AVS Forum banner

Status
Not open for further replies.
1 - 20 of 20 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter · #1 ·
I've recently purchased a new TV for the master bedroom and am not happy with the video quality coming out of it. I am getting both snow and scrolling diagonal lines (very tightly spaced) when I view images that come across the cable from the 3025 in the family room.


Here's the setup:

1. Two DirecTivos in the family room feed the 3025 in the family room.

2. 3025 has ONLY the two Tivos in. There is no RF feed. 3025 xmits channels 33 and 44.

2. Video is distributed via RG6 to the bedroom

3. In the bedroom, we go wall->IR target (Coax)->VCR (Coax)->TV (TCA)


Here's what I've tried so far:

1. Digital camera -> TV (RCA). Image is solid (-> TV okay)

2. Wall directly to TV (Coax). Snow and lines still.

3. Changed CP3025 outputs from the Remote to Local. Snow and lines still.


Some quick reading on this board makes me think I should head to Radio Shack to pick up:

1. Terminator of some sort for unused RF.

2. Low pass filter


Can anyone think of anything else? Also, is there a FAQ that discusses the technical details the types of things that lead to the common symptoms of snow and diagonal lines?


thanks in advance,


gary
 

·
Registered
Joined
·
386 Posts
The pass filter is a must. It will clear up your problems most likely.


Is the IR target powered, as in 2100 (ChannelPlus)? I have the CP distribution amp, 5545 modulator and 2100 IR target wallplates. According to CP, you must use a dc block on any feeds NOT using a 2100 wallplate. Doesnt sound like applies here, but worth throwing out.
 

·
Registered
Joined
·
5,019 Posts
Check that your IR target is wired correctly (these are directional).


What happens when you take the VCR out of the loop in the bedroom ?


Definately use the terminators on all unused RF connectors.


The connection from the 3025 to the bedroom has no splitters, right ? Barrel connectors are OK but no splitters. And keep it on the "Remote" if you are further than 50 feet away.


You could also use the RF input from one of the Tivo's to block out other RF coming. THe 3025 is NOT stereo on its modulators, although you can buy a box (the 5601 I beleive) that can preserve stereo from the line in source.
 

·
Registered
Joined
·
1,897 Posts
I looked this weekend for the low pass filters at Radio Shack but couldn't find them. Sales people weren't much help. Does anyone have any part numbers. I would like to filter all channels above Cable 100 so I can insert on Channel 125.


Thanks,


Doyle
 

·
Registered
Joined
·
1,304 Posts
DoyleS

You should know better than to go to Radio Shack! Try your local security distributer or higher end electronics shop. Wherever you purchase your modulators should have low pass filers. Although you may need a custom filter if you want to pass through everything up to 100. Most of what I have seen, say from Channel Plus, is from ch 84 or ch88.


Alan
 

·
Registered
Joined
·
5,019 Posts
Parts Express has some, so does Smarthome. But like Alan said - they offer like 4 different ranges - and you don't really have a choice beyond those 4. Also the LP filters are not "brick wall" filters either - they gradually cut down the signal until at 5 channels above - its "blocked"
 

·
Registered
Joined
·
1,897 Posts
Yeah, I only went to RatShack because someone had said they had these filters and modulators. In the end all they had were Ch3/4 modulators which are pretty bad. I wasted about 30 minutes on that diversion. Fry's had decent modulators but did not have the filters. There is a specialty TV store in San Jose that has all this stuff and I'll probably just go over there. Mail order on a single small item like this tends to be a pain.


..Doyle
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #8 ·
Just reporting in -


As Doyle says, RatShack has no low pass filters. All I was able to get there was a pair of 75ohn terminators for the RF input. These didn't help.


I did some more swapping around and found that running the 3025 output directly to the TV makes a noticeable difference in the snow but not in the diagonal lines. I'm guessing this is why I missed it last time.


Anyway, it looks like some better cables are in order for the IR->VCR->TV connections. These are cheapy compression ends with very small center conductors anyway and I'm not really keen on how well they hold.


More status when I find a low pass filter vendor.


gary
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #9 ·
Quote:
Originally posted by Scooper
Check that your IR target is wired correctly (these are directional).
Checked and verified. These were correct.

Quote:


What happens when you take the VCR out of the loop in the bedroom ?
I'm going through this right now as indicated in my last post. I'm going to make myself up a few short cables (if I still have F-connectors!) to get rid of the cheesy press-fit connectors.

Quote:


Definitely use the terminators on all unused RF connectors.
I read in another post that the DC out (for the IR target?) was a concern when terminating the outputs of the 3025. Are these what you mean for me to terminate?

Quote:


The connection from the 3025 to the bedroom has no splitters, right ? Barrel connectors are OK but no splitters. And keep it on the "Remote" if you are further than 50 feet away.
Correct, I have no splitters. Eyeballing the run makes me think I'm under 50 feet, so I had it on Local. It's a close call, however, so I thought I'd try remote. Still no difference.

Quote:


You could also use the RF input from one of the Tivo's to block out other RF coming.
This one has me a little puzzled. Are you suggesting the following?


Tivo RCA Out-> to CP 3025 RCA in

Tivo RF Out -> CP 3025 RF in


Are we hoping that the lack of incoming signal on Tivo RF puts a quieter RF into the CP than a completely undriven input?


gary
 

·
Registered
Joined
·
1,611 Posts
Do I understand correctly that you do not have any cable company signals in use? Did you completely disconnect the incoming cable line to your house? If so, a low pass filter will do nothing for you. The filter will only block out what the cable company is using. So, if you don't have anything getting onto the lines running to/from the 3025, then skip the filter.
 

