CF29 GPS, utilizing external antenna?!

First and foremost, this site has excellent information IF you can find it... the search function is terrible... Thus I am posting my question here in hopes of finding an answer...

Here is what I have:

Purchased a CF-29LAQGZBM and a CF-29CTPGBKM (for parts.)

Removed the factory GPS sled from the CF-29CTPGBKM, and installed it in the CF-29LAQGZBM.

Everything works fine, GPS does its thing, etc etc.

The problem i ran into was signal loss in my patrol car... I installed an external GPS antenna, and have it connected to the docking station which utilizes the pass through port on the CF-29.

What I did was purchase a ufl/ipx pigtail and connected it to the pass through and to the antenna location on the GPS sled. (On the pass through there is nothing else connected, wifi was, but since removed.)

With the computer in the dock, connected to the external antenna, I have ZERO signal. Yes it has went through the cold start, sat for hours with nothing. If I connect the factory antenna in the sled back up it works just fine again, until I put it back in the car...

Any idea's on how to get this to work?

 

I think you've missed something here. In doing what you told you need another jumper wire arounf 2-3inhes long or you may use the jumper wire that usaually found on the WWAN sled, the one connected to a main u.fl term of the card. Without ajumper wire from your GPS module. Your gps has no antena connection all the way though a pass thru connector.

I will post a picture later of what kind of jumper wire I am talking about.

ohlip

 

here we go but I have doubt that this is a bit short. You may adjust the location of the gps module in order to use this jumper wire since it is the only one on the sled. There is a lot of space on the sled

Just use your common since.

ohlip

 

Welcome to the Toughbook forum . Have you tried this search...just replace the word test with what you are looking for Let me google that for you

 

Thanks for the replies!

Ohlip, I apologize, I do not believe I was very clear. I purchased a 10 or 12 inch pigtail that connects the GPS module to the ext antenna pass through connector. Eliminating the factory GPS antenna in the sled. My sled and mounting apparatus that I removed from the donor 29 was not set up for the MCX style quick connect... (pictures when I get off shift.)

Basically I have the GPS module connected directly to the ext antenna pass through with a UFL/IPX pig tail... In theory it should work... The only thing that comes to mind is that a huge line drop... However the antenna's are passive...weird.

 

The GPS module on the CF-29 requires an active antenna there is +5V on the center pin of the antenna connector which should also be present on your pass through. If you are using a passive antenna it will be seen as a short circuit to the GPS module.

 

+1


also, that pass through has a couple u.fl's on it: one in from the device, and one out to the internal antenna, and then of course, the out to the passthrough. Not sure exactly how it works, but I'm under the impression that it selects the stronger signal automatically. DOn't know why, just felt it necessary to throw that out there.

 

You also need an antenna that is the right frequency... Some are oddballs! Make sure it is 1575.42MHz ± 2MHz and you will be good to go.

A dumb question... Have you tried using the OEM setup in your car?

 

Okay so I checked everything with a meter, at the pass through coming out of the TB I have 5 volts, when docked, at the trunk lid with the antenna off, I have 5 volts.

I completely by passed any and all other connections to the ext PCB. In testing the PCB, both the ufl male connectors go to the same place. Center pin to center pin etc. I do not think that has any impact on the issue, as there are not any other components on that PCB.

It may just be an antenna issue. If it is not the correct unit I can see why it is not working.

Yes I have used the factory setup, and it works but is spotty. Most of the time I get 3 sat view and that is all. It bounces around and from time to time puts me in the coast of Africa and then back to the states...

 

Dug up the spec sheet on this antenna... appears it is the one for the job...


Larsen GPSNMO02
SPECIFICATIONS
- FREQUENCY: 1575.42 Mhz
- GAIN: 5 dBic / 28 2 dB (LNA)
- TYPE: Active
- PATTERN: Hemispherical
- VSWR: 2:1
- IMPEDANCE: 50 Ohms
- POLARIZATION: Right Hand Circular
- DIMENSIONS: 1.3 H x 2.9 D
- OPER TEMP: -22 to +176 F
- VOLTAGE: 5 V DC
- MOUNTING: NMO Mount
- COLOR: Black

 

Seems that the ground plane may be the issue. I am going to have to pull the NMO mount and make sure that it has contact with sheet metal. The low bidder always seems to half butt stuff. Drives me nuts... But then again I should not be talking garbage just yet, they may have done it correctly...

