diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Everything Else (http://www.diyaudio.com/forums/everything-else/)
-   -   CDMA tri-mode phones (http://www.diyaudio.com/forums/everything-else/41745-cdma-tri-mode-phones.html)

purplepeople 29th September 2004 07:24 AM

CDMA tri-mode phones
 
Hi everyone,

My trusty Audiovox CDM-9000 cell phone finally died. Not bad after 3 years and dozens of 4 foot falls. If you can get one, it's a keeper. Big and ugly but never dropped a call and once, even continued working in a tunnel (go figure?).

Anyway, with all the under-educated masses out on the web spouting voodoo opinions about cell phones, and the continuous turnover of cell phone models, and the poorly informed sales people, I figured it was time to ask those who might actually know...

1) Reception - Which CDMA tri-mode phones are better for reception and why? Short of building a test lab, is there a way to compare the output wattage of various phones? Are there differences in the DSP circuits if they are all using Qualcomm technology? Does Qualcomm have competition and if so, are they better?

2) Antennas - Will an aftermarket antenna improve my signal strength? What are the differences between antennas? Please bear in mind that I've done some looking around and know why external is better than internal, but know nothing about other differences, such as extendable vs fixed, flexible plastic vs other materials, OEM vs 3rd party.

3) Signal boosters - there are little flexi-film antennas of the "As Seen on TV" kind... are these any good? If not, are there powered electronic signal boosters that can be added to the phone? Is there a way to hack the phone so that it's transmit strength and receiver sensitity are increased?

4) How does the specific assigned frequency affect signal strength and quality? Are the better frequencies for different phones? Should I ask if the carrier can change my frequency for better reception?

5) Audio quality - can this be improved by modding the speakers and mics? Has anybody every tried this? Am I limited by the bandwidth of the digital signals?

6) Durability - I am used to having a phone that can take physical abuse. Have all the phones become little disposable gadgets? Other than the ruggedized bricks, are their smallish flip phones that have also proven their durability?

And, please don't trouble yourself to tout features like colour screens, cameras, web surfing, text input, ring tones or games. I really don't care. I don't have a land-line so this phone has to do calls really well. I use it only to keep in touch with people, find friends in the crowds, dialling 911, etc so performance and durability are primary considerations. The features I need are all standard - caller ID, phonebook and vibration alert. I will pay more to get guaranteed performance and durability.

Thanks in advance,

:)ensen.

purplepeople 29th September 2004 07:23 PM

Okay, then. I guess nobody has ever really examined or souped up their phones.

:)ensen.

Swedish Chef 29th September 2004 08:54 PM

Although I haven't studied the actual implementation for this system I can tell you a few things about DS-CDMA systems.

Quote:

1) Reception - Which CDMA tri-mode phones are better for reception and why? Short of building a test lab, is there a way to compare the output wattage of various phones? Are there differences in the DSP circuits if they are all using Qualcomm technology? Does Qualcomm have competition and if so, are they better?
Do different phones really have different RF output? In DS-CDMA the output power of the phone is adjusted a couple of hundred times a second, this is handled by the base station. But maybe the maximum output power is phone specific, I don't know.

Quote:

4) How does the specific assigned frequency affect signal strength and quality? Are the better frequencies for different phones? Should I ask if the carrier can change my frequency for better reception?
DS-CDMA don't use a single frequency - they use ALL frequencies within a band. This is the very definition of DS-CDMA ("spread spectrum").

I seriously doubt there are much things you can mess with yourself in a CDMA phone. It's an incredibly complex piece of engineering.

Maybe this wasn't much help to you but anyway.

Cheers
/Magnus

DigitalJunkie 29th September 2004 10:45 PM

I had a Kyocera phone that was worthless.Sitting right here at my desk,I had 0 reception (there's a tower like 1/4 mile from here..) I never had any reception in the city with that phone..BUT..at the coast,or in Canada it worked great,with full reception!! (go figure?)
Personally,I avoid Kyocera like the plague.
Some of the Newer Motorola flip-phones are pretty bad also,the one my girlfriend just got rid of was horrible,sound quality was poor,(she could never hear me) it dropped calls *all the time*,and the connector for the charger was so flimsy it wouldn't always charge..and if she plugged in the charger while talking it would drop the call.The sad thing is the battery life is soo poor,it need to be charging all the time.(Hence dropping ALL your calls..)
She *hated* that phone.

