SDS 200 Close Call

[tweiss3]

I'm on pickup duty this week, and I figured I would try using Close Call to see what the school was using to talk. I turned on CC only, and other than permanent avoid of a birdie, I found 2 licensees that I wasn't aware of. The first matches the FCC license perfectly. The second is confusing to me.

License indicates 160.0875 MO11K2F3E, 4K00F7W. Makes sense, narrow FM and data. As I'm listening to the conversations, it shows up on the scanner 160.09 or 160.085 (both sides of the license, I figured it's just related to the step) but I see a RAN listed, and in the upper corner it shows both IDAS and NEX4. I see Talkgroups coming across, as well as user IDs. This happens to be the mobile simplex/repeater input frequency, and got nothing from the repeater output.

1) Just verifying I have on issue with my scanner being off frequency.
2) Does this indicate they are using an NXDN system?
3) What would be the next best step? Run a discover search on the license frequency?

 

[KevinC]

You'd have to change you band defaults to a step size of 7.5 kHz to have it land on 160.0875.

 

[kevino]

4K00F7W is reportedly a catch all mode designation for mixed voice & data NXDN. With the information you described from your SDS 200's display, I'd say you were hearing NXDN traffic.

Any chance that this FCC Callsign WQXP593 (NORTHWEST LOCAL SCHOOL DISTRICT) the user you're listening to? If so, 160.0875 appears to be a mobile-only (simplex?) frequency. If 152.930 is the repeater you're referring to, it seems that 159.750 is the input to that repeater.

Hope this helps...

 

[tweiss3]

4K00F7W is reportedly a catch all mode designation for mixed voice & data NXDN. With the information you described from your SDS 200's display, I'd say you were hearing NXDN traffic.

Interesting. So it's ultra narrow NXDN. I wasn't aware 4K00F7W would be acceptable for voice as well. That makes sense.

Any chance that this FCC Callsign WQXP593 (NORTHWEST LOCAL SCHOOL DISTRICT) the user you're listening to? If so, 160.0875 appears to be a mobile-only (simplex?) frequency. If 152.930 is the repeater you're referring to, it seems that 159.750 is the input to that repeater.

Hope this helps...

Not Northwest.

Location 4 is a circle around 3, and location 2 is a circle around 1. Interesting thing is, Location 3 is a building that was sold 3 years ago, I would expect them to be using Location 1, but they are still using simplex on 160.0875 to talk to the front office, probably out of habit.

Now to figure out NXDN logging on the computer, as I don't think SDRTrunk supports NXDN yet. I'd like some confirmation on the other frequencies. I was sitting next to location 1, but didn't hear anything on close call.

 

[tweiss3]

Ok, stupid question, is it possible to do a conventional discovery, but only on the 4 frequencies above?

 

[sonm10]

Create a one-frequency NXDN trunking system. Enter each frequency as a separate site. Set talkgroups and RAN/Area to Search. Press record (function + replay).

 

[tweiss3]

Thanks, I figured that was probably the way to do it. Unfortunately/fortunately, in order to do that, you need some system type information, which luckily I had already.