AVS Forum banner
Status
Not open for further replies.
1 - 12 of 12 Posts

·
Registered
Joined
·
1,476 Posts
Discussion Starter · #1 ·
I finally got my antenna up this weekend. When I hook it directly up to our TV the picture is pefect (just analog for now, digital TV is in the future). However, if I don't want to run the cable through the window :D , I need to use a diplexer to join the signal with our satellite. When I hooked it up this way, the picture was not good.


I'm assuming the diplexer degrades the signal strength? If so, what is the best way to solve this? An amplifier? The satellite signal is still good through the diplexer, so would I want the amplifier to be just on the antenna signal?


Can someone recommend a good amplifier if this is the way to go? I would like to get one that doesn't need power, are any of those good enough?
 

·
Registered
Joined
·
924 Posts
The amp will not solve the "through the window" problem unless you can power it outside and then diplex the signal. A good preamp will be a 2 piece unit with one piece up near the antenna and the other (power injector) inside the house near a plug.
 

·
Registered
Joined
·
1,476 Posts
Discussion Starter · #3 ·
So the part by the antenna doesn't need to be plugged in? That would work. Any particular models recommened?
 

·
Registered
Joined
·
35 Posts
Quote:
I'm assuming the diplexer degrades the signal strength? If so, what is the best way to solve this? An amplifier? The satellite signal is still good through the diplexer, so would I want the amplifier to be just on the antenna signal?
I've just spent the last two weeks trying to resolve this issue. Let me tell you what I've done to see if it helps.


I've got DirecTV, put a RadioShack VU190-XR antenna on my roof (160" boom), used diplexers to connect both to receiver. I live in DC Metro area where at least six stations should be available from one direction; I only received two reliably, even w/ fine-tuning the direction of my antenna. A direct line from the antenna to the receiver gave me four stations, with two more coming in with frequent dropout. I bought a ChannelMaster 3041DSB preamplifier to try and improve signal strength, and this just made it worse!! I think I live too close in to the signals, and the preamp just magnified noise. I could get NO channels with a preamp. My final resolution to the issue was to relocate the antenna to a different spot on my roof. I can now get five channels reliably (all but one with significantly improved signal strength), and the sixth is no worse than before.


I have deduced from my limited experience (and ask anyone who's reading to help clarify if I'm wrong), that 1) you should choose your antenna carefully based on your location. I have four of six digital channels in VHF, but I see that many people have them ALL in UHF; the antenna you pick should have that in mind. 2) Preamps may not help with your give situation, and may hinder depending on your location. Use as a last resort. 3) Diplexers do seem to reduce the signal to some degree; I've seen written 1dB per diplexer (so 2dB in total!), but I don't know if a 1dB decrease in signal strength is significant or not. A direct line is better---I know I'm sacrificing some signal quality for the convenience of not having to drill another hole through my foundation.


I know most of this information is readily available on other threads, but sometimes it takes so long to find it, I'm hoping this helps a little. I'm even hoping some of you will correct me where I'm wrong. After two weeks, I've finally been able to take the ladder down and I'm hoping to avoid my 8-10 trips up the ladder every day just to try and problem solve OTA reception issues.
 

·
Registered
Joined
·
1,476 Posts
Discussion Starter · #5 ·
I have the exact same antenna (the Radio Shack Monster). I had it mounted on the west side of the house originally, and I got no channels at all (all of mine are in the same direction, I live south of all the main towers). However, I got perfect reception with the antenna in the yard on the east side of the house, just resting on a ladder 4' off the ground. So I then moved the antenna to the east side of the house. This seemed to work, I got all channels perfectly w/o using the diplexors. I am about 20 miles from the towers, so based on your experience, the amplifier might help me. Sounds like I have to just give it a shot. I know that Channel Master is a good name, any other amplifiers worth trying? Does Winegard make one?
 

·
Registered
Joined
·
35 Posts
My best signal response w/ the monster antenna was on the ground outside my back door, when I had just assembled it and was testing it out. I even got a signal from Annapolis, which I'm guessing is about 30 miles away and 90 degrees to the left of where the antenna was pointing!


Caution on the amplifier----as I said, it made my reception WORSE! It was ALL "location" in order to get the optimum signal. But the CM7777 seems to be the best thing going right now. Winegard does make them, but I know nothing about their products.


Good luck!
 

·
Registered
Joined
·
269 Posts
I would suggest there's something not right with your duplexer.


It'll have losses, but if you're starting with a clean analog signal the losses shouldn't be noticable. 1-2dB is negligible - it might make a difference if you're starting with a marginal signal, but it doesn't look like that's the case for you.
 

·
Registered
Joined
·
6,557 Posts
Quote:
Originally posted by mddolfan
I have four of six digital channels in VHF
hehe, no you don't. All Digitals signals in the DC area are UHF. All of them.
 

·
Registered
Joined
·
35 Posts
Cyclone, thanks. After posting that, I started reading more, and what I didn't realize before is that even though my receiver is listing those channels as 4-1, 5-1, 7-1, etc., they're actually all broadcasting on UHF! So I guess a UHF-only antenna would have been the best way to go......
 

·
Registered
Joined
·
124 Posts
A word on diplexers....there is a difference in the type you can buy. A standard diplexer that combines satellite and TV frequently has significant signal loss on the tv side. Several years ago I encountered this problem and switched to a Channel Master 4002IFD diplexer at the front end when combining the signals and utilized standard diplexers at the tv end when separating the signal. The results were outstanding....give it a try!
 

·
Registered
Joined
·
1,476 Posts
Discussion Starter · #11 ·
After alot of help from w9wi on PM, and the most recent comments here, it looks like I do have a suspect diplexer. I just bought el cheapo diplexer ( this one ).


Looks like the next step will be to try a better diplexer.


Thanks everyone.
 

·
Registered
Joined
·
1,476 Posts
Discussion Starter · #12 ·
Ok, I just got my diplexors in the mail. I bought Channel Master Diplexors, 4002IFD for outside, and 4001IFD for inside. I still have the same problem.


Recap: If I run the antenna wire directly to the TV, reception on all 5 channels is perfect. If I join it with Satelite, and then split it before the Sat box, 3 channels come in good, 1 with a little snow (watchable tho), and one with ALOT of snow (not watchable).


Anyone have any other ideas?
 
1 - 12 of 12 Posts
Status
Not open for further replies.
Top