CM 7777 preamp the best?


Going to be routing another coax line to a TV in our guest bedroom. This will now require a 4-way splitter on a main line that stretches about 50' before the splitter and I'm thinking about getting the CM 7777. We already have problems during storms with reception so I'm pretty set on getting a preamp and adding it inline. Is the CM 7777 one of the best preamps to get? Thanks to everyone here.


It is one of the best, Tom, but that won't necessarily make it suitable for your location. CM designed the 7777 for exurban and rural locations. In very rough terms, that's at least 35 miles' line of sight from all TV transmitters. More specifically, check your TVFool report: If you have more than a station or two with "Signal" readings above ~ 50 dB noise margin, a 7777 is likely to overload and cause reception issues no matter how many receivers you connect to it. With half a dozen or more strong stations, it's possible for overload to occur at noise margins down to the 40-45 dB range. If this describes your signal environment, you will probably do better by installing a low-to-medium-power (10-15 dB) pre-amp, distribution amp or "powered splitter." That's all you'll lose in a four-way system like that, anyway.

What make/model antenna are you using, where is it mounted, and what kinds of storms clobber your reception? Which RF channels suffer the most?

Tower Guy

Is the CM 7777 one of the best preamps to get?

Noise figure: excellent
Gain: high
Overload resistance: poor
Flexibility: excellent

An overloaded preamp negates the other 3 advantages. When selecting a preamp a rating of 3 out of 4 is not good enough.

A preamp should be selected with full knowledge of the signal environment were it will be located.

There's no way to tell what causes your reception problems without further data such as a tvfool report and the model of your current antenna.
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