AVS Forum Special Member
Join Date: Nov 2001
Location: College Park, MD
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Assuming that you're trying to incorporate Tampa off air (I'm psychic), you have a nice clear antenna path to thirteen full powered transmitters, and all of those signals will be within about 8dB of the same signal strength.
Four of them are VHF, on channels 7, 10, 12 and 13, so you will need to move your analog channel 7-13 programming, as well as your channel 22 and 23, to vacant channels just above 30.
The other nine are on UHF channels ranging from 19 to 47, spanning 500 to 674 MHz, so you can't use the amplifiers you are using now. Replace the amplifiers with ACA-860s. and roughly balance the UHF signals so that they are about ten dB below the output of your analog ones, but make sure that you change the signal meter settings when you go back and forth between your modulated satellite channels and your off-air digital ones. If you are pushing your ACA amps to maximum output at present, you might have to reduce the analog signal levels by about 3dB from where they are now if adding these digital signals winds up overloading them. Off the top of my head, ACA amplifiers typically can put out about 5dB less than the much more expensive BIDAs, so an ACA with a 30 channel analog load can probably be set to about a 45dB per channel output level, and so of you add these 13 digital signals, you might be safest to turn the ACAs back to 42dB measured on the analogs, if that still gets you adequate power to your TV sets.
You will need to do a little pre-filtering to mitigate interference from the off-air signals. At the very least, you should use a UHF/VHF band separator, commonly called a UVSJ, on your antenna downlead, and you should get an inexpensive midband reject filter, called an A-I filter, to put on the VHF line to keep your cable/satellite channels 14-21 clean, and you should also use a high band/low band separator, commonly called an HLSJ, on the VHF line to wipe off any interference that your antenna might be picking up on channels 2-6, if you choose to keep analog programming there.