interesting federal data bursts

[batdude]

the below frequencies have all been monitored from the the east central florida area. Data has been noted on ALL (yes, ALL) of the following repeaters (with the user of that particular repeater also identified when known), the data bursts do not seem to follow any set schedule that I have been able to determine - and yes, some of these data bursts simul-key other repeaters in this list..... This isn't so much a "NAC-hunt" searching for the user... I'm more after the details of the data bursts... what they are for... why they simul-key some repeaters, but not others, etc. etc.

the ?? = i do not know the user and have not recorded a NAC.

164.325 ?? (this is a very strange P25 repeater, very informal comms sometimes... traffic, fire trucks, quitting time... etc...)
164.925 NAC 200
167.7875 FBI
169.55 ??
169.5875 ??
169.6625 NAC 292
169.9125 ICE
169.5875 ??
170.375 NAC 100
170.5375 ICE
170.9875 CBP
171.0125 ??
171.125 ??
172.15 TSA
171.0125 ??
171.6125 FBI
172.0625 CBP
173.50 FBI
407.1375 USPS


A sample of the transmitted data is available HERE:

and

Help / discussion appreciated.


Merry Christmas


doug

 

[batdude]

This photo shows 5 repeaters, with a new one just found, 169.6, all simul-keyed with the data mentioned above.....

 

[TDR-94]

Are you familiar with OTAR?

 

[batdude]

Pre-p25 OTAR, yes. Which sounded like standard CVSD secureNet. I have thought this might be P25 OTAR - but what troubles me is that during the data burst there is NO NAC transmitted..... and this data doesn’t sound anything like any p25 data streams I’ve ever heard .....?

 

[INDY72]

Could be status ack on linked net?

 

[RichardKramer]

Since last Tuesday on 168.875 there is a steady data stream; my 396XT shows data/lnk; the 436 shows lnk/NAC944. On 168.9875 there are data bursts with the 396XT just breaking the squelch no display of lnk/NAC; the 436 showing lnk/NAC947. Haven't heard anything like this in the SE PA area before.
Rich

 

[dlwtrunked]

the below frequencies have all been monitored from the the east central florida area. Data has been noted on ALL (yes, ALL) of the following repeaters (with the user of that particular repeater also identified when known), the data bursts do not seem to follow any set schedule that I have been able to determine - and yes, some of these data bursts simul-key other repeaters in this list..... This isn't so much a "NAC-hunt" searching for the user... I'm more after the details of the data bursts... what they are for... why they simul-key some repeaters, but not others, etc. etc.

You have not looked careful enough....most of these do follow a schedule but it varies among the different ones. Look for something like 2 or 4 minutes or 6 minutes. Some only transmit the NAC. There have been articles about this (in "The Spectrum Monitor" for example).

 

[batdude]

i'll see how the timing looks over the coming days.... i do not think this is "vote scanning".... yet.

 

[rrbum]

Since last Tuesday on 168.875 there is a steady data stream; my 396XT shows data/lnk; the 436 shows lnk/NAC944. On 168.9875 there are data bursts with the 396XT just breaking the squelch no display of lnk/NAC; the 436 showing lnk/NAC947. Haven't heard anything like this in the SE PA area before.
Rich

You are receiving the new Pennsylvania statewide P25 network. Those transmitters just came online last week. More information available in the Pennsylvania regional thread.

 

[batdude]

You are receiving the new Pennsylvania statewide P25 network. Those transmitters just came online last week. More information available in the Pennsylvania regional thread.

i don't think the VHF skip from PA is making it to Florida..... LOL

....quote from the the east central florida area....unquote

 

[batdude]

today, 1230-ish PM, it's just 169.9125 and 170.5375 that are simulcasting the data bursts....see picture.


doug

 

[RFI-EMI-GUY]

Periodically, these federal agencies have to OTAR all of their radios to update the encryption keys. It could be that thus is the week to do it.

Sent from my SM-T350 using Tapatalk

 

[batdude]

Periodically, these federal agencies have to OTAR all of their radios to update the encryption keys. It could be that thus is the week to do it.

Sent from my SM-T350 using Tapatalk

I'd love to confirm that this is P25 OTAR... but I don't have another site or a recording or any other samples compare it to.

This is not just a one time, once a month thing... i hear these data bursts fairly regularly - if not DAILY. Perhaps it's OTAP? I do not know - but someone out there has to have first hand knowledge of this setup.

 

[nd5y]

The FBI and CBP/ICE repeaters here used to key up about every 15 minutes or so for a long time then they quit doing it. I never tried to look at the data or tried to figure out if it was OTAR, something to do with vote-scan or something else.

 

[RichardKramer]

You are receiving the new Pennsylvania statewide P25 network. Those transmitters just came online last week. More information available in the Pennsylvania regional thread.

Thanks rrbum; Gee, the state even has to dip into the federal bands for freqs now.
Rich

 

[ecps92]

He was not replying to you, he was replying to the Person from PA who jumped into your conversation

i don't think the VHF skip from PA is making it to Florida..... LOL

....quote from the the east central florida area....unquote

 

[ecps92]

Do you have any FCC license info ?
Usually the NTIA is requiring them to get FCC licenses [as noted by other states VHF Networks]

You are receiving the new Pennsylvania statewide P25 network. Those transmitters just came online last week. More information available in the Pennsylvania regional thread.

 

[batdude]

He was not replying to you, he was replying to the Person from PA who jumped into your conversation

i know, i was ribbing him (hence the LOL) LOL

 

[eg2138c]

I'm just NW of Chicago, IL and I hear these data bursts all over the VHF range from time to time 155.475 and in the 162-174 range. I have been hearing it on and off since about 2003. I suspected at one time it might be over the air data to stun missing radios or DSS digital spread spectrum system.

 

[ecps92]

What Freq/NAC ? might help define if VS or just a Repeater beaconing.
162-174 is a wide swath and shared with Part 90 FCC licenses.

I'm just NW of Chicago, IL and I hear these data bursts all over the VHF range from time to time 155.475 and in the 162-174 range. I have been hearing it on and off since about 2003. I suspected at one time it might be over the air data to stun missing radios or DSS digital spread spectrum system.