T-mobile SDA (US) - Slow to regain signal (Searching...)

June 6, 2006

I have had my SDA for 1 week and have identified a major flaw. Besides the long (5-7 minute) time required to get a signal after dropping the signal. My SDA in specific locations will continuously search for a signal. The time period is between 1 - 10 hours to lock onto a signal. Both Cingular and T-mobile phone of different models work in these locations. The T-mobile coverage map identifies these areas as strong signal. I have soft reset, hard reset and replaced my SIM card. The phone works in other locations just fine. Actually, I love the phone other than this problem. It is well documented in this thread at HoFo

http://www.howardforums.com/showthread.php...11&page=1&pp=15

I am reaching out to Modaco for a solution. From experience, Modaco users tend to be very technical and creative. I hope that I can use the SDA in the future. I don't want to have to switch to SE.

Problem Areas Identified by me

San Jose, CA

San Francisco, CA

Santa Clara, CA

Omaha, NE

Fremont, NE

Working Areas Tested by me

Denver, CO

San Jose, CA (home zip code)

June 6, 2006

I have had my SDA for 1 week and have identified a major flaw. Besides the long (5-7 minute) time required to get a signal after dropping the signal. My SDA in specific locations will continuously search for a signal. The time period is between 1 - 10 hours to lock onto a signal. Both Cingular and T-mobile phone of different models work in these locations. The T-mobile coverage map identifies these areas as strong signal. I have soft reset, hard reset and replaced my SIM card. The phone works in other locations just fine. Actually, I love the phone other than this problem. It is well documented in this thread at HoFo
http://www.howardforums.com/showthread.php...11&page=1&pp=15

I am reaching out to Modaco for a solution. From experience, Modaco users tend to be very technical and creative. I hope that I can use the SDA in the future. I don't want to have to switch to SE.

Problem Areas Identified by me
San Jose, CA
San Francisco, CA
Santa Clara, CA
Omaha, NE
Fremont, NE

Working Areas Tested by me
Denver, CO
San Jose, CA (home zip code)

You definitely get around a lot in the US. I have the same problem as you (I live in Seattle, WA), although to correct the problem a little quicker, I go into flight mode them back out, and it usually fixes it. Granted not quite the fix, but a quicker one than turning everything off, and such. I hope someone has a better solution.

On the side, did you only go to Omaha, NE, or do you know if T-Mo reaches down to Lincoln, NE. I'm going there for the weekend and wondering if I'll be able to do work there.

Good luck

June 6, 2006

I have had my SDA for 1 week and have identified a major flaw. Besides the long (5-7 minute) time required to get a signal after dropping the signal. My SDA in specific locations will continuously search for a signal. The time period is between 1 - 10 hours to lock onto a signal. Both Cingular and T-mobile phone of different models work in these locations. The T-mobile coverage map identifies these areas as strong signal. I have soft reset, hard reset and replaced my SIM card. The phone works in other locations just fine. Actually, I love the phone other than this problem. It is well documented in this thread at HoFo
http://www.howardforums.com/showthread.php...11&page=1&pp=15

I am reaching out to Modaco for a solution. From experience, Modaco users tend to be very technical and creative. I hope that I can use the SDA in the future. I don't want to have to switch to SE.

Problem Areas Identified by me
San Jose, CA
San Francisco, CA
Santa Clara, CA
Omaha, NE
Fremont, NE

Working Areas Tested by me
Denver, CO
San Jose, CA (home zip code)

I think most HTC smartphones have this problem to some extent. When they lose signal for any reason, it takes a few minutes to get the signal back. But "searching..." for hours is crazy. I believe T-Mobile shares its network with Cingular in Northern California. I am on Cingular and I can confirm that I can get good signal all over the Bay Area. So what you are seeing is certainly odd. The worst that I have seen with my Audiovox SMT5600 and i-mate SP5 is that when I get out the BART/Muni subway it keeps searching for 2 minutes. I put the phone in flight mode and switch it back out to force this to be quicker.

Pavan

June 6, 2006

I left Cingular for T-mobile, knowing that in California and Nevada they share the same network, thus coverage is the same with a Quad band phone. I had major billing and customer service issue with Cingular, which I want to put past me.

