Home Patrol GPS, bad or set up wrong?

[ST-Bob]

The GPS format setting has no bearing on how the HP-1 handles the GPS data format. It's only a display option from what I've read. Why this ever even appears on the HP1's menu is a mystery to me since there's nowhere to see what the GPS is sending. NMEA format always sends the latitude and longitude in a single sequence of numbers which does not change. Having a latitude/longitude display format option on the scanner is useless unless there's a need to display it in different formats.

 

[OCO]

Bob:
The only thing I can figure is that one of the compatible GPSs output the $GPGLL sentence in a proprietary Degree.Minute.Second format. (Proprietary sentences are "allowed" with the proper identifier...)

Maybe there's a hidden Easter egg that displays location info... <grin>

 

[ST-Bob]

The GPS can output whatever it wants but the receiving device (the HP-1 in this case) should ignore everything but the properly formatted NMEA sentences it requires for location. As long as those are present in a compatible baud rate, data bits, stop bits and parity it should be working. My guess is that you have either the wrong mix of gender-changer/null modems and GPS cables. Uniden sells both the standard programming cable used on the other models (which has the wrong gender and pinout) and a specialized all-in-one cable that has the right gender and pinouts. Using the wrong combinations will surely prevent it from receiving the data stream.

 

[OCO]

My guess is that you have either the wrong mix of gender-changer/null modems and GPS cables. Uniden sells both the standard programming cable used on the other models (which has the wrong gender and pinout) and a specialized all-in-one cable that has the right gender and pinouts. Using the wrong combinations will surely prevent it from receiving the data stream.

Bob- I'm guessing you haven't read the thread from the start....

 

[ST-Bob]

There are lots of variables but when I see a non-natively-supported GPS apparently misbehaving by supplying incorrect location data, I agree it could be a proprietary format. However, the way I read it, the HP-1 appears not to see the GPS at all. This could be either totally non NMEA compatible data format, incorrect communication parameters or a wiring problem. An electronics guy would, of course, measure the output voltages and assign them to the proper pins on the GPS's serial cable as I did with the GPS puck I used. Someone not "in the know" electronically will often blindly plug in cables and hope things work... This in not productive from my experience.

For example, if you can plug it into the serial port of a PC and read data with a terminal program you've proven 2 things: a) you have the wrong gender on the cable to use with the Uniden serial programming cable. b) you've got the GPS wired as DTE equipment. If using the special uniden HP-1 GPS cable then you should have all the data on the right pins. At this point nobody has said which GPS cable is being used and I guessed the regular BCD-396 programming cable and gender changer/null-modem were being used.

Until the O.P. tells us what cable combinations he's using, there's no use in guessing. Of course the cabling could be perfectly fine and the GPS puck may simply be incompatible in its present form. That's why it is always best to use one from the known good list.

As an electronics engineer who's made a non-listed GPS work with mine by installing my own 9-pin plug I think I know what I'm talking about. Take it or leave it. Something's wrong and they O.P. doesn't have either the tools or the skill-set to diagnose it.

 

[phask]

The GPS format setting has no bearing on how the HP-1 handles the GPS data format. It's only a display option from what I've read. Why this ever even appears on the HP1's menu is a mystery to me since there's nowhere to see what the GPS is sending. NMEA format always sends the latitude and longitude in a single sequence of numbers which does not change. Having a latitude/longitude display format option on the scanner is useless unless there's a need to display it in different formats.

No bearing on the orginal OP problem

But I had to "match" the output type on my Garmin GPS60 to get it to work. Nothing unusual as I've interfaced it with several devises in the past. But it did have to match. But I'm a map junkie also

 

[OCO]

The OP is using a Uniden GPS, getting a green light on the HP1. It was suggested that there could be a config issue based on the offered options on the HP1 GPS setup screen, hence the line of questioning. Why there is a question of cabling is a mystery to me, unless there is a suggestion that the HP1 will "green light" falsely..

Sure would be nice if the HP1 displayed the GPS info someplace (like on the Review Location screen).

Mo1dmat: Sorry - no closer to an answer at this point, I guess...

 

[ST-Bob]

Just to clarify...

