X2 FBI call sign

[Oakland_Tower]

Here in the S.F. Bay Area, on two different FBI freqs, transmitting "in the clear" I heard "X-ray 2 this is X-ray 4". NAC 167h P25. There was no reply. Sounded like this was from a copter. Some ref from years ago suggested that this is Customs air units. Any ideas?

 

[RaleighGuy]

Some ref from years ago suggested that this is Customs air units. Any ideas?

Customs air units use a TROY callsign

 

[dave3825]

And if you keep posting what you hear as clear, it won’t be much longer.

 

[RaleighGuy]

And if you keep posting what you hear as clear, it won’t be much longer.

Wow, I guess we better shut down the forums for posts on what we hear, if we do that radio users would have no idea people are listening to them.

 

[ecps92]

Here in the S.F. Bay Area, on two different FBI freqs, transmitting "in the clear" I heard "X-ray 2 this is X-ray 4". NAC 167h P25. There was no reply. Sounded like this was from a copter. Some ref from years ago suggested that this is Customs air units. Any ideas?

Which two frequencies ?

And here in the Northeast, that agencies Aircraft is generally using a 3 digit number only no prefix

If using $167 and on FBI channels it is highly probable those were FBI or USM users only.
I've never (in my experience) observed anyone but FBI or USM on $167 radios, unless loaned out as part of a TF/Operation

Keep in mind, call signs being used would be specific to that single agency and would not cross-over or have any bearing on other agencies.