LG phones are great IMO..great reception,sound,and well made.I've dropped mine several times,and it still works (despite a cracked and broken case!) I now have to hold the flip-up earpiece+screen together when I use it,but *it still works great!* this one is a model# LG-TM510. (a bit older,but it's a great phone,that actually works.)
My girlfriend just traded in her POS Motorola for a new LG.
I hate Kyocera,and I'm starting to dislike Motorola... LG's been good to me tho..We'll see how her new LG holds up..(she already commented on how much better it sounds.)

Brian Donaldson 30th September 2004 01:53 AM

My last 2 phones have been Nokia, and I've had no problems with durability or quality. I would recomend one without a flip or sliding gadgetry because they are prone to damage. I'm a contractor, and my phones get dropped from 10 to 15 feet in the air all of the time, the battery usually flysin one direction, the cover in the other and the phone bounces a few times, but put it back together and it works fine. My current phone is a 6340i with a lithium battery that last for days, and I use 1200 min/month. Because I work in loud enviroments, a loud ringer is also important, and it lets you set up 5 profiles such ar outdoors, meeting, home, etc. just select the profile and the ringer goes from megaloud and vibrating continuously for in the feild to one small beep and vibrate for in meetings to something in between for home use. reception is usually good, but consider I live in Houston where everyone has one glued to there head all of the time. The call desity must be incredible. It's hard to believe these things can function at all.

purplepeople 30th September 2004 07:17 PM

Unfortunately, Nokia doesn't make CDMA phones for use on the system being used by my carrier, Telus. Verizon is the carrier in the USA that uses the same technology. It is less popular than GSM and provides for analog roaming for remote geography. Telus in particular only specifies phones with external or extendable antennae for that purpose.

Anyway, I found something about Wilson powered antennas and active repeaters, but these are huge. It would be interesting to make a battery powered unit that could be clipped to the phone's antenna to give extra receive sensitivity and transmit power.

Fortunately, my Mom had an old phone that I was able to activate for a $10 fee. No vibration alert so I will have to look around some more.

For those that are interested, the most thorough site I've found for testing phones belongs to Steve Punter.

http://www.arcx.com/sites/index.htm

Thanks to all so far.

:)ensen.

leadbelly 30th September 2004 11:23 PM

Quote:

Originally posted by purplepeople
Unfortunately, Nokia doesn't make CDMA phones for use on the system being used by my carrier, Telus.
???? I think you should clarify this. They makes lots of CDMA phones, what is the issue?

purplepeople 1st October 2004 02:09 AM

Sorry... bad grammar.

Telus sells a limited number of models, none of which are made by Nokia. They sold a number of Nokia candy bars some years back, but lately, it is mostly LG and Samsung. The Motorola phones are generally for the iDen service.

I'm still looking for the mfg website for Wilson cellular antennas but here's one for Radiall-Larsen Antennas: www.radialllarsen.com

:)ensen.

corbato 1st October 2004 02:24 AM

Both Samsung and LG make very hardy CDMA sets.

I've been using Samsung (absolute el-cheapo model) for almost 3 years now. As you would suspect falls, drownings, and knocks etc have been part of this ownership period. But the set function perfectly.

This is my only connection to outside world. I use it for talking, SMS, and connecting to the Internet.

My wife uses a LG with similarly experience. But I have found net access to be faster with Samsung consistently upto 264kbs. Maybe because it connects to the laptop via a USB ports, while the LG uses a Serial Port.

leadbelly 1st October 2004 08:04 PM

Quote:

Originally posted by purplepeople
Telus sells a limited number of models, none of which are made by Nokia. They sold a number of Nokia candy bars some years back, but lately, it is mostly LG and Samsung.
You are not limited to using only a phone model sold by your carrier. As long as type and frequency are correct and the phone is unlocked, all you need to do is put in your SIM card. You can find lots of good deals on unlocked phones on Ebay or save even more $$$ by unlocking it yourself.


All times are GMT. The time now is 07:22 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2