There appears to be a ditter on about 7000.65 kHz. I am pretty sure I have seen this ditter before, but it is such a long period and so weak I always thought it was noise / RFI / something else. But today it is strong enough to be clear, this is not local noise.
It is a dit, about 0.17 sec long, sent every 22 seconds. There is a very slight chirp on the dit. The frequency at 1700 UTC was 7000.68, and at 1900 UTC it was 7000.63, so there is a little drift to it.
(edit) This signal has definitely been here for a while. I have a recording from 2 weeks ago with it clearly present, and one from several months ago with what is probably the same signal in it. I'll have to look back at older spectrum recordings, if I have any for that freq range, and see if I have any older that include it.
(edit2) It turns out the 6990 to 7010 kHz range is not one I record often. I have a recording from early October 2016 that clearly shows this ditter there. I have a recording from July 2016 that clearly shows it present. I have a recording from Feb 2016 that may show it, there is a lot of interference and I am not 100% sure. And I have a recording from early Dec 2015 that does not show the ditter there at all. So, at a guess this ditter showed up after early Dec 2016 and before July 2016, with a reasonable possibility of between early Dec 2015 and Feb 2016.
(edit3) This ditter can be heard on other remotes in California, and was also reported as heard in Washington state.
T!