Yep. I fired up my Samsung P2570HD TV and got an unpleasant surprise: When I scanned for active channels, it didn't find any channels. I tried it several times, on several antennas, and got the same results. No channels. Since the HDMI, composite, VGA, and DVI inputs all work normally, my guess(tm) is the tuner is blown.
Looking at the available scan settings, it gets even stranger. I can add a channel manually, but there doesn't seem to be any way to remove a channel. Of course, since I can't test it, I'm sure about this. Offhand, I would say you're correct, that Samsung doesn't make it easy to use a rotator or multiple antennas.
Is the virtual channel number correct? Does it even have a virtual channel number?
The US congress critters tweaked the beginning and end of DST in order to somehow save energy in 2007. Many devices didn't clean up their DST act for many years after that.
If it does IPTV, it must surely do NTP (network time protocol) which includes proper DST shifts. I don't think there's a single device available that does EPG (electronic program guide) without bugs, added monthly costs, or both. However, don't blame the guide vendor. Stations often change their programming at the last moment for odd reasons (sponsor pressure, current events, ongoing disaster coverage, etc).
It didn't "fall out of favor". It was massacred by the cable companies, who preferred to rake in the cash from equipment leases than to allow the GUM (great unwashed masses) to own their own equipment. Never mind that the FCC ordered the availability of user owned cable equipment. Comcast also made it look like a frontal attack on Tivo, who is the major beneficiary in CableCard based installations. Incidentally, Comast raised the price of them allowing a CableCard from about $2/month to $10 or $15/month (I couldn't find the exact price) so as to be equal with the cost of leasing a set top box. So much for affordable.
RF Modulator? That's rather low quality video if fed from composite video. What most users want is the ability to record HD programming without DRM issues. A CableCard in a tuner can do that if digitized video can be delivered via ethernet (thus avoiding the encrypted HDMI problem). No, I won't tell you how to do it.
Why bother? Most OTA radio stations also stream over the internet. Just point your web browsers to the stations URL and you have streaming AM/FM audio on the laptop. However, if you do find a station that does NOT stream, just plug an RTL2832U plus R820T2 SDR receiver dongle into a USB port, run one of a dozen receiver control programs, and you have an AM/FM/ham/WX/scanner/whatever receiver.
Sigh. Topic drift at it's best.