In my apartment, the GSM signal is very scarce, if not absent at all, except for a few spots, where there's a decent LTE signal and I can browse internet reliably.

In order to improve the reception across all my apartment, I'm thinking about buying a cheap low-noise RF Amplifier like this and put it in a corner where the LTE signal is decent.

RF Amplifier

  • It operates from 5 MHz to 6000MHz, which is fine because LTE works from about 400 to 3500 MHz.

  • It requires a 5 V input, which is the same voltage provided by USB. I can take a USB cable, cut it, and connect the power pins to the Amplifier.

  • I do not think I need an antenna: the LTE signal is decent enough in certain corners and my apartment is pretty small.

My question: would this setup work? Is there any potential problem that I have not thought about?

(The problem of low GSM signal is know in the building, and it will be addressed sooner or later. It's due to scarce coverage. I have no reasons to think that there are sources of interference.)

  • \$\begingroup\$ Maybe. An ideal cell phone would have a better RF detection stage than something you buy from Aliexpress, but if you can place this where you do have good reception, you have a lot to gain. Can you draw how you plan to connect it? \$\endgroup\$ – winny Apr 11 '18 at 6:43

would this setup work? NO

To make something like that work you would need to connect an antenna (I do not think I need an antenna: is nonsense, some form of antenna is always needed) to the input of the amplifier. The antenna needs to be for the correct frequency band as well. If not, then for example a strong WiFi signal can disrupt the operation of the amplifier, that will prevent you from receiving the LTE signal that you want. The output of the amplifier needs to be directly connected using a cable to your phone. You cannot just "retransmit" the signal through the air as then the amplifier would also be receiving it's own output signal. That might result in oscillations.

Similar to WiFi, for properly relaying/amplifying an LTE signal a proper repeater is needed. A repeater is much more than just an amplifier and also much more expensive. Since it needs to connect to the LTE network your cellular provider has to allow it to connect.

Your best bet: ask your cellular provider if they have a solution or try a different phone with (hopefully) better LTE reception or use a different cellular provider, some use the 800 MHz band for LTE (at least in my country) and 800 MHz can penetrate buildings more easily.

This RF adapter is quite pointless for what you want, cellular and RF is not that simple, you really need to know what you're doing.

Oh and GSM and LTE are not the same thing, they're different networks. GSM is "2G", the old/first network we mainly used for voicecalling and SMS. LTE is "4G" and much newer and can also provide high speed internet access. Compare it to if GSM is like a train then LTE is like an airplane. Both are for travel but the airplane is much faster.


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