be impacting your install.
well, the issues you describe are common outcome for the overload of the received by RF, and several people who have helped many others on the forum with very similar issues have already suggested consideration of that thread.
Maybe take the time to run the spectrum scan and post the output for others to review the RF conditions in your location and then someone can provide you with advice that is specific you your RF environmental conditions.