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Multiple antennas can be provided for a few different reasons... there's a (relatively large) frequency difference between cell types (CDMA/LTE vs GSM, etc.), so I'd be curious to know if the same kit goes into both NA and European exports. Antennas at distance can also be used for diversity purposes (which becomes more important at higher frequencies), but there has to be some selection circuitry somewhere to determine who has the stronger signal.
Termination (quick and dirty) would be achieved by a short piece of similar coax having its center conductor shorted to the outer shield with a 50-ohm resistor (preferably a small surface mount). You could buy one for a few $s if it was your typical screw-on SMA connector, but the connectors seem to be some form of push-on... I'd need to see a close-up if I were to try and identify what connector is actually being used.
Driver side.
I see what looks like three separate devices here.
How to identfy which is which?
looks like it will be possible to isolate just the undesirable functions.
I was busy this morning and have lost the bubble. Are these photos the inside of the antenna or components under the dash?
I'v been reviewing the text descriptions in the diagnostics leading to replacement of the left front or right front antennas. The left front appears to be connected with celllular, GPS, and XM. The XM is the connector that is separate. The cell and GPS are combined in the other coax for the left side. The right front appears to be connected with cell only. I still think both antennas must be disable to prevent cell communication. The two way indications refer to cell comms. There is no comms back to GPS satellites - that receive only.
In the process of reading diagnostics, its clear that there are processes in place that detect the presence of the antenna. Perhaps properly terminated, they will "detect" the antenna.
Are these photos the inside of the antenna or components under the dash?
These photos are inside the antennas.
Originally Posted by Andybump
The left front appears to be connected with celllular, GPS, and XM. The XM is the connector that is separate. The cell and GPS are combined in the other coax for the left side.
Perfect! Inside the left antenna module, the one coax goes to two separate devices. If I wrap only the Cell device, that should retain GPS and XM.
Originally Posted by Andybump
The right front appears to be connected with cell only.
I'll wrap the right side antenna, and only the cell part of the left side antenna.
So since cell is on both sides, the big box must be cell. Time to start wrapping....
Sound logical. Hope its right. And, I do prefer the wrapping method if that works. That said - will that actually work? Perhaps @Dan Hintz can answer that. If the original antenna is radiator, then when wrapped with foil does that just become a re-radiator. That is, if one wrapped foil around a metal antenna mast, wouldn't it still transmit? The signal energy would just conduct to the foil. Perhaps there needs to be some insulation between the original antenna material and the foil, so that the foil blocks the RF rather than just becoming part of the radiating surface.
So since cell is on both sides, the big box must be cell. Time to start wrapping....
Were you able to get to them removing the fender liner or did you have to pull the fenders? Thanks for being the first one to do this so the rest of us can hopefully follow on with your lessons learned
So since cell is on both sides, the big box must be cell. Time to start wrapping....
Exactly which part do you think is the antenna - that actual radiating surface? I dont think it is that metal box. I agree the box is apparently associated with the cellular antanna. Or that would be a logical conclusion.
wrapped foil around a metal antenna mast, wouldn't it still transmit? The signal energy would just conduct to the foil.
The shiny metal is actually connected to vehicle ground once you screw it down. Theres a circuit board positioned vertically inside this "box" that has the wire connected to it. It is mostly open all around the sides, so perhaps thats involved in shaping the signal. So the metal may not be the "mast" but it might be involved somehow. Like you, I'm not an rf engineer.
I'm testing wraps on my phone to see what is needed to cut it off from the world.
I agree it would seem to be proper to have an insulator then a metal wrap.
Originally Posted by rawbar
Were you able to get to them removing the fender liner or did you have to pull the fenders
It may be, but the data coming from the car is being sold and attached to your SSN and can be purchased by anyone, including your insurance company whom it's being marketed to. And my insurance company would be happy to crush me with a rate increase based on that data. Google knows who I am, sure, but they aren't attaching my browsing habits to my SSN and allowing anybody with an LLC and credit card to purchase them.
Look at forensics that are harvested from cell phone data in an accident. You would be amazed the amount of information that is available without even having the physical cell phone that was in the vehicle. It's all tracked and saved remotely.
Look at forensics that are harvested from cell phone data in an accident. You would be amazed the amount of information that is available without even having the physical cell phone that was in the vehicle. It's all tracked and saved remotely.
Understood, I work in tech for the largest mobile telecom in the US. But what you're describing is a very different scenario than anyone being able to buy my data via SSN, name, dob etc and using it however they like. I'm already paying 5500/yr for insurance (2 teens). I really don't want to be paying 10k. There is the potential of a massive economic hit, and it's not just a corner case.
The board in the top of the photos looks like the one you care about. Any chance you could get a more clear/detailed shot of it next to a ruler (with fine markings, like mm)? Pics of both sides of the board would be great, though my guess is it'll be ground plane. I'm trying to figure out those two parallel bars near the top... they could form a filter, but it also looks a lot like a directional coupler (which would be used to measure signal strength). This is when I really prefer to have the board directly in front of me...
If the original antenna is radiator, then when wrapped with foil does that just become a re-radiator. That is, if one wrapped foil around a metal antenna mast, wouldn't it still transmit? The signal energy would just conduct to the foil. Perhaps there needs to be some insulation between the original antenna material and the foil, so that the foil blocks the RF rather than just becoming part of the radiating surface.
What you want is to cover the entire antenna in an insulator followed by a metallic cover, then ground the cover to the coax braid. The insulator is so you don't short out the antenna directly (and stress the amplifier, assuming this is a transmitter... a receiver wouldn't care). You would still transmit, but with enough shielding the signal won't be strong enough to be received at the tower.
If you had direct access to the radiating element (which you likely don't), you could also ground it to the coax shield with a 50-ohm right as it exits the shield, making the radiating element practically zero length. Ideally, you'd just yank the antenna and place a dummy load (50-ohm resistor) there.
What you want is to cover the entire antenna in an insulator followed by a metallic cover, then ground the cover to the coax braid. The insulator is so you don't short out the antenna directly (and stress the amplifier, assuming this is a transmitter... a receiver wouldn't care). You would still transmit, but with enough shielding the signal won't be strong enough to be received at the tower.
If you had direct access to the radiating element (which you likely don't), you could also ground it to the coax shield with a 50-ohm right as it exits the shield, making the radiating element practically zero length. Ideally, you'd just yank the antenna and place a dummy load (50-ohm resistor) there.
Sounds right! By the way, isn't that image that looks like hand with two fingers some sort of warning about potential damage from an electrostatic charge. Should he be grounding himself while workng with the exposed board to prevent damage to something?
I wrapped the metal box things on each side. First insulation, then a couple layers of aluminum foil. Foil making contact with the large metal plate.
No change in the 4G LTE signal strength indicator on the dash.
Hmmmm....
Here's what's strange though. I have 5 bars signal here. Why only two bars on the dash (with no foil)?
Edit: perhaps they're using AT&T. I use verizon.
