Jump to content

Chipset Concerns - Garmin 60CSx - Mediatek vs. SIRF


kemis
Followers 3

Recommended Posts

I bought a new 60CSx from REI (my very first real GPSr) which came with a Mediatek chipset. I later found an older 60CSx on Craigslist for $213 cheaper, which turned out to have a SIRFstar III chipset.

 

The difference between chipsets has been discussed elsewhere, and the main conclusion seemed to be a general preference for the SIRF, but that it didn't really matter in the end. Well.... out of the box, my new MTK-based Garmin inside my home was claiming 14 feet accuracy, while the older SIRF-based model was claiming 40 feet accuracy. Hmmm... not something I wanted to see out of the box.

 

Yesterday, I took them both on my first caching trip to find a cache I was completely unsuccesful finding with my iPhone. The entire time, both devices were telling me to go in different directions for different measurements. Finally, I gave up, looked at the hint, and found it that way. Yeah, I know you shouldn't rely too much on your GPSr & go for geosense instead, but both units were telling me I was about 30 feet away when I was over the cache. This makes me question reliability.

 

Furthermore, I decided to take a 100-sample average using BOTH devices. This morning, I measured the distance between each one and the posted coords... The new MTK device's recorded average waypoint above the cache was about 5' from the posted coords, yet it didn't say that on the screen when I was over it. The older SIRF model (which claims a less-accurate +/- signal lock) recorded an average waypoint that measured about 31' away! That's a big difference in my mind & makes me question the reliability of the unit. This makes me wonder which coords were closer to correct--the posted one which matched my MTK unit, or my SIRF unit. If this were a democracy, my SIRF unit would lose the election.

 

Both devices have the exact same settings, WAAS enabled, etc. The only difference I can't account for besides the chipset itself was the OS version on the new one is 4.1 (yet unpublished on Garmin's site) while the SIRF model has the "latest" v4.0 version. Not sure if v4.1 made the device any more accurate, so I'm assuming this is a chipset thing.

 

Okay, so I'm relatively new to caching & GPSr's in general, but do I have a valid concern here about accuracy/reliability of this SIRF-based model?

 

Thanks for taking the time to read this! --Matt

Link to comment

I bought a new 60CSx from REI (my very first real GPSr) which came with a Mediatek chipset. I later found an older 60CSx on Craigslist for $213 cheaper, which turned out to have a SIRFstar III chipset.

 

The difference between chipsets has been discussed elsewhere, and the main conclusion seemed to be a general preference for the SIRF, but that it didn't really matter in the end. Well.... out of the box, my new MTK-based Garmin inside my home was claiming 14 feet accuracy, while the older SIRF-based model was claiming 40 feet accuracy. Hmmm... not something I wanted to see out of the box.

 

Yesterday, I took them both on my first caching trip to find a cache I was completely unsuccesful finding with my iPhone. The entire time, both devices were telling me to go in different directions for different measurements. Finally, I gave up, looked at the hint, and found it that way. Yeah, I know you shouldn't rely too much on your GPSr & go for geosense instead, but both units were telling me I was about 30 feet away when I was over the cache. This makes me question reliability.

 

Furthermore, I decided to take a 100-sample average using BOTH devices. This morning, I measured the distance between each one and the posted coords... The new MTK device's recorded average waypoint above the cache was about 5' from the posted coords, yet it didn't say that on the screen when I was over it. The older SIRF model (which claims a less-accurate +/- signal lock) recorded an average waypoint that measured about 31' away! That's a big difference in my mind & makes me question the reliability of the unit. This makes me wonder which coords were closer to correct--the posted one which matched my MTK unit, or my SIRF unit. If this were a democracy, my SIRF unit would lose the election.

 

Both devices have the exact same settings, WAAS enabled, etc. The only difference I can't account for besides the chipset itself was the OS version on the new one is 4.1 (yet unpublished on Garmin's site) while the SIRF model has the "latest" v4.0 version. Not sure if v4.1 made the device any more accurate, so I'm assuming this is a chipset thing.

