Not taking anything away from Ben's suggestions above (I own that particular Atlona extender as well as a couple of Gefen ones, not to mentions my fair share of MD-HXs), but if you want to do this the cheapest way possible a Decimator at 10 tvs (or a micro converter, or even Decimator's new LX) is probably not the most cost effective. (Would be rock solid tho)
Here's the cheapest route (that I've personally done when $ was scarce):
To start off, convert the PGM out to HDMI right at the ATEM. You need (1) converter:
Blackmagic has the microconverters at ~$75 used, Decimator just came out with the MD-LX at $99, or you can go with the $30 options from China. I bought this one for a non-critical overflow TV and it has run fine for 6 weeks now:
https://www.amazon.com/gp/product/B01GH ... UTF8&psc=1Note that if you want to have a local SDI output for livestream or something else, get the BM or Decimator options as that will give you an SDI loop at the source. The cheap one does not.
Next, take the HDMI you now have and split it. I like J-Tech Digital's stuff, you can choose whatever you want, but get 10 HDMI outs of your PGM signal:
https://www.amazon.com/J-Tech-Digital-S ... 2B1x4&th=1You can get the Amazon Warehouse deals on these, but even brand new getting a 1x8 and 1x4 and you have your 10 outputs for about $70.
Now the fun part, going over your Cat6 line. If you have wire pulled, great, if not I like this stuff:
https://www.amazon.com/gp/product/B0049 ... UTF8&psc=1Buy the Amazon Warehouse deals on a box of 1000'- usually about $100-$120. Don't go over ~150 feet and you'll be fine. Get some crimpers and connectors (I like these:
https://www.amazon.com/gp/product/B01CK ... UTF8&psc=1 )
and have fun pulling. Use a fish tape or pull rods and maybe some of your youth to do this part.
The HDMI over the wire part has a billion options. My current favorites are these: (
https://www.amazon.com/gp/product/B0133 ... UTF8&psc=1 )
They come as a set, just don't mix up the Sender and Receiver. Buying 10 brand new (again, check the Warehouse deals) will be $380 total.
Ok, so if you buy everything I've listed, you're at ~$580 or so and will have PGM video at 10 TVs. It's not pretty, you'll need a box to hide all those Sender adapters in, but I've done it and had it work. Granted, I only had 6 TVs, but same idea.
Good luck to you!
Last add: best practice really is to pull SDI to the locations, even if you use cheap $30 SDI-HDMI adapters. You could put 3 Decimator MD-HX's to split the SDI to 10 outputs, then pull the Belden cable, crimp the ends, and have 10 cheap adapters. End price would be around $1200 but I would have so much more faith in that system.