In another post you show a lamp modified to use LED.
Did you check whether this lamp have some connection with your 24KHz?
LED drivers PWM are switching at frequencies that might well be around there.
If it is close to your BO hardware it may be the source of interference.
I think you are talking about the guy that replaced the circuline fluorescent bulb with the LEDs. Not me, but cool idea. Anyway, I do have a number of LED lamps, and some CFLs (not many) in the house. The antenna is far - about 80 feet - away from the house, and 60 feet away from the shed where the controller is. To check for local interference, I killed power to the house, and dumped the UPSs. Blitzortung controller uses a wireless bridge client (tested, and does not radiate), which was redirected to my wireless hotspot on my phone. That and the Blitzortung equipment was powered from a battery during that time, with the 5 volts supplied by a power trends isolated regulator - does not radiate much, and actually switches at about 500 khz.
There's really not much there, and it's only evident when the gain is set really high by the server. I am able to receive strikes far away. I was really wondering if it was possible that I was receiving some VLF transmitter.
One thing I did notice in testing is that the Vee generator causes just a little bit of 1khz tone to be induced into the output of the amplifier. I have the display set to timeout after 15 seconds, so that goes away.