jason carr's mousepad Garmin-centric GPS faq

Garmin FAQ

This FAQ last updated on Mon Jun 22 17:57:21 CDT 2009.

General GPS
Will rechargeable batteries work in my GPSr?
What do you mean by Good Charger?
How can I get longer battery life?
My GPS loses receptions when in urban canyons or under tree canopies.
How can I make a screenshot of my GPSr's screen?
How accurate is my GPSr?
But my buddy's GPS says [fitb] while mine says [fitb]!
How do I update the firmware in my GPSr?
Why is my GPSr consistently X-hundred feet off?
What is routing?
What is autorouting?
Why is there a blue circle on my screen?

GPS hardware
What is the difference between the 60-series and 76-series units?
It takes a long time for my GPS to get a lock.
My GPSr lags when navigating.
Will 4GB SD work in my GPS?

GPS USB issues
Do those cheap usb2serial converters work?
My USB GPSr is not recognized by windows!

Geocaching
How do I get started geocaching?
My compass arrow has a break in it, and does not lead me to the cache.
My GPS goes crazy when I get near the cache.
When am I ready to start placing my own caches?
How do I go paperless?
My GPS doesn't take me right to the geocache!
Can I get paperless cache info into my iPod?
Why don't my uploaded caches show up in the GPS' geocaching function?
Can I geocache with my car gps?
How can I make GC hints show up on my GPSr?

Garmin cartography
What good is the Trip and Waypoint Manager?
Where does Garmin get the map data?
I don't get it. How do I upload maps to my GPS?
What is a basemap?
What is a detailed map?
Can MG autoroute?
Can I load multiple maps at once?
What is map hierarchy?
Where can I get free maps?
What are locked maps?
What are lockless maps?
How do I erase the maps I uploaded?
How do I add maps without erasing previously uploaded maps?
Why won't MapSource install somewhere other than c:\garmin ?
How can I get my maps to install to HD instead of asking to put the CD in?
Will delorme (or other non-Garmin-format) maps load on my Garmin?
Do I need Topo?
Why isn't this street listed on my topo maps?
What scale is Garmin National Parks Topo made to?
Why does my unit try to autoroute me using far-off highways?
How is Topo 2008 improved?
Should I buy maps on SD card?
Should I buy maps in NT format?
Can I get MapSource for free?
Can I load all of Topo to my xGB SD card?

Free maps
Do you have a listing of known free maps?
How can I search for free garmin-compatible maps?
How do I load free maps into my Garmin GPSr?
Can I load free maps in MapSource?
Can I make my own maps?

Data
How do I up/download waypoints in my non-Windoze computer?
How do I enter a waypoint for my current location?
How do I enter a waypoint some other location?
How do I up/download waypoints to my GPSr?
How do I convert THIS to THAT?
How do I convert address to waypoints?
How to do get only those waypoints within X miles of Y coordinate?
How do I get those waypoints within X miles of my route?
How do I convert gpx to poi?
How do I convert google .kml to poi?
How do I convert geocaching.com .loc to gpx?
How do I delete Custom POI from my GPSr?
Are there any limitations on Custom POI?
How can I work with .kmz files?
Why does my GPSr only accept 50 waypoints?
What is the difference between auto, time, and distance track settings?
How do I delete waypoints from my GPSr?

General GPS

Will rechargeable batteries work in my GPSr?
Yes, a good charger and rechargeable batteries are probably the most important accessories for your GPSr.
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What do you mean by Good Charger?
A good charger charges the batteries up to their maximum voltage then stops or jumps to a trickle mode. MAHA is famous for making good chargers. A good charge rate that balances speed and battery longevity is around 500mAh. If you want a seriously good charger, get a regulated 12vdc power supply and use a hobby grade charger. The quick charger that came with your batteries is not an example of a Good Charger.
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How can I get longer battery life?
Turn on Battery Saver, turn off WAAS, minimize use of the backlight. Use and charge batteries in mated pairs (I mark my pairs with an engraver). Recharge using a Good Charger. Don't let the batteries go utterly dead.
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My GPS loses receptions when in urban canyons or under tree canopies.
Right. It's not getting clear line-of-sight with the birds. Units equipped with the high-sensitivity (HS) chips (SiRF or MediaTek (MTK) chip in the new HCX line) do better in difficult conditions. I bought a 60cx after losing signal while walking in what turned out to be an unexpectedly dangerous section of Atlanta. There are small differences between the SiRF and MTK but they do the same thing and both are substantially better than non HS chips.
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How can I make a screenshot of my GPSr's screen?
The most common method is to use G7towin. Garmin has released xImage.
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How accurate is my GPSr?
Plenty accurate for the needs of normal mortals. If you want the details or either overly curious, brave, or highly-caffeinated you can dig into the details. It's almost certainly overkill information.
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But my buddy's GPS says [fitb] while mine says [fitb]!
It really doesn't matter. Both of them will get you into the general vicinity of the waypoint. If you need accuracy to survey or military standards, then pony up for a survey- or military-grade GPSr. Remember to bring all your money.
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How do I update the firmware in my GPSr?
The simplest way is to use the garmin web updater. If you are using an unpowered connection be sure to use fresh batteries.
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Why is my GPSr consistently X-hundred feet off?
Make sure you are using the correct datum. Geocaching.com uses WGS84. The USGS generally uses NAD27.
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What is routing?
Routing is computation of a series of waypoints in advance; usually on a PC. It is an ordered list of waypoints. Even simple GPSr can accept routes (usually 10 or 20 of them). More information here.
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What is autorouting?
Autorouting is computation of a navigational route in real time in the GPS (not ahead of time on the PC). This requires autorouting-capable maps loaded into a autorouting-capable GPSr.
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Why is there a blue circle on my screen?
The blue circle indicates the estimated radius of accuracy. It is visible when navigating and Lock To Road is turned off.
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GPS hardware

