CT your just hung up on words.
All radios have to pass an acceptance to be marketed so your not breaking anything to me.
The KW590 had to be, the KW990 had to be as well as all the others before that could be sold in this country.
I have seen these radios appear in the catalogs before that were accepted with a posting to that effect right in the catalog as not to be sold until.
I didn't just come out from under a rock last week!
Good luck.
Yes, that is so that they may be proffered, mass produced & sold, or offered AS "Amateur Radios" in the United States w/o getting on the "banned" list (like the 'Export' radios are.) Even still, there is NOT a "Label" of Part 97 Certification attached to these radios in the same manner as there is for a Part 95 (CB) radio, thus signifying compliance.
Likewise, it is NOT illegal or otherwise prohibited for a person sans an FCC Second/First Class (since superceded by the GROL) to put their "hands", "screwdrivers", or "clippers" to the insides of ANY Amateur Radio, in fact, one could actually HOMEBREW ONE if so desired. However, Part 95 of the CB rules forbid even adjusting the AMC on a radio without a Commercial license, much less modifying it to go out of band.
As an example, my most recent Amateur Radio purchased FACTORY NEW is a Yaesu 2M mobile; on the very bottom there are two (2) labels: The FIRST is FCC Part 15 (interference) compliance, and the SECOND is a warning not to modify it to receive cellular frequencies (something it is incapable of doing anyhow.) Funny.... there is NO Part 97 "label."
Similarly, I have a Cobra 29 LTD CB radio (newer one) that instead of having an FCC Part 95 compliance label (like in the old days), also ITSELF has an FCC Part 15 compliance label which reads: "Certificated for compliance with FCC RULES Part 15 as of date of manufacture", unlike the OLDER versions which read Part 95. Again, I believe this reinforces my earlier post about SPURIOUS EMISSIONS criteria; those Part 15 certificated devices having thus demonstrated their capacities to transmit with an adequate degree of spectral 'purity.' As such, although several (presumably Hams) have demonstrated the ability to convert (for example) a Cobra 148-GTL radio for usage not only in the 10M Amateur Band, but ALSO as low as the 40M (7 MHz) band successfully, if someone were to convert even one of these Part 95 devices for use at 5 MHz (60M band), they too would be quite legal IF they could transmit a CLEAN USB signal on the five (5) 60M "channels" within the limitations of the allocation. Likewise for HOMEBREW radios, which have NO CERTIFICATION WHATSOEVER.
Therefore, I am compelled to assume that the TS590/TS990's you are referencing, in view of the apparent absence of any Part 97 (Amateur Rules) certification, have been therefore merely certificated for FCC Part 15: Spurious Emissions/Harmful Interference, and thus themselves, just like a TS-2000 or a Cobra 148 or even a Homebrew, MAY INDEED be used, when PROPERLY modded, on the 60M band.
FCC Part 15 compliance costs BIG BUX, and as such, you aren't likely to see many upstart, smaller, or bargain-basement offerings even worry about it anymore. For example: Baofeng and Wouxon, rather than even attempt to pursue Part 15, have instead, opted for FCC Part 90 certification and..... VOILA.... these things wind up on the Amateur Bands by the thousands, quite LEGALLY, for roughly less than 1/3 to 1/10th the price of a similarly equipped Part 15 device manufactured by the "Big 3".
Marketing being what it is: Marketing..... IF I were Kenwood, Yaesu, or Icom, and I had a new radio coming to market, guess what? Whether I was awaiting FCC type acceptance or not, I would say I "was", in order to pique more INTEREST in my offering, AND to allow sufficient time for my prospective customers to sell their existing equipment and to raise sufficient capital to purchase MY offering, thereby pretty much paving the way and greasing the skids for a highly successful new product launch. As such, to me, new transceiver roll-outs have waaaaaay less to do with the FCC than they do with "Marketing 101."
Nevertheless, modding ANYTHING for use in the Amateur Bands, whether certificated or not, is not only LEGAL, but quite legitimate and is in keeping with the Spirit of advancing the Radio Art, as delineated in FCC Part 97, Amateur Radio license limitations notwithstanding. As such, if I could make my wife's TOASTER OVEN transmit on 40 meters, and did so, it would probably make quite a compelling article in QST magazine!
Therefore, to the Original Post, I again opine that it is OKAY to mod your Kenwood for 60 meters and will NOT decrease the value, 'legality', or utility of the transceiver. In fact, it may even increase it.
