Stick-on Cellphone boosters?

Factual Questions
1

Okay, I know this has been asked before, but a few inquiries to the Search feature didn’t reveal the post I was looking for. And Googling simply gives metric bushels of “asseenontv.com” pages selling all the common infomercial fare.

Anyway- those stick on printed-circuit-looking antenna boosters for cell phones: Useful or odiferous horsepucky?

Simply from the cheezy infomercialesque ads, I’m strongly inclined to assume the latter, but one or two people have told me that, in certain circumstances a “wave reflector” can indeed help an antenna. However, they have to be specifically emplaced, and their effectiveness depends on a fixed multiple of the signal wavelength. Or something.

The one other post I recall addressing this summed it up nicely- if it worked, why don’t the cell makers install the same device from the factory?

I tend to agree, but, as I said, I can’t find any evidence to the contrary. Unless it’s so low on the totem pole it’s not worth debunking?

So: If it works, how does it do so? Or even if it doesn’t, what’s the so-called reasoning behind it- what story do they give for why it supposedly does work?

2

http://boards.straightdope.com/sdmb/showthread.php?threadid=83192

http://boards.straightdope.com/sdmb/showthread.php?threadid=79122

Those are the threads where this has been asked before, but neither has any real answers, just people poo-pooing the product. The excellent point was made that, if these inexpensive (to make) stick-on films really worked, why aren’t the cell phone makers putting them into the phones in the first place?

Somebody here is going to have to break down and buy one so we can put these threads to rest. Or perhaps Consumer Reports has done something on these?

3

After some googling, I found this page:

http://www.geocities.com/techpro118/

Unless somebody else sees something that I didn’t, this guy does not seem to have anything to gain by promoting the product (unless he makes them himself), and lists a variety of manufacturers who sell the product.

I found a video clip on the NBC Hawaii Channel 8 where they did a consumer report. But thus far I haven’t been able to watch it all the way through because it keeps shutting itself off right when the reporter is installing the thing. I’ve tried re-starting the clip about 6 times but it just won’t play all the way through for me. Maybe somebody else can watch the whole clip and report back.

http://www.khnl.com/Global/SearchResults.asp?qu=antenna&x=19&y=12

4

After many tries, I finally got that video clip from the news station to play all the way through.

Their assessment was that it is a total waste of money.

5

My understanding of antennas and radio waves it’s not the length of the material, it is how far the one end is from the other.

For example, if you were receiving a sine wave like this


   _   _   _   _   _   _   _   _
\_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/

What you want is an antenna long enough to span one full wavelength. And, since radio waves travel in a straight line, this is most efficiently done with a straight rod. Like this:


-----

If you bent up the rod, it would no longer span a whole wavelength:


@

So, it wouldn’t really help you all that much.

More information can be found at:

6

A “reflector” antenna element is nothing new, they are quite standard in many configurations, including a “Yagi” which I regularly used to communicate with amatuer sattelites.

The critical parameter is actually 1/4 of the wavelength, although 1/2 and full-wave are better, they are often impractical for, say, a 2-meter band. In the case of cellphones (correct my math if I would smash a probe into Mars-- (1 / ~900Mhz) * c = .33 meters (taking ‘c’ to be 300,000,000 meters/sec). Don’t see cellphones with foot-long antennas, do ya :slight_smile: at least not anymore.

Okay so what? Antenna theory, despite the best intentions of mathematical geniusus, remains an analog-electronics guru-science in many ways. I don’t pretend to understand why one particular smashed-together bunch of metal recieves band X better than any other kind.

It sure doesn’t make intuitive sense. I have two cellphones, one is made of Magnesium (An ericcson DF388) and the other plastic (Motorola StarTac). Needless to say, both contain all manner of irregularly shaped metal hunks. What difference could one more or less make? unless it were directly connected ot the antenna, or very carfully tuned and placed an exact distance from it.

I read that study and it sounded… wrong somehow. Like how an un-scientific person thinks scientists do things. There is a lack of a really measureable output for one, for another they leave out important details like what kinds of phones were compared, what the antenna configurations were, what the battery strengths/lives were.

Having said that I have no reason to doubt the well-meaningness of the study, but the point is extremely well taken- these things are easy to make, why are cellphone manufacturers not putting them into their phones?

I have to assume the answer is that they are. Let me be clearer- It is in a cellphone vendor’s best interest to make a compact antenna as strongly as possible. It would be their bread and butter. So I have to assume that batallions of very very smart EE-type people have analyzed this problem to death, and continue to do so. And if a stick-on piece of mylar (or whatever) made a difference, I presume it would be added, and further that it would be on the inside of the case.

I would also presume that the specifics of antenna designs in this ultra-competitive industry are trade secrets. I don’t expect many of the engineers involved could talk about it even if they knew.

Which leaves us back where we started… Human perception being as lousy and hopelessly subjective as it is, and cellphone performance metrics being vague and nebulous for the casual user (‘bars’ of signal? as an embedded systems programmer I can tell you thats useless… I might be tempted to make it a log scale, or lie to make the customer feel better, or heck it might just be a guess based on clumsy signal/noise reading in the audio)… I don’t know if a simple answer is possible, and can certainly explain the proliferation of claims.

Anyone have difinitive evidence?

-Curt

7
      • Who the hell cares about a cell phone, man? They’ve got this thing now for 25$, it’s a metal plate, and it’s got like these different thermometers on it, and you leave it outside to help decrease global warming!
        -Ain’t scientifics grand? - DougC
8

While waiting for my daughter to evaluate every CD at BestBuy (or so it seemed), I picked up one of these and started to read the box. Truly impressed–they’ve raised pseudo-scientific gobbledegook to a fine art.

However, the kicker: “Expected lifespan–eighteen months!” (Bolding mine.) So not only do you blow $US20 on something that doesn’t work, you have to replace it every year and a half.

Reminds me of a segment in Mad magazine years ago, in which they were translating a used-car salesman’s pitch. “We get plenty of repeat business!” became “If someone’s dumb enough to buy from us once, they’ll be dumb enough to do it again!”

P. T. Barnum still has it right . . .

9

A batch of 100 on eBay for $1.25 ($15.00 shipping)
Or you can buy 1 at best buy for $20.00

Hmmmm…i wonder where the profit is here?
If it really worked I can’t see a company not including it in the basic design.

10

I have a co-worker who tested one by driving for about an hour with one of these stickers attached and then driving without the sticker attached. I seem to recall that the enhancer/sticker was slightly worse (3 dB or less worse). There are a group of cell phone users who swear by them, but another co-worker has found one that was actually degrading the signal enormously. (This person noticed the degradation right away, but did not connect it to the sticker he had just installed.) In any case, using this device can void the manufacturers warranty (although I have not heard of anyone blaming this sticker for “unfixable” phone problems). My colleagues and I are convinced that the enhancer is worthless.