I'm picking up E* with my OTA

[Derwin0]

I'm guessing that one of the CATV channels 73-125 is pretty close to UHF channel 17.

Nope, CATV 73-125 (except 95-99) falls into the OTA 22-69 range.
The Dish Receivers only put out the Cable channels that fall into the 21-69 range.

For conversion from CATV to OTA:
CATV 73-94, subtract 51 to get OTA channel #.
CATV 100-125, subtract 56 to get OTA channel #.

95-99 fall into the FM range just above OTA channel 6, so are not available on a Dish Reciever. CATV 14-17 appear in the area just below OTA channel 7.

They're probably using a modulator offered by someone else, probably Channel Master.

Here's a chart I made a while back while trying to find a good channel allocation to send my TV2 outputs. Was unsuccesful since the UHF range is pretty crowded around me.

 

[RandallA]

They're "probably using a modulator offered by someone else, probably Channel Master."

I agree. They must be using some kind of modulator.

 

[kb7oeb]

What is the correct way to combine a modulator and an antenna feed and prevent a signal from going out the antenna?

 

[yardline]

What is the correct way to combine a modulator and an antenna feed and prevent a signal from going out the antenna?

I was wondering this myself. I have a OTA with a RS signal booster that has a head unit up on the antenna and a power supply base in my attic, then it goes straight to a splitter and heads to my 622 and other TV's in the house. If I took the modulator output from the 622 and looped it back into the OTA cable coming in, would the amp/head_unit combo keep it from broadcasting back out into the nieghborhood?

Please forgive my primitive diagram.

 

[RandallA]

There was another thread that talked about combining cable modem and OTA here:

http://www.satelliteguys.us/showthread.php?t=78864&page=2

There is a combiner that allows to combine different sources and isolate them.

http://www.solidsignal.com/prod_display.asp?PROD=CP2514

Disclaimer: I've never done it but if you read that thread, it can be done with the combiner.