channel 3 vs 4 (tivo/pvr/dvr)

[jkane]

Thought this might be a good place to ask this question.

I have a Tivo and a Dish 501 DVR.  Both are near the downstairs TV.  No problem with that part.  My wife watches the Tivo upstairs via "old fashioned" coax on channel 3.  Good enough for our purposes.

I've been starting to use the Tivo for some OTA stuff and when I do, she want's to watch the 501 upstairs.  So ... I set the 501 to use channel 4 on the coax TV out.  I put a splitter backwards to "mix" the two signals.  We still get the tivo on 3, but the 501 does not come through.  If I unplug the Tivo coax from the mixer/splitter, the 501 comes in fine on 4!  If I swap the channels so the 501 is on 3 and the Tivo is on 4, the same thing happens.  We get 3, but not 4 if both signals are together.

I suspect is some kind of bleed over by putting out to much signal.  But what can I do about it short of another couple hundred dollar switching toy.  And if I must, what toy would you all suggest.

[Gregg Lengling]

Jeff you need an adjacent channel combiner, you can't pump a modulator signal into you line without degrading the other channels adjacent.  The combiner has filters to protect your channel 3 from overpowering the level of the channel 4 signal you have.  It's like talking on your HT in a weak signal area to the guy next to you, when he transmits you can't hear the repeater because he's desensing you and vice versa.....Got it?  If not give me a call.

[drgingras]

Jeff, we ran into a similar situation about a year ago when my SO complained about having to watch a backfed mirror of someone else's viewing choice on our bedroom TV. After looking at some rather expensive channel modulators and notch filters, I decided to try something cheap and simple first.
I picked up a manual A-B-C switch from Radio Shack, mounted it to the back of the source A/V cabinet, and wired it like this:

A= Dish TV out (4900 with OTA pass-through, like the 501)
B= RF modulator from DVD
C= VCR coax out
Output=single existing coax to bedroom

No stereo, not videophile quality, but it was simple and it works. All 4 sources look good on a 27" analog set. The only downside is having to deal with the manual switching.

Since your Tivo and 501 are both putting out a modulated signal, I'm sure you could get this to work with just an A-B switch.

Dave

[jkane]

That's what I figured was happening.     Guess I'll hve to do a bit of research on a switch vs a combiner.  I would prefer the combiner, so we don't have to deal with switching.  Any suggestions on places to find a combiner for adjacent channels?