 

Okay, pulled the NMO, and as expected it was not right. Fixed that... but still no signal. Nothing...

 

Okay... Let's back up. Have you ever tried the antenna straight to the board without going through the passthrough... Have you tried a direct connection? Or did I miss something?

If you wire it straight to the board to test it and it doesn't work... Well, then it's not going to work. But have you tried that? Every time I try a new configuration I do it on a test bed to make sure it will work prior to installation.

Just a thought... Correct me if I assumed something.

 

Okay gentlemen, here is what I have... Pictures make it easier to explain:

This is the sled as installed. The grey wire is a UFL going from the antenna out to the pass through.

http://i243.photobucket.com/albums/ff3/tm4512/gpssled.jpg

Antenna UFL pigtail routing, no kinks or pinches whatsoever.

http://i243.photobucket.com/albums/ff3/tm4512/gpsantennawire2.jpg

There is no MMCX/MCX connector that goes straight to the pass through on this sled.

http://i243.photobucket.com/albums/ff3/tm4512/gpsnomcx.jpg

Goes from GPS engine/sled to the pass through. This is the bottom side view.

http://i243.photobucket.com/albums/ff3/tm4512/passthrough1.jpg
http://i243.photobucket.com/albums/ff3/tm4512/passthrough2.jpg

Top side view with KB and KB plate removed.

http://i243.photobucket.com/albums/ff3/tm4512/passthrough4.jpg
http://i243.photobucket.com/albums/ff3/tm4512/passthrough5.jpg

With UFL antenna pigtail disconnected from pass through.

http://i243.photobucket.com/albums/ff3/tm4512/gpsantennawire1.jpg

With the sled out of the TB and on the bench.

http://i243.photobucket.com/albums/ff3/tm4512/gpsengine3.jpg

This is the UFL plugged into the GPS engine, the black UFL pigtail goes to the factory antenna on the sled.

http://i243.photobucket.com/albums/ff3/tm4512/gpsengine1.jpg
http://i243.photobucket.com/albums/ff3/tm4512/gpsengine2.jpg

UFL connectors on KB PCB (What exactly do these do?) One is a WiFi the other is un used.

http://i243.photobucket.com/albums/ff3/tm4512/kbpcb2.jpg
http://i243.photobucket.com/albums/ff3/tm4512/kbpcb.jpg

 

connection to slow to look at all pics right now.
KB pcb is just a junction, so they could use 1 board for all the various RF options.

 

Okay so I am at a loss here. If I disconnect the factory antenna, and attempt to utilize any other (confirmed working) GPS antenna, I have nothing at all. I can reconnect the factory and be back seeing a few satellites.

I initially thought that the 12 foot of cable to the antenna was causing a line drop on the 5v, however at the NMO mount I have 5v (true RMS) as required.

Frustrating. This should not be that big of a deal.

 

If you have not yet tried,
hook up the gps to the pass through AND then hook up the gps internal antenna to the "out" of the pass through pcb

Other than that...I'm at a loss.

 

So your power comes from the 1301ZB ....fpc from the bottom?(flexible plastic cable?) On your visible palm rest antenna you want to take a few doughnuts of tape and put on there so "nothing" touches the tip of the antenna. You don't want that tape on there. It seems right but I think it's a post from Toughbook from Jim Gray? that made the statement.
I'm working on one now where I drilled a hole in the palm rest end above the antenna.
FYI...and this is new and not duplicated yet (maybe tomorrow)...a CF-30 engine will connect to the 1301ZB and power up and show in bios. I pick up 4 to 7 sat's in the truck. CF-30 antenna also.
I think it got better when I screwed the gps engine to the sled.(testing still)
I understand this is not answering your question but I got looking at your pictures and couldn't help myself.
You can hook your wireless antennas direct to the card and not use the KBPCB at all.
Good luck.

Jeff

 

I have tried doing as you stated, no joy. Still shows zero sat.

Sadlmkr, I am not quite sure I follow your post. Maybe I am just not reading it correctly?

