Unknown SDR hits in 400 MHz Band

[RaleighGuy]

Wasn't sure if this was better in the SDR forum or Fed Forum, but...

Out at RDU airport this afternoon and came across two frequencies (410.075 and 413.00625) that DSD+ wouldn't decode. It almost looks like paging, but I admit I'm terrible at reading signal types. Thought I'd post them here and see if any of the experts might have ideas.



NOTE: Not saying these are at RDU as from the airport I pickup Durham VA as well as Granville County FBOP freqs.

 

[dave3825]

Might be the stuff mentioned in this thread. In post 10 it does list 410.075 as in use in VA. Are these bursts or a constant data stream? DSD will only decode the usual digital formats so if there not digital maybe there is some other software that will decode it.

 

[RaleighGuy]

Are these bursts or a constant data stream?

I believe they were bursts, but not certain.

 

[dave3825]

Might be the stuff mentioned in this thread. In post 10 it does list 410.075 as in use in VA.

Sorry I forgot to link the thread. Last night was a long night..

410.075 (a)

Anybody know what this is? it,s like constant data bursts vy good cpy here it has a ACARS sound to it almost (lol) although I know it is not that just sounds like it....just curious...vy strong hr so can,t be too far from Suffolk county I presume??...tks 73,s Marcy

forums.radioreference.com

.

 

[RaleighGuy]

Bet that's it, thanks @dave3825

 

[ecps92]

410.0750 is generally the NWS at an Airport for ASOS (Automated Surface Observing System)
this is telemetry reporting the wind, air temp and maybe even ground temp

413.00625 is the likely 413.0125 the FAA assigned for RMM (Remote Maintenance Monitoring) - also Telemetry

I've found only my older Analog scanners can find these in SEARCH as the attack time of the digital radios is quite slow.

from the NTIA FOIA files of last year
excuse the formatting
CLA CDD FRQ BINSER MBR FOI BUR NET STC EMS PWR NTS AUS AUD RVD EXD
XSC XAL XRC XLA XLG XCL XAD XAP XAZ SPD TME ICI MSD
RSC RAL RRC RLA RLG ACL RAD RAP RAZ
SUP REM
U *** M410.075000 C 890491 M NWS FX 16K00F1D W5.00000 S361 J1311635 890915 170404
I8953569
J0721165
J0144646
I9720397
NC RALEIGH DURHAM AIRPORT 355259N0784701W 06GDIPOLEARRY00131H0005T ND 1
NC RALEIGH DURHAM AIRPORT I,NTIA-U 355259N0784701W
AUTOMATED SURFACE OBSERVING SYSTEM (ASOS) CONSISTS OF A CONTROL UNIT *RAD,0003,R
(ACU), TRANSMITING ON A SINGLE FREQUENCY TO SEVERAL DATA COLLECTION *NRM,00010,NET
PLATFORMS (DCP), MEASUREING WEATHER CONDITIONS AT VARIOUS LOCATIONS *EQS,LMS
AROUND THE AIRPORT. EACH DCP TRANSMITS WEATHER DATA BACK TO ACU. SYSTEM *MFI,WEATHER
IS LINKED AT THE ASSIGNED FREQUENCY IAW SECTION 4.3.9 PARA 3. *AGN,ERMO160200
*IFI,ASOS
*AGN,CWA RAH
*AGN,OPS IAW PARA- 4.3.9.3
*POC,TM RUTKOWSKI,6312440139,161209

Wasn't sure if this was better in the SDR forum or Fed Forum, but...

Out at RDU airport this afternoon and came across two frequencies (410.075 and 413.00625) that DSD+ wouldn't decode. It almost looks like paging, but I admit I'm terrible at reading signal types. Thought I'd post them here and see if any of the experts might have ideas.

View attachment 133596 View attachment 133597

NOTE: Not saying these are at RDU as from the airport I pickup Durham VA as well as Granville County FBOP freqs.