WAAS on GPS V but not iQue

[Dave'sNotHere]

I know WAAS problems have been discussed here before and the common wisdom is that the satellites are difficult to pick up since they are too near the horizon.

I just tried a side by side comparison with my GPS V and I was surprised to find that the V picked up a strong signal (75% on the signal strength bar) from satellite 47. Although other satellites were of similar strength on the iQue, 47 is nowhere to be found. It doesn't even register on the compass display, although it occasionally shows on the list at the bottom but with no signal.

And yes, WAAS is enabled in GPS preferences.

I called Garmin and the CS person said he had never heard of this problem. I wonder if the problem is common but we are all just assuming the signal is turned off or the satellite is not visible. Anyone?

Thanks.

--Dave

[jonasolof]

Give it an hour

[Curious Cat]

To elaborate on what Jonas said. See if this thread has anything to do with your situation:

Click Here (http://www.pdastreet.com/forums//showthread.php?s=&threadid=31389)

[alexcue]

Making alot of assumptions here, but have you had a chance to lock on to the 2 WAAS satellites yet?

If not follow the advice above, go to an empty field or lot where there are no obstrutions (as few as possible anyway) on the southern horizon. and leave it alone. Once they collect the almanac for the WAAS, (30 minutes plus) then you'll have an easier time getting them, as they don't have to cycle thru all the available slots.

I don't think it's fair to compare the GPS V and the iQue. In my opinion the GPS V has a better stock antenna, however if you fit the iQue with an external antenna, which many of us have, the acquisition of the WAAS and normal GPS sats is quite abit easier and quicker. YMMV

PS. for $20 you can pick up a great external antenna from gpsgeek.com (no i don't work for them, but you can spend alot more and probably just waste your money for the same if not better quality.)

[jonasolof]

For initial acquisition of the WAAS almanac it is a very good idea to use an amplified external antenna like the Gilsson mentioned.

BTW, the GPS V antenna is a passive quadrifilar antenna, same as in Garmin 176 I think. Not super per se. Lot's of complaints about the 176 also for reception.

[Dave'sNotHere]

Thanks for the responses so far. Here's a little more data for you, and then I'll probably go buy an external antenna.

I just set the iQue up with a clear sky view for about 3 hours. I set the GPS V along side it. The iQue had similar readings to the GPS V on most satellites, including number 29 which is very near to WAAS satellite 47 in the sky.

The GPS V had a solid signal from satellite 47. However, there was no indication in the iQue of any signal whatsoever from 47. Not even a temporary tiny fraction of a bar of signal strength as it cycled through that number.

BTW, I had also gone through the reset procedure that made the iQue rebuild its satellite list from scratch.

I'll give up for now and get an external antenna after which I'll report the results. Thanks for the money saving suggestion, alexcue.

Thanks all.

--Dave

[jonasolof]

Have you enabled WAAS? Options GPS screen. Battery saving off.

[Pekkle]

And yes, WAAS is enabled in GPS preferences

I believe he stated that he has it enabled..

Dave, I am with you all the way.. Since day one I have mentioned about the WASS issue compared to a GPS V. and tried all the suggestion but no help. However with or without WAAS the naviagation seems fine so I just let it go without doing any RMA.. but yes, WASS is enabled and Battery save is off, and hardware reset none helped..

also from R1 to R2 seems make no difference..I think some units just won't get WAAS period.

[alexcue]

just a thought... guys who are much smarter than me, can there be interference between GPS units? Is it a real good idea to put them side by side or should there be some gap between them. Hey, I don't know I'm just trying to help the guy out...


In the end you might be better off sending it back for the problem.

[alexcue]

Originally posted by jonasolof
For initial acquisition of the WAAS almanac it is a very good idea to use an amplified external antenna like the Gilsson mentioned.

BTW, the GPS V antenna is a passive quadrifilar antenna, same as in Garmin 176 I think. Not super per se. Lot's of complaints about the 176 also for reception.

