TV Antenna Help

[Jerry1]

I have an antenna in my attic and I get very good reception. I used to have the cable from the antenna run directly to my Tablo box. Then I had an internet outage and realized I cannot watch tv via the Tablo if the internet is down. I moved the cable directly to the tv and of course that worked. The obvious next step is to put a splitter in line so that I can have the signal go to the Tablo and the tv at the same time with no need to swap out the cable - which I did.

The problem is that now my signal is not good on one of my favorite stations. Way too much pixelation. So I have a couple questions that I'm hoping someone can answer. First - is it true that splitting the signal does exactly that - splits the strength of the signal in half, which would confirm that my adding of the splitter is indeed my problem. Second will an amplifier actually improve the situation? If so, I'm assuming I can put the amplifier anywhere before the splitter and that should solve my problem. My next question would be whether it matters which amplifier I get.

Thanks for the assistance.

 

[rk911]

You might consider an amplified splitter.

 

[GenXguy]

I use a 3 way splitter, and I have to use an amplifier prior to it to get reception with my attic antenna from broadcasters about 50 mile away. It's terrible without it. I bought a Kitztech low noise amplifier with 20 dB variable gain.

 

[Jerry1]

I ended up getting this.

Ultra Mini 2

I figured to amplify the power at the splitter would work best in my case since I only have two things I want to send a signal.

 

[OldShooter]

... The problem is that now my signal is not good on one of my favorite stations. Way too much pixelation. So I have a couple questions that I'm hoping someone can answer. First - is it true that splitting the signal does exactly that - splits the strength of the signal in half, which would confirm that my adding of the splitter is indeed my problem.

Yes. TANSTAAFL. Each leg gets slightly less than half the energy, as some is lost in the splitter.

Second will an amplifier actually improve the situation? If so, I'm assuming I can put the amplifier anywhere before the splitter and that should solve my problem. My next question would be whether it matters which amplifier I get.

A booster should help. The TV signal is attenuated as it goes through the coax cable, so it is best to put the booster as close to the antenna as possible. You don't have to go nus, but 6' to the booster and 50' to the splitter is better than 50' to the booster and 6' to the splitter.

Channel Master is an old and respected name in this market. I would use one of their boosters (Antenna Pre-Amplifiers) The "TV Antenna PreAmp 1" looks like a good candidate. It's probably not necessary but I would replace an off-brand splitter with one of the Channel Master products too. They are cheap enough.

Same-o on coax cable. If you are replacing some, go with a respected brand like Belden RG-6 or look for some test results on the internet. If the current cable is old and it is relatively easy to replace it, I would do that too. Coax does deteriorate. If not easy to replace and the booster/splitter solves your problem I would not worry about it..

I am sure there are other good brands but Channel Master is one I know even from back in my ham radio days. (Amateur Extra license) We don't even watch TV these days so I don't know much about the current market.

 

[GenXguy]

In addition to the Kitztech very low noise antenna amplifiers, another good one is the Televes 560383. 31 dB gain UHF, 22 dB gain VHF. No variable gain, but has automatic dynamic gain. Has built-in LTE & FM filters. You can use these with remote power (via coax) closer to the antenna if you want. I avoid this personally to this point because it gets so hot in the attic in the summer. However, all the broadcasters in my area just changed from VHF to UHF, so I bought a new attic UHF antenna to replace the VHF and have to see how things pan out. It's like deja vu all over again. lol

 

[isisdave]

It's a little late for this, but today this thread was featured in an email to me.

Check to make sure all the connectors are screwed tightly. It's surprising how much a little looseness will degrade the signal.

I am surprised that one two-port splitter would degrade the signal from completely usable to highly attenuated. Usually, you'll notice degraded signal on damp mornings, and that's a sign you have a barely usable signal.

