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Scanner / Receiver Antennas - For discussion of any type of receiving antenna used by a scanner or receiver base, mobile or handheld.

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Old 02-17-2017, 7:38 AM
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Default Scanner antenna near transmit antennas

I was wondering what the potential problems would be of placing a scanner antenna feeding a pro197 with a l bracket trunk mount in close proximity to two 800mhz and one low band antenna that are both used frequently.

My main concern is not frying the Pro197 when that 100w(?) low band fires up.
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Old 02-17-2017, 8:58 AM
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Not good. High probability of desensitizing the scanner by overloading the front end.

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Old 02-17-2017, 9:33 AM
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Are there any solutions to this?
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Old 02-17-2017, 9:35 AM
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Moving the antennas as far apart as possible.
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Old 02-17-2017, 10:02 AM
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There is about 4ft of separation between the low and and the scanner antenna
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Old 02-17-2017, 10:22 AM
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What kind of scanner antenna do you have? If it doesn't resonate at the low band frequencies, you can get away with having them closer without damaging the scanner. I have a scanner antenna about 4 feet from a 25W dual-band antenna with no issues. If the RX antenna doesn't resonate at the TX frequency, you can safely run higher TX power at the same distance.

With 100W TX power and 4ft of separation, I'd be concerned if the scanner antenna was designed to RX the TX frequency. But if not (e.g. low-band TX is 40MHz and scanner RX starts at 110MHz), you'll probably be OK. Unfortunately the only way to know for sure is to key the mic and see if you fry the scanner's RF input.

Regardless of damage concerns, don't expect to hear anything from the scanner (other than yourself) when you have any other radio in the vehicle keyed.
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Old 02-17-2017, 10:35 AM
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The antenna specs say it start at 150mhz and goes up so in that respect I should be ok. The scanner is just for picking up local fire/ems dispatches on VHF systems. The law channels are covered by the 800. Low band isn't used much anymore but it's still used here and there. I'll try it and hope for the best.

Thanks
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Old 02-17-2017, 11:00 AM
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You should be OK with a 4ft separation, but the only way to know for sure is to try it. Another idea, put a https://www.amazon.com/dp/B00AR0837K/ inline between the scanner and its antenna to block low-band signal going to the scanner. That would guarantee nothing bad would happen to the scanner.
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