Antenna help

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RadioChief55

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Can anyone ID if these antennas are UHF or VFH? I'm guessing the shorter white one is UHF and the two metal ones are older VHF antennas. Am I right?

Thanks
John
 

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Ubbe

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You are correct. Top one is 1/4 wave GP and the metal bottom one are 1/2 wave dipoles. You can easily calculate their frequencies in MHz by dividing 300 by their lenght in meters. That top one seems to be 0,5 meters measured from to the top of the bend and as it is a 1/4 wavelenght it is 300/0,5=600 and 1/4 of that are 150Mhz.

Bottom one seems to me 1 meter in total element lenght and are 1/2 wavelenghts dipoles and are 300/1=300 and half wave are 150MHz.

Measure their exact lenght to get the exact frequencies.

The white pole have probably some coils inside it that makes it a stacked dipole but impossible to know the frequency. Normally the frequency will be stamped on a label on the antenna.

/Ubbe
 

rescue161

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The first is a DB-201 and is cut for the VHF band. The second picture has a VHF 2-bay dipole array on the right and unknown on the left.
 

RadioChief55

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Thanks for the info, there was an "up grade" to the PD radio system and wasn't going to touch the FD equipment. Then we come to find that they changed the comparator on the FD side and who knows what else. All I know is now we have dead spots, out dispatch base and repeater signal doesn't travel as far as it did. Then I found these antennas laying on the floor next to our old comparator. Just trying to figure thing out. We are on 154-XXXX so you guys are right. The PD is UHF.
 
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