Re: Cellular Antenna recommendations? (rsage)
As an Engineer formerly in the Cellular Biz, here are some sites below for antennas. The general rules are:
1. Any external antenna [that gets the Cell signal out of the metal can known as a car] will perform better than just using the built-in phone antenna.
To the best of my knowledge, the VW Op Manual warning is boilerplate and not based on any incident or Physics knowledge. Car Manufacturers are paranoid about ANY signal getting on the CAN bus and mucking up the behavior of increasingly-electronic vehicle systems [like airbags blowing at Autobahn speeds, etc.]. The fact is, you get far more signal penetrating the car when driving by a commercial 100,000 Watt radio station than you do from the 0.6 Watts maximum that radiates from a U.S. Cell phone. European phones output up to 2.0 Watts.
High end European cars all offer integrated hands-free phone kits [hidden mic pickup; playback through the radio speakers] and mind-boggling Navigation kits. The small square just left of the top right console map light in a Passat is expressly for hiding a cell phone mic [typically made by AKG].
Given this phone integration acceptance and the higher output of European phones, it's clearly a legal stance on the part of VW and others that causes them to include boilerplate statements regarding cell phone signals.
2. The through-glass and "patch" antennas, shown above, work well and are very popular. If placed on the front windshield, they transmit better to the front of the car, obviously, so you can drop a cell site that is behind you as you travel.
The ultimate antenna is a hard-wired [not through glass] antenna, like the multi-function AM/FM/Cell/GPS antenna shown above. This gets the signal above the ground plane of the car [car body/roof], resulting in the strongest signal and least dropped calls.
3. Antennas have to work at the frequency right for the local Cell Carrier. So, while the stubbies look nice, but they're tuned for only ~1850 mHz [high band, a.k.a. PCS]. If your local Carrier is still using mostly ~850 mHz sites, the stubbies generally won't cut it. High band cell site equipment is generally deployed in urban areas, so ~3" long stubbies work well there. This is why you see them as factory installs on an increasing number of vehicles.
Circular or rectangular "patch" antennas pictured above are also made for ~850 mHz. Lots of antennas of all varieties are tuned to cover both bands. It's only in the short stubbies that you encounter antennas tuned for only the high band. However, if a car [like a new Passat] has metallized windows [to lower the incoming heat solar load], then any through-glass antenna will not perform as well. Keep any through-glass antenna away from in-glass radio or defrosting wires, and an inch away from the car body [ideally]. Through glass and patch antennas are popular due to ease-of-installation; not great performance.
BTW, PCS is a Sprint Marketing term for the standard high band of ~1850 mHz, which lots of Carriers use. That is also the [only] general frequency used throughout Europe. However, European antennas will actually be tuned to about a ~100 mHz different frequency, so order only a European antenna made specifically for the U.S. Market.
The headliner removal can be a hassle, but it's worth it if you're serious about in-car performance of the Cell phone and/or GPS Nav system. The antenna shown above "adds" the circular disc at the base to house a GPS antenna. They work very well; there are 3 leads for the separate signals, or several leads plus a splitter box [depending on the Manufacturer] Don't cut any antenna cable; it's a certain length on purpose. Signal may/will degrade.
I agree that car kits, as from Nokia or Motorola, are the only way to go. Plus, you can have the car kit mute your radio HU [VW 2002 year] automatically.
Good Luck, whichever way you go...