GPS advice please

[offrd]

I need to buy a GPS unit to plot the exact location of each install for the providers i install rural broadband for...

Now this GPS thing is new to me and i dont want to spash on something that wont do what i want it to...

The unit needs to give me my location with i believe a 7 digit readout, even the guy at BCL was a bit unsure.... So they must have different plotting??

It needs to have a goto function so i can add the gps location of wireless sites so when in the rain and fog installing customer units it can tell me the direction of the transmitter i need to align to.

Perhaps mapping functions like a navman so it can get so lost even i cant find me!

and if it was suitable for using on adventure rides then it would be great!

etrex, navman, uniden...

I have no idea, so many on the market!:argh:

Cheers:2thumbsup

Duncan

[JATZ]

Personly I use a garmin 75cx, the csx would be a better option as it can take an sd card however the cx does what you have described.

Hope you've got plenty of time, asking gps stuff 'round her is like asking which tyres are best:argue:

[Nordy]

I have a Garmin GPSMap 60Cx which can do all you ask for.

[offrd]

How do they compare to a Garmin eTrex Vista GPS ??

[dhunt]

The unit needs to give me my location with i believe a 7 digit readout, even the guy at BCL was a bit unsure.... So they must have different plotting??

It needs to have a goto function so i can add the gps location of wireless sites so when in the rain and fog installing customer units it can tell me the direction of the transmitter i need to align to.

GPS position will be like -39.XXXXX,174.XXXXX.

We have used the Garmin nuvi series GPS's which in fleet management mode at least can be told to go to a particular GPS location. I would presume in normal mode they can still do this but can't say for sure.

[mowgli]

If you want to aim antenae you'll still need a wet compass and local magnetic deviation with most GPS units. Most of them point relative to your current direction of travel. If you're perched on a roof top then you ain't moving. The GPS pointer will be meaningless. Azimuth, range and (on some units) elevation should be pretty accurate though.

[offrd]

If you want to aim antenae you'll still need a wet compass and local magnetic deviation with most GPS units. Most of them point relative to your current direction of travel. If you're perched on a roof top then you ain't moving. The GPS pointer will be meaningless. Azimuth, range and (on some units) elevation should be pretty accurate though.

Ok... So i need to walk around the property to get the gps to read and take a visual reference, eg a tree, to use to aim the aerial. That could work?

[mowgli]

Ok... So i need to walk around the property to get the gps to read and take a visual reference, eg a tree, to use to aim the aerial. That could work?
Yup, that would do it. You'd be better walking in a straight line though.

[Nordy]

the 60CSx has a real compass rather than a gps compass that might work better?

[Pogo2]

and require some movement initially so that they can align themselves. If you go to the spot turn them on and wait for the location you will get a lat/long but the orientation might not be correct right away. Move a few metres in any direction and the direction indication will sort itself out. Then their pretty accurate. Some models take a bit of time to initialise (ie find themselves) can be 30 sec to a couple of minutes. Depends on where you are and how far you are from when you last turn it on as it wil look for satellites where it last found them. (Hope that makes sense)

I have a Garmin for aviation use and will always start it up a few minutes before I need to rely on it. Like the idea that Mowgli had of using a compass to quicky ascertain the direction you are pointing. Cheap and easy.

[cooneyr]

If you are going to be using one in fog or poor reception areas then you really want a H version etrex or GPSmap cause they have better GPS receivers.

The vista and the CSx gpsmap (S is the bit in the name that means it has a compass) units have magnetic compasses built in. They also have barometers built in.

All units will show and record to 7 sig fig but the accuracy is more affected by satellite reception quality than the 7 figs. 5m accuracy is equal to .005 minutes and the 5 is the 7th digit so no point in having more than 7 fig.

Pretty much all units will do goto but the mapping units will allow you to choose as the crow files or follow roads if you have the free NZ auto routing map.

Cheers R

[upshift]

Agree with all cooneyr's comments.

Couple of other things to consider are batteries and need to be rainproof. A handheld unit with high sensitivity, mapping function, normal dry cell powered (such as a couple of AA batts rather than some inbuilt lithium), electronic compass, and goto function is your best bet. There are free auto routing road maps available for Garmin units but (as far as I know) none for the other brands. Full set of NZ topo maps for Garmin around $160.

Hence a choice of a Garmin Vista HCx, 60CSx, 76Csx, or Colorado 300. Colorado 300 is the most expensive, best price I know is around $720 but quite a bit ahead of the others if you are also looking at using it for navigation simply because of the bigger screen and option of "navigation mode" display. Pic below shows both a 60CSx and Colorado with the same mapset, the free ones! Vista HCx is the cheapest but still a great unit, if $$$ is a factor then get that and you will not be disappointed.

Once you calibrate the electronic compass, fairly easy but need to do it every time you change the batteries, you can simply turn the unit on and get a heading without the need to move around. It works on the earths magnetic field just like a regular compass. You can choose between GPS compass (requires movement of the unit) or electronic compass. Mine is set to GPS compass but will auto switch to electronic if speed is below 10Km/h, hence walking or standing still speed.

100150

[upshift]

Screenshot of compass on Colorado showing heading to a waypoint.
100151

[offrd]

Thanks for the advice guys, just have to decide what Garmin to get..

:argh:

[yamafitter]

If you are going to be using the GPS to scout out new trails you definitely want to get a Garmin with mapping features. Being as old as I am I also like to have a large screen so I can see at a glance what it is I am doing. That is way for the last number of years I have used a Garmin 276C though the new Zumo 550 works very well (specifically designed for bikes). I help lay out events here in Ontario Canada and would be lost without my Garmin.

