Cellular Playground

[joejoecor]

I am looking to learn more about cellular transmission/reception through project design. Can anyone with some experience in this area help with my goal. Basically I would like to create a cellular signal, detect it and then block it, of course all while in a spectrum region allowed by the FCC. I would also like to find more about buying a spectrum analyzer on the cheap. I heard SDRs can be used as a cheap spectrum analyzer.
Thanks

 

[davenn]

I would also like to find more about buying a spectrum analyzer on the cheap. I heard SDRs can be used as a cheap spectrum analyzer.

Hi, welcome.
Unless you are a serious electronics expert, doing celluelar from scratch is probably not feasible
There are circuit modules out there that you can build other circuitry around

Spectrum Analysers on the cheap, I just purchased a Tiny SA Ultra for less than $300
Absolutely brilliant device for its price and goes up to around 5GHz

tinySA | Main / Buying the tinySA

cheers
Dave

 

[joejoecor]

Thanks Dave. Great info. What is your technical background? Have you heard of OpneBTS from MIT? https://en.wikipedia.org/wiki/OpenBTS I was thinking of building this. Do you know of any good chat rooms to converse with other techies fluent at DIY project designs.

 

[Delta Prime]

Have you heard of OpneBTS from MIT?

I have heard of open BTS by MIT.
I'm rather biased, I prefer
⁸"Cal-Tech."
GSM frequencies are from 890MHz to 915MHz
for downlink. and, from 935MHz to 960MHz for the uplink,with a channel dimension
(or channel separation) of 200KHz.
GSM transmission is performed on a "For profit" licensed frequency band,the connection cost to be payed to Mobile NetworkOperators (MNOs) that own the transmission license and the entire network architecture.
When I was literally a child I got caught for being a rogue base station that was my way of having fun.
An (SDR) Software Defined Radio
can be used as a cheap spectrum analyzer.
In fact... Open (BTS) Base Transceiver System would not exist without the development of the signal processing utilized in (SDR).
The mobile station connects first to the (USRP) Universal Software Radio Peripheral, working as a standard GSM cellular BTS.
This is the only hardware module which enabling radio communications.The transmitted data are later elaborated throughout the GNU Radio software in order to be correctly processed by the OpenBTS software.
Those three components (i.e. USRP, GNU Radio and OpenBTS) create together the standard “Um” interface.
The Asterisk server is used to implement user management and
call forwarding functionalities fulfilling the functions of HLR
and AuC.

 

[davenn]

What is your technical background?

electronics tech all my working life 45+ years and more earlier years as hobby electronics
currently high precision GPS and survey tech

Have you heard of OpneBTS from MIT?

not familiar with them

 

[mineymoe]

Building something like OpenBTS could be a really cool project! Just be careful about the legal stuff since cellular frequencies are regulated. I'd check out the OpenBTS forums online - always helpful people discussing those kinds of projects. And definitely start simple if you're new to this area. Maybe look into SDRs first to get comfortable with wireless concepts. Best of luck!