New to GPS setup. SDS 100 Autolocate not very accurate

[PWScan]

Greetings, I am pretty new at this. I just got the Uniden cable and the BR-355S4 working on my SDS100. Baud rate is set to 4800. GPS shows on the bottom of the display. I drove to the highest point in my town (maybe 600 ft ASL. I'm on the east coast about 6 miles from the ocean). Autolocate pops up 3 times with a coastal town about 18 miles NE (as the crow flies) and says I am near this location. Does this sound right? I would think the GPS would have FAR more accurate resolution than that.

Setting a range of 2.0 miles, appears to receive transmission from agencies WAY beyond the 2 mile mark. Deep into adjacent states. I am aware that many agencies have multiple transmitters, but some of these are pretty far away and are fairly small agencies. Could I be doing something wrong? Or is this just the way it is ?

I did run a test of the GPS by setting my location to Chicago (I am in NH) and it did load and scan the greater Chicago area for a brief period. Less than a minute. Then it "reloaded" the database and started scanning my local area. So I am pretty sure the system is working as it should.

Any thoughts or suggestions? Thanks.

 

[Patch42]

Autolocate doesn't do what you think it does. It uses the active frequencies it receives to try to determine where you are. It's not the GPS. You're right that it doesn't work all that well. At least it never has for me. GPS, however, works just fine. Go to Set Your Location->Set Manual Location. If the GPS is working it will list the lat/long the GPS last provided. Look that up on the map and see how accurate it is. In my case it was within 50 feet, and that minor inaccuracy was most likely due to rounding/display error.

Range also doesn't work as you apparently believe it does. The scanner knows the location and projected range of every transmitter site. It draws an imaginary circle using that range around the transmitter location. It then draws a circle around your location at the range (2.0 miles in your case) you specify. Any system whose range circle overlaps the circle around your location will be included in the scan, assuming it isn't specifically avoided or excluded due to service type. If you set the range to zero, it will include just those sites whose anticipated coverage range overlaps your current position.

The range thing also requires that systems in your favorite lists have location control turned on. If location control is not "on" for the system then that system will always be included.

 

[WX4JCW]

Range 0 is best for travelling with a GPS honestly, never use autolocate

 

[jonwienke]

Autolocate should never be used with GPS, and it resets your range to 20 miles every time you run it, because it is not accurate.

Reset your range to 5 miles or less, turn on location control in all your favorite lists, and quit using auto locate. And read this:

How it Works: Location, Location, Location

Uniden's HomePatrol-1 is the first digital TrunkTracker IV Communications Receiver that requires no user programming. Simply turn it on, enter your location, and you will immediately begin hearing communications in your area. This functionality is made possible by combining the rich radio system...

www.homepatrol.com

 

[djeplett]

Also, some statewide mutual aid frequencies have massive range circles because they can be used anywhere in an entire state, so that is why you will sometimes seemingly hear agencies well out of your area. Because of that, I changed some of those in my favorites list from range circles to rectangles that covered the area of the state I was going to be driving in. Otherwise, my radio was scanning some conventional stuff way before I even entered the state those frequencies were possibly used in.

 

[PWScan]

Thanks to all who replied for the great info. Very helpful explanations.

Here are my takeaway(s).

1. Don't use autolocate period. (Now that I know how it works, that makes sense). But when should it be used? What purpose?

2. When using GPS, set range to "0".

Jon, the link was an EXCELLENT explanation of location. (I do much better with pictures )

What about range when NOT using GPS? Is it still in play just monitoring my FLs? Or does location control have to be enabled for that FL?

All of this said I am still a little confused as to how and when location control comes into play.

Thanks.

 

[kirk5056]

Setting "Range" on the scanner does not effect the sensitivity of the scanner. It sets how far out it looks for the circles/rectangles programed into the departments/sites. It does this from where the scanner THINKS it is located. Zip code and auto locate are not very precise methods of setting that location, but useful if you dont have any other method of getting your coordinates. Setting your location manually or by GPS device are better methods.

