Originally Posted by rabbit73
...you are overloading the amp with your very strong signals.
Maybe we should put that in bold type:...you are overloading the amp with your very strong signals.
You are not now getting weak signals at any TV with your over-amplified system even though the signal strength metering function in your tuners may say otherwise. Your tuner's signal strength meter is not a real signal strength meter. It provides a useful indication of signal adequacy, but the numerical value it displays is derived largely from, and varies inversely with, bit errors, which go up astronomically when an amplifier is overloaded, and result in the receiver calculating and displaying a low signal strength number.
If you go here to Solid Signal for the CM3414 (which is the same as the PCT-MA2-4P), and click on the specifications tab you will see the problem:http://www.solidsignal.com/pview.asp...mplifiers&sku=
The specs say output level 18 dBmV and gain 8 dB, which means that the max input allowed is +10 dBmV, which is the same as -38.8 dBm.
While we all agree that your amplifier is unnecessary and overloaded, the overload information provided with most consumer-grade amplification products is nearly useless. This amplifier is designed and furnished to amplify a large number of equal strength cable TV channels. You are amplifying a small number of broadcast digital channels, which, in your case, and to your benefit, are closer to equal value than those that most home antenna systems must deal with.
I would guess that the engineering data for that amp that was furnished to the sales department before they butchered it is that it can amplify a "full load" of about half, equal strength analog carriers (roughly channels 2-70) and the rest as digital signals which, if 256 QAM, are 6dB weaker than the analog signals (12dBmV), to maximum output level of 18dBmV as measured on an analog carrier at any of the four output ports. But that's just my guess.
As a simple rules of thumb, each time you cut the number of equal strength analog carriers in half, the maximum output goes up by 3dB, but there are other engineering considerations that confound any attempt one may make to calculate maximum permissible signal levels in digital and mixed signal level environments that go beyond the scope of this thread.
Ballparking, if that amplifier can amplify a load of 135 QAM channels to 12dBmV, then it could amplify 67 of them to 15dBmV, 34 of them to 18dBmV, 17 of them to 21dBmV, and 8 of them to about 24dBmV, which is closer to your channel load, But again, this engineering oversimplification does not take into account the fact that intermodulation disrupts and degrades weaker signals more than it does stronger signals, and with a scattered, broadcast channel load, it occurs at certain frequencies more intensely than at others.
Here is a way to ballpark calculate that you don't need an amplifier. Just about any receiver will work with a signal strength of about -83dBm, or -34dBmV. You have a field strength of about -24 dBm to -28dBm. for the local network stations you desire to receive, and they are increased in your system by unknown antenna gain, which we won't even bother to work into this estimate. You would theoretically lose 7dB through a 4-way split, and maybe 6dB per 100 feet of coax at your highest channel. You don't need a calculator to see that you would have over a thousand times as much signal as you need at each TV, even without using an amplifier.