Yet another post on cheap GPSs

[KCDW]

I know this forum has considered this subject ad nauseum. I have read most of the posts, and checked out many of the products. I need to come to a decision, and would like to test my “logic” with those who care to listen!

Selection criteria:

I don’t want to spend a lot.

I am a flying Luddite, who likes using his whiz wheel, map, and mark 2 eyeballs.

Sometimes the above “whiz wheel, map, and mark 2 eyeballs” don’t work as advertised. Usually when cockpit workload is high. It’s times like this when VOR triangulation loses its appeal, and a “cheap” GPS, which tells me where to go to my next waypoint, and how far away it is, would do a much better job.

Conclusion:

So the lack of usable funds and no requirement to use one as a primary navigation device, points me in the direction of a non-mapping / non-aviation database handheld. I say non-aviation database, as having one means you need to update it, and that costs money (£35 a month for the Garmin Pilot 3, I hear).

Options:

On this forum, I have read about 4 that might fit the bill:

1. Magellan 310. c$100.

2. Magellan 315. c$150. I can get this for $230 including data cable and Points of Interest Database.

3. Garmin Etrex. c$110. This goes up to c$250 for the data cable and World Map database.

4. Garmin 3 Plus GPS (ie non aviation model). c$300. Road Moving Map comes as standard – though not sure if UK is available.

Questions:

1. Are the respective non-aviation databases/maps worth the extra money? If not that would reduce the choice to the vanilla forms of options 1-3.
2. Any preferences from the list?
3. Any alternatives?

Yes, I know, huge post for someone quibbling over what is the equivalent price of an hour’s sortie… but hey, that’s the type of guy I am :D.

Any help would be mucho appreciated.

[QNH 1013]

Like you I can't see any point in spending more than you have to. I bought a Garmin GPS12XL having seen another group member using one. My reasons were:
I liked the shape and small compact size + good battery life.
The display was much clearer than the cheap Magellan ones then available.
I could (just) afford it.
I bought the XL version because at that time it had a lower battery drain than the non XL version; 24h c.f. 12h. The XL version also has a city database which frankly I have found absolutely useless for aviation (and possibly useless for anything else as well). The standard GPS12 now has the same 24h battery life as the GPS12XL.
I recommend just doing what I did, enter all your own waypoints. I just add them before a trip as I need them. I tend to put in VORs NDBs and airfields I need. Gradually the database builds up to something very useful.
You can get a cable to interface with a PC and enter the waypoints more efficiently, but I haven't bothered because I only enter a few each trip.

Answers to your questions:
1. No
2. No
3. GPS12

[Evo]

I've got a non-Pilot GPS-3, cost about £120 or so (with UK roadmap). Would be nice to have the HSI-like screen of the 3-Pilot, but in general i'm very happy with it. Personally I prefer a moving map over the most simple GPS displays - arrive at waypoint VFR-style, glance at GPS on kneeboard to confirm, that's it. I'm not using it to dodge airspace or anything else so I don't care that the map is non-aviation.

[flyingfemme]

KCDW - why the down on aviation databases? If you are using it as a VFR backup there is no need to update every month. Every six months would be fine and you have the security of all those waypoints always available inflight.
I use a GPS92 - it's small, light, uses batteries sparingly, can be used with yoke mount, portable antenna, aircraft power supply, PC link as required (or not if you are a true dino). The moving map is more of a diagram - but it is still pretty useful. There is one on Ebay this week at £120 (people moving up to pretty colour map models).......

[springers]

KCDW I agree with your thinking. I bought a basic Garmin GPS72 which works fine for my needs. It's not the most compact but it was the cheapest and it has PC connectivity, etc.

I fly low and slow and find the most useful feature to be the ground speed and true heading display (don't have DI in my a/c).

S

[Pianorak]

Flyingfemme - Have done a search on eBay but cannot find the GPS92, only a GPS95XL.
Could you perhaps points me in the right direction. Thanks

[IO540]

KCDW

Consider also the Bendix-King Skymap 2 (available from www.gps.co.uk among others) - this is arguably the best for strapping to one's leg which is the only available option for many self fly hire pilots.

It doesn't have a built-in aerial but you do NOT want one of those - the suction cup window-attached one is 100% reliable.

I've had this unit for 3 yrs and it's great. 4 hours battery life and no bugs that I ever found. I update the database once a year.

I have to say I am disappointed at the lack of tech progress in aviation GPSs - one could build in a much higher resolution screen for example. This leads one to a PDA-based solution, usually based on a Compaq IPAQ and there are a few of those about. But they aren't anywhere near as rugged.

[Kolibear]

KCDW,

I have a Magellan 310 and for my usage, its fine. You programme in your waypoint/landmark and it will tell you your groundspeed, heading, bearing, course correction, time to go and cross track error. It will take 99 waypoinnts but can only store one route at a time. It has no moving map display or any of the other features found on more sophisticated GPS's.

