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Well now you are going to think something really weird is occuring.

As of 1:30pm (I was unable to check last night), I get both WNED AND WUTV fine, with no drop outs or pixilization, however now WIVB CBS 4-1,3 is disappeared (UPN transmitter with CBS feed is coming in fine).

And CityTV is still off...

A few ideas,

Try to ge the terminators, will perhaps do later today if I have a few spare moments.

Try a different reciever

One thing we haven't tried to do is run NEW RG-6, one striaght from the antenna to the reciever and as well from the line. Maybe there is something wrong with the RG6?
 

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alebowgm said:
One thing we haven't tried to do is run NEW RG-6, one striaght from the antenna to the reciever and as well from the line. Maybe there is something wrong with the RG6?
I would definitely try new cables. If you don't want to do too much work, just try running a new one without taking the old one down just to see. I had some bad experiences with faulty cabling and it was doing all kinds of weird things like missing channels etc.
 

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OTA Diplexed (combined) with rogers cable?

Hi all -- I was wondering about something.

I have a CM4228 up on the chimmney, with RG-6 coming down the side of the house. It then goes through a hole poked in the brick. I'd like to reduce the number of holes in the brick, and in general don't want to work outside now since it's cold!

But I'd also like my rogers cable connection to this TV as well (regular analog rogers ... not digital). Can I diplex or combine these two signals on the same RG-6? And once the signals are on the same cable, can the TV properly tune the signals? I have a samsung with a built in HD tuner with separate ANTenna input, and Cable input. I know for a fact that the cable input cannot tune HD ota ... so I am right in guessing the ANT input won't be able to tune cable either?

Am I stuck poking another hole? (Or larger hole obviously)

TIA
 

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Discussion Starter · #64 ·
CATV and OTA both fall within the same frequency range. There is no way to diplex the two.

Cable TV operates in the 54MHz to 804MHz range.
http://people.qualcomm.com/karn/rr/freqtable.html

OTA UHF operates in the 470MHz to 806MHz
http://www.phptr.com/articles/article.asp?p=169518&seqNum=5&rl=1

EDIT by stampeder: Sorry HDTV101, I have to remove your important warnings about the technical and legal risks of people diplexing antennas and CATV because of the detailed information given. :) As you pointed out, Industry Canada takes a very sour view of that topic so I've removed the technical details of the explanation you gave so that nobody thinks they should try it. cheers, stampeder.
 

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Satellite & Antenna RF modulated??

I have my parents setup with a true FTA setup on a Nexus PCI card. They also have a omni directional antenna(roud pizza type)

I have the Nexus composite video and audio outputs to a RCA mini RF modulator that also accepts an antenna input and you get a basic choice of ch 3 or 4 for watching the video/audio inputs.

This works o.k.!

The problem appears to be that when the PC is on and output form the nexus the overall quality and strength of the signal for the antenna drops off and gets snowy and some channels are not longer viewable.

So the one thought I had was...
I was thinking that it would be great to modulate the Nexus output and then to use diplexers to get the signal the other end... the problem then becomes
each of their two TV's only have 1 coax input... and I cannot find any that would break out the signal back to RCA audio video connectors... not even sure if such a demodulator exists.

The PC and the antenna is all distribute from the basement.

Anyone have any thoughts on how to address this.....
 

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Hi Joedoe,

You mean another RF modulater that would allow me to chose like channel 95 or something like that? So replace the existing one.

This is all new to me, but how would that help?
 

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Yes. modulate the RCA signal to channel 95 lets say and use a combiner to join to antenna. You have one cable running to TV. The modulator would have to be on a channel which the antenae does not use.

There is no reason why this wouldn't work. I am 100% why you are having issue now though.
 

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Discussion Starter · #70 ·
I would use a Trunkline Single Channel Modulator. This will modulate audio & video on a cable (65-125) or UHF channel of your choice for home distribution. The Trunkline Modulators run at a higher power then the channel 3 modulator that’s really only designed for one TV hookup.

http://www.kusat.com/catalog/product_info.php?cPath=14_24&products_id=89


I have 6 of them in my home system all ganged togther making a mini private home cable TV system.

Be sure you use a trap to block the Modulators from back feeding the antenna or an outside Cable TV system!

http://www.kusat.com/catalog/product_info.php?cPath=14_24&products_id=88

 

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Using diplexers with Sat. dish and OTA antenna amplifier?

Already got answer from Stampeder and HDTV101 on one question but have another. When I combine my OTA signal and Sat signal using a diplexer should this be done before or after my uhf amplifier ?
I will be doing all this inside my basement where all cables come into. I only have the capability of one cable going to one of my tv set but would like both sources going to it. Hence the diplexer being used.
 

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probak118 said:
When I combine my OTA signal and Sat signal using a diplexer should this be done before or after my uhf amplifier... ...one cable going to one of my tv set but would like both sources going to it.
Your Satellite receiver has to power the dish's LNBs, so that connection has to have "DC Pass" capability all the way from one end to the other. Your OTA antenna preamp has to be powered by its own DC "power injector". This means you need to make sure that the Sat. and OTA lines do not accidentally share any DC power across them, which could damage everything including your ATSC tuner. If you're using an AC-powered signal amplifier on the antenna line instead of a preamp-power injector pair, just substitute them in my layouts below.

