SDS100/SDS200: Close call SDS-100

w0nwa

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Anyone have any issues picking up with close call? The only thing I can pick up is if I key up one of my radio's I sat in the local hospital parking lot. and also, close call at the airport inside. nothing. Any advice?
 

pb_lonny

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It really depends on your area and what radio users are close by. I have logged from 10km+ away at times, but it is rare.
 

w0nwa

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set UHF and 800+ because all the other hospitals in area are on UHF DMR. and on RR but Abrazo is not in RR. sat in parking lot for like an hour nothing. locked out others because kept getting radio station 94.5
 

Ubbe

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I haven't looked in a SDS100 but all other Uniden scanners use a dedicated frequency counter chip, and as such it isn't as sensitive as the receiver and it needs a single signal to be able to count the frequency correctly. Any other signal will interfere and make it harder for the chip to count properly. The setting for closecall sets the scanners normal bandpass filters to be used during the signal sampling.

The user manual says that closecall sensitivity are nominally between -52dBm to -57dBm for a single signal without modulation. So a pretty strong signal are needed. You can look at the dBm value during normal reception to see what receive levels you have.

Using better external bandpass filters will always help, for normal reception but specifically for closecall.

/Ubbe
 

Whiskey3JMC

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Last edited:

n1chu

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When Close Call doesn’t receive a signal, even after a reasonable amount of time passes, we start suspecting the feature is broken. It’s usually a case of impatience. We strive for immediate confirmations in everything we do. So, when it comes to having to sit and wait, like we do in a doctor’s office waiting room… where the clock on the wall runs slower or backwards, we get impatient. I’ve waited for the better part of an hour without hearing a thing. It was like someone erected a Faraday Cage around me! Sometimes we’ve just got to wait it out. If it’s just a testing session you are looking for, I suggest a big box store such as BJ’s. See if you can capture their frequency and start monitoring their comms. If not, move closer. They don’t call it “CLOSE” Call for nothing!
 

Whiskey3JMC

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gary123

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Close call will not capture DMR or any TDMA signals. If you have the waterfall option enabled you can use that to sweep the band looking for the strong TX spike.
 

Whiskey3JMC

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fantasma25

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Also, see this thread to see if it helps you:
 
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