What is the difference between the 60-series and 76-series units?
See this great comparison with lots of pictures.
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It takes a long time for my GPS to get a lock.
To make power-on locks faster, leave the GPSr in place without moving. This allows the GPSr to get the initial data without interruption and having to wait for the next transmission from the bird.
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My GPSr lags when navigating.
I have noticed this behavior when the Battery Saver (BS) mode was turned on. In particularly tight urban navigations the GPS can't announce turns in time. In my experience, turning the unit to Normal mode alleviates this problem greatly.
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Will 4GB SD work in my GPS?
2GB is the limit of the SD spec. There is a different spec that allows >2GB (theoretically up to 128GB) but it's HDSD and not the SD that consumer electronics currently expect to find when you put a card in their slot.
So 4GB SD is a hack, and a hack with unpredictable operation in devices that expect spec-compliant SD. If it works, be grateful and don't bet your life on stability.
To quote Dr. Johnson, a 4GB SD "is like a dog's walking on his hind legs. It is not done well; but you are surprised to find it done at all.""
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GPS USB issues

Do those cheap usb2serial converters work?
Yes, at least the $6 ones I bought off ebay; their are some more reputable usb2serial converters on amazon.
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My USB GPSr is not recognized by windows!
Be sure you've installed the Garmin USB driver. If that doesn't do it, here are some other tips:

make sure your MapSource is up to date
Use the first usb port
use the same usb port each time
if you want MapSource to see it as a GPS make sure it's not in Mass Storage Mode or it will just look like a USB thumbdrive
use a direct USB port and not a hub.

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Geocaching

How do I get started geocaching?
Register for free on geocaching.com. Then read this excellent tutorial. If you like it, you will likely find yourself getting a premium membership at gc.
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My compass arrow has a break in it, and does not lead me to the cache.
You probably have it set to Course pointer rather than Bearing pointer. Geocaching is simpler with it set to Bearing.
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My GPS goes crazy when I get near the cache.
Stop looking at the GPS when you get near the cache. By the time you get within 50' or so you should start using your caching sense rather than the GPSr. Note that having Battery Saver mode may be counterproductive when homing in on that cache; I find that it introduces substantial lag and a decrease in accuracy.
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When am I ready to start placing my own caches?
The consensus seems to be that after you have found 100 caches you are probably informed enough to start placing good caches.
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How do I go paperless?
First decide whether you are going to go Palm or PPC/smartphone; you non-geocaching needs will probably help this decision along. Then read this guide.
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My GPS doesn't take me right to the geocache!
It's not supposed to. GPS gets you to the general area so you can start looking for the cache. There are several reasons why you can be further from the cache rather than closer: the original coords uploaded by the cache hider could be wrong intentionally (obfuscation, difficulty: be sure to read the cache description) or unintentionally (normal GPS accuracy variances, cache movement/relocation, muggles, datum mismatches, no clear view of sky, etc).
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Can I get paperless cache info into my iPod?
Yes. There are several methods described in this thread.
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Why don't my uploaded caches show up in the GPS' geocaching function?
Geocaches are waypoints like any other. The GPS know which waypoints are geocaches based on the settings in Main Menu | Setup | Geocache | Find. Make sure your waypoints use whatever icon you have defined in the GPS. In addition, the Geocaching mode only shows Found/Unfound caches within a given distance. If you need to see a faraway geocache use "Find by name".
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Can I geocache with my car gps?
Yes, if it runs off batteries. The main problem is that GPSr can take rough treatment in the field (rain, dirt, drops, stepped on); portables are built for this and auto units are not.
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How can I make GC hints show up on my GPSr?
IMO the easiest way to do this is with freeware EasyGPS.
Edit | Preferences | Geocaching | Comment | Geocaching Hint (Decrypted). This will populate the geocache comment field with the hint when you upload the caches.
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Garmin cartography