 

Okay, so I'm relatively new to caching & GPSr's in general, but do I have a valid concern here about accuracy/reliability of this SIRF-based model?

 

Thanks for taking the time to read this! --Matt

I'd suggest rebuilding the almanac and turning off power saving if it's on. Then try again and see if the accuracy improves. Might not make any difference, but it's worth a try. I got my accuracy down to 9 feet (in a clear unobstructed area) just by following that procedure...

Link to comment

Not to sidetrack your thread too much, but my eTrex Summit HC has the Mediatek chip, and performs at least as well as my buddy's older 60CSx with SiRF III chip. My EPE is always at least as good, often better (although we know that could just be function of Garmin's firmware differences) and settles a little more quickly than his. Lock is fast, and never a problem pulling up WAAS quickly.

 

While I've begun to wonder if my Summit HC is an exceptional unit for some reason, I can say that his unit and mine eventually zero out at fairly near the same spot.

 

On the whole, I'd give a thumbs up to both the SiRF III and Mediatek chipsets. The ST Cartesio on my Dakota 20 (and all of the other recent Garmin handhelds) is another question altogether. Slow to settle, darned near impossible to get a WAAS lock, and always a bigger EPE showing than my eTrex.

 

I WILL get the Super-Comparo study done one of these days. I have samples of units with all of these chipsets, and plan a thorough study of the accuracy and repeatability of each unit.

 

Just for grins, here's something else you can do with your to 60CSx units:

 

Let them both settle to whatever appears to be their best EPE out in open sky. Set them a foot or so apart. Turn on tracking, 1 second intervals, and let them both sit and record the "track" for 15 minutes. Save the tracks. Use Garmin's Mapsource to export the tracks as text files.

 

Load one of the tracks into Garmin Mapsource and zoom up.

 

Do the same for the other track file.

 

How do they compare?

Link to comment

Thanks for taking the time to read this! --Matt

 

With your "one cache" test though aren't you at the mercy of whether the cache owner had accurate coordinates in the first place?

 

Not sure what you have in the US, but we have "trig points" in the UK - places where the mapping authorities have definitively concluded what the coordinates are. Only at that sort of location could you be certain that you are comparing an "accurate" reading with either of your two devices.

 

Matt (too)

Link to comment

I've test driven the eXplorist GC and experienced several updates on my Meridian.

 

The hardware is only as good as what the firmware does with the data. I remember arguing about the sensitivity of the two main antenna types. Although there were improvements over the years, the firmware upgrades also effected the performance of the older devices.

 

So the balance of firmware and hardware is precarious. Making an accurate comparison of chipsets only a matter of circumstance.

Link to comment

A classic case of a man with one watch knows what time it is, but a man with two watches is never sure.

 

As someone mentioned, you're basing too much on a waypoint that you don't know is correct. Furthermore it's entirely possible for two GPSs to show different results, with neither one of them being "wrong". Just the act of holding each one in a different hand can cause a difference, because your body can be blocking off different satellites from each one's view. And one may have current ephemeral data, while the others' is stale. Comparing EPEs between two different chipsets is pointless, since no one outside Garmin knows the formula for either, let alone whether they match each other.

Edited by Prime Suspect
Link to comment

As someone mentioned, you're basing too much on a waypoint that you don't know is correct. Furthermore it's entirely possible for two GPSs to show different results, with neither one of them being "wrong". Just the act of holding each one in a different hand can cause a difference, because your body can be blocking off different satellites from each one's view. And one may have current ephemeral data, while the others' is stale. Comparing EPEs between two different chipsets is pointless, since no one outside Garmin knows the formula for either, let alone whether they match each other.

 

Yes, and there could be other issues too...

 

Was it just a bad satellite day? What did the constellation look like relative to your position that day?

 

Do you have the latest firmware?

