Hi folks,I thought this info might be useful in some way. I am still looking for an easier(er) way to get on the air below 500kHz. I remembered that when I bought my TS570 on the 'bay, it was advertised as having had the MARS/CAP modification. However there was not much information other than this would open up access to the 60m band.
I had not explored further, but it dawned on me to test the radio to see the extent of the modification as far as transmit frequency range. Armed with a dummy load and set to 5W out I crossed my fingers.
Alas, although HF is wide open (presumably from top band upwards) there is no coverage below 500 KHz.
However, the extended HF range may make building a transverter of some sort a bit easier, since I could base the scheme around any convenient crystal oscillator to mix down, say, to 630m without needing to work around ham band only output from the "exciter"
More careful choice of frequency scheme (and proper shielding of course) could ensure the exciter didn't cause problems to other services.
Still, I wish it could have worked directly - that would have spawned N amplifier project.
P.S. I have not forgotten the promise to write up my successful taming of a cheap (but noisy) 12V SMPS for ham radio use.
73 to all
Ed/KO6BLM