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View Full Version : Real difference between original TEMS and GDFS-overwritten TEMS



drJaser
2010-12-14, 12:19 AM
I would like to ask finally who has ANY proven trace of any SIGNIFICANT measurement difference between "originally calibrated" and "GDFS-overwritten" K800 mobile ???

1) Did anyone compare in real both mobiles at the same time or it is just theoretical fact of error in measurement?
2) OK, if there is an error ... is it 0,1dB ? 0,2dB? maybe half or even 1dB ?

From my point of view (real life) this 1dB or 2dB doesn't make any big difference.. because I meet the same discrepancy already in picking different drive test car.. for example small KIA with normal window glass or big Nissan with thermo glass ... difference of 1dB already in "car penetration loss" is obvious ..

Same story with the rest of my test mobiles.. Nokia N80 (NTM) shows constantly 2-3 dB better signal level (RSCP) than both Samsungs (Z500 and Z560) .. should I conclude my Samsungs aren't RF calibrated ??? or they are just worst peace of equipment than Nokia ??

So.. what is real difference in dBs between "GDFS-overwritten" k800 and factory calibrated TEMS k800?


Anyone ??

regards as always..
drJ.

s52d
2010-12-14, 02:25 AM
Hi!
Quick summary: never tested if original TEMS is any better as regular terminals.
I have TEMS pocket K800, and I do not like RX sensitivity.

There are two issues:
- RX signal level entering receiver, where antenna, placement, car, terminal model
can make huge difference.
It is not possible to make same condition for different terminals outside lab.


- Measurement done with terminal.
what matters is:
is this signal really -90 dBm? You need absolute calibration for this.
is this signal really 6dB stronger compared to other? Relative measurement.

IMHO, relative signal strength is accurate, while absolute is not.
As it depends on terminal placement and antenna, it is not really an issue.

BR
s52d

knack
2011-01-29, 07:40 AM
Original phones are tested so they don't have a RxLevel less than -80 dBm in lab. A difference of several dBs (3-6) is accepted in practice.

drJaser
2011-02-13, 08:36 AM
I did reflash regular k800i phone with TEMS Pocket 5.3.1 software which can be found here on forum... (FS, SW, custom GDFS, activation script, original GDFS restore back at the end) and of course I did also a comparision between flashed Ericsson K800i and official Nokia NTM mobile (n80). Software was TI 9.0.4 .

here are results :

2G idle and dedicated mode, both mobiles locked on same ARFCN (ch):
Ericsson shows approximately 3dB better RxLev than Nokia

3G idle and dedicated mode, both mobiles locked on same SC:
Ericsson shows approximately 3-4dB better RSCP and 2dB better EcNo than Nokia

I didn't have spectral analyzer at home so I couldn't compare results with measurements from really calibrated system... maybe next time..

I can conclude that flashed TEMS phone has offset of few dB's which is constantly present but on the other hand it isn't that big not to accept measurements as reliable...

ps: Now I can say I am very happy with my new (cheep) TEMS phone :D

Regards as always,
drJ.

NILCTG
2011-02-13, 09:57 PM
From my experience (used Mod TEMS Phone & software on several occasion), problem is not Rxlev or such measurements. Main problem I found is missing L-3 messages. Though haven’t dig deep to find out if its due to SW c+r+a+c+k or Phone c+r+a+c+k. On the other hand, with original TEMS kit, L3 was OK.

drJaser
2011-02-13, 11:24 PM
@NILCTG:
how to you mean "missing L3 messages" ?

your log was absolutely without L3 messages or only some of them were missing ?

My log has all of them .. I don't miss anything..

BR

NILCTG
2011-02-14, 02:58 AM
Not all, some of them missing. Became pretty evident in couple of occasions when account of number of calls (e.g. originated = properly terminated + dropped) were not matched. It was not that, DT Technicians forgot to record calls (because it was scripted).