This is for home use where TVs in the home range from a year to ten years old. I'm not sure of the impact of today's modulator having HDCP that's up to date. (I'm not even sure if that's the right way to say it).

The modulator's output will be attenuated by at least 20 dB, then mixed into an OTA antenna system. In our market several available channels with no adjacent channels or co-channels are available.)

Thanks for any insight you can give on this.

There are very few HD modulators companies on the market:
ZeeVee
PVI
Blonder Tongue
Contemporary Research
Thor Fiber
Cabletronix
Pico Digital

Of those, some only make QAM HD modulators. And of all of them, the PVI is the only ones I know for sure handle HDCP with an HDMI signal - thou some of the others might have models this year now as well.
There are a few other off-the-wall brands out there. But most of them look like rebrands of one of the above.

Note that while ZeeVee has modulators with hdmi input, but only for unencrypted HDMI sources.

Please save me the horror of researching this after a twelve hour day... what broadcast video is not encrypted? Or is it simpler to say what IS encrypted?

unecrypted hdmi sources would be computer/digital signage.

I will not sell a zeevee modulator with hdmi inputs to someone who wants to use it with cable or satellite.

For satellite, I specify zeevee products with the appropriate din connection on it to interface with the din output on directv boxes. Those are looking for analog, not digital, sources

Well, this article [Link: howtogeek.com] shows how HDCP can be eliminated as a problem. Is it illegal? I don't know.

Let me make a parallel here with guns. Is it illegal to own a gun? Is it illegal to use a gun for target practice?

We'd all agree that it's illegal to use a gun to do something illegal, but is it illegal to use the device shown in the article above just to watch something on an old monitor?

Assuming that's a rhetorical question. Here's the deal; certainly, there are ways to strip hdcp off of a signal. Like it or not, that could be considered stealing.
Further, since movie studios are in the business of combating piracy, what works today may not work tomorrow.

Do what you want; I won't sell a zeevee modulator to someone with hdmi inputs if I know they are likely to encounter hdcp issues because I don't want to have an unhappy customer.

Go wild, or talk to Brent about his hdmi over coax solution, which is legal. That's your best approach at this point.

Does Brent's solution give me a signal that I can mix into an OTA system, that will give me pictures at a half dozen TVs throughout the house?

Paging Brent

Fred: Hey old man!

My M3B is a solution, but......
It is not the solution that is being asked for here.
The M3B does except an HDCP encrypted signal, modulate it and broadcast it over coax, however you must have an M3B Rx unit at each display. This way the signal starts and ends as an HDMI cable (this is the only way that we have found to keep the HDCP signal happy).

Brent, did I tell you that I nominated you for the old farts award from ce pro?

Now I am feeling the love........

Oh, that's right, you got that award two decades ago....

We have a few M3B systems installed. Most of the systems we have done combine an OTA antenna and then we have added DirecTV boxes, Roku, and BluRay. The advantage was that the cost was much lower than a HDMI matrix switch and allowed locations to be connected that only had coax ran to it.

The thing to keep in mind is that you must provide a control solution for the DirecTV boxes, Roku, and BluRay player. We use URC Total Control.

M3B transmitters are installed at the rack and set to a channel. That signal is then combined with an OTA signal and sent through out the house. M3B receivers are installed behind the TVs.

I have used the PVI 4 channel modulator to run to a variety of TV's (15 of them) throughout a large home that had been wired 20+ years ago.
2 Cable Boxes, DirecTV and Apple TV are the feeds to be shared.
As mentioned, you will need a control system to change channels etc on the sources. We used RTI in this particular project.

Has been working fine for about 2 years now.