Emergency Medical Services Radio
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Revision as of 22:05, 22 August 2007 by Blackice (talk | contribs) (Undo revision 16516 by Special:Contributions/LikQgd (User talk:LikQgd))
VHF Frequencies
150.7750 EMS (simplex) 150.7900 EMS (simplex) 152.0075 EMS (paging) 155.1600 EMS (also a common SAR frequency) 155.1750 EMS 155.2050 EMS 155.2200 EMS 155.2350 EMS 155.2650 EMS 155.2800 EMS 155.2950 EMS 155.3250 EMS 155.3400 EMS to Hospital (HEAR) 155.3550 EMS 155.3850 EMS 155.4000 EMS 163.2500 EMS (paging)
These frequencies are also often used for other purposes which may or may not be EMS related such as ambulance dispatch and fire department tactical.
UHF Frequencies
The UHF "Med" channels 1-8 (some regions use different names, such as "Mednet") are used by Emergency Medical Technicians to communicate with the hospital. Information transmitted may be as little as the patient's age, sex, and general condition or as extensive as a full diagnostic workup.
In some areas, Paramedics are only able to give certain treatments under authority of an MD or specially-trained RN. This type of traffic is on the decline as well as Paramedics are given more independent treatment authority.
Analog transmission of electrocardiograms was quite common in the early days of modern EMS, but these modulated 1000 Hz tones are heard less and less as more and more EMS medical traffic is handled via cell phone. The FCC regulations (47 CFR Ch 1 Sec 90.20) reflect the old way in that Med 1-3 (and also Med 11-33) are allocated primarily for transmitting this type of telemetry, although this is rarely done and hence the channels are also used for other purposes (such as voice and paging).
Med channels 9 and 10 (and also Med 91-103) were added later below the original band of 8 and are allocated for dispatch purposes instead of medical control. They also explicitly allow paging, typically the same type as used by fire departments.
The UHF frequencies are assigned in pairs. In semi-duplex mode the higher frequency of the pair is usually used by the mobile while the lower frequency is used by the base (usually a hospital). Some EMS systems have the system configured for full-duplex where both parties can transmit and recieve at the same time. In many areas, they are configured as repeaters on mountaintops with the hospitals transmitting and receiving the same as any mobile. PL tones are selected by the ambulance crew to select which hospital hears the traffic, since many hospitals may be able to hear the same repeater on a particular pair.
Med channels 11-103 are "splinter" frequencies added the most lately. They are situated between the original existing channels and all would probably have to be narrowband to prevent adjacent channel interference if they were used in close proximity. The channels ending in a "1" or "3" (which are .00625 step channels) are narrowband to prevent adjacent channel interference.
Mobile and portable stations above 2.5 watts, licensed before July 6, 2000 must have Med channels 1-8. Those licensed between July 6, 2000 and December 31, 2005 must have Med channels 1-8, plus Med channels 12-82 (those intermediate splinters ending in "2"). Starting January 1, 2006, they must have all 40 channels. Base stations and portables below 2.5 watts are excepted.
Mobile Rx Mobile Tx Name Primary Allocation Note 463.00000 468.00000 Med 1 Biomedical Telemetry 463.02500 468.02500 Med 2 Biomedical Telemetry 463.05000 468.05000 Med 3 Biomedical Telemetry 463.07500 468.07500 Med 4 Medical Control (voice) 463.10000 468.10000 Med 5 Medical Control (voice) 463.12500 468.12500 Med 6 Medical Control (voice) 463.15000 468.15000 Med 7 Medical Control (voice) 463.17500 468.17500 Med 8 Medical Control (voice) 462.95000 467.95000 Med 9 Dispatch/Paging 462.97500 467.97500 Med 10 Dispatch/Paging 463.00625 468.00625 Med 11 Biomedical Telemetry narrowband 463.01250 468.01250 Med 12 Biomedical Telemetry 463.01875 468.01875 Med 13 Biomedical Telemetry narrowband 463.03125 468.03125 Med 21 Biomedical Telemetry narrowband 463.03750 468.03750 Med 22 Biomedical Telemetry 463.04375 468.04375 Med 23 Biomedical Telemetry narrowband 463.05625 468.05625 Med 31 Biomedical Telemetry narrowband 463.06250 468.06250 Med 32 Biomedical Telemetry 463.06875 468.06875 Med 33 Biomedical Telemetry narrowband 463.08125 468.08125 Med 41 Medical Control (voice) narrowband 463.08750 468.08750 Med 42 Medical Control (voice) 463.09375 468.09375 Med 43 Medical Control (voice) narrowband 463.10625 468.10625 Med 51 Medical Control (voice) narrowband 463.11250 468.11250 Med 52 Medical Control (voice) 463.11875 468.11875 Med 53 Medical Control (voice) narrowband 463.13125 468.13125 Med 61 Medical Control (voice) narrowband 463.13750 468.13750 Med 62 Medical Control (voice) 463.14375 468.14375 Med 63 Medical Control (voice) narrowband 463.15625 468.15625 Med 71 Medical Control (voice) narrowband 463.16250 468.16250 Med 72 Medical Control (voice) 463.16875 468.16875 Med 73 Medical Control (voice) narrowband 463.18125 468.18125 Med 81 Medical Control (voice) narrowband 463.18750 468.18750 Med 82 Medical Control (voice) 463.19375 468.19375 Med 83 Medical Control (voice) narrowband 462.95625 467.95625 Med 91 Dispatch/Paging narrowband 462.96250 467.96250 Med 92 Dispatch/Paging 462.96875 467.96875 Med 93 Dispatch/Paging narrowband 462.98125 467.98125 Med 101 Dispatch/Paging narrowband 462.98750 467.98750 Med 102 Dispatch/Paging 462.99375 467.99375 Med 103 Dispatch/Paging narrowband
Early on, there were four other frequencies, another 5 MHz below Meds 2, 4, 6, and 8 (458.02500, 458.0750, 458.1250, 458.1750). These were used by Paramedics to relay medical and telemetry traffic from the patient's location to the ambulance or rescue vehicle and then again to the hospital or other medical control. Like the Med channels themselves, they are now all in the public safety frequency pool.