Following my recent Gearhead column about cellular repeaters wherein I reviewed the Wi-Ex zBoost YX510-PCS-CEL, reader Bob Erickson (Dallas, Texas) commented: "I feel kind of guilty about Wi-Ex. It has been around for several years and I meant to tell you about it. But, oh well, you discovered it. Probably a better solution however is Wi-Fi access to improve cost and access anywhere there is available service."

Bob's right — VoIP over Wi-Fi is a great option and a feature that will show up on more and more cell phones, but common availability is a couple of years off for most people.

(Regarding my comments about T-Mobile's lousy customer service, Bob said, "Since I was removed from the telecom world in 2002, I have had the 'privilege' of working in retail cell sales. If you think T-Mobile is a problem, you obviously have not experienced the other three, which are all much worse. My analysis is that in cellular service it is not about whom is best but who is not worst.")

Longtime reader and frequent respondent Dan Wakeman (Ithaca, N.Y.) said of the Wi-Ex zBoost, "Our guys love our YX510 cell repeater. Found it (under the Tessco label) about a year ago. We have two metal shelled structures/buildings with offices within our plant. This fixed the dead zone."

Reader Richard Travsky said: "Interesting, but is security an issue of any kind? Can't help but see this in the same light as wireless and one's neighbors picking up on it."

Good point, but I don't think there's an issue as the cellular signal from the service tower is simply amplified and repeated — essentially a physical layer service. If someone could intercept a call after it was repeated they could equally well intercept the original call.

A different issue was raised by reader Al Nowakowski: "Interesting, but no where did you mention the legal implications of using such a device. The FCC has a strange notion that you ought to have a license to transmit signals with more than 50 milliwatts of output power. They also expect that anything that does transmit signals, regardless of power output, has an FCC certification. You mentioned neither requirement, nor whether you or zBoost complied with those requirements."

Al went on to warn me of dire consequences (such as $8,000 fines from the FCC) for using unapproved equipment and interfering with emergency services. The zBoost gear does in fact have FCC certification. I didn't mention it because I think most of us presume that vendors that sell gear like this have to live up to those requirements.