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Waas/egnos Reception Observations & Question


CbusRog
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I’m aware that the system is not yet fully operational, but I’m curious about some observations I made over the last couple of weeks with a Garmin GPSMAP 60C, 60CS and a 60CSx (only the CSx is mine :laughing: ). From my location (central Ohio), the order of visibility is 51, 48,35 & 33.

 

The 60C and 60CS lock onto 51 and 48 with no problem. When I shield the two units from the southwest sky (51, 48,35), and expose them to the low southeast horizon, they lock onto 33; as I expect they should.

 

The 60CSx on the other hand, won’t even flash a bar for 51 or 48. It doesn’t even see them. It will occasionally, briefly show 35, but never locks on. It’ll always capture 33 when it has a clear view.

 

I’ve read that some of these satellites broadcast a flag that essentially says, “Don’t use me”. I’ve also read some GPSr units honor this flag, and some don’t. The ones that honor the flag will ignore the satellites, while those GPSr unit that don’t honor the flag will attempt to download the almanac.

 

I’m wondering if the SiRFstarIII/firmware in the CSx possibly explains this. It’s no big deal (until October or November maybe). I'm just wondering anyone else has experienced anything similar. My research continues, but I thought I’d ask here too.

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I've noticed the exact same thing here in southern wisconsin, my legendC sees 51, 48,35 & 33. my 60cx will only ever see 35 for a short period(10 sec) then drop it, also when the 60cx sees 35 it's shown in the old location in the south east.

Even though I never get WAAS signal with the 60cx I have had the claimed accuracy down to 9ft out in the open. I'm pretty happy with it but it would be nice to get WAAS corrections.

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One thing I still haven't been able to convince my friends of yet is to do a hard reset of their C and CS units to download the latest almanacs. They're convinced that they're receiving "valid" WAAS data, when in fact they may not - even though they show accuracies of 6 - 7 feet. I understand that WAAS is pretty much an FAA project, not meant for ground units, much less handhelds, but I'll take every little bit I can get.

 

I'd still like to hear about other folks' experience though.

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I had a week with it in minneapolis (#35) in the SW, on my 60cx. When I was in california, it read sat 47 almanac, then 35 showed up in the sw. I got solid bars on 35 and 47, with 'D's on all the others, but when I got back home it was in the SE, hollow bar. I'm pretty confident in the fall when the go online with the new system my cx will be fine. FWIW, I still get insanely low EPE's, my best (in the open) being 7 foot. I average 12-20 foot under light-medium cover, where I'm not so sure I'd get waas.

Edited by drbugs
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I had a week with it in minneapolis (#35) in the SW, on my 60cx. When I was in california, it read sat 47 almanac, then 35 showed up in the sw. I got solid bars on 35 and 47, with 'D's on all the others, but when I got back home it was in the SE, hollow bar. I'm pretty confident in the fall when the go online with the new system my cx will be fine. FWIW, I still get insanely low EPE's, my best (in the open) being 7 foot. I average 12-20 foot under light-medium cover, where I'm not so sure I'd get waas.

 

This morning my 60cx was showing a 9' EPE. It was standing up near the front window of my pickup. With the antenna connected it usually shows 7' on bright clear days. And, by comparing to a known benchmark, the EPE pretty closely corresponds to actual accuracy.

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I had a week with it in minneapolis (#35) in the SW, on my 60cx. When I was in california, it read sat 47 almanac, then 35 showed up in the sw. I got solid bars on 35 and 47, with 'D's on all the others, but when I got back home it was in the SE, hollow bar. I'm pretty confident in the fall when the go online with the new system my cx will be fine. FWIW, I still get insanely low EPE's, my best (in the open) being 7 foot. I average 12-20 foot under light-medium cover, where I'm not so sure I'd get waas.

 

same as you I have a feeling this issue will fix itself this fall.... well I hope so.

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I’m aware that the system is not yet fully operational, but I’m curious about some observations I made over the last couple of weeks with a Garmin GPSMAP 60C, 60CS and a 60CSx (only the CSx is mine :laughing: ). From my location (central Ohio), the order of visibility is 51, 48,35 & 33.

 

The 60C and 60CS lock onto 51 and 48 with no problem. When I shield the two units from the southwest sky (51, 48,35), and expose them to the low southeast horizon, they lock onto 33; as I expect they should.

 

The 60CSx on the other hand, won’t even flash a bar for 51 or 48. It doesn’t even see them. It will occasionally, briefly show 35, but never locks on. It’ll always capture 33 when it has a clear view.

 

I’ve read that some of these satellites broadcast a flag that essentially says, “Don’t use me”. I’ve also read some GPSr units honor this flag, and some don’t. The ones that honor the flag will ignore the satellites, while those GPSr unit that don’t honor the flag will attempt to download the almanac.

 

I’m wondering if the SiRFstarIII/firmware in the CSx possibly explains this. It’s no big deal (until October or November maybe). I'm just wondering anyone else has experienced anything similar. My research continues, but I thought I’d ask here too.

 

There is a free software called Trimble Planning. You can find it at

 

http://trimble.com/planningsoftware_ts.asp

 

This software tells you everything you want to know about the GPS satellites in your location. In real time,

you can find out what satellitess are over head, and you can even plan ahead and choose a future date or location.. This is a cool program..

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Please see one of the other dozen threads talking about this subject in detail.

 

Red, those threads are scattered all over, and I'd rather not have to do a search and comb through them to get the latest. They're enough electrons to go around, and you can just skip topics you don't want to see.

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Great! I wasn't trying to start a WAAS war. Let alone spin-off threads. All I was asking is if the SiRFIII might explain why I couldn't get 48 and 51 on a CSx, yet my C and CS could. On another thread, Garmin and others even responded that the system isn't fully operational yet. That's good enough for me until October.

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48 and 51 are in test mode.

 

I figured as much. I was wondering why my C & CS units can pick up 48 and 51, yet my CSx can not (SiRFIII?). Where can I find current WAAS status? Google doesn't seem to be of much help (2+ year old documents and no real-time data). From where did you get your information that 48 and 51 are in test mode?

Edited by CbusRog
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