Review: Griffin ClearBoost

Boost your signal and protect your iPhone at the same time. (June 11th, 2008)

MacNN Rating:


Product Manufacturer: Griffin Technology

Price: $34.99 US

The Good

  • Boosts iPhone signal for most of the U.S. Includes screen protector and cleaning cloth. Good price.

The Bad

  • Case does not fully cover all ports. Some reports across the Web claim a Bluetooth headset reduces benefits of case.

If the reception on your iPhone is not up to your standards, Griffin offers a solution with a built-in antenna-boosting case. The Griffin ClearBoost is a black polycarbonate iPhone case with rubber accents that do not block radio waves. If you live in an area where you find you have difficulty with reception, you may benefit from the ClearBoost antenna, which can increase signal strength under some conditions.

Not Your Average Late Night TV Advertised Product

How is this different from those stickers advertised on late night TV? Those stickers are generically tuned and sized to fit on any phone. They aren't tuned to enhance any one frequency, and they aren't shaped to couple (or match up in size and shape) to any one phone's antenna. So, they don't really enhance signal or fit any one phone well. ClearBoost's antenna is tuned to enhance signal on a frequency band that AT&T uses widely, and it is shaped to capacitively couple to the iPhone's built-in antenna.

How It Works

The ClearBoost case has an antenna shape in the bottom of the case, exactly matching the iPhone antenna location under the black plastic cover of the lower portion of the iPhone. This antenna shape couples to the antenna of the iPhone using capacitance and the antenna shape extends up the back of the ClearBoost case to the nub at the top of the case. This effectively increases the power of the iPhone to communicate with the cell phone tower.

The iPhone uses four bands, 850MHz, 900MHz, 1800MHz, and 1900MHz. In the US, 850MHz and 1900MHz are common, while other parts of the world use the remaining two band. The iPhone includes all of the bands, so that a user can travel and not be concerned about whether or not the phone will function properly.

When you want to ascertain your signal strength, the iPhone has a Field Test Mode that is intended to be used by Apple and AT&T field technicians. You can test your own iPhone with the instructions on Griffin's support site. My experiment with the Field Test Mode showed that my iPhone reception when in the ClearBoost case is -84 dBm, while outside the case, it is -64 dBm. Plainly, I get better reception with the phone outside the case, but this is due to the frequency band in my area. Experientially, I get one additional bar more than other iPhone users around me.

These results were measured in the 1900MHz band, but the ClearBoost is designed to work best in the 850MHz band, which is the majority of US coverage. Through a little bit of phone calling and judicious Googling, I learned that my area of the country (Raleigh, NC) uses 1900MHz for AT&T, T-Mobile, and SunCom, but Alltel, Verizon, and Sprint customers use the 850MHz band. This means that I don't get the full advantage of the ClearBoost case in my home area. Knowing this, I don't know why my experience is better compared to other iPhone users around me, when according to the Field Test Mode, it should be worse.

The Hard Shell Case

While the ClearBoost is as protective as many other cases, it has the signature Griffin improved means of closing around the iPhone - it requires a coin to spread the face from the back half to remove it. The polycarbonate black plastic protects the phone from most bumps or drops, but has the same problem as most other two-part cases: It allows dirt or dust to get into the case. That dust will abrade and scar the iPhone over time.


Front and Back of ClearBoost

One of the downsides is that this case leaves much of the phone exposed. The whole top portion, from headphone to power button is exposed, and this seems unnecessary. If I need to switch SIM cards, a rarity on iPhone, I can remove the case.

The rubber nub that is the end of the antenna sticks up about a centimeter more than the normal iPhone height, but does not really take up appreciably more room in my pants pocket.


For most US customers, the ClearBoost should enhance your signal, reduce dropped calls, and possibly increase download times where reception would normally be difficult. For people in my area of the country, it seems to have little measurable benefit. Yet, the placebo effect and comparisons with other iPhone users seemed encouraging.

The price is similar to other cases, with potential huge benefits over those others. In addition, the package includes a static peel screen protector and a cleaning cloth. Please note, this case is designed specifically for currently shipping iPhones, but stay tuned for a new suite of products for the iPhone 3G.

Other Griffin Technology Product Reviews:

FlexScreen for iPod nano 3rd Gen

iPhone 3G Cases News Only

Elevator Laptop Stand

Centerstage iPod video Case

iTrip Auto (2006)

Ear Thumps (2006)

PowerBlock AC Charger for USB Devices (2006)

Edited by Ilene Hoffman, Reviews Editor

by Victor Marks


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