On Wed, 23 Sep 2020 13:58:54 -0700 (PDT), "Ron D."
wrote:

masthead amplifiers generally need a power injector which might have coax in coax out and a port for power. The amp is on the mast.

Other amplifiers may just need a power source and are not remotely mounted.

I'm currently using a channel master CM-7777 at the mast with an 18db amp in the attic with an attenuator, so 0-18db. i think the CM-7777 is defective. For distribution to about 12 locations I was using a 30-45db amplifier until it went south. Currently distributing the signal to two locations.

Masthead amps make good targets for lightning hits. I've seen a few
where every semiconductor in the amp was fried.

The CM-7778 has 16dB gain:
https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7778v3.htm
while the CM-7777 has 26dB gain:
https://www.channelmaster.com/TV_Antenna_Preamplifier_p/cm-7777v3.htm
Also see the CM-7777HD (adjustable gain) and the CM-7778HD
(distribution amp).

This might help:
"CM-7777, CM-7778 Titan 2 & CM-7778HD detailed troubleshooting."
https://support.channelmaster.com/hc/en-us/articles/360002548994-CM-7777-CM-7778-Titan-2-CM-7778HD-detailed-troubleshooting-CM7777-CM7778-

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Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558