I have The Things Indoor Gateway and a Dragino LHT65-E1 sensor.
I was able to get the gateway and device registered in a TTN application and can see some data, but don’t understand why it might be 20 min between them.
Gateway and sensor are 39 ft apart.
Twenty minutes is not an unreasonable interval for a node on the shared network.
Of course it’s also quite possible you are missing packets. If you look at the frame count of the received uplinks, does it increase steadily, or are there jumps?
Depending on which exact indoor gateway you have, there are some threads about past problems with the TTIG sometimes dropping wifi during periods of inactivity.
ok, I didn’t know it could be so intermittent.
The frame count increases, but there are jumps too.
I will check the forum for the TTIG.
Thanks
If you haven’t changed it then I believe stock firmware is 20 min updates if on shorter SF. Certainly that is what I have seen with my own deployments… you can use the accessory cable to log in and change through commands if you want short or longer but that is reasonable for update rate vs battery life so Intend to leave as is 
Spreading Factor - the heart of LoRa based technology/radio modulation - sounds like you may need to read up a little to understand what you have bought:
https://www.thethingsnetwork.org/docs/
Or short circuit by settling down to watch this video from Johan - TTI CTO
Johan (TTI) - Everything you need to know about LoRaWAN in 60 minutes