Android Hotspot, WinterHill

The place for discussion about the 4-channel WinterHill DATV Receiver
Post Reply
g6hfs
Posts: 235
Joined: Thu May 26, 2022 3:13 pm

Android Hotspot, WinterHill

Post by g6hfs » Wed Aug 10, 2022 8:28 am

Hi, I am trying to use an android hotspot with whpcrxcom and opened all the required ports as udp, I can get whpcrxcom to change the frequencies etc on winterhill anyhub over the hotspot and it displays where it has sent the stream, but vlc does not display any info or picture, it all works ok on local net any android experts out there that can help?

Brian G6HFS

g6hfs
Posts: 235
Joined: Thu May 26, 2022 3:13 pm

Re: Android Hotspot, WinterHill

Post by g6hfs » Wed Aug 10, 2022 10:25 am

Hi,

Would a mobile wi-fi sort the problem, can you forward ports etc.

Brian G6HFS

g6hfs
Posts: 235
Joined: Thu May 26, 2022 3:13 pm

Re: Android Hotspot, WinterHill

Post by g6hfs » Sat Aug 13, 2022 4:40 pm

Ok, so mobile android hotspot is the problem as no port forward capability, had the chance today to test remotely today at G6EUI’s location, opened the ports and successfully sent commands and received stream.
Attachments
70AA0330-ACF1-4BF0-AD84-7A1EAE18A68D.jpeg
70AA0330-ACF1-4BF0-AD84-7A1EAE18A68D.jpeg (980.68 KiB) Viewed 3487 times

G4EWJ
Posts: 1340
Joined: Wed Feb 17, 2010 10:11 am

Re: Android Hotspot, WinterHill

Post by G4EWJ » Sat Aug 13, 2022 5:06 pm

I don't think the TS is even reaching the Android phone. The activity indicators in the signal strength bars don't flash and the data usage counters don't increment.

I tried sending the TS back to the port that the tuning command came from, in case there was some firewall functionality at the WH end of the mobile network interface, but no luck.

Brian

g4eml
Posts: 666
Joined: Thu Apr 26, 2018 9:36 am

Re: Android Hotspot, WinterHill

Post by g4eml » Sun Aug 14, 2022 12:35 pm

Some cellular networks use something called CGNAT. Carrier grade network address translation. If yours is one of those then you can make a connection from a phone hotspot to an internet host and receive replies from that host while the connection is active. However you cannot initiate a connection from a host to the phone.

My understanding of this is that under CGNAT your phone is only allocated an IP address and port for the duration of the outgoing connection. Once that connection is closed the IP address and port are no longer assigned to your phone. IP addresses and ports are shared by many phones therefore there is no way for a host to initiate a connection to the phone.

I believe there are ways around this using VPN connections but that adds complexity.

Colin G4EML

G4EWJ
Posts: 1340
Joined: Wed Feb 17, 2010 10:11 am

Re: Android Hotspot, WinterHill

Post by G4EWJ » Mon Aug 15, 2022 1:25 pm

Thanks Colin. I looked it up and also found PCP, Port Control Protocol, which may or may not help. EE apparently do use CGNAT.

HTTP does work through a hotspot of course. Is that because it makes a connection and UDP is connectionless?

Is streaming with RTSP likely to overcome the problem?

Brian

g4eml
Posts: 666
Joined: Thu Apr 26, 2018 9:36 am

Re: Android Hotspot, WinterHill

Post by g4eml » Mon Aug 15, 2022 10:24 pm

As far as I understand a hotspot connected to a network using CGNAT can only make outgoing connections. That is of course what most people do when browsing the internet. They make the connection to a remote site and that site responds with the requested data.

You would be able to send data using UDP from the hotspot to a remote host but there would be no way for a remote host to send UDP data to a hotspot.

Colin.

Post Reply

Return to “The WinterHill DATV Receiver”