If you have an unused Rasberry Pi (any will work, in my case Zero W) and want make LoRa gateway experiment, this item is really suitable for your application. Just plugging into RasPi and install and compile source code (with your information) is enough to make your own LoRa gateway appears on TTN.
Yes, it is only single channel gateway and is not LoRaWAN compliant. The full functional gateway can receive 8 channels and SF7-12 simultaneously.
About facing the poor antenna quality, please recheck it. Make sure it fit. We choose antenna from well known manufacturer. We got 5-6 km LOS in field test. I checked quality of our stock by Antenna Analyser and add the test result on product page. VSWR is very good and the freq is matched.