I am travelling to Europe for the remainder of the month. Apparently, this problem does not occur in Europe.

I believe it is a network and device issue combined. When T-mobile and Cingular are on distinctly different MCC MNC towers the problem does not exist. When they share service on the same towers (most likely 850) the phone can not register on the network. Signal strength is not an issue. When in an area where there are no searching problems, I can register quickly.

Next month, I may be in several other states and APAC where I will test the phone more. I signed up for a blackberry with Tmo and will have that as a back device for comparison.

June 8, 2006

I have this problem in austin, tx.

does the same thing, searching for ever.

I do the same thing as phreke, putting it flight mode and back.

June 8, 2006

I am in NJ, near the NYC metro area. Have the exact same problem.

There are so many times my phone is searching for signal, and my wife's nokia 6600 is making and receiving calls right thre in front of me. She is on the TMobile network as well ...

Beats me !

June 9, 2006

what rom are you using???

this one is the latest...

http://www.htcamerica.net/support/SDA_Clearvue.htm

June 9, 2006

My ROM actually is ahead of version posted by the link you gave. (because I flashed my TMO to Imate Rom)

ROM ver :2.0.8.0

Operator version : 2.6.331.2

radio version : 4.0.13.25_01.14.00

Edited June 9, 2006 by pankul

June 10, 2006

...
I believe it is a network and device issue combined. When T-mobile and Cingular are on distinctly different MCC MNC towers the problem does not exist. When they share service on the same towers (most likely 850) the phone can not register on the network. Signal strength is not an issue. When in an area where there are no searching problems, I can register quickly.

The MCC and MNC relates to the country code and network identifier parts of the IMSI and not to radio towers, so that sentance isn't technically correct.

Each cell does broadcast its PLMN information on the BCCH channel but this in itself doesn't prevent the sim from atempting to register with that tower.

The phone monitors surrounding cells and prioritizes them e.g. based on signal strength before selecting a new possible target cell.

Depending on the configuration in the SIM the phone may automatically select cells that belong to its Home PLMN, Registered PLMN or to a allowed set of Visited PLMNs. These lists of PLMNs are prioritized and stored in the SIM card.

How many PLMN's are stored is dependant on the size of the SIM (memory capacity) and operator configuration. As you can imagine it would be imposible to store all PLMN's from all posible networks you are allowed to roam on.

If the PLMNs found druring a search are not present in the SIM, the phone will atempt registration to them one by one starting with the strongest signal first. If registration fails, the PLMN will be added to the forbidden PLMN table in the SIM, so its not tried next time.

The forbidden PLMN table is only so big, so can only store 8 to 42 PLMN's - again depending on SIM capacity. (If you're interested the upper limit of 42 comes from the fact that PLMN info is 6 bytes long. The biggest size of the EF record in the SIM is 255 bytes because the length parameter in the command the phone sends is only one byte. Therefore 255/6 = 42.5 means only 42 PLMN's can be stored in 255 bytes, regardless of how much space the SIM has)

Anyway, the PLMN info encodeds the network only and NOT the frequency. So when your phone turns on, it searches each frequency one by one, 900mhz, 1800mhz, 1900mhz and finally 850mhz.

The search period can be encoded in the sim, but is usually 60 to 90 seconds from my experience.

You would think that the US t-mobile ROM would prioritize the search order 1900,850,900,1800 or 850,1900,900,1800 - but this doesn't seem the case. Thus your phone wastes 60 to 90 seconds searching each band. I beleive the phone remembers the last band it was on if you turn it off, but if you move into a no reception area, it will move to the other bands searching for other towers to roam onto - again rotating 900,1800,1900,850 repatedly.

This is why when you go into a subway for example, the phone may be searching the 900mhz band by the point you return to a reception area, and it can take several minutes before it gets to the 1900 or 850 bands.

By switching flight mode on and off, it reverts to the last band it saw you had reception on, the same as if you turn the phone on and off. This may not work all the time - more why later.

This problem arises on all tri band and quad band phones which havn't had their search list cusomised to the target market.

