FAQs Archive

Q: What is meant by an IP Rating?

The IP (Ingress Protection) Rating is a measure of a device’s ability to withstand solid objects and liquids. In-door applications typically call for a modest rating of IP64. Outdoor ratings are typically IP65 to IP68. For a more in depth look at what these ratings actually mean, view the following website: http://www.aquatext.com/tables/ip_ratings.htm

Q: What is a cross-band coupler?

A cross band coupler refers to the same type of device as a diplexer or filter combiner. These devices allow the combination and separation of signals in different wireless bands with higher isolation (to minimize band interaction) and without the combining loss incurred in other types of combining technologies. The BK-21N is an example of a cross-band coupler.

Q: Should I use tappers, directional couplers or unequal splitters for my DAS applications?

System designers have a choice in the use of directional couplers, tappers or unequal splitters in the "main spine" of a DAS. The directivity of the directional coupler in theory reduces interference between signals on the return path, however since the signals are so small on the return path the effect is generally small. The return loss of the coupled port is generally good which simplifies system modeling. Microlab has a wide range of directional couplers from the low cost CK-66 series to the high performance CK-10 series. Tappers are generally less expensive, are very rugged and have broad bandwidths. The negative of the tapper is the lack of isolation and poor VSWR on the coupled port, but once again these factors may not be critical to the overall system performance. The DK-x8 series are typical tappers.

Q: What is meant by combiner loss?

Combiner loss is a term that refers to the theoretical loss that is incurred in a power combining situation. In a 2:1 combine, the loss is 3dB or 50% of the total input power. In a 3:1 combine, the loss is 4.8dB or ~67%. In a 4:1 combine, the loss is 6dB or 75%, and so on. Insertion loss is the theoretical combiner loss plus the dissipative loss.