by Peter Szerlag - July 30, 1998 - www.geocities.com/capecanaveral/3327/savlives.html
You would not respond to an emergency in a vehicle with three tires would you? Why would you respond to an emergency only knowing 10% of what you need to know about radios and communications? Oh - you know everything you need to know - I understand. Well - please just humor me and read on.
If a police officer, firefighter, or EMT is missing at an emergency, there are several methods that you can use to locate them by using portable radios and/or scanners. I will try to give you the down and dirty facts on a couple of these methods. I have NOT tried these methods - however, I have every confidence that these ideas can be very useful.
1. You have to know the transmit and receive frequencies used by the radios at the scene. You should also know the PLs and DPLs involved. You must know how to listen to the "repeater input frequency" (NOT the "repeater output frequency) (please see my other pages for more info about all of this). If you do not have a complete understanding of the differences and relationships between inputs, outputs, transmits freqs, and receive freqs : then you cannot realistically expect to competently use the following techniques.
2. If a missing officer has a stuck microphone, then you can figure out the direction to the signal by using "direction finding" (DF) techniques. You must program the officer's transmit frequency in your receiver. Then you must hold your radio to your abdomen. Then you should turn around in a circle until the signal comes in the strongest. The direction that you are facing will probably be the direction from which the signal is coming.
3. If a missing firefighter is down and unconscious but does have a portable radio that is receiving OK, then you can walk around the site while transmitting on the same frequency that the downed firefighter's portable radio is receiving on. When you get close to the firefighter you will hear feedback (a high pitched squeal). If the radios are on a repeaterized radio channel, then you have a choice of either transmitting on the repeater input channel or the repeater output channel. If you do not understand why this is so - or you do not understand the ramifications of this choice, then please go back to #1. (I am sure that this method will work best if all other radios at the site on the same channel are turned down or off which will cause tons of problems if not practiced beforehand.)
4. If an EMT is down and missing, you can have all units at the scene switch to an alternate channel and then have everyone be very quiet. At this point, have someone begin to yell into their microphone at the station or at a location down the street. Everyone at the scene should listen intently to see where the audio comes from at the site - this will be where the EMT is trapped. Again - if you do not know which is the correct channel or PL/DPL to accomplish this, then please go back to #1. ((Items 3 and 4 can be combined depending on the situation at the scene))
I hope that everyone in public safety plus all the media people and fire buffs out there can read and understand this material. Some day it could save some peoples lives at a disaster site. One example that comes to mind is the Hackensack New Jersey fire that killed four or five firefighters.
Please keep in mind that there is no way in hell that any of these suggestions will be useful unless they are practiced and understood before they are needed at a real emergency!
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Reviewed - May 29, 1999 - still looks basically correct - 18Dec00 - still looks OK