Link to comment

Just for grins, here's something else you can do with your to 60CSx units:

 

Let them both settle to whatever appears to be their best EPE out in open sky. Set them a foot or so apart. Turn on tracking, 1 second intervals, and let them both sit and record the "track" for 15 minutes. Save the tracks. Use Garmin's Mapsource to export the tracks as text files.

 

Load one of the tracks into Garmin Mapsource and zoom up.

 

Do the same for the other track file.

 

How do they compare?

 

Dang! For some reason, I wasn't subscribed to this thread even though I'm OP. I will remedy that ASAP so I know you guys are trying to help!!

 

Anyway, I love this suggestion & inadvertently observed something similar yesterday, but will make it more formal as soon as I can. Yesterday, I was parked in my car waiting for someone comparing the two units again. After sitting there for 10 minutes, I noticed that my SIRF unit's tracklog in Map mode looked like a 2-year old's scribble. Meanwhile, the MTK unit was sitting still. This, combined with the fact my SIRF had a 50' accuracy reading, while the MTK claimed about 14'.

 

I am honestly beginning to wonder if this isn't so much a "chipset" problem as much as it's likely that this used SIRF model I purchased is simply defective. I just don't see how my experience so far lines up with everyone's reviews of the "trusty" SIRF-based 60CSx's.

 

As for RonFisk's suggestion to rebuild the almanac, how do I do that?

 

THANK YOU, EVERYONE!!!

Matt

Link to comment

Rebuilding the almanac - leave unit in unobstructed open space with clear view of the sky in all directions for an hour.

 

I found my oregon 300 was useless until I'd done this. HTH

 

So, I'm assuming this is simply re-introducing all the possible satellites to the GPSr? What exactly is happening? Would this fix the inability to maintain a lock?

 

Matt

Link to comment

Rebuilding the almanac - leave unit in unobstructed open space with clear view of the sky in all directions for an hour.

 

I found my oregon 300 was useless until I'd done this. HTH

 

So, I'm assuming this is simply re-introducing all the possible satellites to the GPSr? What exactly is happening? Would this fix the inability to maintain a lock?

 

Matt

You mentioned that the OS was at release 4.0. What about the chipset software? Does it show 3.0s? If not, you need to upgrade. And a Factory Reset wouldn't hurt either, along with a new almanac load.

Link to comment

You mentioned that the OS was at release 4.0. What about the chipset software? Does it show 3.0s? If not, you need to upgrade. And a Factory Reset wouldn't hurt either, along with a new almanac load.

 

Yes, the chipset firmware is the latest 3.0s. I'll try the almanac thing later tonight.

 

Thanks!

Matt

Link to comment

You mentioned that the OS was at release 4.0. What about the chipset software? Does it show 3.0s? If not, you need to upgrade. And a Factory Reset wouldn't hurt either, along with a new almanac load.

 

Yes, the chipset firmware is the latest 3.0s. I'll try the almanac thing later tonight.

 

Thanks!

Matt

 

3.0s is for the Sirfstar chipset. OP said he had Mediatek

Link to comment

You mentioned that the OS was at release 4.0. What about the chipset software? Does it show 3.0s? If not, you need to upgrade. And a Factory Reset wouldn't hurt either, along with a new almanac load.

 

Yes, the chipset firmware is the latest 3.0s. I'll try the almanac thing later tonight.

 

Thanks!

Matt

 

3.0s is for the Sirfstar chipset. OP said he had Mediatek

 

Seldom_sn: I am the OP. :-) Currently, I have _both_ a brand new 60CSx from REI with an MTK chipset, but I wish to return it because I just bought a used one with a SIRF. Unfortunately, the SIRF unit is proving very unreliable & I'm very surprised by how inaccurate & literally "all over the map" it is, hence my post comparing/contrasting the accuracy between the two "same" model units.

 

I'm about to put it outside for an hour, so we'll see what happens. I really do think the unit is defective, though. If that's the case, is there any chance of repair? Could the antenna just be loose inside or something?

