How can I move the antenna away from my codec?

5 November 2018

The antennas provided with our wireless products are suitable for typical uses, but not in all situations. For instance, it is sometimes necessary, for a correct performance, to move the antenna farther away from the codec than allowed by the cable of the provided antenna.

In such case, it is not recommended to use the antenna and simply add an “extension cable”. This usually leads to excessive signal losses and a poor performance.

The preferred solution is to go for another antenna, and a cable to link it to the codec. We recommend you to look for a specialised distributor or reseller who can provide accurate advice and propose equipment best adapted to your needs.

The criteria for selecting the antenna are as follows:
* Mounting: indoors/outdoors, on roof/wall/mast/windscreen…
* Directivity: in bad reception conditions, a high-directivity antenna pointed towards a base station can be a good solution.
* Supported bands: a multiband antenna is more flexible, but for a fixed installation a single band device can be satisfactory. In any case, check first the local coverage in the area (and the mobile operator). Our product user manual describes the bands that are supported; you should cross-check this with the specific conditions in your country and with your operator.

Regarding the cable, the elements to be considered are:
* Length of cable needed depending on the installation.
* Characteristic impedance: 50 Ohm.
* Cable quality: determines cable losses. With a longer cable, you should look for lower losses per unit of length. Preferrably not more than a few dB should be lost in the cable, in the frequency band that is used (e.g. 2100 MHz for UMTS in Europe). Generally, low loss cables are also more expensive and thicker.
Note that you cannot use an amplifier like for a TV or satellite downlink, because a mobile link is bidirectional, both downlink and uplink via the same cable.
* Connectors: on the codec side, this is an SMA plug (except for Scoopy+ which features a Hirose MS-151NB antenna socket). On the antenna side, this depends on the antenna model (another good reason to select first the antenna). Avoid connector adaptors as much as possible: every connection brings some amount of signal loss.

Warning : solutions such as “femtocells” proposed by the mobile operators are often efficient for improving the reception, but do not support the “HD Voice” service. As a consequence they are useless if you want to use this service. In fact, if the antenna of the codec is in the coverage area of a femtocell, you must make sure not to include the SIM card in the list of users entitled to access the femtocell.