al extras such as a rubidium holdover oscillator or multiple output connectors for physical signals. For the antenna, many devices in the timing world use an SMA jack as the default connector for an external GNSS antenna (SMA is the screw-on alternative to the SMB snap-on version). Other types of connectors are sometimes used, such as BNC and Threaded Neill-Concelman (TNC), which is a threaded version of BNC, but SMA is very common. SMA (along with MCX) is found on many of the cheap consumer "patch" antennas available for use with devices like portable receivers for car navigation. For some informal testing and proof of concept in a lab environment, one of these with an SMA can be pressed into service. Most expert antenna installations using long runs of cable (>50 m) normally use a very heavy and thick low-loss coaxial cable, SO the SMA connector is too weak to hold the weight and strain of the cable. Typically, this cable is terminated at a junction box (see the bullet point on splitters in the fol- lowing list) with much larger and stronger connectors-such as a large connector known as the Type N connector. Then a lighter Type N-to-SMA patch cable is used to complete the connection to the receiver. This raises the point of how to select an antenna for production usage or for usage in a formal labor- atory setting. This question is often posed to the authors, and the short answer is that the antenna selection and installation should be performed by local contractors who have the required expertise and experience. Many local requirements need to be met to install an antenna safely and accurately (and legally), and an off-the-shelf antenna installed by an amateur may meet none of those. Here are a few items to consider when planning a GNSS antenna installation: The antenna must be chosen based on the (signal) gain it produces, which is then consumed by signal loss caused by attenuation in the cable. The higher the loss in the (lower quality or cheaper) cable, the more gain must come from the antenna to overcome i