Splitters, Attenuators, Filters, Diplexers, Other Signal Gear

[rob50312]

Yes i am using a directional fm yagi and the shielding by the cable is necessary with co-channel signals .

[mlord]

From what I've read OTA and Cable use roughly the same spectrum, so does that mean that I can use a splitter or amp designed for cable for my OTA use?

Yes. I do this here, and they work well.

The amp that I have is a PDI-407AR-6KV (designed for cable modem use) with 54-1000MHz forward path 7dB gain.

You could use that with OTA as well, as a high-grade distribution amp -- that particular model claims 2.4dB NF (noise factor), which is excellent for the purpose!

Cheers

[agmemnon]

Am I able to use a 4x1 DiseqC Switch to combine my ota feed and cable feed together. Is this switch a diplexer?

I don't want to use an amp b/c the distance travelled is less than 25 foot (ant to tv)

Of course only using just 2 of the 4 lines

thanks

[stampeder]

No, sorry but a Diseqc switch is a different animal, and an ATSC tuner would have no knowledge of how to control it.

OTA and Satellite feeds can be combined with diplexers. OTA and Cable feeds cannot be combined because ever since the beginning of Cable TV it has used the same frequency ranges as OTA. The overlap kills one or the other, but the worse hazard is signal leakage, which can get you into trouble with the authorities:

http://www.digitalhome.ca/forum/showthread.php?t=65268

My HDTV has 2 inputs (Antenna and Cable) but most do not. If yours doesn't have separate inputs you'd need to find an A-B coax switch.

[agmemnon]

Cheers, thanks for the info, I have been searching for a link like this for the past 3 hours.


thanks very much

[hungt1999]

Hello

I need help with the following, please look at the schematics

I cannot watch Over the Air on TV2 unless I turn ON the Satellite receiver. If I turn OFF the SAT receiver, all RF signal on TV2 drop to zero

It used to work fine if the sat receiver was OFF. Since yesterday with the cold weather of -20C, this problem started. One of the diplexer is located outside of the house.

OTA on TV1 is working fine and Satellite reception is working fine on TV2

thanks

[stampeder]

Excellent diagram, and I don't see anything electrical that would be causing it except probably a failing diplexer.

Is the outside diplexer iced up? Can you reach it to heat it up?

[hungt1999]

Stampeder, I suspect it is the -20C temperature causing the diplexer that is located outside the house to fail. Physically the dixplexer looks ok, no ice build up.

Since the dixplexer is just a DC pass on one port, I have a hard time imagining how can it fail and if it fails, would it simply pass DC on both ports or will it block DC?

If failed by blocking DC, I would also lose reception on my Satellite box right?

[stampeder]

Ya I'm also wondering about it, but I'm guessing that the diplexer has been frozen into allowing only one of its signal paths to work. Just a guess. I've had enclosed switch gear do that in the past because of moisture.

[000]

Hi everyone,

I live very close to the CN tower and often notice *local channels cutting out even though signals are coming in strong. I read somewhere that this is a result of overload and I should use an attenuator to fix the problem. Which product should I be looking at specifically? I have a DB2 antenna with no preamp.

Edit: Ok I found the CA-20-DF7 at Tin Lee. I'm realising this could also be a problem of multipath interference... Hmm

[hungt1999]

I found the culprit, it was a bad power supply to the GE preamp. I replaced the power supply and everything works ok now. Still I am perplex, it means that during the time the power supply to the GE preamp was bad, the GE preamp got supply from the SAT box which is not supposed to because the diplexer is supposed to block DC on the port going to the aerial antenna.

[stampeder]

hungt1999 that was very strange! It might be possible that DC current was going up to the LNB and then down again through the diplexers to the GE amp in the opposite direction... ??? Glad its working again for you.

[stampeder]

000 is your DB2 indoors or outdoors? Which major street corner are you nearest? Attenuators are cheap and available at The Source too.

[mlord]

Originally Posted by 000

I read somewhere that this is a result of overload and I should use an attenuator to fix the problem. Which product should I be looking at specifically?

Just get an ordinary 1:2 splitter ($1.50 from Active Surplus on QueenStW) and wire that in, preferably with a 75-ohm terminator on the other unused output -- it will cut the signal strength down to half of its present value. If that doesn't fix it, then you know the problem was not signal overload.

Cheers

[hoopitup2000]

Originally Posted by 000

Hi everyone,

I live very close to the CN tower and often notice *local channels cutting out even though signals are coming in strong. I read somewhere that this is a result of overload and I should use an attenuator to fix the problem. Which product should I be looking at specifically? I have a DB2 antenna with no preamp.

Edit: Ok I found the CA-20-DF7 at Tin Lee. I'm realising this could also be a problem of multipath interference... Hmm

Sounds like multipath to me. Exactly how close are you to the tower?

I am less than 4 miles from the Wash DC antenna farms, and have experienced the same dilemma. Bowtie style antennas do not work well here because of the "extreme" multipath. The combination of a more directional yagi style antenna, and a digital tuner with the latest 6th generation chipset completely eliminated the problem.

The only attenuation I do use is an FM trap to filter out the potent FM signals 1/2 mile away.