feed 942 input (antenna) from dvd rf ch3 output

[uponthemountain]

Hello all and merry christmas!

Here is my next question

i have a 942 and a bravia 40 inch lcd

the tv is way great (needs to be 'calibrated' but thats another thread)
BUT it has no pip!

So here starts the question and problem.

I need to be able to Watch my 942 ... a recorded event normally while opening a 942 based pip showing a dvd being played.

To re-word, I need to see a dvd in a pip using my 942.

My DVD player has a rf out .... channel 3

The 942 has antenna in for locals

and in testing I can indeed see my dvd playing on channel 3 on the 942 when connected.

But I'm missing something fundemental on 'matching' the inputs. ... because as soon as I try to combine the antenna cable with the dvd output ... poof ... no channel three signal.

So I think I need to change the rf signal to 'match' the expected vhf signal? I know I'm not wording this correctly but I'm not certain how to.

so anyways here is roughly the setup

DVD rf ch 3 out
942 antenna in
antenna -> 300 ohm to 75 ohm -> pre-amp -> amp -> 942

bottom line, how do I 'mix' the dvd out into the 942 antenna in ... without losing any signal strength or clarity? (don't want to mess up my weak hd locals!)

thanks in advance for any help.
Keith

 

[SimpleSimon]

First thing to try is a simple 2-way splitter hooked up "backwards" so that it's a combiner.

ISSUE: If you have OTA channels 2,3, or 4 you're likely t have interference problems.

 

[uponthemountain]

Simple Simon,
Thanks for the suggestion. When I tried that I had two different problems.

If i used the splitter after the amp, the primary channels came in on average 15 points lower! but the channel 3 was there .... so it worked, but was unacceptable . the 15 point loss dropped some of my channels out of 'lock range' around 60 or so.

The other way was before the amp. when I splitter-combined them before the amp, the primary channels did not suffer any loss, but the channel 3 just flat out did not come in at all! Im guessing the pre-amp some how changes the signals and the dvd rf was not 'matched' to that. Thinks makes me wonder what would happen if I put another pre-amp on the dvd rf out ... the same model as on the antenna?

 

[SimpleSimon]

You've discovered the big bad problems with this - matching signal levels.

Lots of channel 3-4 modulators are crap - they are generic parts now.

Try using the composite or S-Video output into a stand-alone stereo modulator - available at Wal-Mart for around $20-25.

That might give you the signal level you need to combine them.

 

[uponthemountain]

So, to re-word to make sure I'm following ...

It should work then ... to mix a ch 3-4 rf out with a standard antenna pre-amped signal into the power inserter input for output to the 942 antenna input. ... whew what a mouthful.

But ... in my case ... the rf modulator may be inferrior to the point where it is not making it through the power inserter. (this is on a high end lg dvd recorder by the way)

So ... if i get a stand-alone rf modulator and use the svideo out on the dvd player as the input, then take the output from this modulator and combine it with the pre-amped antenna feed into the power inserter .... all may be good?

this begs another question though ... would it be possible to 'broadcast' the channel 3? That way it in now way can effect my current antenna feed, but instead utilizes the attack antenna?

does this beast exist ... rf modulator/transmitter ?

 

[SimpleSimon]

I could NOT follow most of that, and what power inserter are you talking about?

The one thing I DID get from it is to tell you that it is flatly illegal to attempt to broadcast anything. Even the reversed-splitter isn't quite legal, because some of the CH. 3 signal may leak back up to the antenna. In reality, it's not an issue, tho.

 

[uponthemountain]

on the power inserter ...

my antenna amp has two parts

the first part im calling the amp or pre-amp ... it connects at the antenna and sends out the signal from the (pre-amp input) 300 ohm leads on the antenna down to 75 ohm coapre-amp output).

the second part im calling the power inserter. it is located at the tv. not sure what it does exactly, but it receives the 75 ohm coax as an input , it also uses 120v input to some how complete the amp process and then finally outputs 75ohm coax . this in turn is connected to the 942.


on the illegal part ..

ok, and bummer. would have been a 'cool' method for this purpose. but no problem.

on the following. ... sorry about that! I barely understand what I'm talking about, so this leads to ramblimg, poor wording etc. But thanks for trying to follow and help!!!