A worse problem occurs when you move to a new geographic location where the PLMN's may not be in your forbidden list. In this case the phone can waste time atempting to register to other network towers, and rewriting the forbidden PLMN table as each fails. This means the problem may repeat when you return to your home location, as the forbidden PLMN's for that location may have been overwritten due to the limited space available.

Even worse, because the phone electronically switches to each band it can only handle PLMN's on one band at a time. Take the situation where you moved from your home state to another state and turned on the phone. You are on cingular 850Mhz, but in this state AT&T at 850Mhz and 1900 Mhz exists.

- Search 900 band - 60 to 90 seconds - search expired

- Search 1800 band - 60 to 90 seconds - search expired

- Search 1900 band

--- Strongest Found AT&T 1900Mhz , try registration

--- Failed, add to forbidden PLMN list

--- Try next PLMN - non found Wait 10 seconds - PANIC! retry AT&T

--- 60 to 90 seconds + registration failed times later - search expired

- Search 850 band

--- Strongest Found AT&T 850Mhz , try registration

--- Failed, add to forbidden PLMN list

--- Try next PLMN - Found Cingular 850Mhz, try registration

--- Registration successfull

Total time -> anywhere from 60 + 60 + 60 = 180 seconds to 90+90+90+registration failed = 270 to 320 seconds

** this is the case where flight mode switching may not work for 'leaving the subway' scenario. The location of AT&T at 1900Mhz may prevent the phone from switching firectly to 850Mhz after flight mode toggling. Thus you may still need to wait 60 to 90 seconds + registration failure time.

Another bad situation is where you have two networks you can roam on, on two different bands. The phone may pick up a weak signal on the 1900 band, and drop in and out, never switching to the 850 band at all.

The reason for all these problems is that GSM was never really designed to hop between different frequencies. It may well be frequency indipendant, but no one sat down and thought about storing the frequency in the PLMN select table as well because at the time the GSM 11.11 standard was made up, only the GSM 900 band was envisaged.

Really its not a HTC problem per se, and customizing the ROM for a US search order would make the phone work alot better in the US. Put it this way, us europeans have the exact same problems when using european nokias etc in the US. The only difference being that the nokia search mechanism is a little differently organised so its faster in some cases and slower in others.

Also note alot of phones make you manually change band type to prevent these problems.

The only thing you can really do to speed things up is do a manual search when you get to your new location. Pick ever other network you know it won't work with - so they get put into the forbidden PLMN table, and then pick your network last. This should fix the problem.

Any questions, feel free to ask.

EDIT:

I noticed one of the posters is using the i-mate rom instead of the T-Mobile one, are you as well? In this case perhaps the T-Mobile US ROM does reorder the search list, but the i-mate one doesn't (since there's only a World Wide version of the i-mate ROM)

Edited June 10, 2006 by kam_

June 10, 2006

WOW!! Thanks a lot kam_ for the detailed explanation. This is the best analysis I have ever come across for this nagging problem.

Anyway, the PLMN info encodeds the network only and NOT the frequency. So when your phone turns on, it searches each frequency one by one, 900mhz, 1800mhz, 1900mhz and finally 850mhz.

Now I use an i-mate SP5 with a Cingular SIM card. Is there any way I can tell my phone, "don't bother with the 900 and 1800 bands"? Sounds like this would save at least half the time in the subway scenario. Of course, I want to be able to disable the tweak when I am travelling outside the US :)...

The search period can be encoded in the sim, but is usually 60 to 90 seconds from my experience.

Also, is there a way to shorten the search period? How long does it really take for the phone to find a tower anyway -- would it fail to find the right towers if it was shortened to say 30 seconds? Again if this is workable, it would save half the time spent searching.

Thanks again for a most useful explanation!

Pavan

PS: Even with my non-existent technical knowledge in this area, it seems obviously dumb that they (whoever "they" are) don't have separate forbidden table for each band... or at least store the frequency alongwith the tower identifiers! I guess GSM is one of those things that became more successful than the initial designers anticipated or planned for.