 

Matt

Link to comment

Umm... not so happy with the almanac reset. After leaving outside for about 45 minutes (another popular site says it only really takes 15 minutes), I reset the logs & let it sit for another 15 minutes. Attached are some pics of the units before/after this process. The track map is 15 mins worth of standing completely still.

 

Please review these pictures: http://clearchoiceit.com/files/index.php?dir=gpspics%2F

 

I'm about to cold reset the unit & see what happens...

 

Matt

 

P.S. - My MTK unit says I've traveled 0ft on the odometer whereas the SIRF says I've traveled .13 miles at a speed of 2 miles per hour!!!

Edited by kemis
Link to comment

 

P.S. - My MTK unit says I've traveled 0ft on the odometer whereas the SIRF says I've traveled .13 miles at a speed of 2 miles per hour!!!

Yeah - ignoring the EPE difference, the track alone is pretty ugly. My MediaTek Summit HC looks like your MediaTek 60CSx. Rock stable once it's been on for a few seconds. My buddy's SiRFIII 60CSx doesn't wander much, either - certainly nothing like what you had there.

 

I neither case can I say I'm really impressed with the number and height of the bars in photos #2 and #3. Satellite #23 was right above you, and barely running the signal level up at all in those pics. Could be because you were standing over both of them when you took the photos <_< Seriously, there's a huge difference between photo #1 and the other two. Under what circumstances were you taking these measurements?

Link to comment

 

P.S. - My MTK unit says I've traveled 0ft on the odometer whereas the SIRF says I've traveled .13 miles at a speed of 2 miles per hour!!!

Yeah - ignoring the EPE difference, the track alone is pretty ugly. My MediaTek Summit HC looks like your MediaTek 60CSx. Rock stable once it's been on for a few seconds. My buddy's SiRFIII 60CSx doesn't wander much, either - certainly nothing like what you had there.

 

I neither case can I say I'm really impressed with the number and height of the bars in photos #2 and #3. Satellite #23 was right above you, and barely running the signal level up at all in those pics. Could be because you were standing over both of them when you took the photos <_< Seriously, there's a huge difference between photo #1 and the other two. Under what circumstances were you taking these measurements?

 

A big problem I have right now is not knowing what exactly I'm looking at on the satellite view page. I have no clue, for example, what an empty bar means versus a solid bar. I'm pretty sure a D means WAAS is locked in, but I thought the last 2 satellites were reserved for WAAS lock.

 

Anyway, what you're seeing there is the first picture was taken very shortly after both units had a lock after turning on at the exact same time. The other pics were 30+ minutes later.

 

What you said about your friend's SIRF unit not looking like that is what I'm needing to hear (besides suggestions on how to fix it, if possible). I need to know that this isn't "normal" SIRF-based 60CSx behavior, as opposed to just "assuming" it's not what SIRF users are so proud of! :-)

 

I just did a hard reset & have the unit sitting out in my front yard (as opposed to my back yard). I'll let you know what happens...

 

THANKS!

Matt

Link to comment

A big problem I have right now is not knowing what exactly I'm looking at on the satellite view page. I have no clue, for example, what an empty bar means versus a solid bar. I'm pretty sure a D means WAAS is locked in, but I thought the last 2 satellites were reserved for WAAS lock.

Satellites #48 and #51 are the two WAAS satellites.

 

"Hollow" bar means signal is being received, but no valid data (yet).

Solid bar means signal is being received, and valid data is available to compute position.

Height of bar indicates signal strength.

"D" in solid bar means that WAAS information (from #48 or #51) is being used to correct that satellite's data.

Link to comment

"Hollow" bar means signal is being received, but no valid data (yet).

Solid bar means signal is being received, and valid data is available to compute position.

Height of bar indicates signal strength.

"D" in solid bar means that WAAS information (from #48 or #51) is being used to correct that satellite's data.

 

Thanks! That helps. Did you just know that 48 or 51 are the WAAS for my area, or did you see that on the unit? In my living room, I'm picking up 48, whereas I think 51 is the only one visible in my pics.

