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Design & Build Better Cell Phone Antenna?

Discussion in 'Electronic Design' started by [email protected], Apr 8, 2013.

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  1. Guest

    Have a new small LG cell phone that has worse coverage than older larger cell phones.

    If I could, would exchange my LG for another cell phone with better coverage.

    I am not an antenna designer but have lived in marginal FM & TV areas where a simple improvement in antenna made a significant difference in reception so would like to design and build a better antenna for my cell phone.

    Am interested in any suggestions or comments by anyone (especially someone who has actually done this).

    Thanks

    Ken
     
  2. miso

    miso Guest

    I can't believe the iphone needs that junk.

    If you want signal strength, use the app at www.cellumap.com. You get
    the signal strength at the phone and tower. You can also upload it to
    the database if you want to provide the data for public consumption. The
    upload includes rather detailed information about your phone, and of
    course the location. Best not to upload the data at your house or any
    place where you wouldn't want to be know to frequent (McDonalds, dive
    bars, whore houses, crack houses, the Apple store, places like that.)
    Because the 'hits" are very specific, it is possible to identify each
    user. Then if you click at your house, you are totally tagged.

    My impression is the developers kind of got bored with the project.
    There certainly are improvements that could be made. For instance, in
    the boonies, where you are likely to roam, it would be nice to see any
    specific type of signal (i.e. all GSM or all CDMA), and then figure out
    if you have the right to roam on that network. For instance, T-mobile
    could be using AT&T,Cellular One, etc. The database has a few bugs in it
    in that some of the hacked Android phone OSs show up as networks. For
    example But in any event, the app is great for reading signal strength, even if
    you don't upload.

    I have noticed that the OS can alter the signal strength of the phone.
    That is, the OS can change the decision criteria for power level. So an
    upgrade of the firmware can change the situation.
     
  3. Guest

    Hi Jeff,

    "What model LG phone?" LG 320G

    "Which service provider?" TracFone using AT&T network

    "Built a coupling loop or patch antenna to cover the built in antenna." Like this idea want to keep things simple.

    Searched the forum using "coupling loop" and found a 1999 post "Energy-sucking radio antennas!" https://groups.google.com/forum/?fr...i.electronics.design/cBLfoRXSN7U/c9nlBn-lGuoJ

    Did a quick read but not fully understand the technical.

    Googled and found some more recent hits

    "PDF] A Miniature Coupled Loop Antenna to be Embedded in a ... - Piers
    https://piers.org/piersproceedings/download.php?file... by SY Lin ProgressIn Electromagnetics Research Symposium Proceedings, Xi'an, China, March 22–26, 2010. 721. A Miniature Coupled Loop Antenna to be Embedded ..."

    "Inductively Coupled Loop Antenna By Werner Funkenhauser and Pete Haas" http://www.hard-core-dx.com/nordicdx/antenna/loop/inducloop.html
    For AM radio

    "coupling loop for loop antenna bu Jim" http://www.radiobanter.com/showthread.php?t=74935 For FM radio

    Also checked Loop antenna Wiki http://en.wikipedia.org/wiki/Loop_antenna

    Decided to narrow my search to coupling loop antenna "cell phone" and found"A MEANDERED LOOP ANTENNA FOR LTE/WWAN OPERATIONS IN A SMART PHONE C.-W. Chiu and C.-H. Chang" http://www.jpier.org/PIERC/pierc16/12.10072503.pdf

    Finally found "Printed Coupled Loop Wideband Antenna Design for Wireless Communication" http://www.techrepublic.com/whitepa...na-design-for-wireless-communication/32879207 but was unable to DL.

    Probably the best I have found to date is "Patent application title: Loop antenna for cell phone having a metallic or non-metallic casing by Chi-Ming Chiang" http://www.faqs.org/patents/app/20100087235#ixzz2PzBb7hYT

    Also took the back of the LG320G off but did not see anything that looked like an antenna. If you tell me where to send or how to post will send photo.

    Probably more informative would be parts breakdown for LG3320G but have notyet found it.

    Thanks for the link. After viewing the video decided to check if anyone had reviewed it and found "Absolute Linkase Review by Lisa Eadicicco on April5, 2013...The Verdict: Absolute's Linkase iPhone 5 case sports a sleek andfashionable design, but doesn't do enough to improve your phone's Wi-Fi signal."
    http://www.laptopmag.com/reviews/accessories/absolute-linkase.aspx

    Hope a DIY Loop Antenna will do better.

    Thanks again for your help!!!

    Ken
     
  4. Guest

    Hi Miso,

    Thanks for your suggestions and links.

    Ken
     
  5. miso

    miso Guest

    Yes, unless people play the game, crowd sourcing doesn't work. I upload
    AT&T reception via wifi at coffee shops just to be nice.
    If you have tower locations, you can make those maps. I have open source
    software to do it. The problem is you don't always know the tower
    locations and possibly the roaming partners in the boonies. Cell towers
    are no longer in the FCC database, or perhaps don't have to be in the
    FCC database is more correct since some towers do show up. All those
    sites on the sides of buildings are handled by a general FCC
    authorization where if the local municipality is OK with the site, then
    that is all it takes to put it up. So in an urban area the vast majority
    of cell sites are not documented in the FCC database.