There are three specific NMEA 0183 sentences which can be used to provide the bare minimum position information needed for the HP-1 to know where it is and whether the GPS is locked onto the satellites:

$GPGGA - Global Positioning System Fix Data
GGA,123519,4807.038,N,01131.324,E,1,08,0.9,545.4,M,46.9,M, , *42
123519 Fix taken at 12:35:19 UTC
4807.038,N Latitude 48 deg 07.038' N
01131.324,E Longitude 11 deg 31.324' E
1 Fix quality: 0 = invalid
1 = GPS fix
2 = DGPS fix
08 Number of satellites being tracked
0.9 Horizontal dilution of position
545.4,M Altitude, Metres, above mean sea level
46.9,M Height of geoid (mean sea level) above WGS84
ellipsoid
(empty field) time in seconds since last DGPS update
(empty field) DGPS station ID number

$GPGLL - Geographic position, Latitude and Longitude
GLL,4916.45,N,12311.12,W,225444,A
4916.46,N Latitude 49 deg. 16.45 min. North
12311.12,W Longitude 123 deg. 11.12 min. West
225444 Fix taken at 22:54:44 UTC
A Data valid
(Garmin 65 does not include time and status)

$GPRMC - Recommended minimum specific GPS/Transit data
RMC,225446,A,4916.45,N,12311.12,W,000.5,054.7,191194,020.3,E*68
225446 Time of fix 22:54:46 UTC
A Navigation receiver warning A = OK, V = warning
4916.45,N Latitude 49 deg. 16.45 min North
12311.12,W Longitude 123 deg. 11.12 min West
000.5 Speed over ground, Knots
054.7 Course Made Good, True
191194 Date of fix 19 November 1994
020.3,E Magnetic variation 20.3 deg East
*68 mandatory checksum

Any or all of these 3 sentences contain the latitude and longitude in degrees and decimal minutes, the North, South, East or West indicator and whether or not the data is valid. If the HP-1 can hear and understand any one of these sentences then it should know where it is.

There's nothing in the spec that I've been able to discover which gives an option for position format. For example you cannot comply with NMEA 0183 if your GPS sends latitude and longitude as either decimal degrees or as degrees minutes and seconds. Only degrees and decimal minutes fully complies with the NMEA 0183 spec since none of the 3 position sentences have any way of indicating what the format should be. It must be assumed that the latitude and longitude will be a string of digits broken down into degrees and minutes with a decimal point in the minutes value.

It's true that many GPS pucks natively support some proprietary data format other than NMEA 0183. It's assumed that the owner knows this and can set the format to NMEA 0183 before using the GPS with the HP-1 as the HP-1 does not send any configuration strings to the GPS.

As to the green light being lit, that can only indicate that valid NMEA sentences containing the GPS status are being received. If the LED is red, no data is being received. If yellow it's receiving valid sentences but the GPS status is still listed as invalid. Green indicated both valid GPS sentences and a valid data indicator in whichever NMEA 0183 sentence it's using.

I want to help, not prove myself as some sort of expert (which I'm not). I didn't get the impression that the O.P. was getting the green status indicator. If so, then there truly could be some sort of error either in his GPS or in the HP-1's software. There's no reasonable explanation for the green GPS indicator unless the unit is sending NMEA 0183 sentences. They're pretty unique and cannot be easily confused with other formats. For example, for the $GPRMC sentence to be decoded with a valid fix it must contain at a minimum "$GPRMC,,A,,,,,,(checksum)" so there must be some data coming from the GPS that's considered valid. The other two sentences ($GPGGA and $GPGLL) don't require the checksum but have even more stringent requirements for data to be seen as valid since the validity indicator us buried further down the data stream.

I just don't see the probability of getting a green GPS status indicator unless one of these 3 sentences is being correctly decoded, so that (in my opinion) rules out most proprietary data formats. It does, however, leave the possibility of a defective GPS or a flaky data connection.

It also, unfortunately, leaves the possibility that the GPS knows where it is but cannot find any in-range channels due to either the remoteness of the location, bad data from RadioReference.com or a bad data upload from Sentinel to the HP-1. I might recommend a hard-reset of the HP-1 and/or formatting and reloading the SD card if it's suspected that the data may be corrupt.

With that huge data-dump; I'm done. Fix it or don't fix it matters not to me as mine works correctly. I'm just trying to help diagnose the problem and keep everyone from speculating without the needed background data.

 

[N2JDS]

Until the O.P. tells us what cable combinations he's using, there's no use in guessing. Of course the cabling could be perfectly fine and the GPS puck may simply be incompatible in its present form. That's why it is always best to use one from the known good list.