 

So, I did a HARD reset (held down page & enter while turning on) and left the unit outside for 20 minutes. Take a look at the pics 9182, 9183, and 9186 on my pics site now. BIG difference! Is it fixed? Not sure yet...

 

A major question I had was why no WAAS data was being used, but then as I typed this, I realized that it was never re-enabled after the reset. I have to wonder if WAAS is the cause of my problem!? I will turn it back on & do another baking in the open sky over the weekend.

 

Well, nevermind. I just enabled it, & in just 30 seconds, I've "moved" over 31 feet and counting.

 

So WAAS is the problem on this new device!? Isn't WAAS supposed to HELP and not hinder accuracy/reliability? Suggestions?

 

Matt

Link to comment

The tendency of these units to drift is well known. I documented it at http://www.mtgc.org/robertlipe/showdown/ and it was known before. No GPS knows exactly where you are. The choice the vendors make is to give you a best guess (which may move a few feet each second which, over time, adds up) or to filter and strategically fib to you about position. Garmin chose settings for the Sirf models that did the former.

Link to comment

The tendency of these units to drift is well known. I documented it at http://www.mtgc.org/robertlipe/showdown/ and it was known before. No GPS knows exactly where you are. The choice the vendors make is to give you a best guess (which may move a few feet each second which, over time, adds up) or to filter and strategically fib to you about position. Garmin chose settings for the Sirf models that did the former.

 

Hey, Robert! One of my friends just had me read that article the other day. He's a big Magellan fan.

 

Anyway, so I'm assuming that the MTK units are programmed by Garmin for the latter? That makes sense considering that even moving the MTK unit around a bit (slowly) still produces nothing on the odometer.

 

Nonetheless, if I can find a few other people who say their map track looks nothing like mine after 15 mins of sitting still, then I'd say I have a leg to stand on claiming that this unit I just received is defective. Do you agree?

 

Update: Even after turning WAAS off and coming back inside my home, the SIRF unit is drifting around way more than the MTK. I don't think my hard reset or even turning WAAS off really did much. I must say that I think the accuracy number improved just a few seconds after turning WAAS off. This just bugs me, though, since WAAS shouldn't hinder accuracy, right?

 

Matt

Link to comment

Since the manufacturer can't know if the issue is small movements by the user or drift, they're really not in a position to "fib". You can take my MediaTek unit and watch it sit, solid as a rock. You can then move it ten feet, and see the position update, and then hold steady as a rock. Nobody is doing any fibbing -- it's doing its level best to report what it knows. This eTrex Summit HC was my first handheld GPS, and is the standard against which I've measured everything since. Many units "since" have not measured up. What you see below is a TYPICAL experience for me on my Summit; far better in the early readings, I would point out, than my ST Cartesio equipped unit... Newer isn't necessarily better on the business end.

 

Sample MediaTek, 30 minutes of track data for a unit that has settled for 1 minute, clear skies, WAAS enabled, 40 degrees latitude. Total N/S drift, -0.001. Total E/W drift, +0.001:

 

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.255

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.696 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.255

N 40 11.695 W 105 04.255

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.255

N 40 11.695 W 105 04.255

N 40 11.695 W 105 04.255

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

N 40 11.695 W 105 04.256

Edited by ecanderson
Link to comment

Sample MediaTek, 30 minutes of track data for a unit that has settled for 1 minute, clear skies, WAAS enabled, 40 degrees latitude. Total N/S drift, -0.001. Total E/W drift, +0.001:

 

Thanks! Will someone please post something similar for a SIRF-based unit?

 

Matt

Link to comment

Sample MediaTek, 30 minutes of track data for a unit that has settled for 1 minute, clear skies, WAAS enabled, 40 degrees latitude. Total N/S drift, -0.001. Total E/W drift, +0.001:

 

Thanks! Will someone please post something similar for a SIRF-based unit?

 

Matt

Wish I could help more quickly. My buddy has his SiRFIII 60CSx back for the weekend, and I won't be testing it again until Monday. From the data above, you can see why my expectations set a pretty high bar for stability. And again, this was my first GPS, so I've always viewed everything else through my Summit-colored glasses.

