epia m10k + lilliput => gps blocker? - Page 2

mobileh1 · 06-30-2004, 12:09 AM

I have the same setup with the TripNav GPS and I get lock *all* the time, I have the GPS routed to under my hood, which is fiberglass (RF can pass thru).

I can 'see' and lock up with 7+ sats typically. And I have a ton of electronics in the car, ham radio gear, scanners, etc...

I still think that it could be a power issue, until you put it on a powered hub and power the hub indepdent of the ITPS/PW60 I would still bet on power.

Can you bring the car computer into the house and try that?

what if you get a usb extension cable and move it around the car, does that make any difference.

storm · 06-30-2004, 12:24 AM

I have Via M1000. I ment the "extra USB" cable that you connect to the centre of the MB.
I have no idea if this is the reason that it works great for me.
But I have Lilliput too.
the touchscreen is not connected to the "extra cable".
Now it locks faster than ever before.

I have ITPS/PW70A too

TommieG · 06-30-2004, 05:11 AM

Quote: Originally Posted by NaFooEsi

running the usb extension is not a true solution tho. I got tint on the back window, so that doesn't help the reception either...

If it works as it should it seems like a true solution to me..... just change tha back window

Glad I bought the Xenarc

Tom

NaFooEsi · 06-30-2004, 05:14 AM

Okay guys, I did more back-breaking tests, and eventually I took everything out of my car and spread them out in a wide open parking lot. I hooked up both the mini-itx and the lilliput lcd to an 50' outlet I extended from my apartment balcony.

I used an independent laptop installed with street atlas 2004 and the earthmate gps to act as a RF tester/finder. Here's what I found:

- When the lilliput's LCD's off, I got green lights (locks) on the gps as I moved it across the whole vga cable as well as around the lcd. I did lose some reception at the vga terminal of the mini-itx. But I would have to literally put the gps on top of the vga terminal.

- When the LCD was on, the lost of gps reception varied across the cable as you can see on the diagram below.

I'm not sure what's inside the little cylinder knot near vga/usb end of the cable, but I know that it supposes to reduce / shield interferences. Maybe that would explain why the gps gets better reception near there in comparison to the rest of the cable. Perhaps it's a capacitor? (I'm not in tuned with EE/RF engineering). The lcd seems to produces the strongest interference when it's on. My gps would lose lock till I'm 4+ feet away.

Another test I've done was the installaton of touch kit on a desktop computer and then have it input to lilliput lcd. Guess what!? It created interferences with my test GPS too!!! So my m10k board is definitly not the cause. I know that in my first post, I said that the lilliput did not create interference when I connected to a laptop, but in that test case, the laptop did not have touch kit installed and it was a different vga cable (my friend's).

So, from tonight's test(or early morning's test

), I would definitly conclude that the interference is from the vga cable and the lcd screen. I will do a test with my friend's vga cable just in case my vga cable is defective in shielding RF.

If his cable does the same thing, we'll need to figure out how to get rid off this interference. Perhaps grounding the vga cable as "lucho" suggested in the other thread.

Yawn... I'm drop dead tired.....

storm · 06-30-2004, 05:53 AM

This maybe explains why I got better reception when using the extra cable.
Before the GPS was connected to the usb exactly beside the vga cable. Now It is connected to the extra port that is a bit away from the VGA.
I have the VGA-cable from Lilliput.

NaFooEsi · 07-01-2004, 12:57 PM

ok, I tried grounding the cable, and it didn't help. I'm thinking the lcd monitor is the prime suspect here.

So anyone know how to ground or shield this monitor? Thanks!

CorollaVerso'04 · 07-01-2004, 01:45 PM

can't you try to tape the vga cable with alu-tape?

maybe first wrap some thin paper (or something else) around the cable before you tape it... so that if it didn't help it can be taken of easely.
if it does help take all of and tape it again with just the alu-tape so it lasts forever

CorollaVerso'04 · 07-01-2004, 01:53 PM

got a maybe better idea
due to the fact that most alu tape is a few cm's width you take the same length as your cable is long. put it on the floor with the sticky side up :-) then place a less width lenght of paper (the same width as the the cable is round)
then place the cable on the paper and put the alu tape borders together

this way you can take it off the cable very easy
and maybe there are shielded cables factory made :-)

NaFooEsi · 07-01-2004, 04:14 PM

what's alu tape? aluminum tape?

I'm inclined to think that the LCD monitor is the cause here. Someone suggested the CCFL light(backlight) inside the monitor causes the interference. It seems to be logical, because the backlight would only turn on when there's vga signal going into the lcd. If I turn the lcd off, there should still be signals traveling inside the vga cable and the gps would be okay.

NaFooEsi · 07-20-2004, 05:05 PM

Well, I finally found the problem, and I'm ****ed at how simple of a problem it is and how much headache and time it costed me.

But at least it's working now. Believe or not, the interference is caused by the refresh rate of the LCD. When my LCD is set to 85Hz, it creates interference that can even be seen on the LCD sometime. But since it was really minor, I didn't pay too much attention to it. When I adjust the refresh rate down to 60 Hz, the interference is gone, and long and behold, the GPS signal is much much more stable. Why or why didn't I think of this earlier?

I think this explains why some other people who have the same hardware setup with me but no problem for them. So don't try to use the highest refresh rate on your Lilliput!! I hope this would be helpful to people that are having "interference" problems.

Laidback · 07-20-2004, 06:39 PM

Quote: Originally Posted by NaFooEsi

Well, I finally found the problem, and I'm ****ed at how simple of a problem it is and how much headache and time it costed me.

But at least it's working now. Believe or not, the interference is caused by the refresh rate of the LCD. When my LCD is set to 85Hz, it creates interference that can even be seen on the LCD sometime. But since it was really minor, I didn't pay too much attention to it. When I adjust the refresh rate down to 60 Hz, the interference is gone, and long and behold, the GPS signal is much much more stable. Why or why didn't I think of this earlier?

I think this explains why some other people who have the same hardware setup with me but no problem for them. So don't try to use the highest refresh rate on your Lilliput!! I hope this would be helpful to people that are having "interference" problems.

Good find!

Goddy · 04-11-2005, 08:40 AM

I have the same problem, but its a bit more complex then just adjusting the refresh rate. When i set it to 60 hz, i still have the problems, but a bit less. I get the best results when using 75Hz. But i got a signal loss every few minutes, and when i poweroff/poweron the lilliput i have signal. After a few minutes its gone again.

But i have found only one place in the car for the gps to work without any loss of signal.

where ever i put the gps unit, i get a loss, but when i put it on the airbag 'unit' for the passenger i have lock all the time. I thought it had something to do with a magnetic field, because that was the only place i;ve had a magnetic field.

Because i didnt like the setup with the gps unit right on the dash with all the cables i found i better to hide is somewhere. I found a place under the dash on top of the frame with a very great magnetic lock. There is a big metal plate between the lcd and the gps unit. When i have lock, i have a very very good lock on sats. But i got the interference problem again.
Its weird that the only good spot seems to be on the airbag, but i actually dont want that.

When i put the gps unit in the back its working ok, but i dont have great lock there (but no interference with the lilliput lcd).

What can i do, even 60hz isnt working for me :/

wohaha · 03-04-2008, 08:04 PM

this company is running gps jammers, prices are sharp

wywywywy · 04-12-2008, 08:53 PM

I've got the same problem here... and I have tried all available refresh rates already

Has anyone got any suggestion?
Thanks.