·
Registered
Joined
·
5,019 Posts
Yes , I'm suggesting that putting the Tivo RF output on the RF input might quiet that down.


Check that RG6 coax run to the bedroom doesn't have any AC power lines running close to it, especially not parallel !
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #12 ·
Can you give me guidelines for how long a run and how close together the

AC and coax lines need to be together for noise to be coupled in?


I don't have any places in the wall where the coax and power come down the same wall cavity. I also don't have the attic run anywhere near parallel.


What I do have is single entry points into the entertainment center where ALL cables bunch together (including power). So I probably have 2-4 foot runs where I have coax, power and possibly some speaker cable.


I could probably do some simple rearranging and send power out one side and signal (speakers too?) out the other side to get two feet of separation and then keep them apart as they run along the wall to the outlet.


I guess I want to know how anal I should be with this :).


gary


(Can you tell that we're fighting a crosstalk problem at work right now? :))
 

·
Registered
Joined
·
1,897 Posts
Gary,


You mentioned that you ran the 3025 directly into the TV but didn't say whether this was through your house coax or whether you rigged up a short 4-5 foot piece of coax and ran that in. If you did the latter and have diagonal lines then there could be a problem with the TV channel that you have selected. The signal should be clean when run that short a distance and you may want to try some different channels. Not sure whether you are running channels 33 and 44 UHF or CATV. If you are running UHF channels, you may want to switch to lower channels like 15. If you are using CATV channels then try using UHF channels. It is a bit more work but you can narrow down the problem set. If the signal is clean on a short coax then you likely have some sort of crosstalk/interference problem with the coax running in the house. If it is not a highly shielded RG-6 then you may need to look at changing it. Another thought is that you could have some ground loops and possibly trying some power isolating plugs may help determine if that is the problem. That could also explain the problem going away if you put the modulator in the same room and plug as the TV as a test. You also might try disconnecting your DirecTivos and only connecting your camera (using its battery) to the input of the 3025. That should be a very clean signal with no ground loops at the signal source.

..Doyle
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #14 ·
Doyle,


Lots of good tips. Thanks. I'll try changing the modulator channels since that won't require any manual labor :).


I'll save the short coax and ground loop experiments for this weekend when I have time to drag the bedroom TV out to the family room.


gary


btw - where are you shopping for equipment? I work in north San Jose and might be able to use the same places.
 

·
Registered
Joined
·
5,019 Posts
DoyleS -


The 3025 accepts channels inputs from 14-64 UHF, and 65 - 125 (excepting 95-99) on cable. So, if he has it set on 44 and 33, these are UHF channels, no if's , and's , or but's about it. However, you do have a point about making sure that there are no local broadcasters on 33 or 44 (within 2 channels either side of the assigned channel).
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #16 ·
I know that there is a local UHF right AT 44. I'm not sure about 33, though. I would be surprised, however, if there was nothing being broadcast between 31 and 35.


Where would I be coupling this signal in from? The unterminated RF input of the CP3025?


gary
 

·
Registered
Joined
·
5,019 Posts
Well - since you have admitted there is a local channel 44 - THERE'S part of your problem right there. Change channel 44 on the 3025 to somewhere that there ISN'T a local channel and things should be much better.


A good way to find out is to goto www.antennaweb.org , find your address and it will show you what channels are in use, what direction they come from, and even what antenna you need to receive them. Just remember that you need to set your 3025's modulated channels 2 or more channels in each direction away from any other UHF source. And yes - TERMINATE THAT RF Input if you aren't using it.
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #18 ·
Quote:
Originally posted by Scooper
A good way to find out is to goto www.antennaweb.org , find your address and it will show you what channels are in use, what direction they come from, and even what antenna you need to receive them. Just remember that you need to set your 3025's modulated channels 2 or more channels in each direction away from any other UHF source.
Yack! There's NO CHANNEL that will let me leave two channels on either side!


Best I can do is something between 14-19 and the other between 57-62.


Would switching to cable be a better bet? I don't know where the cable frequencies lie in relation to the OTA freqs.


gary
 

·
Registered
Joined
·
5,019 Posts
In that case - terminate the RF input, and use your TV's to find the best channels for your application.


Or - you can get the Low Pass filters on the RF input and terminate that, and you SHOULD get a reasonable block out .
 

·
Registered
Joined
·
12 Posts
Discussion Starter · #20 ·
Okay, some good news and some bad news.

1. I tried channels 19 (that was a mistake - I was going from memory) and 59. Neither one got rid of the slow moving diagonal lines (although the angle and spacing seem to have changed)


2. Moving the TV to the family room yielded interesting results

a. Snow was noticeably better over coax...but didn't completely disappear! I froze a frame and had to stare pretty hard, but pixels did randomly fade in and out. Just because I'd never done this before, I tried the same thing on my normal TV - no snow.

b. Snow was even better over RCA (no surprise) but still there. This was taken directly out of the Tivo, where my main TV had a hop to the receiver in between.

c. There were no diagonal lines on either coax or RCA.


So...the TV itself (20" Toshiba) isn't as good as the one in the family room (27" Sony). I thought I had verified the solidity of the picture by using my digital camera, but I'm going to have to check it with a video source.


So all that remains is to hunt down a low pass filter (and I get a new TV, I guess :) ).


gary
 
1 - 20 of 20 Posts
Status
Not open for further replies.
Top