SDS100/SDS200: Pick up trunked system from 400+ away?

[KK4JUG]

I was on the move this past weekend. I spent the night at a motel near Little Rock. For a little entertainment, I took the SDS100 to the room. It has Jon's internal GPS and I listened to public safety on the Arkansas Wireless Information System (AWIN). When I left there, I put the radio in the suitcase and left for Wichita. Once again, I took the radio to the motel room in Wichita. When I turned it on, I was listening to AWIN again, at least that's what the display said. It displayed info for AWIN/Little Rock PD. I didn't hear anything in the conversation that would actually pin it down to any location, let alone Arkansas. It was general commentary regarding a disturbance call. The GPS had not yet loaded Wichita information. After a minute or two, the GPS did load Sedgwick County/Wichita info and everything was fine.

I'm no expert but I'm pretty sure I wasn't picking up Arkansas's radio system in Wichita, 400+ miles away. What happened?

 

[mancow]

It probably had the same control channel frequencies.

Why are you in Wichita? Ewwww....

 

[ToddWilkinson]

I've noticed my SDR's going crazy since they fired up HAARP, suddenly I'm hitting 70 miles on the ARMER system in MN.

 

[mancow]

There is tropo-ducting extending way up North.

 

[RFI-EMI-GUY]

It probably had the same control channel frequencies.

Why are you in Wichita? Ewwww....

The best way to know is to listen to the traffic for hints of location. I am not sure how Uniden handles the CC information, but Motorola radios can grab the wrong system CC and do a late entry into a talkgroup. Only when the CC ID is decoded and found incorrect will the radio mute.

 

[trentbob]

I'm sorry I must have missed it but without having to look up these systems what frequency range are we talking about? 150 megahertz range stuff?

 

[mancow]

800

 

[tvengr]

It probably had the same control channel frequencies.

Is your SDS100 set to Use Site NAC? Scanners other than the SDS100 and SDS200 cannot differentiate between sites using the same control channel frequencies. They are the only ones capable of using site NAC. Site NAC is like a PL tone for sites. If your SDS100 is set to Ignore Site NAC, it will just look for control channel frequencies and not know which site it is receiving like any other scanner.

 

[donc13]

I was on the move this past weekend. I spent the night at a motel near Little Rock. For a little entertainment, I took the SDS100 to the room. It has Jon's internal GPS and I listened to public safety on the Arkansas Wireless Information System (AWIN). When I left there, I put the radio in the suitcase and left for Wichita. Once again, I took the radio to the motel room in Wichita. When I turned it on, I was listening to AWIN again, at least that's what the display said. It displayed info for AWIN/Little Rock PD. I didn't hear anything in the conversation that would actually pin it down to any location, let alone Arkansas. It was general commentary regarding a disturbance call. The GPS had not yet loaded Wichita information. After a minute or two, the GPS did load Sedgwick County/Wichita info and everything was fine.

I'm no expert but I'm pretty sure I wasn't picking up Arkansas's radio system in Wichita, 400+ miles away. What happened?

Strongly suspect you aren't getting a gps fix in Wichita. Try taking the radio outside until you get a fix or simply use Zip Code location

 

[cpg178]

Strongly suspect you aren't getting a gps fix in Wichita. Try taking the radio outside until you get a fix or simply use Zip Code location

He did state this resolved itself after the GPS booted up.

The GPS had not yet loaded Wichita information. After a minute or two, the GPS did load Sedgwick County/Wichita info and everything was fine.

My guess is the CC for the Sedgwick County or other local system to Wichita shares a CC from the Little Rock area.

 

[APX6k]

I have had the same thing happen here in SoCal with the SDS200 set to "Ignore Site NAC" in addition to being in TG Search (vs. Scan) mode. The Orange County CCCS and the large San Bernardino County system share a few of the same 800MHz control channel frequencies. If you have your display set to "Detail Mode", you'll notice the different Sys ID once the SDS is locked onto the control channel.

 

[KK4JUG]

Okay, I've decided they have the same control frequencies. Sometimes, the radio will take a minute or two to recognize that it's in a new area. I was indoors when I turned the radio on and I'm sure the GPS signals weren't the strongest so it took time to gather the information. In the meantime, the receiver was in full operation. The Arkansas CC freqs matched the Wichita CC freqs so it matched up the Wichita signal with the Arkansas information still in the radio. (This is beginning to sound like an Abbot and Costello routine.)

Mr. Mancow, for the record, I'm not in Wichita anymore. I'm home in Georgia. I used to live in Wichita and still have relatives there. I graduated high school there in 1962 and lived there when I joined the Air Force. For the record, that 1962, not 1862. I'm old but not that old. For it's size, Wichita is not at all a bad place to live. It gets cold in winter and hot in the summer. It's windy and it's flat. If your dog runs away, you can watch him for a week. That said, it's still not a bad place to live.

 

[ToddWilkinson]

It's happening to a lot of us SDR Users, there's flares goin off and HAARP is running for a few more days, mine didn't act up til around the first, the day HAARP was fired up, I know damn well it's messing with my equipment.

 

[donc13]

He did state this resolved itself after the GPS booted up.


My guess is the CC for the Sedgwick County or other local system to Wichita shares a CC from the Little Rock area.

They may be on the same frequency but definately don't share a control channel or site

 

[KK4JUG]

They may be on the same frequency but definately don't share a control channel or site

I didn't mention control channel or site. I only referenced frequencies. A friend once called this type of harmless incident a "transient anomaly." If it ever happens again, I'll be surprised.

 

[trentbob]

I actually have been using the global setting in settings of ignore NAC.. I use it on a tdma 700 MHz system that has one site called simulcast and 24 towers. It works better for me as the system isn't on just one NAC.

I noticed some very interesting tropospheric ducting this morning on Marine Channel 16, I use a Sputnik ground plane, I was picking up Coast Guard sectors that weren't anywhere close to my area and I would never hear on a regular day.

 

[donc13]

I didn't mention control channel or site. I only referenced frequencies. A friend once called this type of harmless incident a "transient anomaly." If it ever happens again, I'll be surprised.

No, you didn't say that, @cpg178 said it and it was his post I quoted.

 

[APX8000]

I graduated high school there in 1962 and lived there when I joined the Air Force. For the record, that 1962, not 1862. I'm old but not that old.

Whats the difference between "old" and "that old" because my math and google says you're currently both lol