Windows 8 Tablets for OpenCPN

[prof_mariner]

Originally Posted by wdkester

Be careful in inserting a micro SD card in the miix 2 8. Apparently I put it in wrong and it's stuck and crooked.

Those Micro SD cards are almost -too- small. Way too easy to loose, or in your case, install incorrectly.

I gave my Mixx28 a more thorough workout today and the internal GPS seemed to work much better than the last time. I noted that the wifi signals from the marina were stronger than yesterday also. Too bad there isn't a "signal strength" display so I can see what orientation(s) improved satellite visibility.

[prof_mariner]

Put some more hours on the Miix2-8 and am seeing a definite trend. GPS and Wifi reception are good during AM hours and lousy during PM hours. Could be caused by one of a number of causes (RFI, atmospherics, satellite locations, etc.). But the GPS reception in general is much worse than the one in my cell phone. I think I'll have to use some sort of hard wired GPS if I want reliable navigation data. Otherwise it's a nice tablet. By the way, mine is a Levono re-manufactured unit I bought for $135. Can't beat that price IMHO.

[RhythmDoctor]

Originally Posted by prof_mariner

Put some more hours on the Miix2-8 and am seeing a definite trend. GPS and Wifi reception are good during AM hours and lousy during PM hours. Could be caused by one of a number of causes (RFI, atmospherics, satellite locations, etc.). But the GPS reception in general is much worse than the one in my cell phone. I think I'll have to use some sort of hard wired GPS if I want reliable navigation data. Otherwise it's a nice tablet. By the way, mine is a Levono re-manufactured unit I bought for $135. Can't beat that price IMHO.

That's not unheard of - for years I had similar problems with HDTV reception in my house during evening hours. I swear that there's someone in my neighborhood running non-FCC approved equipment during the evening. I finally had to give up and get FiOS, simply so I could pick up NBC and Fox broadcast stations (since those were the ones that were affected by the interference).

I am surprised that your WiFi has problems too. GPS is extremely weak and easily affected by noise, but WiFi should be strong enough to work regardless of time of day.

$135 is a great price. Your Office license alone is worth almost that much (assuming it included one). When I went to buy my 2nd Miix2 I checked Lenovo's site for factory refurbished units, but they didn't have them for a few weeks so I went ahead and bought new. I wasn't going to trust ebay or Amazon marketplace refurbished units, because there's absolutely no way to ensure they're truly refurbished ones and not just used/abused/broken units.

[RhythmDoctor]

Originally Posted by prof_mariner

...Too bad there isn't a "signal strength" display so I can see what orientation(s) improved satellite visibility.

There must be a program out there that will display this. I believe that the GPS sends the information as part of the NMEA sentence, so it's just a matter of a program displaying it (perfect thing for a plugin to do, but not sure there's one available).

Well, I just checked and THERE IS A PLUGIN for this! Just use the standard dashboard plugin that comes with OpenCPN, and add a gauge for GPS "Status" It will show you which satellites are in view, with a bar graph for the strength of each one. You could also activate "GPS in View," but that just gives you the number of GPSs that are in view - not quite as helpful.

Before you run any more tests, perhaps you should also install/activate the VDR plugin. Then set it to RECORD during your testing. Then you can post your recording here so we can all look at it and perhaps help diagnose what you're seeing. I do not have any VDR recordings from the Miix2 internal GPS, but I do have several from my boat's Garmin 18xLVC, and you could compare your Miix2 GPS strength to that one and see if there are significant differences.

Of course, signal strength is not the whole story. Signal-to-noise ratio can be far more important, but I don't know of anything that gives that for a GPS signal.

[bcn]

The GSV sentence:

Satellite information
The GSV message string identifies the number of SVs in view, the PRN numbers, elevations, azimuths, and SNR values. An example of the GSV message string is:

$GPGSV,4,1,13,02,02,213,,03,-3,000,,11,00,121,,14,13,172,05*67

from NMEA-0183 message: GSV

There are receivers that don't show the GSV sentence.

Elevation is critical, SNR is basic.

We can recommend the Ublox6 equipped receivers - using one in-house near to the wall.

Hubert

[prof_mariner]

I'm using "Geolocation TCP" found earlier in this thread to connect OpenCPN with the internal GPS. The only sentence I see being sent is "RMC" which doesn't include any GPS signal / satellite information. I'll continue to test and see what else I can learn.

Incidentally, the tablet I bought was through eBay and the vendor claims it is a Lenovo remanufactured unit. The paperwork that came with it seems to support his claim.

[RhythmDoctor]

Originally Posted by prof_mariner

I'm using "Geolocation TCP" found earlier in this thread to connect OpenCPN with the internal GPS. The only sentence I see being sent is "RMC" which doesn't include any GPS signal / satellite information...