I'm using 100% everything that was bought through Scanner Master, to be used on the Home Patrol. There is nothing hodge podged together to try to make it work. Unit does see the GPS, all lights are on, it is not ignored so forth and so on.

 

[ST-Bob]

Well then there's something wrong with either the GPS or the HP-1. I suggest trying a hard-reset and/or formatting and reloading the SD card in the HP-1 as this costs nothing and can cure a world of ills. As long as the HP-1 asks you whether to use the GPS data, you should be golden. If so and you still get no system choices then there's a data problem on the HP-1. If you have system choices but cannot receive anything, make sure the attentuator is grayed out and that the antenna is good. Beyond that, you're on your own.

 

[jackj]

Jeff, you are getting a bunch of crap which has no bearing on your problem, which I figure you already know. Send Scan Master an e-mail and explain your problem. After all, they sold it to you as a system so there shouldn't be ANY problems with formatting or cables. If you can't get any satisfaction from them then contact Garmin. Good luck.

 

[OCO]

Does that "load of crap" include advising the OP to contact Garmin (or checking "coordinate settings" that don't exist for the Uniden puck)? He clearly stated it's the Uniden GPS.. Since Uniden itself doesn't provide much information, any thread dealing with a GPS issue is going to start with how the technology works and applies to the HP1. While there's been some discourse (and speculation) the object was to possibly come up with things for Jeff to try..
I'll back out of here, order my own Uniden setup from ScannerMaster and go back to finding exactly how things work.. One thing I'd still advise Jeff to try is downloading one of the simple GPS programs on the link I provided and setting it up on a PC with a serial port. It'd answer the issue of whether the Uniden puck is supplying the correct lat/long for his location..

 

[KE4ZNR]

Jeff, you are getting a bunch of crap which has no bearing on your problem, which I figure you already know. Send Scan Master an e-mail and explain your problem. After all, they sold it to you as a system so there shouldn't be ANY problems with formatting or cables. If you can't get any satisfaction from them then contact Garmin. Good luck.

No, he is getting help from intelligent folks that only want to see him up and running
with no issues. Your attitude is not needed in this thread. Please let those that were
helping the original poster continue to assist him.
Thanks!
Marshall KE4ZNR

 

[UPMan]

1) What is your specific location.
2) What system and/or channel(s) are not being selected that you are expecting to be selected.

 

[OCO]

Paul:
As long as you're here.....
1: Why is there a location format setting for the GPS, if the HP1 doesn't display the GPS lat/long data anyplace?
2: Does Autolocate just use the currently loaded scan list or the full database when doing its scan? Does it look at more than one "hit" or just the first system that it sees with lat/long info?

Ordered the puck and cable tonight.....

 

[UPMan]

1. It sets the input type for manual location input.
2. I'd have to recheck to confirm but I've seen posted in this thread that it only pays attention to "active" lists (which would be consistent with some other functions).

 

[phask]

Correct on #2@ - it uses whatever DB it's set for. I always run favorites at home and must remember to change to entire DB when I use GPS/mobile.

 

[OCO]

Paul:
Thanks...
1: To confirm then, that setting has nothing to do with the GPS - HP1 interface, even though it's on the GPS page. BTW - if there is ever another HP1 firmware update, I'd lobby for a display of the GPS lat/long output on some screen .
2: Autolocate - My own observations seemed to confirm that it was looking at my current scan list, but it didn't seem consistent as to results. In five tests, there were at least two that were way out of the area. The only reason I could figure for that was hits on talkgroups on one of the statewide systems that I use (MPSCS or Consumers Energy). Also, the time varied for the tests, which lead me to speculate that the results were the product of a fixed number of hits (example - the first 5 transmissions that it could get long/lat info from the DB on) with an ultimate timeout if there's no hits within a certain amount of time.

As usual Paul, thanks for taking time to answer our questions - when you're not around we tend to get in lots of trouble speculating how things
work...

Phask - just to make sure we don't confuse that issue again (see top of this thread), Autolocate is independent of GPS use, not a function of it..

 

[UPMan]

1. The GPS <-->HP1 interface is implemented per NMEA standards. It isn't adjustable.
2. Autolocate is based solely on control channel data (system/site info in the control channel data is compared to RRDB's report of where that tower is located).

 

[OCO]

Thanks - Just was confused by the existence of the Location Format option on the Set Up GPS screen.. On the AutoLocate using CC info for the comparison to the DB, that's useful info for anyone who might only have conventional systems in their scan list..

Again, thanks for the info...