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How to search for nearby frequencies on SDS100 (DMR, NXDN, MotoTRBO)?

LZJSR

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I am going to the Rose Bowl this weekend for a UCLA football game (well, it will be a slaughter but that is another story). The game management staff on the sidelines who communicate to each other (not the football team staff which I know is on a Telex style encrypted radio) regarding entertainment on the field, etc... use UHF radios and I am pretty sure they using a digital repeater, likely MotoTRBO, DMR, or NXDN. I know for certain they are not utilizing a conventional analog UHF system. I am suspecting they are using frequenies between 450-470mhz.

What is the best way to search for their communications, since I can't use close call on these digital systems.

I will be using a Uniden SDS100. What I am unclear on is if I choose "Analyze?" "Conventional search?" "Discovery?" Any detailed instructions on how to best listen in would be appreciated. I am pretty sure they are not digital encrypted, but I am certain it is not conventional UHF. I heard the radio from a few feet away and it was definitely a digital signal.

I will be using a SDS100 scanner.

Thank you so much in advance
 

phyberoptics

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If they are using a repeater, close call should work to help you find the repeater output since it transmits both timeslots in the stream. The reason close call doesn't work for handhelds is because the scanner can't capture the intermittent signal from the single timeslot.

I'd use a combination of close call and Custom Search, make sure your step is set to 6.25...
 

Markb

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A quick search through the forums


netted this:


I would enter these frequencies and not bother with close call or search functions.
 

RRR

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On that note, why is it my TRX-1 can decode a portable XPR6550, using DMR “radio to radio” transmissions (1/2 time slot) but neither of my SDS’s will recognize it, unless it goes through the repeater (Full slot used)? Could this be a hardware / firmware issue?
 

LZJSR

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A quick search through the forums


netted this:


I would enter these frequencies and not bother with close call or search functions.
Should I just put them into one new Department -- Site, and then just program as conventional and see what happens as it scans?
 

LZJSR

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I have definitely heard CSC, and have logged a lot of the traffic in the past off of the license you posted... it is mostly maintenance stuff, ticket takers, etc... I will set it up to record then look back later when I get home and decipher what data I got. One last question, and I apologize in advance for annoying anyone... what is the best way to record a long event like this? I really just need the first 2-4 seconds of each conversation to hear what it was about, then I don't care if I miss the end, as I am trying to figure their system out. What are the recommended best settings so it resumes scanning after about 4 seconds, regardless if there is an active conversation going on... so that I can move onto the next conversation and not get stuck on two people talking about one topic too long?
 

ka3jjz

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I'm surprised folks haven't mentioned this...;.


Mike
 

Markb

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I am not sure if there is one when using the basic record function. I usually just roll the channel knob to the next recorded conversation.
 

Markb

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I'm surprised folks haven't mentioned this...;.


Mike
Yeah, to me there is more bang for your buck just to do a name or geo search [in the FCC/RR db]. Besides, it looks like much of this could very well be analog.
 

LZJSR

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I've used the digital frequency search, but since they use rented radios from BearCom, it is a bit hard to figure things out. I'm trying though and once I get verifiable data I will submit info to the database
 

SteveSimpkin

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On that note, why is it my TRX-1 can decode a portable XPR6550, using DMR “radio to radio” transmissions (1/2 time slot) but neither of my SDS’s will recognize it, unless it goes through the repeater (Full slot used)? Could this be a hardware / firmware issue?
I believe it is a hardware limitation for the Close Call function. According to UPMan "Close Call cannot get a hit on simplex DMR, as it is a 30mS on/30mS off signal. Close Call requires a continuous signal. ".
 

RRR

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Could this be possibly remedied by Uniden in the future? It -can- be done on other brands of scanners.
 

Ubbe

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Close call are working as a frequency counter and needs to calculate the number of frequency waves over a longer sample time, longer than the time for one timeslot. They could make the sample time shorter but would make all close call hits more unreliable and some would be off frequency.

/Ubbe
 
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