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RF Modulators

post #1 of 39
Thread Starter 
I just wanted too know if it could be modded to Output Channel 2?
post #2 of 39
All of the modulators out there that are intended for residential use are either channel 3/4 or UHF/ULTRA (CATV). You may possibly be able to find a channel 2/3 one, but, good luck. Probably the only way you're going to get a channel 2 modulator would be to get a commercial unit.
post #3 of 39
Why can't you use either channel 3 or 4?
post #4 of 39
If you are willing to spend you can modulate to any channel you want?
post #5 of 39
Thread Starter 
I was just asking if it was possible

I just find a cheap Blonder Tongue RF Modulator for Channel 2

Thanks for the help
post #6 of 39
Have a link for the product you found? If the price is over $10-15.... it's not "cheap".
Why do you have a need for Channel 2?
post #7 of 39
Blonder Tongue is not going to be cheap. Of course, I guess it all depends on one's definition of cheap.
post #8 of 39
Thread Starter 
Ch 2, I heard there was RF Modulators with the Ch 2-3 Output

I'm doing this wireless in my house, or Maybe Cable running to the other TV next to my Room

I only want the VHF-Lo band Ch 2-6

Channels

2 - DirecTV
5 - DTV Converter Box 2

The other RF Modulator with the Ch 3-4 Output going to my other DTV Converter Box on Ch 4

If I do the Wireless Route, I watch TV on my Porable TV's I have
post #9 of 39
Are you trying to build a system with DirectTV, DTV-1, DTV-2 available on a single coax cable?
(possibly with an OTA antenna feed also)
If so, then you'd be better off using a relatively cheap agile modulator and adding them above the broadcast frequencies. (IMHO)

I think you'll find that you can't get adjacent channels to work on a single coax line cheaply or easily.

If you're trying to broadcast (transmit) VHF to TVs in the house,(if that is what you mean by "wireless") then that's illegal as far as I know.
(as well as very tricky)
post #10 of 39
Quote:
I think you'll find that you can't get adjacent channels to work on a single coax line cheaply or easily.
Yeah, that. When the cable company does it they use very expensive filters on their modulators and suppress the audio carrier level to avoid adjacent channel interference. That's also why there were never adjacent channels in a broadcast market (Ch 4 & Ch 5 aren't adjacent). Leave some space between channels.
post #11 of 39
Thread Starter 
Quote:
If you're trying to broadcast (transmit) VHF to TVs in the house,(if that is what you mean by "wireless") then that's illegal as far as I know.
(as well as very tricky)

That's my plan, But only like 30 Feet, No less...I want also to watch TV on my Sony Watchman and my Casio Pocket TV
post #12 of 39
Transmitting (wirelessly) on the TV channels is definitely illegal, since you could interfere with any legal weak stations that someone is trying to receive. More importantly, according to my FCC contacts, you put yourself at risk by retransmitting anything that is copyrighted, and anything that could be construed as "porn".
You could just buy one of those 2 GHz wireless video systems. Of course, it requires a receiver at the end with the TV set.
post #13 of 39
Thread Starter 
Well here in Vallejo, In my parts..nothing is on the VHF band at all,

and I'm talking about Analog
post #14 of 39
Quote:
Originally Posted by MarioMania View Post

Well here in Vallejo, In my parts..nothing is on the VHF band at all,

and I'm talking about Analog
Except for all of the cable converter boxes and OTA boxes, and VCRs, and satellite receivers that you and your neighbors currently have in use on channel 3/4. Also an analog transmission can interfere with digital cable/internet if it uses the same frequencies. Signal strength (and shield integrity) will determine if the interference is noticeable to others.

I understand your wish. I have a couple of Watchmen and someone gave me a color Casio. (now all virtually worthless) Could be why TV/video on phones and tablets has become so popular.
post #15 of 39
Quote:
Originally Posted by MarioMania View Post

Well here in Vallejo, In my parts..nothing is on the VHF band at all,

and I'm talking about Analog
At this time, the VHF bands (OTA) are licensed bands, which means that you gotta have a license to use them. Doesn't matter whether they are currently being used or not.

Your scenario does bring up another question though. Those wireless A/V systems that operate in the 2.4GHz band; can the channel be changed on them? If so, there could be another option for you.
post #16 of 39
Quote:
Originally Posted by olyteddy View Post

Yeah, that. When the cable company does it they use very expensive filters on their modulators and suppress the audio carrier level to avoid adjacent channel interference. That's also why there were never adjacent channels in a broadcast market (Ch 4 & Ch 5 aren't adjacent). Leave some space between channels.
I always thought that one of the reasons for the adjacent channel rule was so that as tubes aged and drifted, they wouldn't interfere with an adjacent channel.
post #17 of 39
Quote:
Originally Posted by egnlsn View Post

