Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[alebowgm]

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?

[michaelC]

Originally Posted by alebowgm

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.

[gordee78]

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

[HDTV101]

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/articl...&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.

[57]

Originally Posted by gordee78

so I am right in guessing the ANT input won't be able to tune cable either?

See the Digital Home FAQ "Can I get Digital Cable".

[teenie]

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.....

[Q]

YOu could buy another modulator which you can choose the channel.

[teenie]

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?

[Q]

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.

[HDTV101]

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...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...products_id=88

[probak118]

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.

[stampeder]

Originally Posted by probak118

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
+
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
+
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

[bsr2002]

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?

[HDTV101]

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.

[alebowgm]

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?!?!?!