Help needed fitting GPS antenna

[zedmeister]

Hi all,

I have just received my APS 30 - BE4715 and I want to fit it into my CLK320 W208 coupe tomorrow hopefully. The fitting should be straight forward I hope but I wanted some advice on how to fit the antenna to the underneath of the dash. Do I need to remove anything like the vents or can it be done from the stereo hole? Does it matter which way the antenna is facing? Is there a top or bottom that needs to face the satellites? Can I just stick some velcro to it and reach in and stick the thing to the top of the inside of the dash?

Help please! Thanks.

 

[andy_k]

I found that I got better satellite reception with the GPS aerial mounted behind the radiator grille - when mounted inside the car there too much metal and glass getting in the way of good satellite signals.

HTH

Andy

 

[zedmeister]

I think I just want an easy install - will putting it under the dash be the easiest place? Anyone, help please!

 

[marnix]

You need to receive at least 3 satelites for correct positioning.
The best way to check is to install the system without sticking the aerial. Just position it somewhere and go for a test drive. Once you have a good reception, leave it there. Do not just try while parked next to high buildings or overhead cables as they may interfere with reception..
Also it will not work as soon as you install it, it needs a good 10 minutes drive around for the unit to calibrate itself.
Did you receive the manual?

 

[jberks]

I have mine stuck to the top of the dash, at the edge of the speaker at the bottom edge of the windscreen. Basically it should have line of sight straight up. The more metal shielding it, the worse the reception - hence why MB put them outside on the back window. (not sure why these aren't readily available!?).
So, in the middle of the dash underneath should be ok, as the dash is rubber, provided you are far enough forward to avoid being shielded by the roof and the windscreen isn't heat reflective.

Not sure if you are aquainted with gps but if not, as Marnix says, it can take 10 mins+ to get its bearings and buildings etc can stop it. Once its got a fix, it becomes a little more tolerant, and as its powered up most of the time, this will generally be a one off activity. So, give it a good 20 mins in situ whilst driving around before you assume its not working.

 

[zedmeister]

Thanks guys. I have now installed it and it is up and running! I ended up putting it on top of the dash on the passenger side near the edge of the windscreen. Not sure if its the best location but it picked up 4 sats in my drive with one side obscured by the house so I guess its okay. Will that location cause any problems (signalwise) while driving, being in the corner of the windscreen? Normally shops, houses, etc on the passenger side as you are driving. I have a Navman as well so I was used to the inital setup time though it did taker longer than I thought (about 20 mins). Becker, BTW, suggest you do not move the vehicle while it is setting itself up initially.

Marnix - haven't received the manual yet, but thanks in advance for posting it to me! Can you give me some pointers on setting the thing up? Found a menu to set it up after pressing button 2 and 7 - what options do I need to set? When I went into the manual input for setup it asked whether its a car or a vito, so entered car then it asks tyre size so entered that. There was another option for entering offset and angle but I don't know what to enter for a W208 CLK - any help? Both are currently at "0". Haven't taken it for a drive yet. Works nicely with the CD changer and multifunction steering wheel controls (audio only). I guess I will need to get it programmed for the navigation on the dash - is that expensive?

 

[The Editor]

You need to receive at least 3 satelites for correct positioning.

Correction - you need FOUR satellites for an accurate fix..... The GPS system will triangulate on three sats but needs a fourth sat for 3d data to give altitude as well (this will greatly increase accuracy). Nearly all modern GPS units are 12 channel and should lock onto at least fours sats faily quickly (dependant on whether it's a warm start or full cold start)

For reliable sat lock the antenna should have a clear unobstructed view of the sky. It DOES matter which way up you orientate it and if you put your antenna under the dashboard it won't be able to see as many sats as it should (if any) and you will get unreliable lock and fix.

The two best places would be on top of the dashboard in the middle almost touching the glass or on the rear parcel shelf again almost touching the glass. Check out where manufacturers site their antennas - They do it for a reason.

GPS reception can be interupted VERY easily and the link is fragile. Unless you have inertia sensors within your unit you can even lose sat lock going through a tunnel.

Hope this helps

The Ed

 

[marnix]

Don't bother with offset and angle as the unit is fitted horizontally.
I had a CLK230 before the SLK and the MB garage programmed it for free while servicing the car. Depends how friendly your dealer is.
When installing the system in my CLK (Year 2000) I had to retrieve the speed signal from the passenger footwell as it was not connected to the ISO connector.
Hopefully Merc has got it's wiring sorted out on later models.
The positioning of the aerial should be OK (if you don't mind it sitting there) as once it picks up the sats signals it never seems to loose them.
Posted the manual on Wednesday second class, soo hopefully it should be with you tomorrow.

 

[marnix]

To the editor.
Picky aren't you (3 or 4)
Why does MB sell GPS aerials Part Number A203 820 09 75
that are specially designed for fitting under the dash then.
I have these fitted to both my Mercs, TVR Cerbera and Passat with great reception on all systems.

 

[The Editor]

Hi Marnix,

No you MUST have 4 sats to give you a 3 dimensional fix. It's impossible to get 3d data with just 3 sats as that will only be in 2 dimensions (your accuracy will be off). You will find that with 2 or three sats you accuracy will be circa 150 feet but with a proper three dimensional fix (4 sats or more you accuracy will be around 17 feet). could be the difference of you overshooting an address or being on the wrong side of the road !! :Oops: Okay... an extreme case but you know what I mean!!

You don't really have to worry in day to day usage since your unit will lock onto as many sats as it can find and try to hang onto them.

