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  #16  
Old 01-04-2008, 11:22 PM
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ohohyodafarted ohohyodafarted is offline
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Cory.....

You have the right solution. I even found one at Home depot. A 4 chanel modulator for $179. I think I will get one. Then I will buy 4 of those digital converters that the government is giving coupons for. I will tune each of the 4 convertors to a seperate local over the air digital chanel and feed the output of the converter to one of the 4 modulator inputs.

IN essence I will recieve the digital signal and remodulate it back to the old analog chanel and pump it down a 75Ohm antenna cable to my old tv sets. I think it should work pretty good. 4 analog chanels over the air is what I get now, 4,6,10, and 12. The neat thing is that if I ever want to watch a different chanel all I need to do is retune one of the digital converter boxes to different chanel.

You have solved my delima Cory. I was not aware of the multi chanel modulator box.

Here is the link to the one at Home Depot

http://www.homedepot.com/webapp/wcs/...7X-_-100598727

Bummer!!!! I just discovered that this unit does not modulate to the VHF band. Only to UHF and cable chanels.

Is there a unit that modulates to VHF???
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  #17  
Old 01-05-2008, 03:37 AM
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Unless the amp was made for ATV, a typical ham radio linear amplifier's bandwidth is usually woefully too narrow to carry a 5MHz television signal, and most won't work outside the ham bands (6m, 2m, 70cm).

Theoretically you could try this setup instead (legal FCC/IC/PTT disclaimer intended and you've been warned, and if you're bright/dumb enough to try this you probably know the consequences ):

Cable head-end Modulator--->commercial cable distribution amp-->cable trunk amplifier--->single channel MATV antenna.

-the trunk amplifier is optional unless you need greater range.
-a real head end modulator is best since you can control output levels and it's true VSB, not a pro-sumer one.
-you'll need to use good quality coax cables like RG6 and RG-11.
-the antenna must be located in a manner that eliminates its feeding back into the amps, meaning away from the antenna. No rabbit ears here...
-older "~450MHz" cable amps that were used back in the day work better than the newer ones.
-stay away from ch4, as there are aeronautical users at 72+/- MHz and it would really suck if a 747 tried to land in your living room.

There's going to be a number of analog low power UHF translators going up for replacement (read: disposal) when the "event horizon" comes up. Most of these are solid state, have a proper "channel converter" to take channel "x" and make it into channel "Y", are reasonably compact and don't take up a room, and make some power (=range). If your head-end modulator can generate channel "x" the translator won't know the difference.

Enjoy...
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  #18  
Old 01-05-2008, 06:15 AM
RetroHacker RetroHacker is offline
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Quote:
Originally Posted by thisOne
Here is what Northlan Cable says about it on their website:

• How many television sets can I connect to digital cable?
You can connect to digital cable to any number of TVs in your home for a low fee per month for each additional TV. Alternatively, you can receive the Deluxe Basic lineup on each additional TV for no charge and without any additional equipment.
• Do I need a separate digital cable box for every TV?
No. You only need a digital cable box if you wish to view the channels above 99 or would like to use the digital guide.

Here is what Optimum says about a Theft of Service
Ah, see - you're talking about digital cable. That's proprietary and each cable company rents out the boxes. I don't get digital cable. I don't intend to. I tried it for a month but the picture was abysmal. But no. I'm not going to be stealing service. I pay for it. I'm not going to be circumventing anything, because with analog cable, I'm not renting a box - only using tuners in consumer equipment. In my computer room, I have an early 80's Mitsubishi 15" television. It's connected to a Sanyo Betamax VCR. The VCR does the tuning of the analog cable. No cable company equipment in my house at all.

With analog cable, it doesn't matter to the cable company if I have one set or a hundred, I don't get charged extra per set. Analog cable must be called "Deluxe Basic" by your provider.

-Ian
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  #19  
Old 01-05-2008, 08:44 AM
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http://www.audiokarma.org/forums/sho...d.php?t=102105

$10 TV transmitter.
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  #20  
Old 01-05-2008, 09:27 AM
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Somewhere in storage here I have the remains of the TV distribution system from a hotel that was dumped when they renovated. It consisted of 6 modulators (with A2 stereo, I've yet to see a stereo consumer modulator) set to various UHF channels fed from a bank of now long obsolete MDS receivers and 3 distribution amplifiers.

