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From: DevilsPGD on 5 Jul 2010 01:29 In message <tvb236lnelaof6i0i4tto0fsr5bu8pnu8a(a)4ax.com> John Navas <spamfilter1(a)navasgroup.com> was claimed to have wrote: >On Sun, 04 Jul 2010 18:05:14 -0700, in ><2ub236haaai7n6qsq9fdq3k9jejgjqgklh(a)4ax.com>, DevilsPGD ><Still-Just-A-Rat-In-A-Cage(a)crazyhat.net> wrote: > >>In message <sLTXn.8277$3%3.7081(a)newsfe23.iad> Todd Allcock >><elecconnec(a)AnoOspamL.com> was claimed to have wrote: >> >>>A good cloud service, like Exchange, uses the cloud as an intermediary >>>between devices, as well as a backup. I sync two mobiles and three PCs >>>with my cloud service. If my provider crashes e or vaporates tomorrow, >>>my data is safe in five locations, any of which can restore the data to >>>another server/provider. >> >>Sidekick was similar, except that data was lost after a reboot. > >The Sidekick data was recovered. The problem was incompetant >administration by Microsoft, not the technology. > >>Although it's not as easy a reboot to lose your data in the event of an >>Exchange failure, if the Exchange server comes back up with a blank >>mailbox (using the same credentials) you'll lose all your data on the >>device. Even worse, should you attempt to remove the account from your >>device or change it to a new server, you'll again lose all your data. > >Not if it's backed up properly. That's easier said than done on many devices. >>The model of treating the server as authoritative is a good one in >>general (SyncML is an example of the disaster that happens without an >>authoritative owner) > >SyncML works quite well. It can, if both the client and server happen to share a common set of fields, have similar capabilities, handle all-day events similarly, handle timezones similarly, and never happen to get out of sync. Since this never actually happens unless you happen to have a client and server written by the same folks, the real world is a bit messier. Try supporting a Razr's native SyncML client on virtually any SyncML server out there to see what I mean. Oh, and a restore of either side to a backup made before the most recent sync will result in a permanent out of sync situation unless the user understands how to perform a one-way sync, or is willing to live with (or fix) the duplicates created by a slow sync.
From: Larry on 5 Jul 2010 01:43 Jeff Liebermann <jeffl(a)cruzio.com> wrote in news:q8i136d4hnv31cdkvrpq28cmu594kmv5gd(a)4ax.com: > On Sun, 04 Jul 2010 15:07:50 +0000, Larry <noone(a)home.com> wrote: > >>Jeff Liebermann <jeffl(a)cruzio.com> wrote in >>news:ch1036t0runcdu2aik64spu0pn9o268tva(a)4ax.com: >> >>> Matching >>> a wide range of frequencies is not. > > Hint: I do some antenna design in my spare time: > <http://802.11junk.com/jeffl/antennas/> > >>http://en.wikipedia.org/wiki/Log-periodic_antenna >>http://www.radio-electronics.com/info/antennas/log_p/log_periodic.php > > A log periodic antenna will not fit inside an iPhone. It's also > rather directional, which is not what's needed in a cell phone. With > small antennas, the efficiency is what usually goes down the drain > first. Directionality goes next, as small antennas like to radiate in > a spherical pattern, which mangles the SAR test. Most cellular > antennas are loaded monopoles, PIFA, fractal, or just plain squashed > into a pretzel. If I'm lazy, I just input the target specs into the > modeling program, fire off the optimizer, and leave for a short > vacation. When I return, I have a weird looking, best effort antenna, > which usually works amazingly well. > > Incidentally, I have built LPDA antennas on e=10 ceramic substrates, > which will reduce the size by about a factor of 4. However, for > 800-1900MHz, it's still to big for inside a cell phone. > >>http://www.tpub.com/content/et/14092/css/14092_35.htm > > Close. That's a conical dipole. Inverting the cones results in a > bi-conical, which is an excellent broadband dipole. However, it has > the same problem as the LPDA. It won't fit. > >>http://www.ramseyelectronics.com/downloads/manuals/DA25.pdf > > That's a discone. It's half a bi-conical, with a capacitive hat. It's > one of the worst antennas ever sold, were it not for the advantage of > having a huge bandwidth. For a base station, if you don't mind having > all of your RF going well above the horizon, it's fine. That's why > you see it at airports. > >>Here's your slot iPhone 4 antenna...nothing new... >>http://archive.electronicdesign.com/files/29/9986/figure_01.gif > > Hmmm.... 5 different antennas. Here's some exploded views of the > iPhone that might help you identify which of the 4 antennas is in the > iPhone 4: > <http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/> > Hint: The stainless frame is not a patch antenna because it's no > suspended above a ground plane. It's also not a loop