 

[BlaineS]

The loss through a 2-way RF power splitter for TV frequency range is typically 3dB (50% signal loss). There is also a small signal loss for every connection and cable loss. The longer the cable(s) the greater the signal loss. The losses also increase with an increase in frequency. Your best option would be to amplify the signal, but too much amplification can also cause problems with signal quality.

 

[NXR7]

The caveat with splitters is how many times they split. If they split into two signals, yes, about half is lost. But if you have a splitter with three ports, one will be -3 db (loss of half) and the other two will be about -7 db (loss of half and loss of half again).

Those types of splitters are like wiring two splitters together.

In practice, the loss of half the signal is not as bad as it sounds. But one wideband splitter installed in our RV had a whopping loss of -10 db (the signal strength was dropped to 10%). That piece of junk was replaced by a better splitter.

I, too, have a rooftop antenna with a preamplifier mounted a few feet away. The power to the preamplifier is run up the coax cable. Then 50' away in the basement I have an amplified splitter that pushes the signal throughout the house.

My current problem is broadband electrical interference from somewhere in the neighborhood. I can see it on a piece of test equipment called a spectrum analyzer but it comes and goes. It's not present in the house but somewhere outside. I need to walk around and check all of the transformers because they are the usual cause.

When the interference is present it wipes out almost every channel. Otherwise I have almost 70 channels but can be down to 10, half of which are shopping.

 

[GenXguy]

In practice, the loss of half the signal is not as bad as it sounds. But one wideband splitter installed in our RV had a whopping loss of -10 db (the signal strength was dropped to 10%). That piece of junk was replaced by a better splitter.

It can be "worse" than it sounds. The -10 dB loss you mentioned is a 90% drop in signal power. If you're anywhere near the the edge of good signal reception, it doesn't take much additional loss to start getting drops. I'm using a very low noise Kitztech amplifier myself, which helps me to tune in distant broadcasters.

 

[NXR7]

It can be "worse" than it sounds. The -10 dB loss you mentioned is a 90% drop in signal power. If you're anywhere near the the edge of good signal reception, it doesn't take much additional loss to start getting drops. I'm using a very low noise Kitztech amplifier myself, which helps me to tune in distant broadcasters.

-10 db, yes, which is why I mentioned I replaced the splitter because -10 db the signal dropped to 10%.

-3 db or 50% is usually not noticeable. Old analog TV, yes. 50% would affect the signal. New digital TV with all of its built-in compensations, not so much.

I know you get it because you noted "very low noise amplifier" and not "high gain amplifier".

Not all preamps are created equally and bad ones introduce their own noise on to the signal. You want a preamp with a low noise figure (less self-created electrical noise) but many manufacturers do not even mention the noise figure because they know people think "more gain means a stronger signal" and that is not necessarily true. For the non-technical folks reading this, a low noise figure amplifier is much better than a high gain amplifier.

In case you're interested, these are some nice quality, low price spectrum analyzers. I own two models and they really come in handy for troubleshooting stuff like this: RF Explorer models

When I was aiming my antenna I had one hooked to the antenna while I was on the roof and I had looked up the actual RF channel frequencies. I was able to point the antenna based on the best overall signal. Often you can orient the antenna towards weaker stations because the stronger ones will still get through.

 

[ERD50]

Careful, a true "amplified splitter" will come with a power supply (typically a 'wall-wart' style. You need a source of power. No power supply, and it is just a lossy splitter.

I think you would best be served by replacing that splitter with a "distribution amplifier". If you just use that splitter (which losses some signal), and then amplify it, (or amplify before the splitter) the amplifier is also amplifying noise, plus adding noise from the active amplifier itself.

The distribution amp can often do a better job by buffering the signal for each of the outputs. Buffering is more of an impedance matching to avoid the loss, and I think entails less noise than using gain to make up for the loss (maybe the Ham Radio people can chime in if this is not the case, but I'm pretty sure that is right).

 

[ERD50]

I ended up getting this.

Ultra Mini 2

I figured to amplify the power at the splitter would work best in my case since I only have two things I want to send a signal.

