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Where's Your 'D-Spot?'
John Hering writes "The battle between cellular carriers in the U.S has become especially fierce within major metropolitan areas. The focus of this battle clearly revolves around issues of quality of service (QoS). In an effort to demonstrate superior QoS, AT&T Wireless has just released the results of the Top 10 "D-Spots" in Chicago from a survey conducted online with a random sample of 520 Chicago men and women. Although AT&T touts improved coverage throughout these metropolitan areas now, the vice president of AT&T Wireless, Greg Slemons, has publicly admitted to serious problems with dropped calls. " I have yet to see really detailed coverage maps for cellular provided by the providers themselves; in cities especially a one-block difference can mean 3 bars of reception or none.
I have been with several wireless providers, including AT&T, Verizon and T-Mobile. From my experience so far, AT&T had the worst service of the three. T-Mobile has been growing fast, and I get amazing coverage wherever I have gone. In fact, I've actually seen the network expanding. On my annual drive from my home in California to college in Colorado, there used to be no service at all in Nevada or Wyoming. Now, I have full service on the drive through all those states. I have also found the customer service to be excellent. That's just my 2 cents on the cell phone battle... I think T-Mobile is trying very hard since they are move of an up-and-comer than a giant like AT&T.
There are coverage maps for gsm readily available for various countries, including the US, at gsmworld.com
AT&T knows when their system drops a call. When I used their service a year ago they would credit you some amount for each dropped call. They could simply look at the % of calls that each tower drops. That would give them a good idea of where they need to put more towers. Of course, this would lead to them installing a tower in my house.
Lasers Controlled Games!
Do you have a stucco exterior on your house? I had good reception with Verizon in my dad's house in Jacksonville until he had his walls stuccoed. The metal frame used to attach the stucco degrades the signal to the point where my phone is unusable inside but I get awesome reception by stepping out to the back yard.
That list was pointless...it was essentially the top ten highest foot traffic areas in the city. Of course you will have the highest concentration of dropped calls where you have the highest concentration of people trying to use their phones.
Please, address a real issue, like the fact that Hyde Park has awful coverage when factoring the number of customers in the community.
-R
Anyway, I can't use my cell phone in my own house, which rules out using it as a land line replacement. I can barely get decent reception in my back yard.
I now have a similar problem in the "East Bay" of the SF area.
My house has aluminum foil on the vapor barrier of the insulation, so I expected poor reception when I first got my phone. But it worked fine at that time. (Proababy due to the large windows.)
But lately my reception all over the east bay has been getting rotten, and it has been virtually impossible to get a connection at home.
The phones aren't flaking out. (I've enabled the field test mode in both mine and my wife's. The signal strength meter still indicates about the same strength it used to on the road, and the two phones agree.)
But I've recently found out that AT&T wireless is converting many of its 800ish MHz TDMA cell cites to GSM. (My phones are TDMA.) With the reduced number of TDMA channels available I now have some major dead spots - at home, at work, near the 880/237 interchange, etc.
Even when I DO see good signal strength, making a call will often make the signal disappear. I think what is happening is the phone is reporting that it's in communication with the cell on the control channel - but when all the signal channels are in use so you can't get a new one, the phone reports it as "service unavailable" as if it couldn't reach the cell.
Unfortunately, I have already purchased a pots-adapter cradle for the phone model in question, to use the phone for service in my vacation home, and this wouldn't work with a newer phone. GSM has lower voice quality than TDMA. I use the phone for travel, and TDMA+AMPS coverage is still far broader than GSM+TDMA, and there are few (one?) GSM+TDMA+AMPS phone models available. And if I switched I'd either have to buy the phone or lock into the service for two more years.
So I am in no hurry to switch to GSM. And if I do (and if Verizon has added coverage at my vacation home location, which wasn't available when I first got a cell phone) I'll want to switch carriers as well.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I put my nokia 5160 in test mode and did some tests. 4 bars is about -51dB to -66dB, 3 bars is about -67dB to -83dB, 2 bars is about -84dB to -97dB, 1 bar is about -98dB to -113dB. Each bar seems to be about 15-16 dB. In my experience, call quality is nearing the awful range at about -100dB.
This only works if your cell phone is not a CDMA phone (which works at a frequency range of 1850-1990 MHz).
Here's a cool page that talks a bit more about the subject.
It's not as easy as it sounds. Problem with Chicago areas are that the buildings create multipath for the RF signal and also do wonders with interference and pilot surprise (if you don't understand these terms, you probably don't work in cellular). Basically speaking, there are times that the signal will bounce off a building in such a fashion that you'll get very good "coverage" and other times you won't. No carrier in their right mind is going to give you one of these maps, although I myself have seen them often. This detailing could lead to lynch mobs of the poor sales personnel in the malls that have no clue what RF means...
-- Friends don't let friends buy Nokia.
The original poster is wrong.
I've done this with CDMA. As long as the antenna and coax are reasonably transmissive in the required bands, it works fine.
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Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Let's not forget that Europe has a significantly higher population density than most of the US, which makes it a lot cheaper for the carriers to provide high levels of coverage.
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Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Why wouldn't it?
Thus quoth the original poster:
"This only works if your cell phone is not a CDMA phone (which works at a frequency range of 1850-1990 MHz)."
That was all he said. I believe his reference was just to the frequency involved and that 800 Mhz mobile antennas would not work on CDMA phones in the 1850-1990 Mhz band.
RF in is RF out in this case. Any fancy modulation scheme applied to the carrier, such as frequency hopping (FDMA), or spread-sepectrum modulation via psuedorandom polynomials (CDMA), or simple muxing (TDMA) will not affect the passive repeater in any way, and will simply be repeated through.
It's conceiveable that the local CDMA phone may have some sort of cancellation interferece from the mixing of incoming and outgoing RF signals in the co-ax, but the whole point of spread-spectrum is that everyone is using all the band, just not the same particular part at exactly the same time; it's designed to endure through such collisions and interferences.
(BTW I'm a Ham and used to work as a professional RF design engineer).
-- You are in a maze of little, twisty passages, all different... --
BS, Norway does NOT have a higher population density than the US, and Norway is NOT flat :) It was not very cheap for the two carriers here to provide near 100% coverage in populated areas. Calls are certainly not dropped in any of the big cities, not even indoors.. But then this may be caused by strong regulation that has untill recently forbidden any carriers from starting unless they could cover a very large percentage of the population..
The mountains are not what I would call "densily populated".
No wonder children in Europe usually get their fist cell-phone at the age of 8.
The land area of the US is also 2.5 times the size of western europe.
If you ever decide to switch, go back to T-Mobile and try their phone risk-free like the other poster (I think it's only 3 days though, not 14). I only say this because on T-Mobile's map, my work's complex was the only grey spot on there. I tried it anyway (because no other carriers worked at my house, and I have a work phone anyway), only to find I do get reception (2/5 bars) -- good enough that I've never dropped a call. YMMV, but that's my case.
I don't know if they make mobile antennas for that band
Look to Ramsey Electronics for a suitable antenna. The LPY-2 covers both bands, & it's $35 cheap! If you really want to be clever you can rig up reflector or director elements to enhance gain.
Keep your cable run short though, RG-58C loses 0.25 dB per foot at PCS frequencies. That means you gotta drill holes rather than go around obstacles. Low loss cable is bulky and expensive.
N. Denmark to S. Spain, would be approxiamately Maine to FL, on I-95, where coverage is 99%.
Listen, Europe is smaller than the US. Europe is also more centralized.