Emergency Medical Services Radio
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Revision as of 19:36, 17 November 2006 by BirkenVogt (talk | contribs)
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.
Med channels 9 and 10 were added later below the original band of 8 and each has a specific listed purpose. Both are dispatch related, however, as opposed to medical control for channels 1-8. This is not always practiced, though, as sometimes the lower channels may be used for dispatch as well.
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 even later. 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.
Mobile Rx Mobile Tx Name 463.00000 468.00000 Med 1 463.02500 468.02500 Med 2 463.05000 468.05000 Med 3 463.07500 468.07500 Med 4 463.10000 468.10000 Med 5 463.12500 468.12500 Med 6 463.15000 468.15000 Med 7 463.17500 468.17500 Med 8 462.95000 467.95000 Med 9 462.97500 467.97500 Med 10 463.00625 468.00625 Med 11 463.01250 468.01250 Med 12 463.01875 468.01875 Med 13 463.03125 468.03125 Med 21 463.03750 468.03750 Med 22 463.04375 468.04375 Med 23 463.05625 468.05625 Med 31 463.06250 468.06250 Med 32 463.06875 468.06875 Med 33 463.08125 468.08125 Med 41 463.08750 468.08750 Med 42 463.09375 468.09375 Med 43 463.10625 468.10625 Med 51 463.11250 468.11250 Med 52 463.11875 468.11875 Med 53 463.13125 468.13125 Med 61 463.13750 468.13750 Med 62 463.14375 468.14375 Med 63 463.15625 468.15625 Med 71 463.16250 468.16250 Med 72 463.16875 468.16875 Med 73 463.18125 468.18125 Med 81 463.18750 468.18750 Med 82 463.19375 468.19375 Med 83 462.95625 467.95625 Med 91 462.96250 467.96250 Med 92 462.96875 467.96875 Med 93 462.98125 467.98125 Med 101 462.98750 467.98750 Med 102 462.99375 467.99375 Med 103
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.