I want tape on there, or I do not want tape on there? The tape that is on the antenna is factory.

I am not trying to improve wifi reception as that is already just fine... GPS signal is the situation I am trying to resolve.

I went as far as connecting the GPS engine to a removed pass through PCB and from the other side of the same going to the factory antenna. Nothing.

According to my scope, and meter, there is not any signal loss to report from cable length etc.

 

Tape to keep the tip of the antenna from touching. I punch mine with saddle hole punches. I punch a 5/8 with a 1/4 in the center. They could be square but look cool in the round. They look like doughnuts. Just put a couple on so the tip of the antenna isn't in contact with anything. Even rubber of the bump-out or tape. Then slide it in the bump-out.

On the wireless I was responding to your question.

I had just come in from a frustrating bit in the shop w/ a GPS and was on the way to the barn (getting dark) and I may have left a word out here and there.

You're way over my head on the extension antenna, and I wish you the best.

Jeff...I have an ohmmeter $5.95

 

Thanks for clearing that up. I sincerely meant no dis respect, was just a bit lost on what you were saying.

 

Not a problem man. I've read the GPS thread through over a half dozen times and some of this stuff just falls out of my head. I went and looked for it but didna find the exact post. I was too early as I think it's late in the series.

G'luck.

Jeff

 

My guess is the pigtail between the GPS and the Pass-Thru is picking up some RF interference from something on the motherboard and scrambling your signal. Most likely suspect is the CPU or wifi card. Panasonic uses some very high-tech tape to shield these wires from any such interference. I would say at the very least try to re-route your pigtail away from any RF emitting devices or find a way to shield the wire.

 

Never connected to the passthroughs on mine but have noticed the little button at the centre can be pressed in - so I'd guess it operates a skeleton switch on the board inside - if so are the switch contacts confirmed good?
If you're sure all connections are good then maybe try the complete rig away from the car and possible interference from data link, radio, gps tracker etc.

 

With the pigtail coming directly out of the TB and onto a removed PCB no joy.

The pass through PCB ohms out with very very little resistance, as for a switch inside of it, I believe it is simply spring loaded for shock isolation purposes due to it having continuity at all times.

On the bench with the factory antenna it works fine, on the bench with any of my pigtails it doesn't work period.

Will try another crack at it today when I get home.

Thanks for the input men.

 

Bad pigtails?

Even though the specs may seem correct, it's possible the external antenna's are incompatible.

Can you get a short lead for your external antenna and try that?

Official antennas
antennas

 

+1 on Shawn

see if you can hook your external antenna up without the passthrough (right to the gps board)?

IF it dont work, then it wont work.

 

Pigtails check out, two of them were brand new from HSI. One is a pull from a functioning donor 29. All cables ohm out with VERY little resistance as would be expected.

Did what inerestingfellow stated, no joy.

The antenna is within spec, and woks flawlessly with another dept CF31, IMMENSELY improves sat view.

I may just be out of luck here gentleman, I do appreciate all of the input.

 

The CF-31 uses a different GPS engine than the CF-29... Perhaps that is it.

When you say it works with the CF-31... Do you mean THAT particular antenna... Or one just like it.

I'm thinking a bad connection somewhere or maybe even a bad antenna... There are only a few things that it could be!

 

Yeah...if you threw the exernal antenna right onto the GPS engine and it didn't work, then your SOL.
Might try a DIY solution with an EM408 (or customtoughbooks kit),or a different antenna......

Sorry dude.

 

31 was used with the same antenna...

Antenna was connected directly to engine, still no joy.

Its quite all right... I have woosah'd through much worse!

Thanks again men.

 

I hate it when we can't figure something out!

 

Do those antennas require a bit of juice. Low voltage? Factory voltage/amperage from 1301Z (etc.) card works for a short run possibly?

Electric is like wind I can't see it so I don't understand it.

Jeff

 

Just wet your fingers and hold these wires...I can easily help you FEEL it though.

Odd thing is that if electricity goes bad you can usually smell it.

 

Yes, the antenna's are active requiring 3-5v to operate.

True RMS reading at the NMO on the trunk deck alternates from 4.9 to 5v... so very little line loss if any.

Even with the antenna itself pulled and tested within 6 inches of the engine, no joy.