Jonas, I'm no expert like some of you guys, but my seat of the pants approach, tells me that my GPS V acquires a signal much better than the stock iQue does.

Once i put the external antenna on it all bets are off 'cause the iQue gets acquistion in a matter of seconds, even during a cold start it is less than a couple of minutes in bad conditions (foliage, etc). Getting WAAS to work with the stock antenna is a pain while in my Tundra, but it will eventually get it. No such problems with the Gilsson.

OT: Jonas, what handheld GPS (has a good antenna) would you recommend for hiking in the woods and such?

[apersson850]

Try Jonas' patent: Place the iQue on a frying pan, turned upside-down, when attempting to get the WAAS signal.
If you care about your reputation, put it on the car roof or hood. Anything with steel under the antenna will help reception.

I've never seen any Egnos signal (European counterpart to WAAS) with the internal antenna, before trying the frying pan. I do see it a lot with an external antenna, which also has the advantage of sitting on the car roof.

Good handheld GPS (receptionwise) for hiking: Garmin 76 series or Magellan Meridian.
Since you already have a Garmin, I recommend a GPSMAP 76. Then these units can share maps.

[alexcue]

Thanks Anders, recommendation appreciated!

[Holgado]

Having been a long time user of Garmin GPSmap76, which is a very good GPS unit, you will have some problems getting sats in tree covered places, except with an external antenna.

HOLGADO

[jonasolof]

I agree with Anders. And on www.gpsinformation.net you can see comparisons beteen magellan sportrak and garmin 76. Sportrak and Meridian are the same in this respect. (Only meridian color has an external antenna connector, don't know abt G76).

I'd say the G76 is a very good choice for the reasons given by Anders. A good hiking gps receiver is nice to have. My total posts re sportrqak is abt 6, which is 1 % of number for the iQue, which tells a story of nice, uncomplicated sevice.

Re the iQue internal antenna: There is something severely wrong at least with some of them. I bet they mounted the patch antenna upside down inside the flap! It is weird that adding that frying pan or voilvo roof should do such a big difference. Antenna and radio professional Robertp366 noted the same thing but he has gone silent on the topic since then which I take as a sign that he's up to something (That's why I claimed a patent for the use of the properties of a frying pan :p

When I get my Wi-Sys 3964, I'll try it right on top of the garmin flap.

http://www.wi-sys.com/products/antennas/3954.php

The 64 is the model that includes a ground plane. I got a mail from the european rep of wi-sys today, broadband.uk.com and they confirm that both antennas have a ground plane but that the one which is large and circular makes the patch antenna perform better. Note the current consumprion, 2 mA!

(Note that this antenna is for OEM and is totally nude, it needs some cover. Price 30 USD.)

Jonas

Uhu, somebody is dragging me out of this hole. I hear a voice saying : Your wife brings her regards. You are leaving for Christmas vacation in a day and need to do some packing. I want to negotiate. No sir, but you need a shave, come on here... :mad:

By the way, as an old ear-nose-and throat doctor, I can confess that I never really liked looking at peoples' tonsils. Why doesn't Amnesty international think of that army medic and the situation he was exposed to?

[alexcue]

Thanks guys for the info on the 76, and apologies to the original poster for hijacking his thread. But darn if these guys aren't good!:D

[placido]

I am curious about the frying pan experiement to boost sat reception. Will I get the same effect if I replace the metal plate that comes with the sucsion cup antenna mount with a larger one? Is there an optimal size to get the best sat reception ?
:)

[apersson850]

I don't know for sure, but my stomach tells me a couple of times bigger than the antenna itself. Then the effect of increasing the ground plane will probably decline.

[jonasolof]

Things I know I don't know:

What happens if you unscrew the magnetic footplate? Does it also serve as a ground plane?

What is the optimal (tuning, design) size of a groundplane for the Gilsson antenna? I asked but did not get a reply.

What is the effect of using ferrous metal for the ground plane? Seems to be better, but no systematic analysis to date.

