high frequency intermittent noise

@jea48   

LOL, Yes, I know where my cell phone is.  I tried turning it off, no effect.

My system does sit against the outside wall, which is at the same level as the cell phone tower.  I do not directly face the tower, but the tower is in direct line of sight just 2 units to my right, so for line of sight purposes, it may as well be right in front of my unit.  I also have the Empire State Building in direct line of sight, and a friend of mine thinks the Empire State Building is radiating all kinds of emissions...says I need to be wearing sunscreen while listening to my system because of the Empire State Building.

I will post a photo on my system page so you can see the towers.

The problem with the towers is they are nondescript - no signs indicating ownership or contact info.  All I see on the towers are WARNING labels everywhere.
That is an outstanding post you found on ProSoundWeb.  Thank you very much with all of your attention on this thread.  You are a real asset to the community.

Thank you EVERYONE who has participated on this thread for that matter.  I really do appreciate your ideas and posts.

Something I’ve been looking at to correlate the noise to the cell tower:

https://www.amazon.com/gp/product/B007L09DLY/ref=s9u_simh_gw_i2?ie=UTF8&fpl=fresh&pd_rd_i=B007L09DLY&pd_rd_r=68bbfce7-caf8-11e7-8cdf-51a46fae6b0a&pd_rd_w=4szrl&pd_rd_wg=JjucN&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=&pf_rd_r=T88X159BY8J205PDCWS2&pf_rd_t=36701&pf_rd_p=8f696f0a-3abd-4660-b9bd-1931764e0008&pf_rd_i=desktop

Here is an example of cell phone noise:

https://www.youtube.com/watch?v=s99i0H-nBw4

If I had the tool, I would be able to correlate with certainty.

I hate to say it, but this is a common problem is the audio equipment has poor RFI rejection.

There is this design aspect known as a 'stopping' resistor, that is used in tube and solid state circuits to prevent oscillation, and also has a big effect on susceptibility to RFI.

The resistor is in series with the signal and is placed as close as possible to the input connection of each amplifying device (grid of a tube, gate of a MOSFET and so on).

The resistor interacts with the input capacitance of the device, preventing it from causing oscillation by acting as a low pass filter. This is effect of RFI for the same reason.

The thing is, many audio designers don't employ stopping resistors (the Japanese really didn't use them at all for several decades) so you run into problems like this if you have heavy RF sources nearby and otherwise poor grounding.

The 'I hate to say it' part is you may have to change out gear to something more stable to get rid of this. May.

What happens if you operate your cell phone close to your stereo? Do you get interference?

No, my phone has no affect.  I wonder if it's because I'm on Verizon, and the offending tower may be a GSM tower?