[offrd]

Thanks,

I just ordered a garmin vista HCX and included bar mount, car mount and car charger!

[cooneyr]

Thanks,

I just ordered a garmin vista HCX and included bar mount, car mount and car charger!

Oh umm - the bar mount and the etrex don't really work on motorbikes. The power connectors onto the main circuit board are sprung fingers (I hope this makes sense) and they can often part ways (the fingers and the main board) i.e. loose contact when bumpy. This means the unit shuts down which is a pain in the arse if you don't notice it and restart it.

The ram mounts work a treat as does my home made special for damping out the bumps which eliminates this problem. In saying this give the bar mount ago but just don't rely on it being on if you use the bar mount.

Cheers R

[offrd]

Oh umm - the bar mount and the etrex don't really work on motorbikes. The power connectors onto the main circuit board are sprung fingers (I hope this makes sense) and they can often part ways (the fingers and the main board) i.e. loose contact when bumpy. This means the unit shuts down which is a pain in the arse if you don't notice it and restart it.

The ram mounts work a treat as does my home made special for damping out the bumps which eliminates this problem. In saying this give the bar mount ago but just don't rely on it being on if you use the bar mount.

Cheers R

Oh crap..... Well it can sit in the clear map section on my tank bag then! :doh:

and what is this ram mount and your special home made mount?????

One last thing to sort.....

easting / northing and NZMG....

Just my luck it it wont do that....

and how to convert a location on google into northing/easting

[Transalper]

and what is this ram mount and your special home made mount?????
Ram Soultions NZ guy... Click me (http://www.ramsolutions.co.nz/webapps/site/62807/64745/shopping/custom/shopping-ram.html?find_groupid=6602).
By the time you get all the bits it's not the cheapest of things but it is versatile and works for me. Infact i went and made a second purchase so now have enough RAM bits to mount my roll chart box and gps at the same time.

[NordieBoy]

Oh umm - the bar mount and the etrex don't really work on motorbikes. The power connectors onto the main circuit board are sprung fingers (I hope this makes sense) and they can often part ways (the fingers and the main board) i.e. loose contact when bumpy. This means the unit shuts down which is a pain in the arse if you don't notice it and restart it.

Vasaline is your friend...

[offrd]

Vasaline is your friend...

SLAP :dodge:

[cooneyr]

Oh crap..... Well it can sit in the clear map section on my tank bag then! :doh:

and what is this ram mount and your special home made mount?????

One last thing to sort.....

easting / northing and NZMG....

Just my luck it it wont do that....

and how to convert a location on google into northing/easting

Home made mount is a little close to the "real deal" but lets just say it
involves some alloy tube split lengthways, some alloy flat, some bolts and tap washers like these :D
<a target="_blank"><img src="http://www.choiceful.com/prod_image/59676_m.jpg" border="0"></a>

The unit will do lat long, NZMG and a whole host of other co-ord systems that are for far flung countries. In saying this pretty much everything on the web is typically done in lat long - I don't think NZMG will work with Google earth. Unfortunately co-ord systems are generally hard to change between. Apparently NZMG is a twelve term function or something ????


Vasaline is your friend...

If you can get it apart in such a way that you can get it back together again which apparently is not impossible but not something I want to try. The terminals of concern are buried somewhere inside.

Cheers R

[upshift]

Oh umm - the bar mount and the etrex don't really work on motorbikes. The power connectors onto the main circuit board are sprung fingers (I hope this makes sense) and they can often part ways (the fingers and the main board) i.e. loose contact when bumpy. This means the unit shuts down which is a pain in the arse if you don't notice it and restart it.

The ram mounts work a treat as does my home made special for damping out the bumps which eliminates this problem. In saying this give the bar mount ago but just don't rely on it being on if you use the bar mount.

Cheers R

Commonly called Vibration Induced Shutdown. Additionally there is a small spark across the contacts everytime they seperate which will give rise to a resistive oxide on the contacts which makes this even worse. My first GPS had problems on the very first day I had it on the bike and then continued to have intermittent shutdown problems permanently, even off the bike. Eventually fixed by cleaning all contacts (internally to the cct board plus within battery compartment) with iso-propyl.

RAM mount is needed. Possibly also di-electric grease on the circuit board contacts as well. It is possible to solder the spring contacts to the board but of course I'm not recommending that. You can alternatively power it from the bike 12v supply with appropriate voltage regulation but still need to watch all the contacts in the power supply path. e.g. blade fuse instead of a spring held one, di-electric grease on all contacts.

You can convert co-ordinates here
http://www.linz.govt.nz/apps/coordinateconversions/index.html
but may cause you even more confusion initially, as well as different projections and datums there are decimal minutes or decimal degrees etc.

WGS84 is the reference system that is used by GPS receivers. This is essentially the same as New Zealand Geodetic Datum 2000 (NZGD2000) which is the official datum for NZ and off shore islands. No conversion is necessary between the two. You can convert from NZMG at the above link.

[NordieBoy]

RAM mount is needed.
Not really.
The RAM is only one way of doing it.

Proper preparation with di-electric grease (vasaline) helps.
Vasaline is clear, non-staining and thick.
It helps by damping the movement of the batteries as well.

[upshift]

Finally found the link I was looking for last night on this subject so will put it here for future reference. Explains the problem and how to avoid it plus some specifics for Garmin 60 series and etrex models.

http://www.cycoactive.com/gps/gps_batteries.html

Not an issue for those with Zumo's of course {is there a smilie for envy?}