What happens to multipath, reception lobe, antenna frequency tuning, left hand circular polarization signal mitigation (ie reflected signals) as you increase the size of the ground plane?

All these are very complex questions. Couldn't find enough info on the internet or by calling companies (in Sweden). I have to read up so a professor of antenna technology will bear with my questions for a while. Need to find a good tech library for that first. Didn't have the time yet. For anybody that is seriously interetsted I can give some links for articles (best by private message).

I hope that the forthcoming antenna test by Sam Storm van Leuve will shed some light. I provide the antennas. Hopefully we'll be able to add some diffrent ground plane sizes to see what that does. Testing takes time though, and I don't know how much time he'll be able to devote to this.

The reason for doing this is that the iQue functions very well with a well designed external antenna - and is the second worst gps I had with its provided flap antenna. I have five other GPS receivers that are much better.

The short answer is: The design ground palne is about 70-100 mm in square. Above 200 you get other unwanted effects - detuning, loss of polarizatiion sensitivity etc.

Jonas

[OneShot]

Originally posted by placido
I am curious about the frying pan experiement to boost sat reception. Will I get the same effect if I replace the metal plate that comes with the sucsion cup antenna mount with a larger one? Is there an optimal size to get the best sat reception ?
:)

It does not have to be much bigger than the antenna. Gilsson redesigned their suction cup mount to take advantage of this effect Look Here (http://store.yahoo.com/gilsson/gaiq36gpspda.html) .

[apersson850]

Even if the link you refer to doesn't say that it would have been even better, had the bracket been twice as big, it doesn't say the opposite either.

[placido]

I think Ander is right. The reception will improve if it is about twice the antenna. I try a very INFORMAL experiement to-day. I was outside of my garage in my car. I attach the antenna to each of the following surfaces and look at the sat signal strength 1)the suction cup metal plate mount, 2) a 5 inch diameter, 3) 7.5-inch diameter and 4) a 10-inch diameter metal surface. The circumferential metal surfaces that I attach the antenna to are simply lids from several cokie tins. I assume that they are some kind of ferrous material since the magnet on the antenna sticks to it.

The result of this informal experiment shows that the 5-inch diameter consistently gives better singal strength than others. The signal strength for the 7.5-inch and the 10-inch diameter surfaces are not as good as the 5-inch surface. The 7.5-inche and the 10-inch diameter metal surfaces seem to be a little better than the original suction cup metal plate mount.

As I said this is a very informal test. I dont know what kind of metal compound this cokie tin lids are made of. The amount of ferrous material may also influence the result.

I would be great if someone can do a better experiment than the one that I did.

[apersson850]

Did anybody watch you while doing these experiments?:D

[jonasolof]

Placido

Good experiment and it corroborates what is said in the litterature that a groundplane of abt 100 mm is optimal. That would by the way be the size of a patch antenna where air was used instead of ceramics as insulation between the two surfaces of the patch, not that I know if that matters.

However, you will always get reflected signals that influence reception. Sometimes reflections will be in phase and increase the heigt of signal bars, more often they will be out of phase and decrease them. If you have a prticularly strong signal, see where the sat is and check whether there is a surface that might refelct the signal, Then wait 15 minutes. As the sat continues in its orbit, the angle of reflection will change and what was in phase will be out of phase. I saw quick variations from nil to over the top line in sat screen signal strength scale in about 30 minutes from a sat which was clearly visible at 45 degrees elevation all the time.

Because of this, a test for diffrent ground planes would better be made with equipment that can sort out reflected signals or in an environment that hsa very few multipath signals. Dry sand is said to give very little reflections, especially if the surface is irregular. Flat water a lot.

So go to the beach or a golf course bunker, make a shallow hole where the antenna can't see any nearby reflecting surfaces and check amplification overr time. If you have children, you can pretend you're playing with them :) Or say you lost your ball in the bunker :D

Aren't they just commemorating those guys playing on the beach at Kitty Hawk in 1903?

Nothing like real tests for performance. More of that!

Cheers

Jonas