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      07-02-2011, 03:34 PM   #1
andy8400
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iPhone adapter roof antenna problem

Hi. First post. I had ordered my 2011 X3 with the iPhone adapter specifically to improve the signal, even if only a bar or two, through the roof antenna since the adapter includes a coaxial cable connection for that purpose. I tried this with an iPhone4 and subsequently with an iPhone 3GS (using the correct cradle for each) but saw no improvement with either phone. All other functions (music, etc.) worked fine through the adapter.

My question please: Has ANYONE used the cradle adapter with ANY iPhone model and if so, was there any signal improvement? Thanks much, Andy
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      07-02-2011, 04:06 PM   #2
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Yes. iPhone 4. Notably stronger signal in areas with poor coverage compared to Bluetooth connection.
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      07-02-2011, 05:57 PM   #3
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iPhone 4 with cradle and no signal problems but I've never compared with and without cradle to see if you get more bars. All a bit Emperor's New Clothes until you do and I've been meaning to check. Will let you know
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      07-05-2011, 10:42 AM   #4
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Usually, iPhone 4 poor reception in my driveway (1-2 bar).
Nothing has changed with cradle adapter
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      07-05-2011, 10:52 AM   #5
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Thanks all for your replies. They were very helpful. The answers from my BMW dealer were equally varied. I expected the improvement that Nahoa obtained but Haldol's experience was like my own. Sfax, if you wouldn't mind, I would be interested in your results. Thanks again, Andy
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      07-05-2011, 11:03 AM   #6
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I have noticed that my signal is stronger in some known weak areas. However, this is a really subjectively measured situation... no antena of this caliber can overcome a crappy signal altogether, so I guess it depends on just how bad the signal is and why - if there is local interference for example, the shark fin antena may provide no better reception than just the uncradled phone.
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      07-05-2011, 11:37 AM   #7
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Is there an iPhone app that records signal strength? This would provide something empirical as you could compare the same route with and without the cradle. I'm not being lazy, I just couldn't find one!
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      07-05-2011, 12:10 PM   #8
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Quote:
Originally Posted by sfax View Post
Is there an iPhone app that records signal strength? This would provide something empirical as you could compare the same route with and without the cradle. I'm not being lazy, I just couldn't find one!
You're just being lazy. Is that what made Britan great? No... no I say! Now stiffen that upper lip and get out there and find one.


God save the Queen.
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      07-05-2011, 12:48 PM   #9
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You're just being lazy. Is that what made Britan great? No... no I say! Now stiffen that upper lip and get out there and find one.


God save the Queen.
- can you at least help me with some app store search phrases?! Searching on "signal strength" yields "Authentic Yoga with Deepak Chopra and Tara Stiles"
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      07-05-2011, 12:54 PM   #10
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Quote:
Originally Posted by sfax View Post
- can you at least help me with some app store search phrases?! Searching on "signal strength" yields "Authentic Yoga with Deepak Chopra and Tara Stiles"
Yes, but if you practice the yoga you probably won't be as annoyed by the signal strength issue. Perhaps this is a sign...
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      07-05-2011, 01:40 PM   #11
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OK, found something that will give you more precise measurement. Type

*3001#12345#*

and then press Call

This puts the iPhone into Field Test mode and if you then look in the top corner highlighted below, you get a more accurate dBm reading of your current signal strength and it's automatically updated every 4 seconds. One would think that this would show an improvement when in the cradle but not tried it out yet






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      07-05-2011, 01:58 PM   #12
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You live on Baker Street, don't you!
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      07-05-2011, 02:16 PM   #13
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OK short experiment results for you.

My iPhone signal strength is 0 to 5 bars. In my current location I can move around and get it to vary from 1 bar to 3 bars (1 bar can be induced my holding the iPhone in its infamous death grip position!)

