Cpn not showing ais targets when not connected to routerr

[delcrest]

Hi, some help please, I am using Aismon to monitor ais targets with CPN ver4 of on a laptop running win8.1
ouput options from Aismon are selected as follows com1, baud 4800, UDP and log file ticked, IP Port 127.0.0.1:10110, the same IP address is set in connections in CPN
This setup works well only if my laptop is connected to my router, unplug the router and AIS targets are lost in OPENCPN
Is this a win 8.1 problem, on older win 7 machine it works fine
please any help would be appreciated, thanks in advance

[LeoA]

In OpenCPN, try setting UDP port at 0.0.0.0:10110 and leave UDP settings in aismon at 127.0.0.1:10110

[delcrest]

Thanks will try that, would be great if that's all it was causing the problem.

[muttnik]

This has come up before in another thread with no resolution. I would't put money on setting the OpenCPN's receive port to 0.0.0.0: it's good practice anyway but that is actually what will be done whatever you set the receive address to.

This sort of *sounds* like an AISmon issue rather than an OpenCPN one. Perhaps someone who has wireshark an AISmon installed could check for UDP packets on the AISmon output port under 3 conditions:
- packet snooping on the external interface when up with a router-assigned address
- packet snooping on the loopback interface when external interface has a router-assigned address
- packet snooping on the loopback interface when the external interface is down and/or has no assigned address.

If we see no packets in the latter case it maybe isn't an OpenCPN problem and someone should punt it to the AISmon yahoo group.

[delcrest]

Originally Posted by muttnik

This has come up before in another thread with no resolution. I would't put money on setting the OpenCPN's receive port to 0.0.0.0: it's good practice anyway but that is actually what will be done whatever you set the receive address to.

This sort of *sounds* like an AISmon issue rather than an OpenCPN one. Perhaps someone who has wireshark an AISmon installed could check for UDP packets on the AISmon output port under 3 conditions:
- packet snooping on the external interface when up with a router-assigned address
- packet snooping on the loopback interface when external interface has a router-assigned address
- packet snooping on the loopback interface when the external interface is down and/or has no assigned address.

If we see no packets in the latter case it maybe isn't an OpenCPN problem and someone should punt it to the AISmon yahoo group.

Thank you for your response, after searching the net I have found some similar information regarding "" loopback"" wouldit be possible to install some sort of virtual com port on win 8.1 Sorry I am completely NON computer literate

[muttnik]

Originally Posted by delcrest

Thank you for your response, after searching the net I have found some similar information regarding "" loopback"" wouldit be possible to install some sort of virtual com port on win 8.1 Sorry I am completely NON computer literate

I wasn't suggesting you do the debugging: people generally only have and use wireshark if they're networkily inclined but it was a general appeal to techie OpenCPN users who might have the same setup as you (sadly I don't run windows). You're not the only user to have encountered this so it would be good to nail the problem down.

I believe that you can get software for windows which will create a couple of virtual com ports which both output the same data you feed in on a physical com port so that may well be another solution (connect AISmon to one, OpenCPN to the other virtual COM port) but again, windows stuff is beyond my ken so others are better able to advise.

[LeoA]

I don't use aismon, but it is installed on my Windows 8.1 tablet. Using SDRSharp with aismon 2.2.0 will output to Opencpn only when connected to a network. When I disable the wifi or disconnect from from my network, there is no output from Aismon. Rtl_ais and aisrec both work whether I am connected to the network or not. I would say also that it appears to be an aismon issue.

[LeoA]

Free Virtual Serial Ports from FREE Virtual Serial Ports driver, Rs-232 null modem emulator will create serial ports that aismon and opencpn can use.

[rgleason]

LeoA and Muttnik thank you so much for your clear explanations and knowledge. Delcrest has been diligent persistant and patiently trying to find the solution. You have rewarded his effort with several alternatives. How can we preserve this knowledge for others?

[delcrest]

Originally Posted by LeoA

Free Virtual Serial Ports from FREE Virtual Serial Ports driver, Rs-232 null modem emulator will create serial ports that aismon and opencpn can use.

Hi LeoA thanks for the info tried the virtual driver, but now cant get Aismon to see the virtual port. it only gives option of com 1,2, and 3.so I am back to square one
I would really like this to work as currently I can see targets up to 50km away granted I am at a hi altitude

[LeoA]

Make sure that you are creating bridge ports. The virtual port program will make a pair of ports, use one in aismon and the other in OpenCPN. Aismon will not distinguish that the ports are virtual or physical, it will only show the port number, ex. com4. OpenCPN will show the ports as a HHD Software Virtual Port.

[rgleason]

Del Had you tried the other suggestions from muttnik? On O set UDP 0.0.0.0 and the port.
The other one LeoA had was associated with use of aismon and sdrsharp and rtl_ais on his win8.1 and needing to have a router! It sounds more like an opencpn problem to me. Is that possible?

[LeoA]

Give AisRec or rtl_ais a try. Links to download both are located in the rtlsdr thread.

Sent from my XT1031 using Cruisers Sailing Forum mobile app

[rgleason]

Another thought is to try NavmonPC for the virtual ports it also displays AIS as well

[delcrest]

Originally Posted by rgleason

Another thought is to try NavmonPC for the virtual ports it also displays AIS as well

Is your dongle and Aismon working. on my pc if have all working very nicely, except the router issue, I think the answer is to just use a route back plug, which I believe ""fools"" win into thinking its connected to a router
What you think?