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Mystery 170.625 signal in Kona

DeDawg

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Kona, HI
Got up this morning and turned on radios to try and figure out another problem.

Got a "close call" hit on 170.625 MHz. Fired up the SDR to see what was about. Every 2.00 minutes exactly there is a burst of noise/buzz no more than half a second in duration.

Been going on for a few hours now. Might have always been there, do not listen to anything in that band.

Any ideas who or what this signal is? Receiving this very strong near Lako and Queen K.
 

DeDawg

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The two minute transmission period has me curious. If FBI, wonder if it is some kind of tracker.

Might take a HT out with me today and see if i can narrow down the location. Heck, might be on my car!
 

ecps92

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Taxachusetts
What type of Buzz ?
P25 ? if so what NAC
Analog - DVP/DES [old school]??
DMR ? - if so what CC / SL / TG ??

170.6250 is known to be a variety of agencies, depending on the state/region/.


That said, try this
https://wiki.radioreference.com/index.php/Federal/Non-Federal_Interoperability#DOJ_High-Risk_Metropolitan_Areas_Interoperability_Assistance_Project
If you can get a NAC, then this tourist can help


Got up this morning and turned on radios to try and figure out another problem.

Got a "close call" hit on 170.625 MHz. Fired up the SDR to see what was about. Every 2.00 minutes exactly there is a burst of noise/buzz no more than half a second in duration.

Been going on for a few hours now. Might have always been there, do not listen to anything in that band.

Any ideas who or what this signal is? Receiving this very strong near Lako and Queen K.
 

DeDawg

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Premium Subscriber
Joined
Mar 26, 2017
Messages
180
Location
Kona, HI
Tuned to it direct with my BCD325p2, no indication of any digital mode during the ver breif transmission. My TRX-2 does not have a manual tune mode, but setting up a very narrow range search only showed "FM"when it caught the short TX.

The sound varies a bit between radios. Burst of static to a buzz like a door opener.
 

ecps92

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Jul 8, 2002
Messages
10,470
Location
Taxachusetts
double checking my notes at home last night...this is/was the HI DOJ Interop
so the NAC should be $653, but until someone can validate a NAC, all we have is speculation

Tuned to it direct with my BCD325p2, no indication of any digital mode during the ver breif transmission. My TRX-2 does not have a manual tune mode, but setting up a very narrow range search only showed "FM"when it caught the short TX.

The sound varies a bit between radios. Burst of static to a buzz like a door opener.
 

DeDawg

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Mar 26, 2017
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Location
Kona, HI
Occur the the repetitive tx could be just FCC station ID. A monitoring station would make sense down south, not on the volcano we live on here. This is a very strong signal.

Had some longer transmissions this morning, sounded the same, just longer. Might try to program it into the TRX-2 as a P25 site for grins.
 

DeDawg

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Early morning typing. Like a civilian repeater, might they need to periodically broadcast the Fed equivalent of a call sign?

Dunno what FCC rules they have to follow.
 

DeDawg

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Kona, HI
Finally got my act together with the 325P2. Programmed in a conv freq with digital and search for NAC.

Ran it from Proscan so I could watch the display better. Set it to hold on 170.625 and watched.

Took several tries as the NAC flickered by so fast, but with a timer to get ready, finally got it:

167

The RR Fed NAC code says:

BP, FBI, TVA, USMS, RAF Croughton UK

Dunno what any of those would be doing in a minor Big island town..............

Funny, yesterday when i first caught the freq on close call, they did a tx every 2". This morning they did several longer transmissions, then back to the periodic stuff. Now as I sit and watch for the NAC, they are going far longer between transmissions. Almost like they are still setting up a site?
 
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