With regard to your MB part number and fitting under the dash - I have no idea?? Do you have a pic of it? A gps antenna would work under the dash if you had a re-radiating antenna somewhere in the car already fitted.

The Ed.

 

[zedmeister]

Antennas normally work under the dash as the dash is almost see through to satellite signals. This is because its plastic and rubber. Different case if you have metal in the way or metalised screen.

 

[The Editor]

GPS receivers require a line of sight to the satellites in order to obtain a signal representative of the true distance from the satellite to the receiver. Therefore, any object in the path of the signal has the potential to interfere with the reception of that signal. Reflective surfaces can cause the GPS signals to bounce before arriving at a receiver and cause an error in the distance calculation. This problem is known as multipath and can be caused by a variety of materials including but not limited to water glass and metal.

I'm just trying to point out the optimum conditions to use your GPS receiver in. Yes you can get it to work by sticking the antenna in all sorts of places :Oops: but you will not be getting the best out of your sytem !

Ed

 

[marnix]

Here are the pictures as requested

 

[The Editor]

Ahhhhhhhhhhhhhhhhhhhhhh... Now I see what all this under the dash business is you're on about :Oops:

It looks from that pic that the top edge of the mount is self adhesive. So it sticks 'underneath the dash' - DOH. I had visions of people sticking their antennas down in the footwells somewhere i.e. underneath the whole body of the dash like under the glove compartment or something. I was thinking "How the hell are you going to get a reliable fix????"

Yes this would work (it's still not ideal as the best set up would be an external antenna on the roof as BMW uses on their 7 series).

Right I shall go away now and beat myself with a wet kipper.... :Oops:

Cheers

The Ed

 

[andy_k]

Antennas normally work under the dash as the dash is almost see through to satellite signals. This is because its plastic and rubber. Different case if you have metal in the way or metalised screen.

hmmmm

not strictly true, there is an awful lot of metal underneath a dashboard, and the aerials view of the satellites would also be obsucred by the bulkhead, the roof and to a degree the solar reflective glass fitted to Mercs.

We live in an area where satellite reception is a bit flaky, an aerial mounted under the dash in my car wouldn't receive a single satellite (neither will a handheld unit inside the car) whereas with the antenna mounted behind the radiator grille I get 4 satellites.

Spending a little time getting the best place to fix the antenna will pay dividends

HTH

Andy

 

[zedmeister]

hmmmm

not strictly true, there is an awful lot of metal underneath a dashboard, and the aerials view of the satellites would also be obsucred by the bulkhead, the roof and to a degree the solar reflective glass fitted to Mercs.

We live in an area where satellite reception is a bit flaky, an aerial mounted under the dash in my car wouldn't receive a single satellite (neither will a handheld unit inside the car) whereas with the antenna mounted behind the radiator grille I get 4 satellites.

Spending a little time getting the best place to fix the antenna will pay dividends

HTH
Andy

You have probably got a metalised screen. This is not a problem relating to the dash as you say you can't get anything through the glass. The under dash mounted antenna only has to go through an additional layer of thin plastic which does not affect it much as long as you place it forward of the roof it has no problems.

 

[zedmeister]

Well, I have fitted the whole thing now (APS 30). Many many thanks to Marnix for the manual - got it yesterday.

When I installed it in my drive, using the pos button it told me correctly what street I was on. I took it for a drive. Got 5-7 satellites no problem, so I decided to enter a destination (my brother's house) and drive there. Shortly after setting out it started getting confused and giving a different street name to the one I was on. When I got to his house it was still telling me the wrong street (by many many miles) and most of the way home it was telling me I was still on that same street. Can anyone tell me what the issue is? I'm pretty sure I have GAL signal as my old audio10 used to up the volume on the motorway. Is it a setup problem? Doesn't an angle need to be set for it to work properly? I have set the tyre size correctly.

There is an auto-calibration option on the menu. When selected it asks to delete old data which is okay. It then says comence calibration ride and immediately comes back (before I even move the car) saying calibrated okay press RH button. Don't know if that is supposed to do anything or not.

Help!

 

[marnix]

I had the same problem when I fitted it to my CLK in 2000. It looks like you have no speed signal and the Sat/Nav is waiting for the car to move to update the positioning.
If you look at the power supply plug, has it got a wire to pin 1?
If you have a look on this link it will tell you how the wiring should be at the back of the radio.
www.beckerelectronics.com/1492.html

If the speed signal is not connected to the ISO connector it can be found in the passenger's footwell. There are 2 green/black cables connected together with a clamp. These cables carry the signal.

The speed pulse can also be found on the small connector of the ETS black box (usual position in the engine compartment) at pin n°3 wire colour Black/Green.

 

[zedmeister]

Thanks again Marnix - will open it up tomorrow and have a look. Assuming I do not have a connection to A1, how did my Audio10CC change volume at speed? Is the speed pulse on any other connector such as the C block? Do you have the wiring for the C block as it not shown on the becker site.

If I need to wire it in, I do not want to go to the engine bay. The passenger footwell sounds easier! Is that under the carpet or under the glovebox? How will I know its the right one - or do I just connect up to the green/black cable?

 

[marnix]

To your first question: I don't know
To your second question: That would be to easy
There is a flap under the carpet where some connectors are located.
The wire you want is green/black. Just tee off and solder the wire to it and take it to pin 1 on block A.
On mine to insert the wire, I cut a small piece of the plug A away where wire 1 goes and used one push on connector as in the picture. you can get these in 2.8mm wide(just whats needed for this application). They are available from all electric shops