 

I also keep painting the Colorado series with the Cartesio brush. That is incorrect. The Colorado also uses the Mediatek MTK3318 just like my Summit HC. It's only the Oregon/Dakota units (of the handhelds - several of the Nuvi models do as well) that use the ST Cartesio chip.

 

Starting to gather a lot of hard-core data on the units I have in hand, and will keep adding to it. I finally found a location not too far away where there is an agreed-upon set of coordinates. We're kinda short on "trig points" here in the U.S. Most of our benchmarks are pretty crudely placed having been placed eons ago, and it's hard to know which of the ones whose notes indicate that their coordinates were later corrected by "GPS" were corrected with anything accurate enough to help.

Link to comment

Matt,

Are you comparing both units, set up the same way, outside? Last night I pulled both units from the external antennas on the roof, and watched the results from inside my mobile home. Miserable readings from both the MTK and the SiRF units. The MTK receiver did get some WAAS readings for a short spell. On balance, I find the MTK more stable, and dosen't bounce, drift, or as "jumpyfied" as The Sirf. But, several days ago, I had the SiRF 60CSx over at a surveyed point, set up to "all d's", and only had to move the receiver less the 2 ft to get it to read to "truth", or what the GPS surveyed said was truth. What $50 thou worth of equipment and Post processing can do!

Another problem that I have when comparing units, besides the winter hanging on, is most of the day I have 14 regular Sats useable, and each unit selects a different 12. I need to wait for it to warm up more and pick a time of the day when both units have the same Sats for a fair test.

There is a slight difference between most all units, but when you have both set up the same, and sitting outside in the clear for about 15 min, then pick them up and keep them abpve your head, as you walk over to you test point, so that they don't lose lock, you should fid them close to the same, unless there is something wrong with the SiRF unit. I have found out from 4 years of using SiRF unit, that it works best when I let ie sit and settle for a spell before I position it over the chosen point. Then hit the mark button after about 4 or 5 seconds, before it starts to get jumpy. Otherwise, it's probably averaging time. Still testing, still learning.

Link to comment

P.S. - My MTK unit says I've traveled 0ft on the odometer whereas the SIRF says I've traveled .13 miles at a speed of 2 miles per hour!!!

 

Apologies if this is somewhere above in the thread, but these results look as if the MTK was set to "record track by distance" and the Sirf was set to "record track by time" or "Automatic". Record by distance damps the noise drift.

Link to comment

The OP doesn't say exactly how old his Sirf unit is, but here's yet another point to consider: There is a fairly well known issue with 60's antenna connections cracking when the antenna is repeatedly flexed by external force, more information for example here. Easiest way to check this would be to use an external antenna and see if there is any improvement.

Link to comment

The OP doesn't say exactly how old his Sirf unit is, but here's yet another point to consider: There is a fairly well known issue with 60's antenna connections cracking when the antenna is repeatedly flexed by external force, more information for example here. Easiest way to check this would be to use an external antenna and see if there is any improvement.

 

I have been wondering this the whole time. Especially since almost all the satellites seem to be getting a "stronger" signal with the MTK, especially when inside the house. My SIRF unit was mfg in 2007 or so. I will investigate the cracked antenna link you posted & let you know what I think.

 

Who sells external antennas where I can return it if necessary? REI? Academy?

 

FYI, both units were setup the exact same way when those pics were taken. Record method for track was set to Auto for both.

 

THANKS!

Matt

Link to comment

Am I allowed to call Garmin for support on a used, second-hand 2007-model unit?

 

Also, I just entered diagnostics mode (held down ENTER while powering up on both units). Here are some interesting comaprisons, but I have no clue what these figures really mean. I'm only highlighting those which seem to be way off:

 

MTK:

Software Ver: 4.10

XO Drift - 0.00

C/NO - -1.00 (steady)

 

SIRF:

Software Ver: 4.00

XO Drift - -1.89

C/NO - bounces around 25 (ranges 10 - 30+)

 

NOTE: I did swap batteries in the units, but nothing changed, so I'm sure the batteries are not the source of any problem.

