Morse Code 5 5 5

[AlphaFive]

In Buncombe County, if you run a custom search (Uniden) / limit search (RS), on Buncombe County 700 Mhz frequencies, a strange thing occurs in Asheville. Although this occurs on any Buncombe County frequency, I'll use 774.68125 as an example. As the normal transmission comes in and is received, there is no issue. When the signal drops out, it appears a second transmission has ridden in on the sound wave, and is left over. There is a very clear Morse Code sent. Five dots . . . . . That is repeated three times and the signal stops. As far as I know, five dots , three times, would represent 555. Makes no difference whether the Buncombe frequency is a control channel or not. It will arrive on any freq.
I have tried several different formulas for checking for an I.F. issue. Nothing comes anywhere close to a band where this might occur. I have just learned that non directional beacons down in HF emit their identities using this method, but 700 Mhz is a long way from HF. Also this is not the top of the hour, once an hour station i.d. that is required. This can occur several times within a ten minute period, at any time of day.
There is one I.F. number that has worked several times for my BCD536, it's 761.4725 or there abouts. That could put the transmission originating around 10000 kHz. I know nothing about that range. Has anyone in W.N.C. experienced this?