|
Cotton,
If I were working with your system, a preamp is something I would not install. Instead, I'd favor the distribution amp. The reasoning here is that preamps "push" the signals down the line harder. Your plot shows good to moderate signal availibility. Preamps are generally for weaker signal situations and/or offsetting long coaxial run losses. If you apply preamps into situations where good to moderate signals exist, you run the risk of degrading your reception. This is overloading. Too much signal at your TV has the opposite effect you are desiring.
Plus, the RCA preamp if you install will reduce your VHF/UHF combo antenna to VHF reception only. The RCA preamp does separate antenna bands into single VHF and UHF inputs for amplification. This has the potential to reduce UHF reception of Knoxville. Your antennas with the RCA preamp will become Knoxville VHF only, Tri-Cities UHF only. It doesn't seem this would be your ideal situation as you like having both markets.
It is correct, if you install the RCA preamp you won't need an A/B switch. I recommend that A/B switch set up because both antennas get to work at full capacity without "stepping on each others toes."
There are preamps out there that are single input that don't separate by band, however, that puts you square back into each antenna "stepping on each others toes."
I'm not sure what the electronics store owner was thinking, a different era perhaps. Hindsight is can be 20/20, that is for sure and we are in the digital age now. It seems these boxes you describe provide multiple amplifications of the TV signal. Multiple amplifications of a signal is tricky business, it is best to do it once if you can and be done with it, IE a distribution amp or a preamp with no additional amplification down the chain. In my opinion he had you install a "messy" chain. That is, going from one box to another then having one coax lead split off six times - it's a recipe for having the six TVs that fed off the single lead to have quality or signal degradation issues.
As discussed, the single lead coming down off the antenna or a single jumper coming from the A/B switch ought to feed the distribution amp directly with the distribution amp providing dedicated feeds to each TV is the cleanest way to go.
As to your tree, think of them as razors to a signal. Your plot may be nice, but a tree in full bloom destroys signals by cutting them up and deflecting them. I've seen many people ask why they have unreliable reception in a favorable setting. The reason - shooting into trees. If it is off to the side, that is better than in your pathway.
It sounds like your system is getting the "100,000 mile" service. If you want to focus on one market a combiner (Antennas Direct makes a great one: EU385CF) on the mast will work with only swapping out the "two into one combiner", it has the potential to reduce Knoxville UHF signals though. If you want both markets as reliably as possible the dedicated leads for each antenna into an A/B switch is recommended.
I would further retire both those boxes the electrician sold you and put in that channel master 8 port distribution amp and feed each TV with a dedicated lead from the amp.
I run an A/B switch set up feeding 2 TVs. I have a dedicated Antennas Direct 91XG with a RCA preamp pointing to magnetic 141 for a secondary CBS affiliate that is 60 miles away. I also have a RCA Ant751 unamplified pointing to my local towers at magnetic 80. I chose to run separate leads for two reasons: the first that it's nice to have secondary antenna if something happens to the antenna system and the roof isn't safely accessible (IE winter). Also, I have some local VHFs, the 91XG sees them, but the ABC isn't reliable. The 751 sees ABC reliably. Of course, the 751 doesn't even register a signal on the secondary CBS though.
Let us know what you do!
|