Disappointing range results RAK2245 / Wisgate D4 (150m)

Dear all,
I hope someone has an idea what could be wrong … I have no more ideas…

Issue: Range of the gateway (868MHz) is extremely disappointing. Basically I get connection only line of sight with a max. of ~150m.
With one line of buildings in between and 50m distance I have ~-115dbm rssi and very instable connection

Gateway is my newly bought Wisgate D4/RAK2245
As a node I tried a Dragino LGT-92 GPS and also a TTGO T-Beam - both with similar range results.
Nodes should be OK. in a larger city here in Germany I archived 3km of range with them with high buildings in between.
I am using TTN which basically works but with bad range.

Antennas tried: I tried the original one which resulted in a range of 50-80m Line of Sight
I also tried the RAK 8dbi Antenna I bought together with the Gateway. Then I get the above described ranges of 150m
Antenna is placed outdoor on a balcony 9m over ground.

I also checked the antenna connections on the board which seem to be ok.

Is there any additional setup to be made? Is my unit defective?
Any idea where I could start the search?

Thank you so much


In the street “Kranwallstraße” I have already no signal. Longest distance is ~200m Line of sight (the very left point). These results are with 8dbi Antenna.