Please carefully read the user manual to a usb modem. The instructions should indicate whether the modem input for connecting an external antenna, where on the body it is located and the name of this nest. If manual is missing, visit the official website of the operator and review the instructions on the website. Be sure to compare models of modems.
Examine the body of the modem and find the input for connecting an external antenna. If you are using a homemade antenna, you need to attach its cable connector in accordance with the specifications of the modem. Such connectors can be found in shops of radio components. At this point of time on the Internet there are many sites that sell such products. Review the options of antennas for modem and order by mail.
If the modem has no special input for connecting an additional antenna, it is possible to open up the modem and solder the wire from the cable directly to the PCB of the modem. However, in this case you will probably void the warranty on the modem, as it will violate the integrity of the case and will make changes in the circuitry of the device.
The easiest way to attach an external antenna — just wrap the end of the antenna cable around the body of the usb modem. This type of connection will not void your warranty on the device will not cause the risk of the modem failure, but will greatly improve the signal level.
You can find several types of different external antennas to boost the signal of your usb modem. You can purchase a suitable specimen or to make the antenna with your hands — enough to have wire and wire to create a frame. In General we can say that to make the antenna for the modem is quite simple, however, the signal is increased not by much. The main factor that affects the increase of the signal is the presence of special stations in your community.