If you want to increase what the scanner receives then increase it's range (more departments/sites well come within the scanner's circle). If you want to limit what the scanner receives then decrease the range (make the scanner's circle smaller).

 

[jonwienke]

Location control is always on for the database. If you could turn it off, it would crash the scanner trying to scan everything in North America. Range always works the same way. The only thing GPS changes is your scanner location automatically updates as you move. Connecting GPS does nothing at a fixed location if your location is already set accurately.

 

[PWScan]

Jon, thanks for the reply. Yes, I read about location control being always on for full DB. I just wasn't sure how it was invoked. Now I know.

Are zip code and manual location settings related? I'm not clear if they work together or independently.

Is the zip code location I set manually (usually my home zip) a static setting? In other words, if I have it set to my home zip, then go out on a trip in the car with the GPS connected, does my zip code stay the same? Or does it update per the GPS? IE does it remember the last place the GPS took a reading?

Conversely, do I have to reset my ZIP location to my home zip when I return?

 

[nessnet]

1. Don't use autolocate period. (Now that I know how it works, that makes sense). But when should it be used? What purpose?
(Don't use = YES - When, basically never. It is essentially worthless.

2. When using GPS, set range to "0".
Again, yes. However, using >0 isn't wrong. It depends on how you have things set up. For instance, I use very well defined rectangles for all of my systems/depts. I use range = 0, because I want the radio to switch when I cross a state/county/city boundary. If it was set to 1 for instance, it'd switch a mile before the boundary, 2 would be 2 miles, etc, etc...

What about range when NOT using GPS? Is it still in play just monitoring my FLs? Or does location control have to be enabled for that FL?
Range is in play whenever you use location control, even without GPS. Remember, you can manually set your coordinates. Then, whatever range you have set uses THAT location plus 1, 2 (whatever your range is set at). Having GPS just changes that location as you move...

 

[PWScan]

Nessnet, Thanks.

Your last answer: Range is in play whenever you use location control, even without GPS. Remember, you can manually set your coordinates. Then, whatever range you have set uses THAT location plus 1, 2 (whatever your range is set at). Having GPS just changes that location as you move...

Does this mean if I am only scanning my FLs, none of which at this time have location control enabled for them, that the range setting is ignored? Assuming without the full DB loaded (no GPS).

 

[nessnet]

Nessnet, Thanks.

Your last answer: Range is in play whenever you use location control, even without GPS. Remember, you can manually set your coordinates. Then, whatever range you have set uses THAT location plus 1, 2 (whatever your range is set at). Having GPS just changes that location as you move...

Does this mean if I am only scanning my FLs, none of which at this time have location control enabled for them, that the range setting is ignored? Assuming without the full DB loaded (no GPS).

Yes

 

[jonwienke]

Jon, thanks for the reply. Yes, I read about location control being always on for full DB. I just wasn't sure how it was invoked. Now I know.

Are zip code and manual location settings related? I'm not clear if they work together or independently.

Is the zip code location I set manually (usually my home zip) a static setting? In other words, if I have it set to my home zip, then go out on a trip in the car with the GPS connected, does my zip code stay the same? Or does it update per the GPS? IE does it remember the last place the GPS took a reading?

Conversely, do I have to reset my ZIP location to my home zip when I return?

Zip code is just a way to set your scanner location coordinates. GPS updates that once per second. If the GPS is turned off or unplugged, the scanner will continue to use the last coordinates it got from the GPS, so there's no need to re-enter a ZIP code.

 

[ofd8001]

1. Don't use autolocate period. (Now that I know how it works, that makes sense). But when should it be used? What purpose? Autolocate, which only works on P25 systems, is probably best used if you have no other way of setting a location of about where you are in your scanner. It will get you in the ball park.

2. When using GPS, set range to "0". This is subject to debate based on user preference. You can increase this to cast a bigger scanning net, though the cost is hearing more than desired.