What good is the Trip and Waypoint Manager?
T&WM isn't that useful in itself; you could manipulate waypoints, routes, and tracks just as easily with freeware like EasyGPS. T&WM is more important for a side effect; it gets you a legal copy of MapSource, which is the underlying gps software garmin uses to deliver their map products. You get T&WM free with many garmin GPSr, or you can get them cheap off eBay from folks who don't need it. You can even buy a copy at retail but most folks don't.
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Where does Garmin get the map data?
Check out this summary of who gets what data from whom.
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I don't get it. How do I upload maps to my GPS?
Start with an overview. Then get the detailed instructions in pdf format.
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What is a basemap?
The basemap is the simple map built into your GPSr. It is not erasable in any normal sense, but when you uploaded "detailed maps" the basemap is hidden.
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What is a detailed map?
A "detailed map" means an additional garmin-format map that is loaded on top of your basemap. It is usually more detailed than the basemap, but it doesn't have to be.
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Can MG autoroute?
Yes. v4.x does it intrinsically, but other versions can be induced to autoroute.
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Can I load multiple maps at once?
Yes, but you have to load them at one time since any subsequent upload effectively erases the ones before it. Under normal circumstances, only one map covering a given area will be visible at a given time due the map hierarchy. Transparent overlays are an exception, but if you knew about those you wouldn't be reading this question anyhow.
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What is map hierarchy?
Only one map for any given area is visible at one time. The most detailed map is on "top" by default. You can turn off maps in Map Setup menus in the GPSr in order to see the maps underneath them.
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Where can I get free maps?
See my listing of free Garmin-format maps. Or google it.
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What are locked maps?
Locked maps are tied to the serial number of your GPSr in order to limit unlicensed use of the maps. Generally speaking, more $$$ maps are locked while less expensive maps are lockless. Example: City Navigator.
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What are lockless maps?
Lockless maps do not require an unlock code to upload to any compatible GPSr. Example: Topo, MetroGuide. This makes them a good bargain on the used map market.
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How do I erase the maps I uploaded?
Upload other maps. This works because the uploaded maps are stored in a single file called GMAPSUPP.IMG. Uploading any other mapset overwrites that file. You may also use sendmap20 to "erase" the map, although it is likely just uploading an empty mapset (assumption; I haven't tested that theory). If your maps are stored on SD you can delete the GMAPSUPP.IMG from the \GARMIN directory.
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How do I add maps without erasing previously uploaded maps?
There is no direct way to do this, for the reasons given above. If you still have a copy of the map you want to keep it is best/fastest to just combine all the maps and upload them again. If you don't have the original maps you can use sendmap20 to suck down the existing mapset and combine it with the new ones. This will take somewhat longer. Or if you have it stored on your SD card you can save the IMG to your HD and save/combine it with sendmap20.
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Why won't MapSource install somewhere other than c:\garmin ?
Because it (or the installer) is brain dead. Don't fight it. Let it install wherever it wants and you will stop punching your monitor.
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How can I get my maps to install to HD instead of asking to put the CD in?
This thread is said to have the clearest instructions on doing it. Basically either you copy to HD and install, or hack the registry.
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Will delorme (or other non-Garmin-format) maps load on my Garmin?
No. You may be able to use delorme, Streets & Trips maps, etc, for things like this:

Realtime tracking (ie, garmin cabled to laptop running the software). In this use the GPSr takes the place of the "GPS mouse" provided with some packages.
Trip planning (ie, create waypoints or routes from the map display and upload the waypoints/routes to your garmin)

