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Discussion Starter #1
I have been thinking about adding a preamp to my OTA. I have the antenna split with one feed going into my dish 811 and the other into my Mitsu WS-55613.


According to my 811 the signal strength coming in is


2-Fox= 89%

5-NBC= 85%

9.1-.3- PBS= 85%

11-WB= 84%

31- ABC= 89%

46-UPN= 49%

56- CBS- 90%


I can not see UPN on channel 46 on the 811 b/c the signal strength is too low for the 811, but I can see it on my Mitsu and it looks good. I know UPN is not HD, but I like some of the programming on that channel


If I place a preamp on my OTA, what are the chances that I would make the other signals too hot or would I be able to regulate the pre amp to keep that from happening. Also, how much more visible would the PQ increase if I took a signal from 89% to 99%


Finally, can anyone recommend a good preamp. I live out in Wentzville, (west of St. Louis) so I am about 45 miles from the towers I believe and my antenna is in the attic. It's one of those square UHF antennas
 

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Discussion Starter #2
Gee Whiz, getting someone to reply to a post here is like pulling teeth. I tried in the St. Louis thread and no one pay my question any attention for over 2 days. Then I tried in a more general area, no replies yet


Am I asking this question in the wrong forum, if so, please let me know, and I will gladly move it


I don't think I smell, I take a shower every day, I promise


Am I doing something else wrong? Am I breaking some kind of rule?


It can't be that PEOPLE in the great AVS forum are speechless or ignorant about what I am asking


Maybe some of the bigger fish just don't want to play nice with the smaller newer fish.


I guess those big fish forgot that they too were small fish once!!!
 

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Using a Channel Master 7775 preamp on my attic antenna installation (CM 4221) made a significant improvement in signal strength. Since you are splitting the signal, it might be pushing that one weak station to the brink. I don't think it will overdrive the already high strength stations, but you won't know until you try :)


As for getting responses, sometimes I think it is just a needle in a haystack problem!


-Lance
 

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Actually, I think you did a good job on the thread title so you attract people who may have some experience in you problem area. I suspect that a lot of people were occupying their time in the chatter on Janet's stunt.


As for your question, a preamp is a considerable question. It should make the 811 able to see UPN, on the other hand, powering a preamp and splitting the signal takes special splitters which will pass the DC power to the preamp. As for picture quality, digital channels PQ (IMHO) don't get brighter, sharper, etc. with increased signal although they may become more reliable.


Did you just for grins put the existing antenna signal direct to the 811 to see if there might be another issue with UPN than signal level?


TerryB
 

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I'm amazed your signals are that strong 45 miles away from an attic antenna. Have you checked the broadcast power and location of UPN relative to the other stations? It may be simply that it's located slightly off-bearing and in that case a preamp is not likely to help. If that's the case, you could consider a rotor. The square UHF antennas (CM 4228 maybe?) are very directional. If it is a 4228 you could also consider stepping down to their 4-bay model which is less directional but you would risk losing gain on the other channels.


The relative signal strength should not affect PQ with digital signals as long as you don't have dropouts.


Charles
 

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I also suggest a rotor as the answer to your problem. CM makes a good one. I had tried the CM 7777 pre-amp and lost all reception so I put that baby into mothballs. But that's just my personal experience
 

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Discussion Starter #7
Thx for those that have provided advice


Prior to me putting the splitter on, I first had the antenna going straight into my Mitsu TV b/c I did not have the 811 at that time. And I was receiving UPN perfect.


Then I got the 811 and plugged my antenna straight into it and could not get UPN. I tried to troubleshoot with Dish, they even had a guy come out with a new 811 in case the OTA adapter was bad. But I could not get UPN with that receiver either


Finally I got tired of changing my antenna from my 811 to my Mitsu, so I bought a splitter to split the signal.


I lost maybe anywhere from 2-4% on my other channels, but UPN always read 49% with or without the splitter


The antenna I have in my Attic is the: 8 Bay UHF- Model 4228. Looks a lot like a CM-4228, but the installation folks said it was an Andrew


Did Andrew make such an antenna?
 

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Will a preamplifier help? This question gets asked a lot. And usually we get the information you supplied: digital signal strength as measured by your signal strength meter.


