Hi Rob,
This night, 22 June just after local Midnight in California, I checked the Omni Antenna at kfs again:
- both ports indeed show exactly the same signal (port 8073 and 8083) as it should - as it is the same signal
- the signal level seem to be further reduced as the background noise on 10m today is at -108dBm level, which is ok...  my earlier observation (see above) showed a background noise level on 10m (at the time of dead band) about 6-8db higher...
- no OV clipping indication
- no IMD at the low end frequency (1.8...3Mhz)
- notch arround 3.5Mhz persists...

Last Sunday, I checked the bands on all antennas in the local morning time at earlier daylight hours. I hoped, that noise and interference may be little less than during the week, assuming sourrounding light industrial/commercial activity be more quit on Sunday.
I was shocked however how strong the QRM from broadband noise sources was at about 8h30 in the morning on the high bands especially 12 and 10m... The Noise was at least 10db higher than I have it usually here. That said, I believe my antenna's net gain is probably not less than what the KFS kiwi's see there. I am using a terminated Rhombic on 10m with additionally 17db net preamplifier gain.
Still my noise level is 10db lower !   Noise level on 10m on all antennas at kfs was extremely high (in the -90s dbm !)
I was not prepared to make a detailed report and didn't have the time at Sunday unfortunately, but I will check it again next weekend.

Now at midnight today the noise on 10m is much lower at kfs = there must be something locally radiating like hell to produce that bad reception last Sunday morning (broadband power line noise ?! Influence of local rain shower ?)
May be other local Hams can have a further look to that as well and report the reception on 12m/10m during local daylight hours from kfs...

Greetings to KH6!

Ulli, ON5KQ