    This guy started a database, but hasn't updated it in years:
    http://sfocellsites.com/

    Google has a database of cell sites that you can access through a API,
    but it so full of errors that it is useless. I have another app to get
    this information, but it is not worth the effort due to the poor
    accuracy. To be specific, poor accuracy in GSM type towers. CDMA towers
    supposedly report their exact GPS locations. Why the hell GSM doesn't do
    that is a good question. So with the proper app, you could get all the
    CDMA tower locations.

    If you have a rtlsdr (and I bet you do), you can search for LTE signals
    and then get signal strength. You can also detect the frequency error of the rtlsdr using the LTE
    tower as a reference. The 700MHz band LTE can be found, but the dongles
    quit around 1760 or so, which is not high enough to get the T-Mobile LTE
    carriers.
     
  6. info%

    info% Guest

    Hi All!

    =================
    =================

    First I'd like to say thanks for using my program! I'm aware of the glitches you mentioned, but couldn't find any "cleaner" way to do it, so that's just kind of how it is. I haven't gotten "bored" with the project, I just gotit working to a point where it was working pretty good and decided to leave it like that for a while. I'd like to add LTE to it soon, so I may get back to work on it sometime this year.

    PS- It's just me so it's "developer" in the singular term ;)

    ==============
    =============
    I think we found the problem ;) LG makes really bad GSM/UMTS phones (their CDMA is a little better). If you want a budget GSM phone with good reception, get a Nokia, or Motorola. Otherwise look into a repeater, or femtocell (but you'd have to get an AT&T subscription for that to happen I believe)

    ==============
    ===============
    Thanks again for using my app. I actually built in in 2008-2009 as an experiment on my Nokia N95 phone. I built it to use for myself originally, but then decided it would be cool to open it up to the public to see everyone elses coverage plots as well. It's coming up on 1 million points soon, I'm glad to see people all over the world have found it useful for various purposes :) The app is free and the advertising barely pays for the server, so I'm definitely not in it for the money ;) I am a cellular network engineer, so it's an interest of mine.

    ===============
    ================

    SNR is "Signal to Noise Ratio" and tells you how "clean" the signal is (ie:if it has alot of interference or not). The "Power control" in the phone and base station determines how much the transmit level should be. SNR playsa factor, but signal loss does as well.

    RSSI (Receive Signal Strength Indication) is what's shown in the Cellumap app. That's the total received signal power, interference and all.

    ================
    =================
    That's a nice plot, what open source software did you use to make that? Most simulation software (like TEMS) is usually very expensive. Also, how do you determine what transmit power and antenna gain to use?
     
  7. miso

    miso Guest

    The open source way to make such plots is with radiomobile or splat! However, you don't always know where the tower is located. Or if you do
    know where the tower is located, you don't know about the cell on the
    side of a building, i.e some place where a tower wasn't erected.

    I leave cellumap hits quite often. I was at a place where GPS use was
    not allowed, so I left a cellumap hit just for the lols. Cell phone use
    wasn't banned, just GPS.

    I don't know if you saw my post, but the cellumap web interface could
    use an upgrade. Often I want to see ANY service, rather than specific
    service. That is, I may need a burner phone for a certain region, but I
    don't know the carrier. Presently you have to pick the carrier on the
    webpage, then look at the map. So it would be nice to show all GSM or
    all CDMA. Then you could contact your carrier to see if you can roam there.

    I used the Fairview app, but they got bored and dropped it. The nice
    thing about fairview is you could keep the hits on your phone. It would
    be nice if cellumap could do that, then upload later. I would force my
    phone to competing networks just to get the data, then upload when I was
    back on a network where I had service.

    The only other alternative to cellumap is opensignal, but their maps
    lack the data to back up the signal strength. For instance, if an iphone
    has poor reception, that doesn't mean my phone will have trouble. In
    fact, I've gone to spots where the cellumap showed poor reception and
    left a hit showing the area is just fine.
     
  8. miso

    miso Guest

    The open source way to make such plots is with radiomobile or splat! However, you don't always know where the tower is located. Or if you do
    know where the tower is located, you don't know about the cell on the
    side of a building, i.e some place where a tower wasn't erected.

    I leave cellumap hits quite often. I was at a place where GPS use was
    not allowed, so I left a cellumap hit just for the lols. Cell phone use
    wasn't banned, just GPS.

    I don't know if you saw my post, but the cellumap web interface could
    use an upgrade. Often I want to see ANY service, rather than specific
    service. That is, I may need a burner phone for a certain region, but I
    don't know the carrier. Presently you have to pick the carrier on the
    webpage, then look at the map. So it would be nice to show all GSM or
    all CDMA. Then you could contact your carrier to see if you can roam there.

    I used the Fairview app, but they got bored and dropped it. The nice
    thing about fairview is you could keep the hits on your phone. It would
    be nice if cellumap could do that, then upload later. I would force my
    phone to competing networks just to get the data, then upload when I was
    back on a network where I had service.

    The only other alternative to cellumap is opensignal, but their maps
    lack the data to back up the signal strength. For instance, if an iphone
    has poor reception, that doesn't mean my phone will have trouble. In
    fact, I've gone to spots where the cellumap showed poor reception and
    left a hit showing the area is just fine.
     
  9. Guest

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