Hi-Fix UK Frequency Allocation The frequency band 1899 to 1901 kHz was allocated for HiFIx by what was then the Post Office. If this sounds narrow, it should be noted that the bandwidth of the receiver was only 100Hz and normally chains would operate with 200 Hz spacing if the chains were close to each other. If they were more than 300 miles apart, then closer spacing could be used or even co-frequency but a small difference of 20-30 Hz was normally used to improve performance under skywave conditions. Hyperfix UK Frequency Allocation Fortunately the OFCOM website is sufficiently out of date that Hyperfix figures in the uk government frequency allocation table. The relevant entries read: 1 800-1 810 kHz RADIOLOCATION RR485, 486, 487 1 800-1 810 kHz FIXED MARITIME MOBILE RADIOLOCATION HYPERFIX navigation system operates within this band. FIXED MOBILE except aeronautical mobile RR484, 488, 495 1 850-2 000 kHz AMATEUR FIXED MARITIME MOBILE RADIOLOCATION Land Mobile Government use. The Amateur service operates on a primary basis within the band 1 850-2 000 kHz phone. BT currently operate 22 coastal services within this band. Maritime DGPS operate within this band. HYPERFIX system operates within this band. 2 160-2 170 kHz RADIOLOCATION RR485, 486, 487, 499 2 160-2 170 kHz FIXED MARITIME MOBILE RADIOLOCATION Government use. Hyperfix navigation systems operate in this band.