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Cellular Phone Forum / Providers / Verizon / January 2005Do I mean "Rx"?--What's a good one?
Tx, Janie > Tx, > > Janie Problems communicating? Notan No, I've simply read different places that the Moto 265 has "superior RF" (?) when compared to the LG 6100 and wondered what a "good" RF is. Tx. >> Tx, >> [quoted text clipped - 3 lines] > > Notan It's relative (and more than likely subjective if you heard it here). They are simply saying that they either see more boars on their 265 than they thought they saw on their 6100 (or their friends) or they found that they could get a signal on there 265 in locations where they couldn't on their 6100. 90% of people on here don't know what a db is. They are simply comparing subjective impressions derived from end usage (making calls and looking at the bars). Naturally there are a lot of additional factors that go into the end result. How good the RF section of the phone is could be one of them. My wild guess is that there isn't a whole lot of variation in RF design from one phone to another. I suspect that the 1/2 wave length antenna on my Kyocera 7135 compared to the normal 1/4 wave length antenna found on most CDMA phones makes a whole lot more difference than the RF chips used in it compared to others. There is good information when numerous people post to say they tried this phone and that phone and got better reception with one or the other. This can be taken into account to weight one's decision when choosing a phone. I think your question is quantitative and you will probably not get an answer here. I believe you're asking for some standard RF test measure. For example given a signal of a certain power, what is the db of the received signal at a certain distance under controlled conditions. Given this measure what qualifies as "good". -Quick > No, I've simply read different places that the Moto 265 > has "superior RF" (?) when compared to the LG 6100 and [quoted text clipped - 9 lines] >> >> Notan > .... 90% of people on > here don't know what a db is. > > -Quick Just for starters, one-tenth of a Bel is a "dB", not a "db". >> .... 90% of people on >> here don't know what a db is. [quoted text clipped - 3 lines] > Just for starters, one-tenth of a Bel is a "dB", not a > "db". Well, I spelled "there" and "boars" wrong. This wasn't a spelling mistake though, just an error. I gave up shortly after they started using "K" for both 1024 and 1000. It was about the time they followed up by making "B" and "b" ambiguous -:) It probably was OK in the context of my reply but my bad none the less. I believe you're one of the 10%. Are there some basic tests and measures commonly used for RF sensitivity (in phone or similar applications)? Is there any significant variation in the RF section design of mainstream cell phones? Is there any significant variation in performance? Was I correct in the assumption that the physical antenna is probably the most significant contributing factor to performance in cell phones? -Quick Doh! > Was I correct in the assumption that the physical antenna > is probably the most significant contributing factor to > performance in cell phones? that should read "RF performance". -Quick >>> .... 90% of people on >>> here don't know what a db is. [quoted text clipped - 10 lines] > ambiguous -:) It probably was OK in the context of my > reply but my bad none the less. No problem. I hate that "M" can be a thousand or a million, too. > I believe you're one of the 10%. Thanks. Even your 10% estimate could be generous. Just see how many circuit-design people will try to distinguish between "Voltage dB" and "Power dB", for instance. > Are there some basic tests and measures commonly > used for RF sensitivity (in phone or similar applications)? What I think is the best receiver measurement isn't commonly used. Noise Figure, or equivalent Noise Temperature would be my engineering choice, but you'll rarely see that quoted anywhere. Without that, we're stuck with an ambiguous number involving microvolt sensitivity, which isn't defined by everyone the same way. > Is there any significant variation in the RF section design > of mainstream cell phones? I'm no expert there, but I think a large number of handsets use Qualcomm chips, which give everyone about the same starting point. I think Qualcomm has gone, or is going toward, direct conversion to baseband, which means heterodyning in one step down to an intermediate frequency of zero. I used to say that couldn't work well, but Qualcomm has some extremely respected engineers, and if they say it works, I'm inclined to believe them. > Is there any significant variation in performance? > Was I correct in the assumption that the physical antenna > is probably the most significant contributing factor to > performance in cell phones? Yes, there's some variation in performance among handsets, but it'll