A friend and I both have BC-125AT scanners and were talking about the "Close Call" feature. Is the sensitivity worse on a particular band or is the problem just lack of sensitivity in the 'Close Call' function?
BC125AT: BC-125AT close call
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JethrowJohnson
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I'm not really sure. I programmed at BC125AT for a friend of mine and I have a BC75XLT which is similar but less advanced, but it has CloseCall too and it's only supposed to alert if it gets a transmission within a few hundred feet of it. Although, mine alerts when the volunteer fire department in the next town over transmits. I figure it's just that their repeater's signal is so strong that the scanner thinks it's right next door or something.
avaloncourt
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I posted a topic about CloseCall a couple months ago. I was trying to locate the frequencies in use by a race track and was having zero luck finding anything yet I knew they had radios. I tried with both a BC125AT and an SDS200. I had already tried to find an FCC license for the site. Having had zero luck for weeks I began to suspect that they were using FRS/GMRS radios. I was told in here that the signal level would be so low that it would never trigger a CloseCall capture. The next week, I went to the track with preprogrammed set of FRS/GMRS and, sure enough, that's exactly what they were using, FRS 5. You might not have enough difference in the scanner analysis of the signal to trigger the capture.
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Close Call requires three criteria to be met to trigger a hit:
1. The signal must be at least 18 dB stronger than /any/ other signal in the band.
2. The signal must be at least 18 dB above the noise floor.
3. The signal must last long enough for Close Call to determine the frequency (non-TDMA).
These are much stronger signals than the normal scanning mode.
Even if you are standing next to someone with an identical scanner, they may be picking up a signal within that 18 dB spread that is weaker at your location only a foot away or so, so one may hit while the other may not.
1. The signal must be at least 18 dB stronger than /any/ other signal in the band.
2. The signal must be at least 18 dB above the noise floor.
3. The signal must last long enough for Close Call to determine the frequency (non-TDMA).
These are much stronger signals than the normal scanning mode.
Even if you are standing next to someone with an identical scanner, they may be picking up a signal within that 18 dB spread that is weaker at your location only a foot away or so, so one may hit while the other may not.
So Close Call = Next to you OR really *really* powerful transmitter just around the corner/block
JethrowJohnson
I love P25
Not always. I used to use CloseCall DND on my BC75XLT and it would get transmissions from 155.13 MHz as CloseCall hits. That frequency was the Wood County Fire North repeater. That's in the next county over from me.So Close Call = Next to you OR really *really* powerful transmitter just around the corner/block
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So Close Call = Next to you OR really *really* powerful transmitter just around the corner/block
That depends on what you call "really powerful".
Generally, base stations can trigger up to 2 miles (my record is 15 miles - outside antenna in the middle of the night)
Mobiles can often get up to a mile or more.
5W portables can get up to 75 feet.
2W portables can get up to 25 feet.
Low power devices such as wireless mics may not hit with the antennas touching.
These are not absolutes and performance will vary by location and conditions. But this should give you a rough idea.
To add to that, when I’m away from the city my CC capture range increases dramatically (lower noise floor and less in-band signals).
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