You use it like a VOR, it will keep you on course and you use your map & flight guide for all other information. It encourages you to map-read, but keeps you honest.

[flyingwysiwyg]

KCDW,

I have just bought a GPSIII pilot and can't fault it for what I want.
The reception is excellent on the internal aerial. (I have even had it on the passenger seat and just picked it up and glanced at it) It has a fairly accurate Jep Database (although it should not be 100% relied upon). It does give you controlled airspace warnings if you want them, but you can turn them off. The map is fine for checking position relative to your chart. The GOTO function is useful if you need to divert. Its extremely simple to use with very few button pushes required.

The only downside is its a bit more expensive than the units you have listed. If you're not too worried about the Jep Database then just update once a year. For the bit of extra cash you get an excellent middle of range GPS.

All in all, a great bit of kit.

Just my 2ps Worth.

FWyg

[Three Mile Final]

I am with WYSIWYG and agree with what he says.

I have had a GPS Pilot III for about 9 months. It is fine and very reliable for aviation features and I've used it in the UK, Tenerife and Crete without any trouble.

I don't like the rocking button for the cursor though, as it always sets off at 45 degress to the direction I want.

I am not sure that I would be happy without the "gross error" check that the mapping gives if I only had a GPS that said "Its over there"

It's most irritating factor is that the Non Aviation map (i.e the ground features, as opposed to the airfields, nav aids and airspace boundaries which I've found very accurate) is pretty rough and ready and AFAIK there isn't an update available.

I first got to use my Pilot III on a boat on the Thames last autumn and it consistently plotted me as about 1/4 mile away from the river. Last week I had it in the car while journeying to work From Guildford to Ashford on the M25 and M20 and the M20 is about a mile out of place near Maidstone .... it isn't even on the right side of the railway line !!!

IMHO that isn't too clever for the major line features you follow VFR.

However at £390 ish to give a good indication of where you are .... you can always insert your own accurate waypoints from the GPS guide or your own "on the ground" knowledge .... it is very good and does all the things I need as a backup source of navigation.

I haven't updated the database yet - since last October - after all I only buy a 1/4 and 1/2 mil chart once a year and reckon if I update the GPS 6 months after the charts come out I am OK and getting a cross check.

Anybody know how good the land database is on the Garmin 196 ??? Is it an improvement from an accuracy point of view ????

[KCDW]

All, thanks for the replies. Really helpful. Thoughts so far:

So tempted to stray from my budget and get a Pilot, but I can’t. The slight inaccuracies of the road database mention by 3MF is a bit of a put off as well.

Skymap – too expensive.

Flyingfemme – hear what you say, so now not put off by the database update factor, but it seems that most GPS with aviation databases put me out of my price range.

Evo has a good point of having a visual cue of a map (albeit a road map) by using the non Pilot verson of the GPS. Also would be useful in the car. I would go for this, but I can’t find one anywhere near 120 quid with UK roadmap. Any pointers?

Otherwise I think it is a choice between the vanilla Magellan 315 or 310, and the Garmin 12. The Garmin looks the business (if upside down – shouldn’t the keys be on the bottom?).

Anyway – keep the ideas coming – decision time is tomorrow.

[Evo]

Got mine from a Transair offer - end of line or something. Got the last one they had. I've seen them on eBay for similar. It's a GPS-III, not a -III+ for what it's worth.

One point - the roadmap is useless when you're driving, too little detail.

[Mike Cross]

I have a Magellan 315 and a Garmin 12XL

I use the 315 for preference, half as many batteries and they last longer. Also have a flexi mount for it which suckers on to the windscreen and puts it exactly where I want it.

12XL takes a remote antenna, 315 will not. Never had any loss of signal in the Luscombe so not a problem.

I have the DataSend Aviation and DataSend Europe CD's. They enable you to upload cities/towns/villages and ad's which is very useful and makes it dead easy to find your position on the chart relevant to ground features shown on the GPS. Cable will also supply power to the unit via cigarette lighter socket.

Capacity to hold plenty of routes and user waypoints, far more than I need.

Never any problem with it and can thoroughly recommend it.

Mike

[flyingfemme]

Fred R I pm'd you the address. No bidders yet.

[rotorcraig]

I was faced with pretty much the same selection criteria as you, and was tempted by the Garmin GPS12 having tried a friend's unit. No frills, but all I wanted was a good "second opinion" on my map, compass and eyework!

I actually ended up with a GPS76, actually wanted a GPS72 but not available in the UK then and couldn't wait! To me, these appear to be pretty similar in functionality to the GPS12 but with a better screen, both dimension and quality wise.

Haven't regretted it (but must admit being jealous of my GPS12 friend who has since upgraded to GPS196!!!)

RC

[Tocsin]

Three Mile Final,

About the 1/4 mile error... have you checked the map datum setting? On most GPSs there are separate settings for Grid (OSGB, UTM, etc.) and Map Datum (WGS 84, British Grid, etc.).