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Do I need Topo?
Have you used paper topo maps in the past and found them useful? Do you know how to read contour lines? If so you might find Garmin Topo to be useful. According to garmin you can "you can view highways, roads, hiking trails, snowmobile trails, backwoods trails, elevation contours, point elevations, summits, some bathymetric contours, geographic names, churches, and schools", as least as they existed when the mapset was created.
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Why isn't this street listed on my topo maps?
Topo is based on USGS surveys, and is not updated regularly the way the other detailed maps are. Topo is more useful for seeing terrain than it is for seeing man-made features.
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What scale is Garmin National Parks Topo made to?
24k, which is to say that 1 unit on the map is equal to 24,000 units in the Real World.
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Why does my unit try to autoroute me using far-off highways?
It sounds like it is autorouting on the basemap. Since the basemap is routable, the basemap only has major roads, the GPSr is routing you via the closest roads it sees. Did you load other routable maps? Is your card seated correctly, etc?
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How is Topo 2008 improved?
Check out this thread for a nice writeup by Hogrod.
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Should I buy maps on SD card?
Card-based maps are generally only a good idea for folks that crave simplicity or who do not have access to a PC where they can load from DVD. Limitations of card-based maps: the maps are locked to that card, are not downloadable, will not accept other maps in addition to the preloads, can't be manipulated in MapSource, rather $$$, can't be backed up, etc. Say "No" to card-based maps unless you have a specific reason to do otherwise.
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Should I buy maps in NT format?
NT maps are compressed in a way that makes more map fit in smaller devices/cards. Most NT maps are on cards, some are in DVD format. In a world of 2GB cards, I see no reason for the extra expense of NT maps. On the plus side, users generally report that speed of compressed NT maps is not slower than the non-NT mapsets (possible exception on HCX units). Note that not all GPSr can use NT maps (see the compatibility tool on the right side of the page). Note that traffic-capable receivers may require NT for some reason.
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Can I get MapSource for free?
Generally not, but there may be a workaround.
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Can I load all of Topo to my xGB SD card?
No, because there is a maximum number of map segments the GPSr can tolerated. This limit is something like 2025, while Topo has 6639 segments. Canadian Topo has over 7000 segments. You may be able to combine map segments, which the loss of some data.
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Free maps

Do you have a listing of known free maps?
Yes, see my listing of free Garmin-format maps.
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How can I search for free garmin-compatible maps?
Google free garmin map or similar.
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How do I load free maps into my Garmin GPSr?
Traditionally this is done with freeware sendmap20. It's about 2/3rds down that page.
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Can I load free maps in MapSource?
See the question above for the normal method. But if you really want to do it in MapSource, you can hack the registry. You may or may not be able to use a file called GPSMapManager to automate the hack.
Note: things may be different on Vista x64.
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Can I make my own maps?
Yes, although it takes time, savvy, and patience. There are many tutorials. I like this one.
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Data

How do I up/download waypoints in my non-Windoze computer?
gpsbabel is available on many platforms. Here is what it looks like on linux serial port:

upload: gpsbabel -D2 -i gpx -f example.gpx -o garmin -F /dev/ttyS0
download: gpsbabel -D2 -i garmin -f /dev/ttyS0 -o gpx -F example.gpx

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How do I enter a waypoint for my current location?
Hold down the clickstick or the Enter/Mark button, depending on your unit.
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How do I enter a waypoint some other location?
Enter a waypoint as above, then edit it to match the coords you want.
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How do I up/download waypoints to my GPSr?
Start on the geocaching.com waypoint downloading intro. I prefer EasyGPS for my waypoint transfer needs.
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How do I convert THIS to THAT?
The answer is almost always GPSbabel.
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How do I convert address to waypoints?
You can use various online geocoders, but be careful not to abuse them.
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How to do get only those waypoints within X miles of Y coordinate?
Use the gpsbabel radius filter.
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How do I get those waypoints within X miles of my route?
Use the gpsbabel arc filter.
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How do I convert gpx to poi?
gpsbabel -i gpx -f example.gpx -o garmin_poi -F example.csv
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How do I convert google .kml to poi?
gpsbabel -i kml -f example.kml -o garmin_poi -F example.csv
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How do I convert geocaching.com .loc to gpx?
gpsbabel -i geo -f example.loc -o gpx -F example.gpx. Note that the rich dataset available from Pocket Queries were never in the .loc, so will not be in the resulting .gpx.
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How do I delete Custom POI from my GPSr?
Either upload another set of POI or mount the card and delete the files in \Garmin\Poi.
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Are there any limitations on Custom POI?
There may be a 256-category limitation. Custom POI cannot be deleted in the field.
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How can I work with .kmz files?
These appear to be zipped .kml files. Unzip them and parse the .kml in your usual fashion.
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Why does my GPSr only accept 50 waypoints?
It doesn't. It's only showing you the 50 nearest. Try searching by name or some other approach. Or download them back from your GPS to prove to yourself that they really are in there.
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What is the difference between auto, time, and distance track settings?
See this nice writeup by EraSeek.
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How do I delete waypoints from my GPSr?
For GPSr with a geocaching mode, see this fine post by Miragee.
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