CB Antenna for Public Safety Motorola Radio

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squirrel911

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Ok, a good friend of mine just bought a used Motorola UHF radio from someone. The radio antenna connection is the same as a CB antenna. He hooked the Radio up to the antenna and it works just fine. He can TX and RX just fine. As a matter of fact he lives in the next county over from the rescue unit he is on and can TX and RX great. Someone told him that this could blow his radio. Is this true? How can this antenna work? Oh and it is a magnet antenna. Thanks for the info everyone.
 

FFPM571

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Yes it works. A coat hanger will work in a pinch. If the antenna is not the correct band it will throw the SWR Standing wave ratio off and that will cause RF power to be sent back into the transmitter of the radio and cause problems and fry the radio over time. Its best to get a real UHF antenna
 

fineshot1

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FFPM571 is right on target with his answer.

If his used radio is not too old the only thing protecting it
from damage may be the auto power output reducing
protection circuits that kick in when high swr is detected
on the antenna port during transmit.
 

kb2vxa

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"How can this antenna work?"
He got extremely lucky the antenna just happened to be close to the correct wavelength multiple to give an acceptable match or the transmitter final would have gone POOF in a heartbeat. The question is HOW acceptable so the "when in doubt don't" rule comes into play. Putting the wrong antenna on a radio is like playing Russian Roulette with 5 loaded chambers, he really should have heeded the rule before he picked up the gun.
 

n5ims

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It is a Wilson 5000 antenna. How can we check the SWR on it?
Take the radio to a radio shop who will have a good SWR meter like the Bird 43 with the correct element for the frequency and power for the radio under test. They will also know and understand how to use that meter.

Funny how your signature indicates that you're the Owner/CEO of a company that sells Vertex radios Squirrel 911 Lights and Sirens (Squirrel Lights and Sirens) | MySpace but you don't understand how hooking up a CB antenna to a UHF radio might be a bad idea. Do you have anyone in your shop that knows and understands the radios you sell or the test equipment that would verify that they are installed and working correctly?
 

kb2vxa

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Since "UHF" isn't far from the 70cM Amateur band a good VHF/UHF meter will give you a reasonably accurate reading also but I'm only answering your question, I make NO recommendations other than the following. Just because the Wilson didn't blow up the radio doesn't say all is well, still I would tell "your friend" to discontinue its use immediately and seek assistance from a qualified technician.
 

squirrel911

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Take the radio to a radio shop who will have a good SWR meter like the Bird 43 with the correct element for the frequency and power for the radio under test. They will also know and understand how to use that meter.

Funny how your signature indicates that you're the Owner/CEO of a company that sells Vertex radios Squirrel 911 Lights and Sirens (Squirrel Lights and Sirens) | MySpace but you don't understand how hooking up a CB antenna to a UHF radio might be a bad idea. Do you have anyone in your shop that knows and understands the radios you sell or the test equipment that would verify that they are installed and working correctly?
Yes i own a Lights, Siren, and Radio Shop but i didn't do this radio. It is a friend of mine in Kansas. I have only seen it in pictures. I am fairly new to the business so i am still learning everything there is to learn about radios. Now Lights and Sirens i can work with. I figured this would be the place to get some help if i needed it.
 

n5ims

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Many of us will be happy to help you get up to speed on radios. Please be aware though that although we're happy to answer your questions and help point you in the right direction, it is expected that you'll put as much thought and research into your question as you'd like the respondent to do in providing an answer.

For example, a common question we get is a very simple one like 'What is the best <insert item here such as radio, antenna, etc.>?'. It is obvious that very little thought was given to the question so the appropriate answer (using the same amount of thought that went into the question) would be "One that does the job!". Obviously neither the question nor the answer is of much use to either party.

A better question that would almost certainly yield a better answer would be a question that provided specific details on how the item being asked about was going to be used. For example. Instead of simply asking "What's the best antenna?", providing details like "I'm trying to monitor the Podunk, ID 800 MHz system, but I only get a weak signal. I live in a town about 15 miles away in an upstairs apartment so an outside antenna isn't possible. What things should I try to help me get a stronger signal?" would provide the respondents with something to help base their answer.

Good luck expanding your business and hope the RR community is helpful in getting you up to speed.
 
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