Random Question

[rabid_hobbit]

recently I did troubleshooting for my friend who had messed up the connections on his directv system, and I noticed something peculiar. If someone can shed some light on this, I'd appreciate it. Here's how it was set up-
R15-300
nothing connected to sat-in ports
1st cable from dish connected to "out to tv"
2nd cable from dish connected to "antenna in" on the tv.

Obviously, I know what the problem is with this setup. The part I find intriguing, is that the tv had a searching for satellite message on it. So the rf output on the reciever was somehow going up the 1st line, and being sent back down the 2nd line to the tv. What I'm wondering is if the multiswitch would be expected to repeat the signal to all outputs, or if it just happened to be a fluke.

[carl6]

I suspect the searchng for signal was the TV (not the DirecTV R15) searchng for signal.

[HoTat2]

recently I did troubleshooting for my friend who had messed up the connections on his directv system, and I noticed something peculiar. If someone can shed some light on this, I'd appreciate it. Here's how it was set up-
R15-300
nothing connected to sat-in ports
1st cable from dish connected to "out to tv"
2nd cable from dish connected to "antenna in" on the tv.

Obviously, I know what the problem is with this setup. The part I find intriguing, is that the tv had a searching for satellite message on it. So the rf output on the reciever was somehow going up the 1st line, and being sent back down the 2nd line to the tv. What I'm wondering is if the multiswitch would be expected to repeat the signal to all outputs, or if it just happened to be a fluke.

I can't see your friend's entire system, but from what you have described I would guess since the receiver is a legacy SDTV R15-300, he probably has a non-HD set-up with a multiswitch which is for the Ku band only (or "L band" for a satellite LNB output between 950-1450 MHz) with an optional input for OTA diplex, or a "3 by x" type switch. Thus the channel 3 or 4 RF signal from the receiver is simply traveling up the coax in reverse and then down to all the other outputs which are diplexed in parallel for off air TV signals between 54-806 MHz.

[boba]

I would guess he had composite connections to the TV seeing no coax was going to the TV in your description.

[HoTat2]

I would guess he had composite connections to the TV seeing no coax was going to the TV in your description.

No, the OP said there was a connection to the TV from the dish (however I assume he actually meant below "from the multiswitch").

NOTE:

... Here's how it was set up-
R15-300
nothing connected to sat-in ports
1st cable from dish connected to "out to tv"
2nd cable from dish connected to "antenna in" on the tv.


And like I said it's likely a Ku band only multiswitch with a built in OTA diplexer and the RF ch. 3/4 output from the receiver is traveling up though the diplex circuity back down to the input of the TV set which is set to ch. 3 or 4

[rabid_hobbit]

you specify ku-only multiswitch. would there be a different effect with a wideband multiswitch?

[HoTat2]

you specify ku-only multiswitch. would there be a different effect with a wideband multiswitch?

Yes, there should;

Simply because a wide-band or Ka/Ku compatible multiswitch such as a WB68 does not and cannot have a built in OTA diplexer as it must accommodate the satellite Ka-lo (or B-band) from 250-750 MHz. Thus there is no available bandwidth to pass off-air TV channels from 54-806 MHz through the switch at the same time.