Mystery Simulcast Beeps on 3550 3900 6700 7050 7450 7950 23 MAY 2025 0325utc

[l0ngwire]

The half-second beeps spaced 2 seconds apart are being simulcast now on at least six different frequencies.  In CW receive mode I hear them on 3550 3900 6700 7050 7450 7950 here in central California.  Listening on several Kiwi SDRs around the US they are roughly the same signal strength.  I have heard them several times over the past year-- the transmissions last about 40 minutes.

I first noticed them on the 40 and 80 meter ham bands on 3900, 3550 and 7050.  There was a recent post on HF Underground/Facebook, which i no longer can find, by Jose Luis in South America who noticed them outside the ham bands. I scribbled down his frequencies--I could not hear all of them, but did hear the simulcast beeps on 6700, 7450 and 7950.

Any ideas?

[l0ngwire]

Update:  also hearing the beep on 3150 at 0624 UTC.

Update No. 2:  signal gone at 0627 UTC.