Multiple gsm modules, one antenna

[overmindx]

hi everyone, a friend of mine bought a multi-sim iphone clone from china. i was so amazed at this. as a hobbyist, i want to create my own pc-based multi-sim gsm terminal. so i want to use 4 gsm modules(sim300). one for each gsm-provider here in my country. but my problem is i want to use only one antenna and the four modules share on this antenna. just like the iphone clone of my friend. I am pretty sure that it uses 2 modules but these modules share on just one antenna. can you guys share your thoughts on this? how can i do this? thanks in advance

 

[vk6kro]

The module you describe would have taken many hours to develop, even with specialiised test equipment and expert, experienced designers.

Tuned circuits at such frequencies often take the form of a small piece of printed ciruit board track. A quarter wavelength at 2400 MHz is 31.25 mm. If it was made 30.25 mm long, it would resonate at 2479 MHz which is 79 MHz higher. That was only 1 mm shorter or 1/25 ths of an inch.

If your friend got a good deal, you might like to do the same.

 

[oswaler]

I would first like to acknowledge the creativity and curiosity of the individual who wants to create a PC-based multi-sim GSM terminal. It is always exciting to see individuals exploring and experimenting with technology.

In terms of using multiple GSM modules with one antenna, there are a few considerations that need to be taken into account. Firstly, it is important to ensure that the antenna is compatible with all the GSM modules being used. This includes checking the frequency bands and signal strength requirements of each module.

Secondly, using multiple modules on one antenna may result in signal interference and reduced performance. This can be mitigated by using filters or amplifiers to isolate and strengthen the signals from each module.

Additionally, it is important to consider the power requirements of each module and ensure that the antenna can provide enough power to support all of them simultaneously.

In terms of implementation, there are a few ways this can be achieved. One option is to use a multiplexer to switch between the different GSM modules and connect them to one antenna. Another option is to use a combiner to merge the signals from each module onto one antenna.

It is also important to note that using multiple modules on one antenna may require regulatory approval, depending on the country and its telecommunication laws.

In conclusion, using multiple GSM modules with one antenna is possible, but it requires careful consideration and implementation to ensure optimal performance. I would recommend consulting with experts in the field or doing thorough research before attempting this project.