because it's > broken into 2 seperate antennas (one for BT and Wi-Fi, the other for > cellular). There's no meandering line or slot. > > However, the iPhone 4 antenna might be a PIFA antenna, which is the > "inverted F" in the picture. I can't tell from the photos or the FCC > page. When I get my hands on an iPhone, or better photos, I can make > a determination. I wouldn't be surprised if the frame antenna is just > a piece of wire with a messy matching circuit. > >>http://ceta.mit.edu/PIER/pier86/10.08090701.pdf >>very broadband antennas can be made for microwave frequencies from PC >>board material. > > Yep. UWB antennas are difficult but possible. However interesting, > the iPhone 4 is not a UWB device and only needs to operate on 800, > 900, 1800, and 1900 MHz. > >>http://www.sumobrain.com/patents/wipo/Broadband-tem-horn- antenna/WO1997 >>012252A1.pdf > > That's a horn antenna. I'm trying to visualize how one would use a > horn antenna with a cell phone. Certainly they're broadband, but are > more suitable for illuminating a dish antenna, than cramming into a > cell phone. Same problem as the others... too big and too > directional. > >>Matching a wide range of frequencies isn't much of a challenge in >>2010. > > It is difficult in a cell phone. If you don't care about size, shape, > directionality, SAR, gain, and price, it's easy. > > Hint... do some searching in the IEEE Antennas and Propagation > Journal: > <http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=74> > Type "cellular antenna" into the search box near the top of the page. > You won't get the contents, but the abstract should be sufficient for > this exercise. 3800 articles. > >>Placing the antenna where it will have a reasonable chance of >>radiating into space is becoming more and more of a political problem >>as the greenies take over the political system. > > That's true for cell sites. I'm somewhat involved locally in the > process. However, I don't think that politics had anything to do with > the design of the iPhone 4 antenna. > Geez, Jeff....I was making a JOKE! 73 DE W4CSC -- Global Warming and Creationism are to science what storks are to obstetrics... Larry
From: Larry on 5 Jul 2010 01:46 Jeff Liebermann <jeffl(a)cruzio.com> wrote in news:4cp136pa0cel3fe6u2cogopnt6fd4fd3ic(a)4ax.com: > Where the FCC > is going to find 500MHz of spectrum of uncontested spectrum needed for > mobile and fixed wireless (actually for auction), is anyone's guess. > > We just ran the analog TV broadcasters off a huge piece of real estate..... -- Global Warming and Creationism are to science what storks are to obstetrics... Larry
From: Larry on 5 Jul 2010 01:49 Jeff Liebermann <jeffl(a)cruzio.com> wrote in news:ujb236pbt0umnad7rmcqav60qp55k20nd9(a)4ax.com: > Assuming the FCC want to make a substantial profit on this auction, it > would not make much sense for the broadcasters to sell. Huh?? The broadcasters don't own the frequencies they've been using since WW2. Those are all public airwaves. FCC doesn't need any permission as the broadcasters are slaves to the FCC, not the other way around.... I think it should be a Federal felony to SELL the public's airwaves to anyone or any entity. What the hell are they gonna sell next, Yellowstone National Park?! It's not theirs to sell, dammit. It's OURS. -- Global Warming and Creationism are to science what storks are to obstetrics... Larry
From: John Navas on 5 Jul 2010 01:52
On Sun, 04 Jul 2010 22:29:10 -0700, in <f8o236pjsh5dedba2jvttou9aho7ediasi(a)4ax.com>, DevilsPGD <Still-Just-A-Rat-In-A-Cage(a)crazyhat.net> wrote: >In message <Xns9DAB71F4CB77Enoonehomecom(a)74.209.131.13> Larry ><noone(a)home.com> was claimed to have wrote: > >>Ruling out other causes is very easy. Just pick up the cheapest free phone >>ATT sells and dial out a call right next to iPhone 4. Does the call work? >>Yes? Not the infrastructure or traffic's fault. That points it quickly at >>the real cause of failures.....iPhone 4's defective antenna system. > >I had a friend down in the US try it. He can reproduce the signal drop >problem fairly easily, but only when he's in an area with already >marginal signal. Luckily his daily commute passes through just such an >area so he's been able to test. > >The only way he can get the iPhone 4 to drop a call is to keep driving >until his other phone drops a call, then grab his iPhone 4 the "wrong" >way. > >If he leaves both sitting on the seat beside him, the iPhone 4 holds on >to the call longer. If he holds it the "wrong" way, it's about 50/50 >which call drops off first but they're very close. > >Testing was done on a 3G Blackberry of some sort, I believe he's using a >Bold these days. So he's got a bum Blackberry too. ;) Ask him to try a better Nokia or Motorola. -- John "Assumption is the mother of all screw ups." [Wethern�s Law of Suspended Judgement] |