This is very approximate but:

-114dBm => 1 bar
-104dBm => 2 bars
-99dBm => 3 bars

So I found that I could get a fairly constant -93dBm to -96dBm (3 bars+) when in the cradle but outside the cradle in various positions inside the car in varied a lot from -93dBm (3/4 bars) down to -114dBm (1 bar).

Now, here is the interesting part. I closed the armrest for 30 seconds with the phone in the cradle and then opened it to see what the last reading was: it had dropped to 1 bar! I repeated this a few times, same result every time. No question. So the cradle only works when the armrest is open, so the cradle does absolutely nothing other than hold the phone in a constant position. This is only true of my cradle of course, which could be defective.

I would be interested to see what other people experience using this test - particularly the armrest experiment! I'm using an iPhone 4 and a basic iPhone 4 snap-in adapter.
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      07-05-2011, 03:02 PM   #14
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Try driving around town whist holding the iPhone up through the sunroof and measure the results.

Okay, now I'm just being annoying for its own sake.... I'll stop now. Well, soon anyway.
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      07-05-2011, 05:43 PM   #15
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Hmmm, the "open cradle" experiment doesn't seem to match my results. Mine approach was kinda less sophisticated than the sfax standard. I had the phone in my hand and it had two bars, I put it in the cradle and closed the armrest and it reported 4 bars. Driving through a former 0-2 bar location, I consistently get 3-5 bars in the cradle. iDrive lying to me? Could be. Well, except that I've held calls through that dead area where they would previously drop. That suggests the reported value might be accurate.

I'll see if I can do a more specific test. How do you read the phone in test mode with the armrest closed?

(Eager to see the remote video monitoring system sfax whips up to surmount this challenge.)
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      07-05-2011, 05:43 PM   #16
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Wait, how do you get out of field test mode? Power off and on? Something more elegant?
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      07-05-2011, 06:10 PM   #17
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Just press the big button!
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      07-05-2011, 06:14 PM   #18
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The home button takes you out of test mode? Spiffy.
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      07-05-2011, 06:15 PM   #19
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Well, it did for me.
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      07-05-2011, 06:22 PM   #20
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Didn't mean to come across argumentative -- was just happy to hear it was so easy. Clearly you were bolder than I and just tried it out!
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      07-06-2011, 12:36 AM   #21
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Wow! Quite a response. Sfax, the db test is most interesting (and I will try it for fun) but looking at the bars is enough for me. I rest the phone on the cradle without snapping it in and look at the reading (bars on the phone). I snap it in and wait 10 seconds for resampling and see if there is a change, and there is none. I then move the car because there is always the possibility that the roof antenna is in a "dead spot" and moving would eliminate the variable.

I was once an active mobile ham radio operator before cell phones and had experience with vhf and uhf signals with both internal and external (roof & trunk) antennas and the external will always win even with the loss in the coax, which could be substantial at cell phone frequencies.

Just another conjecture - the signal didn't change either up or down. This suggests that it may never had really connected in the first place. The X3 brochure promotes the increased range as a benefit. Still not sure why it doesn't work as advertised. Even an increase from one or two bars to three bars will go a long way to get you a handoff to the next tower, reducing dropped calls. I'm pursuing this through my dealer as well. If I learn anything, I will post it here. THANKS all for your suggestions. - Andy
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      07-06-2011, 12:37 AM   #22
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Quote:
Originally Posted by Nahoa View Post
I'll see if I can do a more specific test. How do you read the phone in test mode with the armrest closed?
Wait, you don't have x-ray eyes? I thought they were standard. Next you'll be telling me you don't hear people crying for help 100s of miles away.

Because the data displayed on the device is up to 6 seconds out of date (see bottom of the screen for when it was last updated), all you need to do is leave the phone in the armrest for a while and then quickly open it, at which point you'll likely see a reading from up to 6 seconds ago when the armrest was still closed.

I may have a bad cradle but the closed armrest / open armrest difference seemed very clear in my case
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