Some nice little bits of GSM test equipment that have recently fallen in to my hands courtesy of eBay!

Firstly a Sequoia SWGPRS023 Signal Strength Tester for GSM/GPRS Network Coverage. Details here: http://www.sequoia.co.uk/shop/product.php?p=280

This little device allows detailed interrogation of 2G GSM cell sites on the 850, 900, 1800, 1900MHz bands which are detected within range.

The information returned about cells includes:

• The Absolute Radio Frequency Channel Number (ARFCN)
• The Base Station Identity Code (BSIC) which identifies the BTS beacon frequency
• The FSSI Signal Strength in dBm (decibels referenced to 1mW)
• The Local Area Code (LAC) which identifies the area in which the cell is situated
• Mobile Country Code (MCC)
• Mobile Network Code (MNC)

Secondly an Anritsu MT8801B Radio Communications Test Set with options 02 (SG Local), 07 (Spectrum analyzer) and option 15 / MX880115A (GSM Measurement and Call Processing Firmware) fitted. Just in case Mrs. R finds out it did cost a LOT less than the $50K list price back in 1999!

With the GSM option various GSM frequency bands are supported. These include:

• GSM450
• GSM480
• GSM710
• GSM750
• Trunking GSM (T-GSM-810)
• GSM850
• Primary GSM (P-GSM)
• Extended GSM (E-GSM)
• Railways GSM (R-GSM)
• Digital Cellular Service (DCS1800)
• PCS1900

Of course in the UK we are only really interested in GSM-900 and DCS-1800 bands. e.g. ARFCN 0-124 and ARFCN 512-885.

The GSM option call processing functionality supports GSM connection tests such as Location registration, Terminal call origination, Network call origination, Network disconnect and Terminal disconnect.

Also there is a frequency hopping function that changes the channel (ARFCN) used for communication between the base station (BS) and mobile station (MS) by each 4.62 ms frame. Frequency hopping is operated by the Measure Channel and Frequency set value of hopping frequency table-ARFCNs

Fun!