The first questions is where is your RMC actually coming from? It could be coming from a Wifi map, since the GNSS sensor has that capability. But the Wifi mapping only outputs RMC because there are not satellites involved.

Are you getting fresh RMC sentences every second, or every 10-60 seconds? If it's the former, then it's coming from the GPS chip. If the latter, then it's coming from the Wifi map.

I'm inside right now and my Miix2 cannot pick up GPS signals, so I'm getting RMC sentences every 30 seconds. Right now I'm not willing to go out in 10 degree weather to try to get a GPS fix. Maybe later today.

It is possible that the GPS chip does not generate a GSV sentence. Broadcom's web documentation does not say. The best way to tell is make sure you're getting RMC sentences every second, and then see if there are any GSV sentences.

Integrated Multi-Constellation GNSS Receiver - BCM4752 | Broadcom

New Location Architecture With BCM4752 | Broadcom

[prof_mariner]

The internal GPS and GeolocationTCP are the only source of GPS data at present. I haven't set up wifi or anyother networking yet.

[RhythmDoctor]

Originally Posted by prof_mariner

The internal GPS and GeolocationTCP are the only source of GPS data at present. I haven't set up wifi or anyother networking yet.

You do not need to connect to Wifi for the Wifi mapping to work. The GNSS sensor detects location by seeing nearby SSID without even connecting to it. The only way that I'm aware of that you can be completely sure the location is coming from the GPS satellites is that you are getting updated sentences once a second. If they're coming in less frequently than that, then it's not coming from the satellites.

So the critical question is: Is Geolocation TCP showing a fresh update every second? If not, then it's not using the GPS chip.

I can tell you from experience that the Miix2 takes A LONG TIME to get a true GPS fix. Every time I've tested it I waited and waited and waited, and typically give up waiting and set it down and walk away. And every time, when I come back 5 or 10 minutes later, it's getting GPS updates once a second. It boggles my mind, but that's how it worked, and once it had its fix it would keep it as long as you didn't put your hand along the silver strip at the bottom rear.

[prof_mariner]

Yes, when it's working it is getting an update every second. I keep the "wifi" turned off as a rule so the system doesn't roam and waste battery life.

[RhythmDoctor]

Originally Posted by prof_mariner

Yes, when it's working it is getting an update every second. I keep the "wifi" turned off as a rule so the system doesn't roam and waste battery life.

OK, then I think you've proven that the Broadcom GNSS chip does not output anything besides RMC. Sorry I was so insistent - I just wanted to be sure.

[Opie91]

Originally Posted by RhythmDoctor

OK, then I think you've proven that the Broadcom GNSS chip does not output anything besides RMC. Sorry I was so insistent - I just wanted to be sure.

I have seen only RMC coming out of my Miix2-8 Broadcom chip also. Could it be the Geolocation TCP app not sending the information on?

[Franziska]

Hi Rythmdoc,

got a Miix 2 8" few days ago. Great piece of kit.

Will see now how to mount it on my cat.
Question regarding your dual installation of OpenCpn. I installed mine directly on a 128Gb sdxc card.
How would you create the portable second copy from that?
I only found instructions how to extract it from an installation on a c drive.
Any pointers?
Thanks for all the knowledge already shared!

Franziska

Sent from my C6603 using Cruisers Sailing Forum mobile app

[RhythmDoctor]

Originally Posted by Franziska

...Question regarding your dual installation of OpenCpn. I installed mine directly on a 128Gb sdxc card.
How would you create the portable second copy from that?
I only found instructions how to extract it from an installation on a c drive.
Any pointers?

Hi Franziska,

Since you already have a portable copy, you should do this to create a second one:

• Move your charts to a separate folder from your portable OpenCPN program folder.
• Go into OpenCPN and set it up to access the charts in the new location for your charts.
• Copy the folder that contains your portable OpenCPN files to another folder by a different name.
• Create shortcuts or batch files to launch each instance of OpenCPN

By keeping your charts in a separate folder, you will avoid making a second copy of this very large folder on your SD card.

The SENC folder can grow very large too. I've been experimenting with putting those files in a separate folder also, with both instances looking into the same folder. But that change requires manually editing your opencpn.ini files. Search the .ini file for

[Directories]
S57DataLocation=
SENCFileLocation=

...and add something like

SENCFileLocation=E:\\Charts\\SENC

I need to wait for awhile before I can fully endorse moving the SENC files like this. But perhaps you can experiment too.

[Franziska]

Hi Rythmdoc,

thanks for the swift reply!

Will try tommorow evening.
Got to fix my main Pc first.

Franziska


Sent from my C6603 using Cruisers Sailing Forum mobile app