I doubt I'll ever have a place big enough to need such a set up, but it would be almost ideal (I would prefer VHF modulators as I have a few VHF only sets, but for some reason every setup I've seen like this uses UHF modulators). Just replace the old receivers with a few SD set top boxes and your ready to go.
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  #21  
Old 01-05-2008, 12:44 PM
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Last edited by andy; 12-07-2021 at 02:01 PM.
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  #22  
Old 01-05-2008, 08:26 PM
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I've been to a few big hamfests and there are always guys with piles of commercial equipment that has gone obsolete. I'll have to pay attention on the next trip. Some of that stuff goes very cheap.
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  #23  
Old 01-06-2008, 11:52 AM
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Most low power UHF translators are fed from an existing NTSC transmitter which is transposed from one RF channel to another without taking it down to baseband (video/audio).

If they are exempt in the U.S. (they won't be in Canada), they will be in an interesting position. When the feeding analog transmitter (usually VHF, sometimes another UHF translator/transmitter) is no longer available, they will cease to function.

I haven't yet tried transposing a digital signal from one channel to another.
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  #24  
Old 01-06-2008, 03:43 PM
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Quote:
Originally Posted by colorfixer View Post
Most low power UHF translators are fed from an existing NTSC transmitter which is transposed from one RF channel to another without taking it down to baseband (video/audio).

If they are exempt in the U.S. (they won't be in Canada), they will be in an interesting position. When the feeding analog transmitter (usually VHF, sometimes another UHF translator/transmitter) is no longer available, they will cease to function.
I suppose you could use a digital receiver STB with a channel 3 RF output jack to feed the translator input (assuming the translator input can be set to channel 3) to create an analog translated output.
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  #25  
Old 01-06-2008, 07:56 PM
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ChrisW6ATV ChrisW6ATV is offline
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A commercial "agile modulator" is probably the best device to use for in-house VHF signal creation. There is at least one on Ebay right now, item #120206024645. It goes down to 40 MHz, so you could even use it for Channel 1.
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  #26  
Old 01-07-2008, 08:22 AM
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Good day Gentlemen,

Try this Greek made 100mW transmitter:

http://www.aspisys.com/tvpll.htm

All modern world standards (NTSC-M, PAL B/G, PAL-I, SECAM L, B/DK) in one unit. Synthesized, fully programmable.

Full choice of channels VHF and UHF + hyperband cable channels.

Enough power for full coverage of a normal house with near broadcast quality, however, DSB output (no vestigial sideband filtering) so technically can't qualify as "Broadcast".

I've got 6, ready for analog blackout if/when it ever happens.

I repackage in metal box, (i don't like plastic) and the metal provides good heat-sinking for the + 5VDC, +12VDC which otherwise run hot.

Not my company, just a happy customer.

Best Regards

jhalphen
Paris/France
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  #27  
Old 01-07-2008, 01:25 PM
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Last edited by andy; 12-07-2021 at 02:01 PM.
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  #28  
Old 01-07-2008, 02:44 PM
thomash85715 thomash85715 is offline
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I just emailed that greek outfit on that modulator. I could not find a US price on their site.
Sorry if I sounded ignorant on the ham radio linear idea. My buddy the ex-ham told me that a linear would not pass the full 6 mhz needed for such a task. It was just a thought but this aspisys thing seems much better IF it can be brought into the country legally and IF it works and IF it is not expensive. I shall advise if I hear from them. --Tom
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  #29  
Old 01-07-2008, 03:10 PM
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jhalphen jhalphen is offline
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Hi Thomas,

Some help:

Aspisys home page:
http://www.aspisys.com

Pricelist:
http://www.aspisys.com/pricelist.htm

The UTV-100TX is currently at Euros 132.00

Contact Engineer/Owner Mr Sotiris:
info@aspisys.com
sales@aspisys.com

As said previously, i have 6 units.

3 of which are the first generation model i purchased in 2002:

http://www.aspisys.com/tvpll2.htm

The newer model is even better & more powerful

BTW, my NTSC & PAL B/G transmitters are transmitting about 15 hours/day

Before these products i tinkered with broadcast quality agile modulators + wideband "Gain Blocks" from Avantek & Mini-Circuits to reach + 28 dBM RF out. Works well, but 19" rack units + the RF amps takes up precious real-estate...

Best Regards

jhalphen
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  #30  
Old 01-08-2008, 12:43 AM
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Quote:
I suppose you could use a digital receiver STB with a channel 3 RF output jack to feed the translator input (assuming the translator input can be set to channel 3) to create an analog translated output.
They would have to modify the translator to make it a full transmitter by adding the exciter (the modulator if you will), thus making it no longer a translator. Like someone said earlier, the modulator from a stb would be double sideband, and would therefore not meet FCC technical requirements on the air.

Broadcasters are always trying to one-up one another. So if some broadcaster in a given area runs digital, they all will, or if they do what they did near my dad's place, a number of SD stations went in and put up one digital transmitter and each runs on a sub channel.
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