GPS and RRDB data

[troymail]

After several trips to North Carolina and scratching my head trying to determine why when in the most southern parts of NC I see the 436 trying to scan the Virginia STARS system, I finally took a look at the specifics. I now see that, due to the limits of using circles (point and range) for the system (and other) coverages, the RRDB suggests that some sites and "departments" of the VA STARS system should be scanned over the entirety of North Carolina and as far south as almost Columbia South Carolina (see map)... absurd.

In contrast, for some other systems and departments, the circles are set as small as 1/2 mile - which from a scanning perspective doesn't make alot of sense either. If I am in the site footprint of a system and activity from a small town is being carried on that site, I usually want to hear that activity - not have the radio assume that is the case only if I am not driving directly through it. And before you say it - no, I don't want to set the range value higher in my radio.... I already have it thinking I should be scanning Virginia STARS in South Carolina... and all of this just slows the scan rate down.

I suspect I am not the only one who thinks there needs to be some changes --

First, the areas of coverage tracked and exposed through the RRDB need more than just "points and circles". Looking at the Sentinel software, it would appear that you can "manually" define a series of boxes to provide better/tighter coverage maps. As far as I know, RR doesn't support it so anything you do "manually" will continue to be manual and subject to loss and/or have to be reproduced each and every time you create a new favorites list from the library data.

Additionally - to make the location data more useful in the scanners, there also seems to be a need to provide a separate "department" range setting from the "system/site" range setting in the radios. Right now, a single lat/lon and range is used to manage both.

Just putting it out there for thought...

 

[jonwienke]

Site and department range are separate settings in Sentinel, as they should be. There is not a 1:1 correlation between the service rage of sites and departments--a single department may use multiple sites, and logically the department service range should be larger than each site range in that case. Conversely, if you have a small town that uses only a small portion of a site's coverage area, it is reasonable for the department to have a smaller service radius than the site.

Ideally department service areas should coincide with their geographic service area as closely as possible, so that if you want to scan that entity when you are 5 miles outside its borders, you set the scanner Range to some value >= 5. Setting a small scanner Range value to minimize scanning extraneous stuff doesn't help if department range settings are excessively large.

 

[troymail]

Site and department range are separate settings in Sentinel, as they should be. There is not a 1:1 correlation between the service rage of sites and departments--a single department may use multiple sites, and logically the department service range should be larger than each site range in that case. Conversely, if you have a small town that uses only a small portion of a site's coverage area, it is reasonable for the department to have a smaller service radius than the site.

Ideally department service areas should coincide with their geographic service area as closely as possible, so that if you want to scan that entity when you are 5 miles outside its borders, you set the scanner Range to some value >= 5. Setting a small scanner Range value to minimize scanning extraneous stuff doesn't help if department range settings are excessively large.

You obviously didn't comprehend my entire posting.

 

[phask]

All the statewide TG's have 238 as their range and the same lat/lon - sites look OK - but I'd say some more granularity should be applied.

No idea how their statewide systems break down - maybe not possible. But Bay Bridge/tunnel at 238 seems a big nope.

 

[jonwienke]

You obviously didn't comprehend my entire posting.

You obviously didn't comprehend I was agreeing with you.

 

[marksmith]

The database has lots of strange information in it with regard to ranges.

For some reason a lot in the WV system has a statewide range, so you can be halfway through PA north and it is still scanning a WV system that was out of range a hundred miles ago.

When I have certain trips that I make location controlled favorites lists for, almost all systems (and some departments or services, where needed) are tweaked for both center of circle and the range, so that systems click in and out at reasonable and logical times and ranges from systems.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[phask]

True - I got a few cleaned up and it took several messages back and forth with the admin.

I'm almost 60 miles from any WV border, yet a zero range will load a lot if I do an append on range or just use the entire DB (which is rare).

The database has lots of strange information in it with regard to ranges.

For some reason a lot in the WV system has a statewide range, so you can be halfway through PA north and it is still scanning a WV system that was out of range a hundred miles ago.

When I have certain trips that I make location controlled favorites lists for, almost all systems (and some departments or services, where needed) are tweaked for both center of circle and the range, so that systems click in and out at reasonable and logical times and ranges from systems.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[marksmith]

I have found in many cases systems have a range significantly longer than what the database activstes. These are generally nondirectionsl Motorola systems, but in some cases are also p25 systems.

By setting the range at +20 or something, you can offset this, but then it adds in a lot of truly out of range stuff.

Best situation is to make your own favorites list witwh as tever adjustments make the systems load at appropriate times. This is of course only when you are familiar in advance. I tend to just bear with it when unfamiliar and just using the full database.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[ofd8001]

I imagine that the shape of Virginia also comes into play. With it being a lot wider than it is tall, a large range value is needed so that parts of the state are not cut off during scanning.

I agree with Mark - it's almost a non-issue when scanning during a road trip. While Virginia may be loaded, not all of it would be "on" during scanning, let along received, tying up scanner time.

 

[troymail]

I imagine that the shape of Virginia also comes into play. With it being a lot wider than it is tall, a large range value is needed so that parts of the state are not cut off during scanning.

I agree with Mark - it's almost a non-issue when scanning during a road trip. While Virginia may be loaded, not all of it would be "on" during scanning, let along received, tying up scanner time.

It's far from a non-issue and the point of my comments about needing better coverage options in the data than circles. Anything that the radio is trying to do that is dumb (like scan the VA STARS system from South Carolina) impacts on it's performance. The radio already has enough trouble stopping on traffic but then add to the scan loop scanning of stuff that doesn't make sense to scan and seeing the radio "hang" on systems/sites for now obvious reason causes even worse performance.

