ST(17)006 ST(17)006 Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk JRC current assignment criteria using OfW49 Alessandra Lees Joint Radio Company Ltd Alessandra.Lees@JRC.co.uk Tel: 02077065196 Skype: alexlees_jrc
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk JRC assignments key points • Generally follow ACP including non-adjacent cell channels for additional capacity. • No longer assign inter-leave channels – not compatible with digital equipment. Some existing systems still use them. • Cross polar discrimination also used. • Standard outstations are those with 12element Yagi • Non-standard outstations not used in calculations of systems EIRP or interference.
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Basic 12 cell repeat pattern Worst case 150km cell centre to cell centre. Worst case 200km interference check Figure 1 taken from OfW49 document: https://www.ofcom.org.uk/__data/assets/pdf_file/0026/77336/tfac_ofw49.pdf
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Maximum path loss assigned = 143dB Total path loss = free space loss + terrain obstruction loss+ clutter loss Clutter loss limited to 20dB, up to 30dB considered on case by case basis. Figure 2 taken from OfW49 document: https://www.ofcom.org.uk/__data/assets/pdf_file/0026/77336/tfac_ofw49.pdf
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Maximum end to end circuit loss assigned = 134dB EECL= total path loss + (total scanner losses – scanner gain) + (total outstation losses – outstation gain) Total scanner/outstation losses include: Feeders Other losses: Other miscellaneous loss Connector loss Feeder tail loss Antenna tail loss Figure 6 taken from OfW49 document: https://www.ofcom.org.uk/__data/assets/pdf_file/0026/77336/tfac_ofw49.pdf
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Assigning path: End to End Circuit Loss (EECL) Information taken from JRC authorisation document Minimum EIRP limited to -20dBW Exceeds EECL max
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk EIRP Receiver input port level = -122dBW (-117dBW duplicated equipment with common antenna) Calculate EIRP: Scanner EIRP = Outstation receiver input port level + Loss to Outstation • Loss to Outstation = EECL - Sc Feeder Loss – Sc other loss + Sc gain • If the worst outstation EECL is > EECL max then use EECL max Outstation EIRP = Scanner receiver input port level + Loss to Scanner • Loss to Scanner = EECL – Os Feeder Loss – Os other loss + Os gain • If the worst outstation EECL is > EECL max then use EECL max
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Scanner EIRP = Receiver input port level + Loss to Outstation = -122.0dBW + 128dB = 6dBW 2011 Loss to Outstation = EECL max - Sc Feeder Loss – Sc other loss + Sc gain 123.9dB - 3dB – 1dB + 8.1dB = 128dB
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Maximum transmitter output powers for the assigning path: (unprotected or protected two aerial working) 2011 Scanner: Tx power (dBm) = outstation wanted signal (-92 dBm) + EECL max (-30 for dBW) Outstation: Tx power (dBm) = scanner wanted signal + Individual EECL (or EECL max ) A protected single common aerial system has an extra 5dB receive signal level (-87dBm)
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Extra 5dB passive splitter for receive path Figure 3 taken from OfW49 document: https://www.ofcom.org.uk/__data/assets/pdf_file/0026/77336/tfac_ofw49.pdf
Joint Radio Company: Making the spectrum and technology work for your business www.JRC.co.uk Summary of current OfW 49 Assignment Criteria Current OfW 49 Unfaded wanted signal -92dBm Interference + Noise 99.9% ≤ -114 dBm Unfaded W/U 22dB Maximum path loss 143dB Maximum EECL 134dB
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