Unknow signal lewis county Washington state

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unknown signal lewis county Washington state (solved)
Frequencies 1000 kHz
Frequency Range 1000 kHz - 1000 kHz
Mode AM
Location Lewis County, Washington.
Short Description

recording on a PDA off of a unshelded Mic line. also heard on the AM radio band at random times.

I have heard it on my car radio at 1000khz, 1420khz, 530khz and intercoms , PA systems over 33 miles apart.
I/Q Raw Recording Download file
Audio Sample

I have been hearing this sound for the last two years on my truck radio while listening to an AMAmplitude Modulation radio station. I thought it was in artifact of the radio till I heard it coming over the PA system at our church. I made a unshelded mic to input into a Hi-Z amp at home and heard it. I have also heard it on the old amplified speakers at my work computer 40 miles from home. It seams to be a Digital signal as there is a start series and a query with a stronger reply, sometimes it is quiet for days other times it I'll hear it ten time in a day.I'm thinking it is some kind of control system.

Answer: This is an interference signal captured when an electronic device with a speaker output or recording feature is nearby a cell phone. Various devices with standard or poor RFRadio Frequency shielding will hear the sound, such as TVs, AMAmplitude Modulation/FMFrequency Modulation radios, computer speakers and the like. This is just the cell phone communicating with the towers and can most often be heard just before receiving a call or text. This interference affects a lot of non-radio devices that contain audio amplifiers. Some headsets with active noise cancellation will suffer from this, as will many inexpensive amplified (wired or wireless) speaker sets. This sound is from a UMTS or LTE device. CDMA2000 (1x or EVDO) does not produce this sort of interference.