Not what you really want to know. A monopole uses the 'ground system' as an image plane. Even with a good radial system and the best baluns it is probably not possible to suitably distinguish CM from differential+CM noise.

A termination only tells you that current on the coax with no 'sink' at the antenna is low enough. It usuallly is but if you can't terminate and see the Kiwi noise floor then you do have a problem to fix somewhere, possibly CM through the groundplane of the kiwi in/out the LAN/SMA or PS/SMA. Anything that keeps you from a 50-ohm Kiwi noise floor needs to to be fixed first so go ahead and try it just don't think that you are nearly done...

Glenn, Clint,
At https://wspr.live/gui/d/ereVvgn7z/station-noise-stats?orgId=1&refresh=1m&var-site=TI4JWC&var-receiver=All&var-band=All&var-type=rms_level
you will find my noise raspberryIKWI recordings. Dec-11 is 50-ohm termination at the KIWI. Dec-12 levels with a 50-Ohm termination at the cable at the base of the antenna.
Dec-13 and on are when running normally. The antenna is only used as a probe at 60M, 180, 630.
The noise levels Radio-only .vs. radio-feed-line range from a low of 2 db for 17, 20 M  to 23 db for 80 M
From the antenna to KIWI, in the shack I have in series T1-T transformer, AM filter, FM-filter.
I have recommended 14 db amplifier on the bench but I need a "limited Attenuation High pass filter"
Unfortunately, with only one good eye, my construction days are passed. 

John

Probably still several layers to peel away here.  A quick look brings more questions.

As mentioned, terminated coax noise floor doesn't tell us much.

But Dec 12 v 13 heat map is very suspicious. 

        Noise actually drops on 60 & 630 bands from Dec 12 to Dec 13.  !!  uhhh.. Really?  It would seem to imply two mechanisms with some cancellation on the 13th. Yccch.

Sharp steps from the 13th on at least 12-20 are a Bad Thing©. Propagated noise doesn't do this. More fodder for the local ingress theory. Compare your shape over a day with a known quiet site/system, perhaps KPH.

Is the T1-1 the very closest thing to the Kiwi?  It should be or you risk providing a return path through a chassis/common of the filters to something. You don't want this, you want to float that end of the Kiwi to CM currents.

Amplifiers in the right place can provide relative suppression of ingress, in the wrong place they don't help. Until you have peeled away the, apparently, multiple mechanisms it is hard to even say where to put one the closer to what you consider to be the antenna is generally better.

I don't know what ou mean by 'only used as a probe'. Is that just saying this is not a main stream rx for you?  I didn't get the relevance nor the inclusion of selected bands (at least two of which are suspicious as described above).

More peeling required.