Request from JEAN (France) 12.12.2003

Good morning,

for start I present you my congratulations for your website.
I  project to build a power amplifier for my siemens dect phone (I live in
france )and you are the only one who treat of this subject
I have found several power amplifier but I want to be sure that is possible
to do it.
I think to use a ma02205af (500 MW pa) or a RF2125P ( 1 W pa )
Can you recommend me?
Is there any particular encounter?
Thank you to answer me soon as possible

Hallo ....Jean ,,..


i was very busy during Christmas time ,.....
and laser stuff was on my priority .....

so my answer ...

it's very hard to expand the range of dect device ,,, because the height data
rate ....even 3 times more than GSM provide ...

so field strange had to be very strong ...

normally 250mw of rf will cover at least a mile without any problem like PMR
(private mobile communication) and line of sight even more than 10 miles.

But reflections from any wall or tree will damage the information, there are
different ways to reach our cordless ,,, and any data will come another time ,,, 
like an response of a sound in a big hall.

So if you understand to program our cordless to lower the data rate ,,, and
transmit not only 1 of 24 timeslots ... range will expand more & more ....

(Internal microprocessor convert the 32kbit up to any 56kbit analog or 64kbit
isdn line....)

I couldn't program as well ,,, so my only chance was to power up the rf
stage .... and it's not easy to work without any expensive rf equipment ....

so i try to use cly10 ,,, which easy handle 24 dbm input and boost up to 30
dbm under good conditions.

But also think to our power supply ... ,,, siemens use 2 AA batteries most
time ,.,.., i think 2.4 V will never gain up to 30 dbm.

So our handset need a dc/dc switching supply that provide about 5V .... ,,,
but for that you don't have to think about diversity ...

but amp. before the pin switch separate between rx & tx stage...

don't use big cabs to stabile the amp ... you need to switch the amp like the
original rf stage ... (in 1 of the 24 slots [217hz])

Now the BS (Base Station) .... you have to amp before pin switch separate
between both antennas.

So diversity will gain you ....

1 antenna and 1 % error rate 0db

2 antenna about 9.8 db of extra gain !!!!

4 antenna about 16 db of gain ,,, and 8 antennas even 19 db ....

without diversity our cordless have to transmit 24dbm + 9.8db = 33.8dbm !!!!

so diversity is even very important in height frequencies ...!!!

If you don't like to spend hundred of hours ,,, in only a few meters ....
try to program the timeslots or buy a analog 886/931 Mhz cordless

witch easy cover a large area without any problems ... so rf amp will come
from any old siemens s6 or s9 handy ...

I love those rf chips .... ... small ... height gain ... and very stable ....

10 mW will easy amp up to 2 W ... from a small adjustable resistor to the
control point &  Vcc +

but frequencies closed down in Germany ... i don't now in France ...

also any CT2 cordless ,,, (digital ... 868 Mhz ... 100khz bandwich) ... work
well .....


so far ,,, greetings from Germany ,,,,

thanks for our interest in my project ....

tell me about you ....


what is our phone ??? how old are you ....??? why is 300m not enough ???




p.s. I'm ham radio licensed ... but i don't like to speak about that ,,, so
electronic is my life ,,, and not those damn ham or CB nonsense...





sorry for that poor English ...



Chris