You're falling into the "client" vs "server" confusion.
For UDP transmit ports
, "Address" is where you want to send the data TO
For UDP receive ports
, "Address" is semantically the address you are receiving it on but in practice OpenCPN doesn't care about the value in this field for "receive" udp connections (except for multicast which we'll ignore)
You have some options.
1. Broadcast the data from the pi. This sends to data to all machines on the network
2. Unicast the data. This sends just to your client
(3. multicast the data, but we'll ignore that for the moment).
(1) is how most commercial
devices you would buy would do this and what many apps expecting "nmea data over udp" expect. To do this:
First find your network broadcast address, either from the ifconfig command on your pi (it will be preceded by "Bcast:" in the section for your wireless interface), from the configuration interface of your router, or by examining the properties of your network connection on the windows PC. For the latter I'm no expert at windows but if it only tells you a net mask ("IPv4 Subnet Mask"), if this is "255.255.255.0" then your broadcast address is 192.168.0.255. If for some perverse reason it's "255.255.0.0" your broadcast address is 192.168.255.255.
On the server (pi) set:
Address: <the broadcast address you just worked out, e.g. 192.168.0.255>
Click Transmit on this port.
On the client (pc) set:
Address: 0.0.0.0 (actually it doesn't matter what you put here)
Click Receive Input
Apply it and you should be done.
There's actually a section in the manual on this:
However I'm not at all sure about that "x.x" syntax they're using: I took a quick scan through my (old) copy of the code and couldn't find any reference to that shortcut. Can anyone confirm or deny if that actually works?
Option (2): Send just to your PC.
On the pi:
Address: 192.168.0.197 (remember, this is where you're sending *to*)
Click "transmit on this port"
On the PC:
Click "receive data"
Now why would you do (2) when (1) is a far more common? There's a couple of reasons you might but the most important over a wifi
connection is that unicast (i.e. sending to one receiver) allows the underlying wifi
to make the connection "reliable" by retransmitting lost
data. OTOH if your PC has an address assigned by dhcp which might change when you next boot it up, you might want to avoid the hassle of checking your server configuration each time and just go with broadcast.
And then there's multicast but let's not complicate things: try the above first. Maybe the broadcast option because it's simpler and more common