Signal Booster circuit for cell phone

looks like you're stuck with a passive system, which actually is good, because you won't need a duplexer (ir diplexer.... the differnce between the two is a minor one)...
if you build a high gain antenna, and place it in a spot where signal is good, then locate another high gain omnidirectional antenna in your house, and connect the two with low loss coax (look at the specs for loss per 100m at 1Ghz, choose the one with the lowest loss, that you can afford to buy). the loss of the coax run should be less than the signal loss at your location. if you lose 20db of signal going from where you want to place the outside antenna, to inside your home, then the cable loss should be much lower than that. let's say the cable length will be 50m, and the cable loss is 20db/100m (that's a ridiculously high number for good cable, but it will illustrate what i'm talking about), so that's a 10db loss for 50m. that's a net gain of 10db though, because inside your house was a 20db loss to begin with. with 9 or 18db gain antennas, the margin gets even better.

you can find duplexers in old mobile phones already tuned to the correct bands.

I can't help but think there is enough parts in two old phones to accomplish the task, amplifiers and all.

If those old phones are old nokias with external antenna sockets then you can enable the nemo, nokia engineering mode
which you can use to test your antenna system.

i have an old nokia but how can i enter engineering mode?

roltex_rohit123 said:

i have an old nokia but how can i enter engineering mode?

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Look it up on line.

nokia logo manager and a programming cable.
As pyro said, the information is online.

Guys, I think I've got an easy solution.. RFMD has come to my rescue. They have suggested me a product. RFPA2126. It seems to be the correct one... what do you say?

roltex_rohit123 said:

Guys, I think I've got an easy solution.. RFMD has come to my rescue. They have suggested me a product. RFPA2126. It seems to be the correct one... what do you say?

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OK that may help you boost your transmit but how are you going to boost the recever?
See post #2 of the thread.

View attachment 66898 the commercial circuits use two modules of same kind but in reverse order. Some one at another forum posted me a picture of the booster commercially available booster to demonstrate the circuit. they said you have to maintain the antenna distance, otherwise it creates an oscillator. I am thinking of the same. the picture shows a module of repeater booster. I am trying to reduce the circuit by the component of RFMD

The RFPA2126 is a liner power amp for transmitting.
This is just one part you will need much more for a complete system.
You will need a preamp to amplify the receved signal.
Its a two way radio and you need to amplify both the input and output.

and it's a 2 way radio that does automatic T/R switching many times per second, so a booster has to do such switching very quickly, and automatically to avoid losing portions of data packets...

theres a 50Mhz separation between the transmit and receive channels in the cell phone bands, so it would be possible to have an active amp and preamp simultaneously operating as long as the filters that route the signals through the booster have a sharp enough slope

Any regular cell phone signal booster may not cut it because you said you needed it for a remote area. You need one that has a LPDA antenna which focuses signal in one direction. These type can get you signal in weakest spots. Here's a link that elaborates this and shows examples: signalbooster.com

nickwandres
Welcome to ETO!
Did you realise that this thread is nearly 8 years old? It always pays to check dates before posting.

alec_t said:

Did you realise that this thread is nearly 8 years old? It always pays to check dates before posting.

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There is a feature which will warn someone who tries to reply to an old thread.
The warning may be overridden, but this will not be a severe deterrent to a purveyor of processed meat products.

JimB