External GPS antenna connector Mod for CF30...

I finally got around to doing this. I haven't tested it yet.

 

more photos......

 

Great job Shawn. Now all you need to finished off this is a black cap to cover it when not in use...now where did I see one .

 

That is a great idea. I had not thought of a cap..

 

Well some thing like the caps they have on bleeder screws on brakes

Rubber Caps On FMSI

It's not the style I was thinking of but will give others the idea of what I was talking about

 

Shawn,

Blair is spot on with the bleed screw covers... (Awesome idea Blair!) Home Depot should have them too (or something similar)... Look in their steel bins in the hardware section.

I am curious why you would need an external antenna though... Fill me in...

EDIT: By the way... Awesome execution!

 

Well. I don't know if I really "NEED" an external antenna. But the absence of NEED has never stopped me before .
The idea started when I saw the factory GPS roof antenna for Ford Rangers. I have done a lot of customizing to my own Ranger. I wanted the roof antenna on my truck, so then I needed something to attach to the antenna. That's how I got the idea to put the ext. antenna jack on my cf30. The roof antenna should be an improvement over the stock cf30 antenna inside the steel cab of the truck.
The stock antenna usually works great, except I temporarily lose signal driving in valleys or heavily wooded areas. Western WV for example.

The antenna I am going to use is much better than the stock Ford antenna.
I have a Mobile Mark roof antenna.
SMW-UMB Series Antennas.. Surface Mount Multi-Band Antenna
2 dBi Gain, Frequency (800-2700 MHz) Cable #1 CELLULAR
5 dBi Gain, Frequency (2400-2485 MHz) Cable #2 WIFI
GPS (1575 MHz) Cable #3

 

Shawn,

Let me check when I get to work, I might have a screw on cap for the bulkhead connector. I'll PM you later.

Really nice job. :thumbsup:

 

Shawn! It tells me that you don't have a docking station on the truck that's why you installed the connector at the top of LCD. Also on that setup you can screw or attached the Geohelix antenna cap which provide more reliable signal.


ohlip

 

This was the style that I was thinking of last night...well kinda but you get the picture :thumbsup:

http://www.ebay.com/bhp/brake-bleeder-cap

 

Correct, I dont have a dock. I saw the screw on antennas and was curious about their performance.
Yes, I figured the external sma connection would give me many options.

 

With a cap.......




THIS CAP SHORTS THE CENTER PIN TO GROUND
I RECOMMEND A DIFFERENT STYLE OF CAP>>

 

Now it looks finished. :thumbsup: Nice job Shawn. Where it came from is not important. What is important is that the cap works and gives the mod a finished, professional look. My take on it.

 

Some news on an update coming once my hand heals. I found a used Sarantel geohelix antenna. Well it's in a device. I will have to pull it out. I ordered a male SMA connector. I plan on soldering the Sarantel to the SMA and heat shrinking it. That will give me a removable Geohelix antenna. I'm curious to compare the two kinds of antennas.

I have too much time on my hands while having access to fleabay... Oh well....the antenna and connector cost me $10.00 total.

 

Not positive, but I think the chain for the cap caused a problem....The GPS would never find a satellite if I had that cap screwed on. Remove the cap and it worked...until recently...
Now the Ublox GPS won't get a lock on a satellite...
I am suspicious that the metal chain being connected to the metal lid was grounding out the power for the active patch antenna. That prevented the GPS from getting a good signal and eventually toasted the GPS module...I have temporarily disconnected the ext antenna and when the new Ublox gets here, I will try again.

 

Just curious, did your cap make contact with the center conductor of the SMA connector? The schematic makes me think only the center would have VCC RF present, not the outer shield but I could be wrong.

 

It did not appear to touch the center conductor.
I appreciate your thoughts as this has me stumped. The module may have just failed for unknown reasons. But I am certain that with the cap on, the gps would not get a signal to lock on. I tried it many times...as soon as I removed the cap, it got a good signal within seconds..

 

You've got me scratching now, are you sharing this new ext. SMA with the WLAN card or am I seeing things in your pictures? I began to wonder if the RF out from the WLAN could be feeding in?

 

No the gps is completely isolated from the wlan. Separate antennas, separate external jacks, separate antenna pcb's

 

My last stab at it for now, could the center conductor and shield have gotten swapped at the junction board or somewhere else? I'm not knowledgeable about powered Ants. but the shield and center should be open from a continuity standpoint for any coax. I saw a spec. sheet for your Cap and that said it was insulative (teflon) sealing material. I'd ohm the center conductor and shield separately all the way back to the GPS board connector before I put the new one in (to keep the smoke in) I've repaired a few ICOM handhelds over the years so I've got some RF background, but I'm no expert. Good luck, I'll keep thinking too.

 

I did a continuity test of the external antenna connector and cap....

The cap DOES touch the center connector..When it is on, it shorts the powered center connector to ground. Not good.

Hopefully it only toasted the GPS module and not the GPS port on the motherboard....

 

I saw several vendors drawings for the Cap and they showed a Teflon insert to insulate the Cap from center conductor, could your Cap be a 50 ohm Terminator or is it missing the Teflon gasket? Glad you figured it out anyway, I'm sure there are several levels of buffering between the Antenna connection and the Data Bus in the Toughbook.

 

That's a good question...
Could you post a link to those datasheets?

 

I'm apparently not sharp enough to figure out the method to insert a link so... google SMA Cap and you get several hits that have a drawing. The I-com pdf shows a good picture, the 50Ohm Terminator or a shorting Cap will have a pin instead of the Rivet. (yes they make pure shorting Caps for Calibration purposes)