Quote:
Originally Posted by olyteddy View Post

Yeah, that. When the cable company does it they use very expensive filters on their modulators and suppress the audio carrier level to avoid adjacent channel interference. That's also why there were never adjacent channels in a broadcast market (Ch 4 & Ch 5 aren't adjacent). Leave some space between channels.
I always thought that one of the reasons for the adjacent channel rule was so that as tubes aged and drifted, they wouldn't interfere with an adjacent channel.
It was mostly so they could build cheaper tuners was my belief. Suppressing the audio carriers by 10 or 15 dB also cuts down on cross modulation and other distortions in an analog cable system.
post #18 of 39
Quote:
Originally Posted by olyteddy View Post

Suppressing the audio carriers by 10 or 15 dB also cuts down on cross modulation and other distortions in an analog cable system.
Yes. The spec was (is) 13-17dB below video.
post #19 of 39
Thread Starter 
Thanks all for the info..

Have there been any old VCR's from the early 80's with the Ch 2-3 option?
post #20 of 39
I want to say my parent's circa 1984 Montgomery Ward VCR might have had that, but I'm working on ~30 years of memory, so I could be mistaken. Every other VCR I've used did 3-4.
post #21 of 39
The only thing I ever saw with 2/3 output were obscure game consoles. maybe ColecoVision or Intellivision.
post #22 of 39
Thread Starter 
Yeah, I have a Atari 2600/7800 with the 2/3 output, but I don't know how to hack it so I could use it for outputing something else
post #23 of 39
If you ever noticed in all TV markets there was never a channel 3 and 4 only one of the 2.
All devices were made to modulate on those channels so no matter where you use that device one of the channels will be open.
post #24 of 39
Thread Starter 
Yeah I know

Have there been RF Modulators with the Ch 2/3 Output?
post #25 of 39
post #26 of 39
Thread Starter 
I emailed him, I'm just waiting for a reply..

I staill want to know if the VCR's from the Early 80's have the Ch 2/3 output
post #27 of 39
I don't remember ever seeing any VCRs that did. Cable boxes, yes. But not VCRs.
post #28 of 39
Quote:
Originally Posted by MarioMania View Post

I staill want to know if the VCR's from the Early 80's have the Ch 2/3 output

You should send a PM to the member, Citibear. He hangs out in the DVD recorder forum. He's a wealth of info on early (and late model) VCRs. If anyone would know, he would.

But even if one did, good luck finding one. There might be some Betas still around in the hands of enthusiasts, but most VHS models were probably junked in favor of newer ones (which were also probably junked when DVD/DVR/HTPCs came along.)
post #29 of 39
Quote:
Originally Posted by MarioMania View Post

That's my plan, But only like 30 Feet, No less...I want also to watch TV on my Sony Watchman and my Casio Pocket TV
It's UHF (15) if your not married to the channel 2 plan. http://www.ebay.com/itm/Wireless-UHF-Audio-Video-Transmitter-Sender-for-TV-DVR-Directv-Cable-WV-350-/181047100166?pt=US_Audio_Video_Transmitters&hash=item2a273f8306 And unfortunately is mono (wouldn't natter for the Casio or Watchman)
post #30 of 39
Just received your PM, MarioMania.

Unfortunately no, I do not recall ever seeing a VCR with channel 2 modulator output. I have owned, rented, borrowed and resold many, many VHS and BetaMax VCRs since 1980 (more than I can count), but not a single one varied from the channel 3/4 standard modulator. AFAIK, all the '80s Montgomery Wards models were made by Panasonic/Matsushita using the standard 3/4 modulator: if Tulpa is remembering correctly about his parents' Montgomery Ward VCR, the odds of you tracking down that one particular "renegade" 1984 model are slim to none. Aside from one or two oddball items, pretty much every consumer video product since 1975 has used the channel 3/4 modulator.

All of the cheap, affordable, consumer-grade accessory modulators are for channel 3/4. If you absolutely must have channel 2, you'll need to spend more money for a pro or broadcast-grade RF modulator from mfrs like Blonder Tongue. These pro-grade modulators are special-ordered for whichever channel you require. The cheapest Blonder Tongue Channel 2 Modulator costs approx $155 from dealers like this. Note they do occasionally pop up second hand on eBay for a fraction of that cost: there is one available now for $25.

Otherwise you may want to reconsider migrating to a UHF frequency. Reasonably-priced UHF modulators with variable frequency are available from electronics dealers like MCM for approx $50.

The Sharp modulators you linked to are an obscure specialty product not commonly available as a single unit. That surplus vendor has them priced under $5, but prefers selling to commercial buyers in quantities of 200 or more. Perhaps they will let you have a couple of "samples" if you offer $10 apiece. They look rather tiny and low-powered to me: more of a specialty cable-service part than something suitable for your home system.
Edited by CitiBear - 4/12/13 at 5:48pm
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