Both have to be set correctly to get an accurate match to map or real life.

(Apologies if I'm teaching you to suck eggs!)

[Dave Gittins]

Tocsin

Don't worry about me and eggs ....... we never stop learning.

It's on WGS 84, which AFAIK is what the instructions told me to use in the UK. It actually drifts about. The M20/M26 junction is spot on, but the M20 slowly moves away and near Maidstone has wondered about a mile and crossed the Railway ..... in respect to the crumb line.

Soooo ........ I think I have got it set OK it's just that the database isn't all it might be. Which I found pretty disappointing considering how accurate some are !!!

As far as the River goes. It had some points spot on .. others 1/2 mile away. The average was probably about 400 metres.

Big question (for when I've saved my pocket money) is a Garmin 196 database any better ?????????????

[IO540]

Three Mile Final

Do you know how old a design your Garmin is? It could be 10 years, though I would have expected Garmin to have updated their software since then...

I have a Skymap 2 which has always been dead on - but it has a suction cup aerial which avoids the marginal signal problem of a GPS with a built-in aerial.

When the data was moving about like that, how many satellites were you receiving and what was the signal quality on them?

The bit about roads showing slightly off is, I am convinced, crap map data from Jeppesen. They tend to get the aviation data right but roads and railways aren't as accurate. My GPS is within 10-30m horizontally and perhaps the same vertically (I live close to an OS triangulation point with a known altitude) but I can drive with it down the A23 or whatever and it shows me up to a mile off the road. I don't think Jepp give a **** about this sort of thing though.

[Mike Cross]

FWIW representing maps on a screen is a bit of an odd science.

You might think that it is a simple matter of drawing a map and scanning it in. However this uses up a lot of memory.

The map is therefore simplified by using standardised symbols and using vector graphics, which draw lines on the screen.

Also a lot of the info has to be able to rotate. If you turn an OS map upside down all the place names are upside down, as are all of the symbols. Most GPS's will rotate a lot of the data so if you are heading South everything's still the right way up.

This results in an approximation rather than an accurate map. I live in Portsmouth and Microsoft Autoroute has me driving in the middle of the harbour when in fact I'm going along the M275!

For these reasons reliance on the GPS map for close-quarters navigation is not sensible.

Mike

[Tocsin]

3MF/Dave,

Mike Cross probably has it right - if you're using the in-built mapping it will be "slightly" inaccurate for ground features, and will probably be using WGS 84 internally.

If you want to check out the accuracy of the GPS (and not the in-built mapping!), use a real map (1:50000 Landranger or 1:25000 better), set the format to British Grid and datum to OS GB. Plot your position on the map, see how close to real life it is, then alter the datum and see how much it differs!

If using maps for flight planning/VFR navigation aided by GPS, then correct datum is important - real maps should have the datum used in the legend, electronic ones should specify somewhere!

[KCDW]

and the decision was....

the Magellan 310. I trotted down to J&R in lower Manhattan, and paid $108 for it after tax.

Initial impressions: does what it says on the tin. Had to walk over to East River to get an initial satellite fix, but after that, it's been working in NYC very nicely.

It will be used for real when I go on a long cross country next weekend to Gettysburg. That's a distance of.. let me see now... 152 NM from KCDW acording to my route :), which took about 5 mins to code the 5 waypoints into it.

I will be happy to report back on the outcome.

Thanks all for helping me with this

KCDW

[Three Mile Final]

No doubt there are things that I don't understand well enough about how the database works, that define some of the problems and which Datum is which, which could affect it. The software is V2.12, the land database V2.0 and the last update was Nov 2002 - so I think it's as current as it reasonably can be - due for an aviation update soon (CAA chart + 6 mnths = August).

I flew over Portsmouth this morning, (Fairoaks - Sandown and back) and whilst the ground features are not spot on (and I am sure the comment about Jeppesen's interest in this is pretty accurate and the main reason for what I observe) for a less than £400 piece of kit, it is good enough for secondary naviational use and (what I used it for this morning - in conjunction with a map and a calculated VFR plan) accurate track keeping whilst dodging round the showers and in and out of bits of low clag. It also agreed with the aeroplanes VOR/DME kit as to where MID was and EGHN was totally accurate, my landing and take-off were straight down the little line of the symbol.

Interestingly the A3M / M27 junction wasn't too accurately represented - by 1/2 mile or so) and I put an extra waypoint in for Ryde from the Pooley's GPS companion which missed the "Ryde" in the Jepp database by about 0.4 mile and the "Pooley's" Ryde brought me nearer the pier than the Jepp one.

All in all my view is that it is just inaccuracies in the land database as it is not uniformly out of kilter and the EPE doesn't affect it much with varying satelite coverage either.

Jeppeson/Garmin ....... 8/10 - could try harder.