take an expert from that technical specialty to tell us why. In some cases it could be antenna style and/or placement. In other cases it could be better or poorer impedance matching between the antenna and the circuitry. I can tell you from direct, first-hand experience that antenna design for handhelds is a hot technical specialty all over the world. The antenna people are doing the very best they can, considering the difficult constraints imposed by the handheld environment. I have one friend, in fact, who designed a kind of triple-unit antenna for handhelds, working in space-diversity mode to combat selective fading in narrow-band telephony like GSM and other TDMA systems. (It's not effective for CDMA, though, because of the wider bandwidth.) That antenna is used in some current-production handsets by NTT. Given all that, my personal opinion is that the antenna is only a second- or third-most abused factor in practical handset design. I readily agree with you that it could be the top factor if were not being handled as well as it is. Too many user complaints involve poor audio quality, so I think that the mundane area of audio has suffered from design compromises. But without any inside information, my opinion is no better than yours. >>>> .... 90% of people on >>>> here don't know what a db is. [quoted text clipped - 96 lines] > But without any inside information, my opinion is no > better than yours. Thanks. That's pretty much what I figured. I lump the impedance matching in as being part of the antenna so that should move it up a notch. (I'm feeling pretty full of myself. I only had to mumble when I read "space diversity mode". Not bad for an upper level software guy.) -Quick > (I'm feeling pretty full of myself. I only had to mumble > when I read "space diversity mode". Not bad for an > upper level software guy.) > > -Quick Ah, good deal. I used to do system software, too, Quick. At first I thought my buddy's antenna had to be polarization diversity, because I thought his spacings were too small to allow space diversity. But he gently corrected me, saying that he had *just barely* enough distance available in the handset to make space diversity work for him. Thanks, Quick, for your explanation. I realize how stupid I am when I ask a question that I think can be answered by "XX", only to find out that I have no clue what I'm asking. When I first got my 4400 (now have a 6100) my phone was not connecting properly with the tower and consequently didn't ring 1/2 the time. I wrote about it on here and Josh told me how to check the RF. I thought that I could remember what a "good" reading is because it's only been a year and a half, but I can't. I'm sure it doesn't even matter anyway, I just was curious if my 6100 "had a better signal" than my 4400 and asked what I (in my finite wisdom :) thought had a simple answer. My 6100 is great and pretty (such a important feature for me, Ha) and the volume got even better after I removed the blue protective covers from the earpiece and speaker! Read about that on Howard Forums--what a Bozo! Thanks again, Janie > It's relative (and more than likely subjective if you > heard it here). They are simply saying that they [quoted text clipped - 44 lines] >>> >>> Notan > Thanks, Quick, for your explanation. I realize how stupid I am when I ask > a question that I think can be answered by "XX", only to find out that I [quoted text clipped - 5 lines] > matter anyway, I just was curious if my 6100 "had a better signal" than my > 4400 and asked what I (in my finite wisdom :) thought had a simple answer. Don't get sucked into the advertising hoopla of "superior RF." After all, do you think anyone's ever been honest and advertised "inferior RF?" <g> Notan >> Thanks, Quick, for your explanation. I realize how >> stupid I am when I ask a question that I think can be [quoted text clipped - 15 lines] > After all, do you think anyone's ever been honest and > advertised "inferior RF?" <g> Ummm, there wasn't any advertising involved... It was the posted experience/impressions of users that prompted the question. Something like "I can make a call in my basement with my 265 and I couldn't with my 6100. The 265 has superior RF performance" or "I get 5 bars in my office with my 6100 and only 3 bars with my 265. The 6100 has superior RF performance"... -Quick Do not be fooled by bars. Not all of the signal meters are calibrated the same. Therefore, three bars on my phone may equal 5 bars on your phone. Judge the phone by the RF performance, not the number of bars. >>> Thanks, Quick, for your explanation. I realize how >>> stupid I am when I ask a question that I think can be [quoted text clipped - 26 lines] > > -Quick If you have any of those "special" Rx's just send them my way. I could use all the oxy,hydro - codone you can get. Yes...that's what I said. > Tx, > > Janie |
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