Modulator recommendations
 

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Blonder tongue BAVMZ and AM series units are fairly good for this kind of application, and if your cable wiring is not extensive enough for your taste you can make lamp cord dipoles for them to transmit wirelessly and easily cover as much of your property or block as you want.

Look in ebay or such web site for used agile TV modulators. The kind your cable company is getting rid of. Something like this
http://www.ebay.com/itm/BLONDER-TONG...item35d72b1df0 (no affiliation).

And if you're handy with solid state electronics, I've changed the TV channel on various consumer RF modulators. Remove the combo channel 3 and 4 crystal (sometimes called a surface acoustic wave SAW resonator), and for channel 2 use a 18.432MHz crystal (should be 18.41666MHz but it's close enough for a TV set tuner to tune it in, 18.432MHz is pretty common and cheap). for Channel 5, something close to 25.75Mhz should work, and channel 6 is 27.75MHz. You want something within around 300KHz to get the RF modulator reasonably on channel. Be aware that these consumer modulators don't filter the vestigial sideband, so if you have a channel 6 modified modulator, channel 5 will be trashed. So you can only have channel 2, 4, and 6. 3 and 5 will be trashed, and unusable.

Just bought a Blonder-Tongue AM60-860 from eBay, and it works great. Got it for less than $40. It has an LED channel/band/power level display with simple pushbutton setup, which is much nicer than the DIP switch arrangement on earlier models. Handles stereo audio, and even provides for EAS input (this is ONLY a test....):D

Only mods it needed were a BNC to replace the F connector they used for video input (this was a factory option, BTW), and a front panel power switch to shut it off when not in use. Only 1 rack unit high, for a standard 19" rack mount.

EASILY covers the whole house (and well down the block) on VHF Ch3 using a simple dipole antenna tacked to the ceiling in a basement shop. This is at the minimum RF output level setting.

Could be the heart of a nice pirate TV station if one were so inclined. :D
Puts out 60+dBm unmodified, and I'm thinking that the output level could easily be increased by replacing the BGY885 output amplifier with the higher power BGY888, which would be a plug-in swap.

B-T also made 8 and 12 channel combiners to go with these units, which would be PERFECT for setting up your own private CATV system. Also available cheap on eBay, as cable systems are scrapping all their analog headend stuff.

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The MICM units are factory set to desired channel. Probably possible to reset them, but good luck finding schematics or instructions to do so. B-T doesn't make that stuff available.

They do use a PLL synthesizer, so probably a simple matter of programming rather than component replacement. But you would need to reverse engineer the programming interface and protocol.

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Depending on how many stereo devices you want to use, you may just want to get a couple of MICM-S units along with several mono units. My assumption is that a bunch of mini-mods in a rack chassis won't consume as much power as those with their own power supplies.

I'd just wait for fixed channel units with those you want. Knowing how to assign a different channel would be a definite plus though.

The HAVM consumer level units don't incorporate vestigial sideband filtering, and will not operate on adjacent channels without interference.

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How about a genuine B-T 12 port combiner, such as the units likely were originally hooked into?

http://www.ebay.com/itm/BLONDER-TONG...item3cf8751a31

Better to get an active combiner.

The output channels of the MICM-S mini-mods cannot be changed without special equipment, but that's kind of a moot point now as this setup is more or less ideal. I had one and opened it; there's a 4 or 5 pin header in them marked "programming".

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I just looked up the thread where I saw active combiners mentioned. It doesn't look like there's any difference aside from a built-in amp.