I haven't used the "full database" since the first day I used this radio - that will certainly result in missing most of what you want to hear.

Maybe it doesn't affect what you monitor in your area but around here, there is a ton of frequency reuse - even within the state. In one case, two different P25 systems use a common trunking frequency within the same county - and having things enabled two states away from where they really are many times can result in people thinking they are actually listening to that system when they are not.

Clearly, as I learned when I first tried the "full database" in 2014, there are apparently some who don't care what they hear on the scanner even if that mean you miss follow-up activity (responses, etc.). On the other hand, I see people posting all the time that they are missing activity from various systems.

Bottom line is the GPS stuff is a "toy" like the SIREN app and some other "features" provided (or promised) with these radios. Those of us who really care about what we're listening to (and hearing or not hearing) have no choice but to do our our custom programming and toggle things on and off as we go.

 

[UPMan]

While the circle has a big overlap of adjacent states, the actual state is only loaded if you are within 30+RANGE miles of the border (RANGE=Range setting in the scanner).

 

[jonwienke]

Also, just because a state shows up in the loading screen doesn't mean anything from that state is actually scanned. I live in southern Pennsylvania, and when I turn on the database, it loads stuff from West Virginia. But nothing actually gets scanned, even ftom the WV-SIRN system, because I'm not within the service range of any of the SIRN sites. If the scanner is trying to scan STARS in South Carolina, then there is probably an error in the service range of one or more STARS sites set too high in the database.

GPS scanning is not a "toy", but it does require that the location and service range data be accurate. If it isn't, there's nothing stopping you from submitting a correction or update to the database and making it work better for everyone.

 

[troymail]

While the circle has a big overlap of adjacent states, the actual state is only loaded if you are within 30+RANGE miles of the border (RANGE=Range setting in the scanner).

I do not think this matches my experience but I'm about to travel to NC again tomorrow and will see what happens...

GPS scanning is not a "toy", but it does require that the location and service range data be accurate. If it isn't, there's nothing stopping you from submitting a correction or update to the database and making it work better for everyone.

...then it is a toy - partly because the data cannot be considered reliable -and- the map overlays are inaccurate because of the (potentially) huge circles (sometimes caused by the former) vs. more accurate mapping outlines.

 

[UPMan]

Well, it is a toy that works great for a lot of people, then.

The scanner's themselves support using rectangles instead of circles, which would be a much better fit in most cases. However, RRDB does not yet support doing that.

 

[tglendye]

In my mind, the solution is probably easier than reality. I envision a "paintbrush" type tool that could shade the covered map area in the RRDB, and the GPS coordinates referenced by Google Maps (or wherever) within that area would be loaded as the GPS attached to the scanner changed while traveling. I don't believe that circles or squares are a solution. Paintbrushing the area would allow a user to truly set the range from 0-20+, as desired. This could be broken down to States, City/ County or even sites/ talkgroups. That would be great, at least in my opinion.

 

[UPMan]

Well, while something like that would be nice, it would require an enormous amount of real-time processing that is not practical for a scanner.

 

[marksmith]

I would agree. Once you get away from one coordinates point and a range, regardless of shape, there is just too much info to process.

While I think the scanner has held on loading things beyond 30 miles from a border, because it is out of range, the only thing effected is scanning efficiency.

While some seem to disagree, I think the GPS capability, even as crude as it sometimes works, is an excellent and exceptional feature on these scanners when traveling. Continued refinement of the database will make it better, and in very familiar or frequent travel trips, this is proven by making these improvements in range or coordinates accuracy in a location controlled favorites list.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[ShyFlyer]

I'd be happy with a feature within Sentinel that allowed one to "draw" on a map the desired areas (circle around a point, rectangles) that one wants.

I know that there are websites and such to accomplish this, but it would be nice to have a "one stop shop" to get the required information.

 

[ofd8001]

It's far from a non-issue and the point of my comments about needing better coverage options in the data than circles. Anything that the radio is trying to do that is dumb (like scan the VA STARS system from South Carolina) impacts on it's performance. The radio already has enough trouble stopping on traffic but then add to the scan loop scanning of stuff that doesn't make sense to scan and seeing the radio "hang" on systems/sites for now obvious reason causes even worse performance.

With the typical site Range being 25-30 miles, on this trunked system, few sites will actually be scanned if someone ventures into an adjacent state. Yes those statewide Departments with a 238 mile Range may be loaded, the other part of the equation is that the scanner has to be receiving a control channel from one or more sites. So little time is being spent on this trunked system.

It's not like the entire system with its 60 plus sites is being scanned when someone crosses into North Carolina.

Now if this was a conventional system, it would be a different matter.

 

[jonwienke]

With the typical site Range being 25-30 miles, on this trunked system, few sites will actually be scanned if someone ventures into an adjacent state. Yes those statewide Departments with a 238 mile Range may be loaded, the other part of the equation is that the scanner has to be receiving a control channel from one or more sites. So little time is being spent on this trunked system.

The sites are what are actually scanned, not Departments. Departments only exist to help identify and filter traffic discovered when scanning site(s). If there are no sites in range, then the scanner will not waste any time scanning the system at all. WV-SIRN has one "mobile" site that has a statewide service area because the site can be moved anywhere in the state it may be needed.

VA-STARS has 3 similar "mobile" sites with a service range of 238 miles. If you Avoid these 3 sites, then VA-STARS won't be scanned at all in southern North Carolina:

Mobile Site - Appomattox Division - Off None Auto 8
Mobile Site - Chesapeake Division - Off None Auto 8
Mobile Site - Richmond Division - Off None Auto 8