For digital reception, only one thing matters for reliable, artifact-free viewing: a clean signal. It can be 3db above the noise floor or 30db above the noise floor and it will make no difference. Believe me, I know, because I get the same signal strength from towers 20 miles away as 75 miles away according to my signal-strength meter.


Perform the following, the so-called "analog test": Tune to an analog UHF station that is broadcast from the same tower (or as close as possible) at about the same power (take analog and divide by 5 to come up with the digital equivalent) from about the same height. Be sure to account for directionality.


If you don't know the variables mentioned above, go to: http://www.fcc.gov/fcc-bin/audio2?x=tvq.html Input the station ID and then select TV Query from the bottom list of five options. If there is an STA listed, assume that it is the current status of your station.


Check the picture of the UHF station. Is there snow? If yes, a preamplifier is likely to help you. Is there ghosting? If yes, then a preamplifier is more likely to make things worse than better. If you have both, it's hard to predict if things will be better or worse.


For all practical purposes, getting that antenna outdoors will be a better solution. Not only will this double the received signal strength (in db, not according to your STB meter), it will eliminate many sources of multipath (ghosting) that attics seem to abound with. Preamplifiers in attics are usually going to make things worse because multipath that was weak before the amplification may now be strong enough to confuse your receiver. Still, if you buy from a place with a good return policy, it can't hurt too much.


If your splitter is indoors, putting the preamplifier before the splitter will simplify a lot of the installation hassles. And honestly, the cable run after the amplifier isn't that big of a deal unless it's hundreds of feet.
 

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Discussion Starter #10
sregener


I am able to get the local analog UPN(Ch 46) on my 811. Yes it is snowy, but no ghosting images. But for the life of me I can not get the so call digital version (ch 46.1) on the 811.


The biggest question no one has been able to answer is: why am I able to get the digital UPN on my Mitsu WS-55613 but not on my 811, even though the antenna is in the same position and no pre-amp
 

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I had the same problem with a split signal and my localFox channel. I can get it with no split but can't with a split.


I have an amplified antenna, so that didn't change anything. Don't split the antenna signal, if at all possible.
 

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Okay, first off, WRBU-DT is using a pathetic 109kw of ERP. The height isn't bad. WRBU analog is running at 5000kw, which means their digital equivalent should be about 1000kw. Why 109kw is listed as "Full Service" is beyond me. Maybe someone else can shed light there.


Now, since WRBU-DT is very low power, you're likely dealing with a "threshold" issue. One of two things is occuring. Either the cable length is longer to the 811 box, meaning the additional attenuation is killing the very weak signal, or the 811 just isn't quite as sensitive to weak signals. I suspect the latter.


Adding a preamplifier can only help WRBU-DT, but as others have mentioned, it may cause problems on other channels that are golden right now. If it was me, I'd get a minimal (10-15db) UHF preamplifier from Winegard or Channel Master. If that doesn't harm anything but isn't quite enough for reliable WRBU reception, then look into the 26-28db preamplifiers.


Every STB has different capabilities. Some are slightly more sensitive than others. Some are very sensitive. Some die with a minimal ghost. Others hold up until the ghosting obliterates the screen. If you had 811s in both places and were seeing this, I'd be suspicious of a hardware problem. As it is, you're likely right on the edge of reliable reception and just need a little boost from a preamp.


Hope this helps.
 

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sregener covered it perfectly - I would only add that you really should get your antenna outside if at all possible. It could possibly make the pre-amp unnecessary, and give you that much more floor.
 

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Discussion Starter #14
thx again all


I guess I can always just switch to my Mitsu if I want to see UPN. It just really bugs me that I can not get UPN on my 811. It's just one of those things that will irk me till it is resolved.


I placed my antenna in the attic to play nice. I know that I legally have the right to place my antenna on the roof of my house, but considering that I already have 3 dishes on my house (2 for Dish, 1 for direct), I did not want the Housing association to give me grief


I will see if I buy a pre-amp, but UPN is not that important that I am willing to wreck my major network signals
 

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Your housing association can't complain about a terrestrial antenna. Well, okay, they can, but they can't do anything about it.


It's probable that a Winegard AP-4700 would fix UPN for you without doing any harm to the other stations. If you buy from Stark Electronics, all you'd be out is the shipping (and return shipping) if it didn't work out. Given the costs of mounting an antenna outdoors, that's probably your cheapest choice right now.
 
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