For those suitably equipped on 73 khz with a better than average antenna
and able to generate 1w erp there is a possibility that they might be
seen on slow cw or wobble mode across in W/VE.
Long before a transatlantic qso took place on 160 metres between radio
amateurs, marine operators were working this route on 500 khz with very
modest levels of RF output. Some /mm have worked and been heard
operating from European waters into South America.
With this history it would not be unusual on 136 khz to do the same
thing given a proper antenna for the job and reasonable power. The same
applies to 73 khz, but one has to think beyond the modified G5RV and a
converted Decca tx. Perhaps 5w erp would be more realistic and a good
rural noise free qth. At these frequencies the small back garden is a
non starter and that is also the problem on 136 khz presently. The only
suitable installations at present capable of making repeatable qso's are
MM0ALM, OK1FIG from his commercial tower and G0MRF from his high rise
block, the rest with some luck will be one off jobs and that will need a
TAIL WIND.
G3KEV