Multiple transmitters?

[josephdaniel]

Just curious if anyone here runs 3 or 4 agile modulaters at once where two of them are playing a loop of some tv series and the other for just what ever you wanted to play?
Seems like something I would do just for the fun of it

TITLE EDIT: multiple not mutile

[compucat]

Is it possible to feed those modulators into a common antenna and have each transmitting on a different channel?

[ohohyodafarted]

Yes, you can do that. I have 5 modulators tied to a combiner. It is the same sort of thing that was commonly used in motel systems. My setup feeds each of 4 modulators with a digital converter box each tuned to a different local digital channel and a 5th modulator is fed by a dvd player. All 5 modulators feed the combiner, and the combiner output feeds a single coax to the tv sets. The combiner can accept input from 24 modulators and output the signal on a single coax. This is just like the combiner I use.
http://www.ebay.com/itm/Holland-1GHz...item1e763ebf53

[zenithfan1]

Originally Posted by josephdaniel

TITLE EDIT: multiple not mutile

Fixed it for ya.


Bob has a nice setup that works well, those combiners are great. I have that kind of setup too but it is dismantled at the moment.

[Steve McVoy]

Coaxial splitters work fine as combiners. For 4 channels, connect the modulator outputs to the splitter output, and connect the splitter input to the antenna. Much cheaper than a combiner.

[jr_tech]

High Port-to-Port Isolation

* High Isolation Design
* Consistent Port-to-Port Performance
* Front Panel Test Port
* HCG-12 can be used as a splitter
* Operates at a full 1 GHz Passband

The HCG-24 input passive head-end combiner, intended to combine multiple modulator and processor inputs into one output while maintaining the highest isolation between ports.

The isolation between ports is important to prevent spurious signals as a result of the output of one modulator getting into the output stages of another modulator. A simple splitter will not provide isolation between the ports.
jr

[josephdaniel]

Originally Posted by zenithfan1

Fixed it for ya.


Bob has a nice setup that works well, those combiners are great. I have that kind of setup too but it is dismantled at the moment.

Thanks!

[earlyfilm]

Originally Posted by Steve McVoy

Coaxial splitters work fine as combiners. . . . . . Much cheaper than a combiner.

They do, provided you don't use adjacent channels within each of the three VHF bands.

Jas.

[Charlie]

On the ship I used to work on, our cable system was put together in this manner. We had 3 modulators that put out two channels each and DVD players and Dish receivers were connected to the modulators. You could be in any cabin on the ship, and get all 6 channels. I think there were at least two dozen TV's being fed throughout the ship. When the ship went away a couple years ago, the captain let me take the modulators home. I will use them later once my shop is completed. The system worked quite well.

[Steve McVoy]

jr_tech, look at the specs for splitters. Typical port to port isolation is about 35 db, probably about the same as a combiner. If you look inside a combiner you will see it is made up of directional taps, which are simply splitters with uneven outputs (splitters provide identical output levels on all ports).

[jr_tech]

I stand corrected... thanks!

jr

[compucat]

That is good to know. Someday I would like to set up a 6 channel analog TV service in my house using digital converter boxes tuned to favorite digital stations. I currently have one analog channel using a converter box and Blonder Tongue agile modulator on channel 5 and it works quite well. I know better than to use adjacent channels for these things.