Ooops, missed this from OP. Looks like a good choice. How'd it work out?

 

[NoEZmoney]

I have an antenna in my attic and I get very good reception. ----------------

The problem is that now my signal is not good on one of my favorite stations. Way too much pixelation. ---------

I have the same situation using an old Channel Master roof antennae inside my attic. I get good reception from most the major networks but NBC and PBS. Major reason is the transmission power from those two stations as they are more directional in their signal spread than the others and where I live gets a grade b or c power contour.
As some have stated, getting a good inline signal amplifier can help but there is a difference between passive and powered amps, the latter being better in most cases. You could try a lower-cost (passive) amp and see if that works for you and if not return for a credit/refund but keep in mind some electronics stores won't accept returns on some (emphasis on SOME) electronic equipment, so choose wisely.
Good luck.

 

[OldShooter]

Sorry, an unpowered aka passive amplifier would be the electronic equivalent of a perpetual motion machine.

 

[triangle]

I thought this was an interesting video. He mentions a couple of issues that could be affecting those who are noticing that their antenna does not seem to work as well as it did in the past.

 

[Al18]

Thanks for posting - that was a good video

 

[GenXguy]

I thought this was an interesting video. He mentions a couple of issues that could be affecting those who are noticing that their antenna does not seem to work as well as it did in the past.

Thanks for posting - that was a good video

Unless I missed it, he didn't even mention the issue I ran into multiple times that I mentioned in an earlier post. Several stations in my area moved from VHF to UHF channels, so the existing VHF antenna didn't work well, even after rescanning. And I had seen no indication this was going to happen in advance on any of the channels. I had to figure it out on my own.

 

[jim584672]

We have 3 VHF channels and you need rabbit ears to pick them up since the waves are longer than UHF waves. A plain UHF loop works where I am for UHF.

 

[GenXguy]

We have 3 VHF channels and you need rabbit ears to pick them up since the waves are longer than UHF waves. A plain UHF loop works where I am for UHF.

That would never work where I'm located. I have a big directional antenna and low noise antenna amplifier up in the attic. Fortunately, all of these distant stations are in the same direction (within 1 degree). The last of our VHF stations recently moved to UHF, so I have no more VHF stations. A few months ago, most of them were VHF.

 

[GenXguy]

In case you're interested, these are some nice quality, low price spectrum analyzers. I own two models and they really come in handy for troubleshooting stuff like this: RF Explorer models

When I was aiming my antenna I had one hooked to the antenna while I was on the roof and I had looked up the actual RF channel frequencies. I was able to point the antenna based on the best overall signal. Often you can orient the antenna towards weaker stations because the stronger ones will still get through.

I used a spectrum analyzer originally to aim my new UHF antenna, which is an Antennas Direct 91XG. The signal didn't change much with minor aiming changes of the antenna. But I was experiencing dropouts on my TV, often losing some stations completely in the afternoon. I moved my antenna amplifier to the attic temporarily, but that didn't help.

I ended up taking a laptop up to the attic, remoting into my home theater PC, and watching the signal level & broadcast video while moving the antenna around. What ended up improving my signal significantly was titling the antenna about 45 degrees (left to right) while leaving it aimed straight ahead as before. I tripled checked, and the signal always was best with this tilt of the antenna. So I anchored it into place like that, and haven't had any dropouts at all since.

All except PBS are more distant channels that are within 1 degree of each other, so the antenna is aimed and tweaked to best receive those. The local PBS station, which was already UHF, and is in a different direction, still comes in fine, just as it did when I used the VHF antenna, which is completely removed now that everything is UHF.

 

[NXR7]

Exactly. That's why aiming based for the strongest signal is not always the best method. Aim for the weaker stations and the strong stations can still be picked up. The strongest, closest stations to us are due east but I aim southeast towards another, further city and the strong stations still come in.

As you found, signal polarization shifts are a real thing as the signals propagate.