SDS100/SDS200: GPS Behavior

[Jeff19]

I received a Uniden GPS BC-SGPS for Christmas and installed in my vehicle (at the top of the windshield, sticky side up) next to my EZPass. The SDS100 shows that the GPS is acquired, and turns off a system and a department (in a different system) exactly when I leave geofences. However, when I come back into the fences, the system and department did not turn back on until I hit the channel button. I tried it in multiple locations to confirm it wasn’t coincidence (once was 2 miles into the fence).

Could this be a sign of poor GPS reception? I figured it would be all or nothing. I’m curious if others have mounted their receiver on their windshield. I’m hoping this isn’t a firmware type issue.

 

[jonwienke]

If you have a hold on something, GPS will not override the hold, unless you're holding on something that isn't being scanned anymore. In that case, the hold is cleared and the scanner starts scanning new stuff.

 

[Jeff19]

Thanks @jonwienke ...although I’m not sure that’s it. Going westbound it’s scanning two systems, and cuts one out at the fence. Coming back eastbound without touching anything it doesn’t seam to want to turn the other system back on unless i push something.

 

[jonwienke]

Turn on detailed view and have it show GPS coordinates. If the GPS is working, you'll see the coordinates changing every second or so while in motion.

 

[djeplett]

Did you set the geofences manually? You have to make absolutely certain that they are where you think they are, too. I think ProScan can show them, but I've never used it. I checked and created them them manually using Google Earth.

 

[nessnet]

By "geofences".. do you mean circles or rectangles (suggests rectangles, but need to ask)?
Also, what is your range set at?

Crap - I just saw the "at the top of the windshield, sticky side up"...
NO!! The sticky side goes down. The GPS antenna is on the top (sticky side being the bottom).
Right now, from your description, you have the GPS' antenna pointing to the inside of the car.
I would recommend the bottom of the windshield (sticky side down).

 

[Jeff19]

Thank you...i has described my setup because i wasn’t sure if the antenna was orientation specific. I’ll flip it and see what happens

 

[WX4JCW]

I learned external hard drives will disrupt GPS too

 

[Jeff19]

The mounting of the antenna wasn’t the issue. I corrected it, and got coordinates the whole time.

Drove in one direction, everything was working. Drove all the way to the house in reverse, nothing updated, and the second i hit any button, all of the systems corrected themselves to my new location. I think I’m going to try to scrub the sd card. Any other suggestions?

 

[jonwienke]

Card problems can cause all kinds of weird issues. You were getting continuous coordinate updates in both directions?

And definitely check your GPS boundaries in ProScan.

 

[Jeff19]

I tried a SD card reset to no avail and visually checked my boundaries, but I think I may be on to something. The strange operation occurs only after "system 2" turns off as expected, and only "system 1" with one site is being monitored. I remember one of the middle firmware updates eliminated "housekeeping" when scanning a single site. I seem to remember a long time ago Paul saying one of the functions of housekeeping was to check the GPS coordinates.

Is it possible I stumbled into a firmware "issue," in that the scanner doesn't review the GPS coordinates while scanning a single site, but then remembers to check them upon a button click?

 

[Patch42]

Is it possible I stumbled into a firmware "issue," in that the scanner doesn't review the GPS coordinates while scanning a single site, but then remembers to check them upon a button click?

Speaking as a programmer I can say that sounds like a fairly typical logic issue that could easily crop up, particularly if you don't have another programmer to do code reviews for you.

I just got my GPS at Christmas and haven't had opportunity to give it much of a workout so I don't know if this would work, but could you add a couple very small "systems" that are NOT under location control and see how it behaves? That should keep you from dropping into the one system enabled minimized housekeeping.

 

[Jeff19]

Thanks everyone for the replies. I was able to confirm my hypothesis yesterday. If the location control limits the scanner to a single "site,' the scanner will still receive real time coordinates, but will not "examine" them in regards to the location control function. I put two conventional frequencies on for my whole drive that I had interest in, and the GPS performed flawlessly.

This would also make sense when I noticed it resolved by pushing the channel button. When the scanner goes into site hold associated with a talkgroup hold, it must check the coordinates first.

Jeff

 

[jonwienke]

Interesting. That definitely sounds like a firmware bug if adding more stuff to the scan rotation reverts the unit back to normal behavior.