June 11, 2006

Now I use an i-mate SP5 with a Cingular SIM card. Is there any way I can tell my phone, "don't bother with the 900 and 1800 bands"? Sounds like this would save at least half the time in the subway scenario. Of course, I want to be able to disable the tweak when I am travelling outside the US :)...

I could tell you how to do it in a nokia.. but not a HTC. I can see if i can find anything in the registry maybe. I personally think the phone manufactuers should have this as a configurable option in their phones. At the least you should be able to choose between 900/1800 only, 850/1900 only and 900/1800/850/1900.

Also, is there a way to shorten the search period? How long does it really take for the phone to find a tower anyway -- would it fail to find the right towers if it was shortened to say 30 seconds? Again if this is workable, it would save half the time spent searching.

I was writing from memory and just looked this up. Actually ONLY the HPLMN search period is stored in the sim to a resolution of minutes. In a no reception case tho, this will effectively be the search period for any PLMN. Typically this is set very high, because in a roaming situation the phone looks for the home PLMN ever 'HPLMN search period' minutes. If this were set too low you would see battery life decrease when roaming. If set to 0, then you would need to manually switch to other networks when already locked to one.

Anyway this field is usually not protected and with a SIM reader and some free software you could modify it yourself. How usefull that would be is a nother question tho. It apears i got it slightly wrong, and that with multiband phones the search period in a band ISNT actually standardised. However it is 30 to 90 seconds from my experience.

PS: Even with my non-existent technical knowledge in this area, it seems obviously dumb that they (whoever "they" are) don't have separate forbidden table for each band... or at least store the frequency alongwith the tower identifiers! I guess GSM is one of those things that became more successful than the initial designers anticipated or planned for.

Well yes and no. The reason for problems like this is that they have to maintain backward compatability of SIMs so that they work with phones that were made using an earlier definition of the standard. There are workarounds, but none are ideal, and they won't fix this problem in the standards unless it becomes widespread. Anyway the GSM SIM definitions are closed now and they're working on USIM now. Fortunately USIMs have alot less restrictions as they can run applications. An operator could then choose to make his own solution.

June 12, 2006

Thanks again for a detailed reply! Let me know if you figure out how to "disable" some bands on HTC phones. Even if it's a registry based solution, I can see myself creating separate CAB files with the registry settings for US and non-US operation...

June 14, 2006

Thanks for taking the time to explain all that -- my SDA performed fine in this respect until I flashed it with the iMate ROM -- too much useful new stuff for me to flash it back, but will definitely flash an updated T-Mobile SDA ROM when available.

FYI -- it was the worst ever on a recent trip to Vegas -- constantly switching between T-Mobile and Cingular, and a lot of 'searching....'

The MCC and MNC relates to the country code and network identifier parts of the IMSI and not to radio towers, so that sentance isn't technically correct.

Each cell does broadcast its PLMN information on the BCCH channel but this in itself doesn't prevent the sim from atempting to register with that tower.
The phone monitors surrounding cells and prioritizes them....
.....one of the posters is using the i-mate rom instead of the T-Mobile one, are you as well? In this case perhaps the T-Mobile US ROM does reorder the search list, but the i-mate one doesn't (since there's only a World Wide version of the i-mate ROM)

Edited June 14, 2006 by chaznet

August 8, 2006

Whelp, after searching around at least I know I'm not crazy.

I've had my SDA since late March and have always had this same issue. In San Francisco, LA, Vegas, Orlando, wherever....whenever I lose reception, it can take 10 minutes, 20 minutes, 60 minutes, 300 minutes...whatever to regain it. The worst part of it is that I tend to notice when I go to use my phone and then it makes me wonder how long it's been trying to reconnect. I've never tried the flight mode trick, but usually shutting off my phone, taking the battery out, putting it back in, and rebooting the phone does the trick. A very annoying process. Whenever I do get reception again, always turns out I've missed an important call or two.

I'm almost at the point of just putting my SIM card in my old Samsung E715 because my fiance and I are going to have a baby any day now and I'm afraid I'll be away and miss the all too important call that it's time to go to the hospital because of this rediculous optimization.