 

Does this info help at all?

Matt

Link to comment

Am I allowed to call Garmin for support on a used, second-hand 2007-model unit?

 

Matt

Yes, you can contact Garmin for tech support for older and used GPSr's. You just might have to pay for any repairs because the unit is no longer under warranty. They offer great support for your units. I have a 60csx that I bought about 3 years ago that has been replaced twice. Once because the rubber seal was coming apart and the second time because the on/off switch would not work.

 

All three of their accuracies have been great and I have not nor was I concerned about which chip was in them. I do compare my accuracy with a new Delorme PN-40 that I purchased in December and they are pretty much dead on.

 

I also have two Legend HCX's and a Venture HC that my daughters use and they are all pretty much the same in accuracy. Sometimes my GPS'r will tell me it's in one area and theirs will say something different or vice versa. A lot of times for us it's about the battery in the unit. If they are starting to run low, we will sometimes have accuracy problems but all in all we really don't think about it that much.

 

Good luck

Link to comment

The XO was 0.00

C/No was -1.00

on both receivers.

The XO on the MTK did try to slip in some numbers on me, until I shifted the fist full of double wrapped foil around a bit, to cancel it back to zero. where it stayed.

Can only guess what some of the numbers mean.

Play "stump the Garmin CS rep" on Monday,huh.

Link to comment

 

XO Drift - -1.89

 

...

 

Does this info help at all?

Matt

It's been a while, but I recall XO being the Crystal Oscillator drift, and 1.89 strikes me as a very large number. I wish I knew how to throw the eTrex Summit HC into diag mode. I've never been able to figure it out. It doesn't seem to follow the other eTrex models in this regard (i.e., holding scroll/enter button down while powering up).
Link to comment

Oh - and the C/NO is the "carrier link to noise" ratio (a figure of merit for the quality of the signal you are receiving). More is better. The -1.00 number makes no sense to me unless the unit under test was entirely shielded from any satellite signals.

 

I have no idea if that's Garmin's average for the 4 best satellite signals it is receiving for a primary lock, or an average for all of them, or whether the bouncing around is because it is cycling through all of them that it can see. It's really a different number for each satellite.

Link to comment

Sample MediaTek, 30 minutes of track data for a unit that has settled for 1 minute, clear skies, WAAS enabled, 40 degrees latitude. Total N/S drift, -0.001. Total E/W drift, +0.001:

 

Thanks! Will someone please post something similar for a SIRF-based unit?

 

Matt

Wish I could help more quickly. My buddy has his SiRFIII 60CSx back for the weekend, and I won't be testing it again until Monday. From the data above, you can see why my expectations set a pretty high bar for stability. And again, this was my first GPS, so I've always viewed everything else through my Summit-colored glasses.

 

I also keep painting the Colorado series with the Cartesio brush. That is incorrect. The Colorado also uses the Mediatek MTK3318 just like my Summit HC. It's only the Oregon/Dakota units (of the handhelds - several of the Nuvi models do as well) that use the ST Cartesio chip.

 

Starting to gather a lot of hard-core data on the units I have in hand, and will keep adding to it. I finally found a location not too far away where there is an agreed-upon set of coordinates. We're kinda short on "trig points" here in the U.S. Most of our benchmarks are pretty crudely placed having been placed eons ago, and it's hard to know which of the ones whose notes indicate that their coordinates were later corrected by "GPS" were corrected with anything accurate enough to help.

Link to comment

Sample MediaTek, 30 minutes of track data for a unit that has settled for 1 minute, clear skies, WAAS enabled, 40 degrees latitude. Total N/S drift, -0.001. Total E/W drift, +0.001:

 

Thanks! Will someone please post something similar for a SIRF-based unit?