The solution is to let the Sat. receiver run its DC power all through the diplexed connection, while giving your OTA gear its own DC power only on its own isolated branches with the antenna and with the ATSC tuner. If your diplexers do not allow DC Pass on either line you need to get two that have at least 1 line that can do that. Your layout will have to be like this:

LNB(s) -> LNB switch (if more than one LNB) -> diplexer #1 DC Pass input -> incoming coax line -> diplexer #2 DC Pass output -> Sat. receiver
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Antenna -> preamp -> preamp's power injector -> diplexer #1 non-DC Pass input -> incoming coax line -> diplexer #2 non-DC Pass output -> ATSC tuner


If your diplexers allow DC Pass on both lines you have a problem that could damage your Sat. LNBs and your preamp because both would be getting injected power from eachother. An easy workaround to that is to get two top quality 2-way splitters that either don't allow DC Pass or only allow DC Pass on one output but not the other. Use this layout:

LNB(s) -> LNB switch (if more than one LNB) -> diplexer #1 DC Pass input A -> incoming coax line -> diplexer #2 DC Pass output A -> Sat. receiver
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Antenna -> preamp -> preamp's power injector -> splitter non-DC pass input (cap DC Pass input) -> diplexer #1 input B -> incoming coax line -> diplexer #2 output B -> splitter non-DC pass input (cap DC Pass input) -> ATSC tuner
 

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OTA Setup with Sat. Diplexer

Ok, this would be a typical FTA/OTA setup:

http://www.dmsiusa.com/diplexer.htm

I know it says DSS but I'm assuming FTA works off the same principle.

Now, if I'm using a preamp with my OTA would the diplexers be before or after the preamp AC plug?:eek:
 

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Discussion Starter · #74 ·
When you use an antenna mounted preamp you have two parts. The amp that’s mounted at the antenna and the power supply that’s inside your home that the coax connects to before going to the TV. This power supply sends 30 volts DC up the coax to power the amp at the antenna. Now with your satellite system the satellite receiver does the same trick by sending 14 to 18 volts DC up the coax to power the LNB. When you use diplexers they will pass only DC on the satellite (DSS) LNB side. They will not pass any DC on the OTA antenna side!!! You can only have ONE DC path per coax since DC is ZERO Hz in frequency.

If your going to use an antenna mounted preamp there will be no way to send power from the power supply to the antenna mounted preamp. You will have to use 2 separate coax lines and forget about using diplexers all together.
 

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new and exciting results

Well, I am going to bring back up this old thread to post some new and exciting results.

I finally got my hands on the BDS-P1 Diplexer, made for the BMS-58 Multiswitch. Unlike most diplexers, the Frequency range is 54-5120mhz on this baby and coems with a DC Blocker. Put this baby on instead of using the Eagle aspen 5-2400mhz diplexer and vola! Both satellite and Antenna working.

Unfortantly, I think my antenna has shifted because even without the diplexer, the only US station I can constantly get right now is WKBW (also getting CBC E/F, CTV and sometimes SunTV). So I have other issues I need to fix here in the spring. But as long as I get WKBW, I will get Superbowl!!!

Also, there was no difference in results with or without the DC-Blocker. I figured I would use it as it shows on the Diplexer install, as it probably is a good thing?!?!?!
 

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For the DBS part, if its a single LNB there shouldn't be any problem, but FTA multi-LNB systems need a DiSEqC (pronounced "Die'-sek") switch, which can be really sensitive to line length, injection losses, etc so it might not like being run through a diplexer.
hdtv101 said:
If your going to use an antenna mounted preamp there will be no way to send power from the power supply to the antenna mounted preamp.
Either that or you could locate the diplexer in a place outdoors where you can also mount the preamp's power supply in a weatherproof case with AC power, with its input coming directly from the preamp on the mast and its output and the DBS output feeding into the diplexer and its own line going indoors.
 

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Signal Leakage Between CATV and OTA - How And Why To Prevent It

If anyone is contemplating running a combination of Cable TV and OTA to the same TVs or receivers, there are specific safeguards you must take to isolate the two signals from eachother. This is not a casual concern, its very important that you do it correctly!

Satellite and OTA into the same TVs or receivers are not a problem.
 

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Would you care to elaborate Stampeder? I have a few friends who have purchased new TV's with integrated ATSC tuners, who also use analog cable (too cheap to spring for HD terminals). What precautions should one take? TIA!
 

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Gladly! Here is the situation: you have two signal sources that are feeding your TV using essentially the same frequency ranges. OTA antennas feed VHF Low, FM Radio, VHF High, and UHF to your TV, but so do CATV systems, albeit with their own sub-channel maps over the same frequencies. They do not get along with eachother.

This frequency overlap is due to historic reasons because in the 1950s-60s there were no Set Top Boxes yet for cable channel tuning, so the CATV providers had to overlap the regular 13 VHF channels and later the UHF channels with their own signals in order to feed your TV. This is why CATV gear is so heavily shielded to this day - there is a direct conflict with OTA. If we could redo CATV all over again I'd advocate assigning a third range of frequencies apart from TV and Satellite.

So, if you simply connect the antenna and the CATV with a splitter you will cause signal leakage of the CATV signals through your antenna and vice-versa, which will cause garble and interference not only for yourself but for your neighbours too. Connections like that are ILLEGAL. Industry Canada and CATV providers constantly check for signal leakage and will come down really hard on you if you let it happen. The leakage problem does not happen with Satellite because its incoming signals are way off in another part of the frequency spectrum from TV.

What is the solution then? An A-B input switch is one method, or if your TV has 2 coax inputs you could test to see if they are discrete (separated inside to prevent leakage). Some people run the OTA lead right into the TV and the CATV lead into the VCR and then over Composite or SVHS into the TV. There are a few solutions like that if you think about it. I think there might be remote control capable A-B CATV/Antenna coax switches out there too.

Check out previous posts in the OTA Forum by HDTV101 and others about this issue.
 

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Stampeder,

I have a T.V that has 3 inputs. 1 for Direct T.V and then Antenna A and B
I have Antenna B with basic cable in it and Antenna A has OTA. The T.V has built in ATSC . How do I check for "leakage"?

Thanks in advance
 
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