I've been hoping a firmware update to fix this issue would have been released by now. But I haven't even seen much talk of some type of update to curve this problem. Or just with SDA reception in general. In some buildings in SF I'd quickly lose reception while my fiance with her Samsung E315 (on T-Mobile) would still have a decent 3 bar signal. I recently moved from San Francisco to Pleasanton, CA (about 35 minutes from San Francisco) and I get one bar on my phone 95% of the time in my place, if I don't lose reception. My fiance has a Samsung E315 and gets two, sometimes three bars. I tried my old T-Mobile phones (old Samsung E715, another old samsung, and a nokia phone) and all have 2 or 3 bars most of the time. A friend with an SDA came over tonight and he had basically no reception in my place.

So with that, I hope a firmware update is released that assists in resolving both the "searching..." issue and the signal issue. Sidekick 3 just came out and have heard that there's already a firmware update on the way that fixes some of its reception issues. Wish the SDA got the same support.

Almost wish I didn't sign a new contract with T-Mobile early this year or I'd just go with another carrier at this point. Enjoy T-Mobile, but the coverage in the area I'm in now is weak and other carriers are said to be much better. But alas, I'm stuck with them for now and have to deal with it.

Edited August 8, 2006 by DaToole

August 21, 2006

that's solved if you use latest c600 2.0.14.0 rom... although you must tweak the registry in order of having wifi and media buttons to work

August 23, 2006

Try this radio (version 4.1.13.19_02.37.01). It supposedly fixes the 'searching' problem:

http://www.modaco.com/Tornado-Radio-Update...01-t244555.html

Edited August 23, 2006 by merwin

September 6, 2006

So does this really solve the 'searching' issue? I have yet to find a solid report that says that it does.

September 6, 2006

So does this really solve the 'searching' issue? I have yet to find a solid report that says that it does.

My phone recovers from "Searching" now after about 1 minute (compared to 5 to 10 minutes before).

September 7, 2006

I just updated my radio to 4.1.13.19_02.37.01 based on the instruction from the thread mentioned above. Let us see what happens.

for other people who want to try it... go ahead, as I did not lose any info. ints only a radio update.

I will post results as I find them

October 2, 2006

After few weeks of testing by living in poorly lit up sites like my home and work. I must say that this problem is not fixed by the radio update.

:rolleyes:

October 2, 2006

After few weeks of testing by living in poorly lit up sites like my home and work. I must say that this problem is not fixed by the radio update.
:rolleyes:

Can you go into more detail? What ROM are you using?

October 2, 2006

Can you go into more detail? What ROM are you using?

Here's the link with the radio update:

http://www.modaco.com/Tornado-Radio-Update...01-t244555.html

October 3, 2006

Here's the link with the radio update:
http://www.modaco.com/Tornado-Radio-Update...01-t244555.html

Sorry - I should've been clearer, I was asking pankul for more details on why the radio update was NOT working - what ROM he was using, etc. - because it seems that most of the people using it says that it IS working.

January 30, 2007

I tried this and it worked for me

Goto regedit:

HKEY_LOCAL_MACHINE

System

State

Phone

Click on Values, then Change signal strenght from 100 to 150 and Signal strenght Raw from 100 to 150

I have had my SDA for 1 week and have identified a major flaw. Besides the long (5-7 minute) time required to get a signal after dropping the signal. My SDA in specific locations will continuously search for a signal. The time period is between 1 - 10 hours to lock onto a signal. Both Cingular and T-mobile phone of different models work in these locations. The T-mobile coverage map identifies these areas as strong signal. I have soft reset, hard reset and replaced my SIM card. The phone works in other locations just fine. Actually, I love the phone other than this problem. It is well documented in this thread at HoFo
http://www.howardforums.com/showthread.php...age=1&pp=15

I am reaching out to Modaco for a solution. From experience, Modaco users tend to be very technical and creative. I hope that I can use the SDA in the future. I don't want to have to switch to SE.

Problem Areas Identified by me
San Jose, CA
San Francisco, CA
Santa Clara, CA
Omaha, NE
Fremont, NE

Working Areas Tested by me
Denver, CO
San Jose, CA (home zip code)

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