 

Matt

Wish I could help more quickly. My buddy has his SiRFIII 60CSx back for the weekend, and I won't be testing it again until Monday. From the data above, you can see why my expectations set a pretty high bar for stability. And again, this was my first GPS, so I've always viewed everything else through my Summit-colored glasses.

 

I also keep painting the Colorado series with the Cartesio brush. That is incorrect. The Colorado also uses the Mediatek MTK3318 just like my Summit HC. It's only the Oregon/Dakota units (of the handhelds - several of the Nuvi models do as well) that use the ST Cartesio chip.

 

Starting to gather a lot of hard-core data on the units I have in hand, and will keep adding to it. I finally found a location not too far away where there is an agreed-upon set of coordinates. We're kinda short on "trig points" here in the U.S. Most of our benchmarks are pretty crudely placed having been placed eons ago, and it's hard to know which of the ones whose notes indicate that their coordinates were later corrected by "GPS" were corrected with anything accurate enough to help.

Link to comment

I received a new unit from amazon uk and its sirf3 ( 3.00s )

I was waiting the new chipset.

A good review of the two units would be great.

 

Unfortunately, I had to return my new MTK-based unit to REI since there was no way to return my used SIRF, so I can no longer do any sort of real side-by-side comparison other than the points I've touched on already in this post. Furthermore, I'm still not convinced that my SIRF unit behaves the same way a NEW SIRF unit would.

 

Actually, I am working to borrow one of my friend's older SIRF units for a while so I can see for sure if it's the "older/SIRF" that's the problem, or if my particular unit has maybe just been dropped a few too many times. ;-)

 

From what I've read on other forum posts concerning the differences between the two units, everyone tends to come to the conclusion that the chipset inside the 60CSx has no real effect on the model's offerings feature-wise. Although my particular experience proves otherwise (the SIRF unit appears inferior), I may be a special case.

 

Once I get my hands on another SIRF unit for side-by-side comparison, I'll update this thread.

 

THANKS AGAIN FOR EVERYONE'S HELP!!!

 

Matt

Link to comment

My GPS 76csx has the SIRFIII reciever in it ,it is about 5 years old,I checked this morning and I was getting an EPE of either +- 5m or +- 6m on metric ,when I switched to statute I was getting +-18' or +- 19', this was indoors sitting by a window and also recieving a WAAS signal.This is pretty much normal for my unit.The best I've ever seen is +- 4 m.I have software 3.70 and chipset firmware 3.00.I am not planning on loading 4.00. So thats a far cry from your 60csx.About 4 months ago I emailed Garmin about the 4.10 software on the newer units and they said that it would soon be available for general download.I'll probably pass on that one.I think if your unit said you were within 5' from a geo-cache and you were really that close then you were probably pretty lucky.I dont think geo-caching would be that much fun if we all had military /survey accuracy.You could walk right up and just bend down and pick it up.I usually stick to puzzle caches myself.I am sure newer GPS units will continue to get slightly better reception,I am sure its only a cost factor now.

Edited by Forkeye
Link to comment

I haven't seen many reports of issues, but the performance of my 60CSx seems to have degraded somewhat following the most recent firmware update.

That wouldn't suprise me,I am very leary of Garmins software upgrades now.You could always try reverting back to a previous version.

Link to comment
You mentioned that the OS was at release 4.0. What about the chipset software? Does it show 3.0s? If not, you need to upgrade.

How does one update the chipset software?

 

I'm running 2.90s. The Garmin site only shows updates for the Software, nothing for firmware. Where would I go to update that?

 

Nevermind...I learned that I need to use webupdater.

Edited by Skippermark
Link to comment

Hello,

 

I had a 60csx with Sirfstar chipset, but recently I acquired one with Mediatek chipset.

 

I am hunting for the software version 4.20 of 60csx, which is the latest one for units with Mediatek, although Garmin  does NOT make it available neither on its website, nor via email on request.

 

Can anybody here help me with it and can send 4.20 to me? Either just the .rgn file or together with the updater.exe file?

 

Thanks a lot,

Zoltan

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Followers 3
×
×
  • Create New...