What about range when NOT using GPS? Is it still in play just monitoring my FLs? Or does location control have to be enabled for that FL? It isn't as critical because you generally aren't moving and thus not turning systems, etc., on and off.

All of this said I am still a little confused as to how and when location control comes into play. You have the choice of turning Location Control On/Off when programming your Favorites Lists. If you are in a fixed location and have been very judicious about creating Favorites Lists with respect to sites and departments, LC probably is not necessary. However if you import a large statewide system into a Favorites List and do not delete/avoid distant sites and departments, then LC is helpful to avoid monitoring things too far to receive. Also, you may have your scanner in a vehicle (this mostly pertains to mobile scanners) and just do local travel (50 miles or less). Location Control could be helpful.

I mix and match on Location Control. Some Favorites are set to be location dependent, others are always on which happens when Location Control is off.

Thanks.

 

[Bottlecapr]

So if my sds is used here at my home, not mobile.
I manually put in my gps coordinates
Turn on location control for the FL
Set my range to 0
The only sites I will scan are the ones that their range circle touches my gps location?
If I set range to 15 miles I make an imaginary circle from my gps of 15 and what ever circles it touches I will get the sites on my scanner
Am I understanding this correctly?

 

[ofd8001]

Let me put it a little differently, that being from the site's perspective, rather than your location's perspective.

Short answer: Increasing the Global Range (the one you set on the keypad) essentially has the scanner reaching out farther in an effort to see if you can receive something). That "outreach amount" is the number you set on the keypad.

A little more long winded explanation:
A site will have a certain "reach" or range for the coverage footprint. For sake of this discussion, a site has a range of 30 miles, or it's radio coverage footprint is anticipated to be 30 miles.

Scenario 1: Your scanner has its global range (the one you set on the keypad) is 0. If you are within 30 miles of that site, the scanner will attempt to receive it. If you are 30.1 miles (or more) away, the scanner will turn the site off.

Scenario 2: You have installed a good exterior antenna, used good cable and have it mounted on your roof or even higher tower. You should be able to bring in sites that are a little farther away. We'll assume for explanation purposes the antenna set-up gives you an extra "reach out" of 10 miles. In that case you set the global range to 10 miles, or you are reaching out an additional 10 miles. If there is a second site, which also has a range of 30 miles and it happens to be 39 miles away, your scanner will attempt to receive it. That's because you get the 30 miles from the site's range plus the 10 mile extension (total 40 miles). Sites that have a range of 30 miles and are 40.1 miles (or more) away, the scanner will turn those sites off.

 

[JoeBearcat]

So if my sds is used here at my home, not mobile.
I manually put in my gps coordinates
Turn on location control for the FL
Set my range to 0
The only sites I will scan are the ones that their range circle touches my gps location?
If I set range to 15 miles I make an imaginary circle from my gps of 15 and what ever circles it touches I will get the sites on my scanner
Am I understanding this correctly?

Yes - provided they are strong enough to receive.

 

[JoeBearcat]

A little more long winded explanation:
A site will have a certain "reach" or range for the coverage footprint. For sake of this discussion, a site has a range of 30 miles, or it's radio coverage footprint is anticipated to be 30 miles.

Not exactly. It's based on the service area of the department in question - not the RF footprint.

If a department has a service area of 30 miles, and your range is set to 0, and you are within 30 miles of their coordinates, you should receive them (signal strength allowing).

If they are a town with a radius of 5 miles, you your range is set to 0, and you are 6 miles away you will not scan them even if their transmitter is still full scale where you are.

 

[jonwienke]

For a multi-site trunked system, department location circles are based on the service area of the department--a town, county, or whatever. Site location circles are based on the approximate RF coverage area of the site.

 

[Bottlecapr]

Ok another question off topic.... let’s say I have a department with 4 sites (that’s where my CC are located, right?) Would it benefit me for faster scanning to combine ALL CC into 1 site or am I missing something here? 😉