Antenna on Type I Ambulance

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I need a little input, please. We have a new Type I ambulance. There will be (2) UHF radio's and (1) VHF radio installed in the unit. We have considered putting phantom antenna's on top of the ambulance box, but they won't give any if faced with a tree-branch or other item and will just break. Then we considered just using quarter-wave antenna's on the box, but they will stay bent in all directions and affect performance. I know in the past, quarter-wave antenna's on the ambulance CAB will have signals blocked by the box itself. So now, we are down to putting three 5db gain antenna's on the cab so as to reach over the box. Anybody have anymore suggestions or input?? Thanks for any advice.
 

omniryx

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For ten years, I was director of a seven-county EMS system and a Level One trauma Center. Our rolling stock included 45 box-on-chassis life support units, one heavy rescue vehicle, one mobile decontamination vehicle, seven supervisory vehicles, and two helicopters.

We always used quarter-wave antennas mounted on the cabs and, so far as I can remember, we never had a problem with signals being blocked by the boxes. Every situation is different, of course. We had very flat terrain and lots of repeaters. Your mileage may vary.

Best of luck. Let us know what you do and how it works out.
 

prcguy

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Look at the transit antennas for buses, trains, etc. They are usually shallow dome shaped or low rectangular shaped with rounded sloping edges that don't get caught on trees. They also mount with a lot of screws around the perimeter and won't rip out like an NMO mount.
prcguy
 
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Thanks for your responses. I'm in SW VA, so I'm surrounded by mountainous terrain. I will look into the transit-type antennas. Thanks.
 

Alliance01TX

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Antenna's on Ambulance

Howdy

I think a few questions to ask to better think about the size, type and location of antenna's and also determine a few other things like possible coverage gaps, etc...

1. What are the frequencies used? You mention VHF and UHF but that covers a lot of frq ranges....

2. What is the average distance to each freq repeater(s) typically?

3. Has anyone performed a 'drive test' to check the basic area coverage of each freq? This would help establish several things, including power required to hit a repeater or simplex (CSQ) operations, etc....

4. Will the equipment mostly be for medial (EMS) runs or combination of EMS and other things, such as Command Post, etc...? Reason I ask is we use a telescopic antenna set up for remote Command Post work only and have standard whip type antenna's althought they are 800 mhz so smaller sizing....

Several companies (Motoroal) make some Heavy Duty "Spring Loaded" antenna& bases for the reasons you speak of, but if the equipment is going off-road or heavy wooded areas then even these type antenna's may not work as well and the 'low profile' antenna are great for city spaces, but they might not have the 'reach' of a typical whip antenna would have perhaps...

Hope this helps in your thinking thru options...

Bill
 

N0YFE

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Antenna

I need a little input, please. We have a new Type I ambulance. There will be (2) UHF radio's and (1) VHF radio installed in the unit. We have considered putting phantom antenna's on top of the ambulance box, but they won't give any if faced with a tree-branch or other item and will just break. Then we considered just using quarter-wave antenna's on the box, but they will stay bent in all directions and affect performance. I know in the past, quarter-wave antenna's on the ambulance CAB will have signals blocked by the box itself. So now, we are down to putting three 5db gain antenna's on the cab so as to reach over the box. Anybody have anymore suggestions or input?? Thanks for any advice.
Here is one site that has the transit type antennas. Around here most of our ambulance rigs have these mounted on the roof.

PCTEL, Inc. Silhouette Low Profile Transit Antennas Mobile Antennas
 

jim202

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Alliance01TX

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Ambulance Antenna's (Cont)

Jim makes a great point in his response (antenna bandwidth) is a key component....another thing to to consider is the relatively new Federal Interoperability frequencies and state assignments across the spectrum, so just another item to consider,especially if involved with State / Federal agencies and naturally the level(s) of "Mutual-Aid" that your trucks are working in a County area or region.... Hence, many of the questions in my prior post~reply...

Bill
 
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