I purchased this kit from WIFI Expert on Ebay “FlightAware 1090MHz ADS-B Antenna + Cable + PRO USB Stick PLUS from Flight Aware”. Just messing with it before I mount the antenna to the roof, I get .4 messages/sec with it just leaned up against the window. If I hold the base of the antenna the messages go to between 30 and 50/sec. Do I have a bad antenna, or am I missing something?
Probably the cable in the socket is broken and you hold it by chance that it is connected?
Even 30 to 50 can be bad, did you check other receivers in your neighborhood about their performance?
Antennas are complex and interesting things. So are radio waves. It’s not uncommon that even standing near an antenna affects reception. Anyone who remembers rabbit ear antennas knows how frustrating they could be because just getting near them to adjust them could fix reception issues. If you look up Yagi antennas, those have all sorts of antenna elements yet most are unconnected. Usually just a couple of them are active - the rest are passive yet their presence really affects the directionality of the antenna. By holding the base of the antenna, you were likely acting something like a ground plane and enhanced the antenna’s reception since antennas and ground planes are famous in how they get along, or in some cases, don’t get along.
Or it could be broken. But I doubt it. Bet it is you coupling into the antenna and affecting the reception by giving the signal something to bang against.
Did some more testing with it. You are correct, just walking around the antenna was bosting the reception. I move the Pi and Antenna outside and even at Ground level it instantly went up to about 400 messages/sec and started getting reports almost 200 miles out. I guess my house is very RF noisy. I would guess it would get even better once it is up on the roof and not on the ground between two houses.
Now I just have to read up on here how to setup the same pi to run both 1090 and 978. I have another reciever on the the way for 978. Just need to find the Antenna for it.