Multi-channel RF moderator - Videokarma.org TV - Video

site123a · #1 10-26-2008, 03:22 PM

I was thinking that since the FCC is soon going to shutdown the NTSC, all of are TV's is only going to be set to channel 3. I thought that was a little wasteful, so I was wondering if there was a device that can transmit a signal from multiple device's to other channels instead of 3.

For example, to access a DVD, VCR or a converter box, they would connect to a multi-channel moderator that would transmit the devices individually on CH3, 4, and 5; So to view them you would simply change the channel on your TV.

So is there such a thing as a multi-channel RF moderator? Or that can only be done through the airwaves.

vinyldavid · #2 10-26-2008, 03:50 PM

Some VCR's have a switch that outputs signal on 3 or 4, so you could do that and possibly combine the signals.....but I have no clue if that could work, or how practical it would be.

wa2ise · #3 10-26-2008, 06:08 PM

Quote:

Originally Posted by site123a

So is there such a thing as a multi-channel RF moderator? Or that can only be done through the airwaves.

I've seen such boxes that can do 4 channels, but all the channels are up on UHF. Must be some screwball FCC regulation that says "No VHF except 3 or 4".

An example: http://www.solidsignal.com/prod_display.asp?prod=5445

kbmuri · #4 10-26-2008, 06:36 PM

http://cgi.ebay.com/ws/eBayISAPI.dll...m=370094967880

Hemingray · #5 10-26-2008, 08:30 PM

DISH Network's VIP622 HD DVR (and maybe some others, dunno) have the ability to output it's dual tuners to any one of two UHF channels from 21-69. We have one downstairs and have both UHF channels set up. one on 54, and the other on 60. Works very well, combined with our second HD receiver on the usual Channel 4. Some other Dish DVR boxes may do this as well, not sure.

forgot to add: Even tuned to an HD channel, output continues, Just appears letterboxed on a standard set.

ChrisW6ATV · #6 10-26-2008, 10:16 PM

As others said, there are modulators with two or more channels built-in, but they are all on UHF. One basic reason for the use of UHF is that most areas have several adjacent unused channels between each station as opposed to VHF where often every other channel is in use. Special filters are needed to put signals on adjacent channels, one reason the modulator in the Ebay auction above is more expensive than the typical consumer devices. VCRs could use 3 or 4 because they are not intended to be mixed with other TV signals.

If your desire is to have a bunch of VHF local analog signals in your home, the best way is to look for bargains on variations of the Ebay modulator above; I have seen them sell for US$20 often. Get several of them and a signal combiner, then feed all of your antique sets.

site123a · #7 10-27-2008, 04:33 PM

I always thought the main reason channel 3 was used was because that's low-band VHF, guess I was wrong... I'm planning on hooking up a bunch of devices to my TV so right now I'm just playing with ideas.. I don't mind using the UHF channels to access my devices, plus it's more convenient; I just hate the idea of never using my tuner again. However I don't have $140 to spend, so I'll have to put that idea off for now. I do like that four-channel video modulator that wa2ise suggested...

I have a new question. My Insignia D/A converter doesn't have analog pass-thru, and I still want to be able to watch NTSC:

As you see in the diagram, in order to do that I need to split the antenna signal to both the converter box and the TV; Will a standard 2-way RF splitter like the one below work fine? Or do I need an amplified RF splitter.

Tripqzon · #8 10-27-2008, 05:07 PM

That splitter should work fine. It passes up to 1000MHz (1GHz) which will cover the UHF TV band as well as VHF.

kbmuri · #9 10-27-2008, 08:44 PM

Quote:

Originally Posted by ChrisW6ATV

...

If your desire is to have a bunch of VHF local analog signals in your home, the best way is to look for bargains on variations of the Ebay modulator above; I have seen them sell for US$20 often. Get several of them and a signal combiner, then feed all of your antique sets.

I agree. There are cheaper bargains -- especially "channelized" models -- fixed output at a specific channel (rather than choosing your own via dipswitches):

Channel 7, fugly without the black brushed-metal faceplate, but probably functional.
http://cgi.ebay.com/Blonder-Tongue-C...1%7C240%3A1318

Channel 8, this one's purty.
http://cgi.ebay.com/NEW-BAVM-s-BLOND...1%7C240%3A1318

Curious what they end up getting. Without the SAW processing, they won't adjacent-channel as well, but you can still do channels 2, 4, 6, 7, 9, 11, and 13.

And some UHF too -- someone got this one (Channel 20) for $2.24 + shipping:
http://cgi.ebay.com/BLONDER-TONGUE-M...1%7C240%3A1318

so there are deals out there.

I don't know what "Channel Q" is. Anyone?
http://cgi.ebay.com/USED-BAVM-s-BLON...1%7C240%3A1318

3Guncolor · #10 10-27-2008, 09:17 PM

Channel "Q" should be about CATV channel 29. At one time in the cable world we used letters for our channels so they would not get mixed up with UHF channels.

ha1156w · #11 10-28-2008, 12:37 AM

Smarthome.com used to sell a boatload of modulator variations with selectable channels (even digitally selected and MTS output flavors).

Anyone know where you can get an ATSC modulator? It's the easiest way to distribute hi-def to several sets from a single source via existing coax installs. Problem is I can't find a modulator!