I have been running my Raspberry PI in my attic with the inside antenna, but after the second unit died (most likely due to heat), I decided to redo my setup.
I installed a FlightAware 1090 ADS-B Antenna to an anemometer mast about 30’ above the ground. I used a 8M TRENDnet Low Loss Reverse SMA Female to N-Type Male Cable (Model TEW-L208) and a FlightAware 1090MHz Band-pass SMA Filter and a 6” DHT Electronics RF coaxial coax cable assembly SMA female to MCX male. I hooked it to a new NESDR Mini 2 SDR. My results were horrible 
. I wasn’t getting anything further than 50NM and not many of those. I relocated my Raspberry PI back to the Attic with the inside antenna and I’m seeing a lot more traffic. I must say that the Mini 2 SDR seems to be picking up more traffic than the older SDR.
Any thoughts on what may be the problem? I was a little concerned mounting the antenna to the anemometer mast, but a photo in the antenna description showed a similar setup. Winter is coming fast and I won’t be able to get to it much longer.
The reverse SMA connector could be a problem. The filter uses SMA.
See below for details
oscarliang.com/difference-sma-r … pv-copter/
Thanks a bunch! Looking at it closer, the cable was mis-labeled and it’s really a MALE RP-SMA. This fix is going to be much easier than climbing up on the roof again 
If you connect a female SMA and a male RP-SMA they will thread together OK but there will be no center pin contact. Don’t mix SMA and RP-SMA. The FlightAware filter is SMA.
TEMPORARY WORKAROUND
The SMA-male has center pin. The reverse SMA (RP-SMA) male does not have a center pin, it has a hole. The center wire connection is open because of missing pin. A temporary workaround is to cut a short piece of center wire of coax and insert in hole of RP-SMA male. This piece of wire will act as the missing pin, and connection will be established.
DIFFERENCE BETWEEN SMA AND RP-SMA
Thanks to all. I took abcd567’s suggestion and I’m up and running on the outdoor antenna. What a difference!
https://www.amazon.com/gp/product/B0018PVVBS/ref=oh_aui_detailpage_o05_s02?ie=UTF8&psc=1
I used this cable, recommended several times on the forum. Had N connectors like the FA antenna.
Then had N to F at end of cable, into grounding block, then into house. The cable comes in lots of lengths, and really simplifies connections.