re 4765 kHz R Progreso from old USSR relay site Bejucal (RadioCuba #2)
of the 1965 years era, each 50 kW; and combined also to 2x times as 100
kW in total. (11840 kHz R Moscow relay .... for example)

13 SW masts of 1965 Sowjetunion Leningrad firm design at 22°51'55.24"N  
82°20'11.10"W
instead clean free WONDERFUL Latin AM music program Radio Rebelde heard 
instead: a thousand times 'I like it'
https://www.radiorebelde.cu/audios-bajo-demanda/radio_rebelde_en_vivo_frecuencia_am.html
Bauta {former Brown Boveri gear of 1962}
RadioCuba #1 site is refurbished a decade ago and replaced by latest 
BBEF Beijing Made in P.R. of China gear. 6 x 100 kW BBEF, 1 x 50 kW 
reserve unit.
Quivican San Felipe TITAN, RadioCuba #3 site.
Soviet antenna design - mid/end of 80year era,
16 x curtains,
2 x NVIS fountain non-directionals
5 x 250 kW is also different gear.
Maintained, and refurbished in 1999 ... 2001years, by  Radio 
Comunicaciones del MICOM (Ministerio de Comunicaciones),

(thanks Olle Alm-SWE)
MW origin TXs was NEC Made in Japan in 1970, TESLA CSSR in 80ties, 
Chinese from 2002y onwards, and also some NAUTEL - Made in Canada - origin.

Glenn, you should include the technical infrastructure used at RadioCuba 
centers in the discussions.
Your description of intermodulations on the SW bands from low 
transmission strengths portion - also FM-like scratching audio tones 
appearance, you have to look at each transmission center separately, not 
to mix Bejucal 4765 kHz with 13700 kHz Bauta gear example intermodulations.
technical knowledge.
The equipment provided by RadioCuba is very different in year of 
construction and design.

73 wb