Reception Problems - Page 2

jc5000 · 11-Jun-2011, 2:06 AM

KIAH breaks up routinely. Local Channel 26 breaks up somewhat as well.

I can get a different cable and hook one TV directly to the new transformer that I put on the antenna. I suspect that I will have to move a TV to do this.

One of the 4 way splitter ports has a cap on it. The others have cables attached to them.

Yes, all original transformers/amps are now out of the system. I am on pure antenna power. Do you think if I put the transformer/pre-amp back into the system and get rid of all other transformers, this will boost the signal enough?

Quote:

Originally Posted by GroundUrMast

I presume you are referring to KPRC (NBC, real channel 35, virtual channel 2.X) and KIAH (CW, real channel 38, virtual channel 39.X).

Is reception of KIAH stable or does it break-up?

Can you afford to buy a 'test' cable? I would be curious to know how the system performs when you connect the antenna to only the TV you are using as your signal meter. The goal is to determine with some certainty, the quality of the signal from the antenna and to remove (while testing) the possible problems in your distribution network.

Are all of the 4-way splitter ports connected to sets or 'capped' with terminating resistors?

Broken, bent or missing elements are not going to improve the antennas performance. However, if only one of the longest elements is missing, I doubt the effect on the UHF channels will be much. In your area everyone is using high-VHF or UHF channels, K04QT is an exception but rabbitears.com indicates it is not on the air and you would need to use a rotator or separate antenna to get it anyway.

If you have been able to loosen the hardware to replace the matching transformer, I'm inclined to hold off from recommending replacement of the antenna... for now.

GroundUrMast · 11-Jun-2011, 5:38 AM

Does the "cap" look like this? Or is it just a dust cap? An un-terminated splitter port could cause trouble on one or two channels

A new cable between the antenna and one set will offer the most helpful diagnostic information at this point.

If I were offering suggestions for a all new antenna system, an amplifier would not be on the list of needed items. You should be able to receive enough power with a roof mounted antenna, to feed eight sets.

John Candle · 11-Jun-2011, 10:37 AM

By giving an example of a 8 way splitter GUM is making a point that the Tv transmissions are strong. He is not saying install a 8 way splitter. I say that if 1 Tv is connected then use No splitters at all. I say that if 2 Tv's are connected then use only one 2 way splitter with the 2 outputs from the 2 way splitter going directly to the 2 Tv's with no other splitters in the coax lines. And the same with a 3 way splitter , the outputs of the 3 way splitter go directly to the 3 Tv's with no other splitters in the coax lines. There will be no splitters connected between coax the comes from the antenna and the input of , 2 way splitter , 3 way splitter , or 4 way splitter.

John Candle · 11-Jun-2011, 11:00 AM

A "test cable" is simply a loooong length of RG-6 coax connected to matching transformer at the antenna and then directly to one Tv. The looooong length of cable can be run through a open door across floors to the Tv. Is the antenna on the outside of the building on the roof or is the antenna in the attic?? If the antenna is in the attic of the building structure , is the place where the antenna is at have a metal roof , is the building wrapped with any kind of metal. Is there any foil backed insulation in the attic?? What direction is the antenna pointed??

jc5000 · 11-Jun-2011, 1:38 PM

The cap looks like the one in the link you sent. I am pretty sure it is a terminator because it has the center wire in it. On a similar note, I do have an open jack in one of my rooms with no TV currently attached. Does this also need a terminator?

The antenna is mounted on a mast on the roof. It is pointed SSE. Today I plan to get a length of cable, attach it to the new transformer I put on the antenna, and then attach the other end of this cable directly to a TV somehow. This will eliminate all existing cabling.

GroundUrMast · 11-Jun-2011, 4:25 PM

JC's points are correct. The signals available to you are strong, you don't need an amplifier. If you have a need to split to two or more sets, the ideal method is to select a splitter with just enough ports. Unused ports need to be terminated, not left 'open' at the far end of a cable run.

John, thanks for clarifying the definition of 'test cable'.

jc5000 · 11-Jun-2011, 4:27 PM

I completed the test with a "good" cable directly to the transformer on the antenna and then to the TV on the other end. The reception on the poor channels was definitely improved. They are still not as strong as the "good" channels; but they appear stable at about 25dB. No improvement on the "good" channels. Do they ever get any better than about 30-32dB?

So, if you think the antenna is sufficient, I guess I must test the rest of the system piece by piece until I find the weak link.

jc5000 · 11-Jun-2011, 4:31 PM

Perhaps the next and easiest thing to test is to put a terminator on the open wall jack to see if this helps.

Quote:

Originally Posted by GroundUrMast

JC's points are correct. The signals available to you are strong, you don't need an amplifier. If you have a need to split to two or more sets, the ideal method is to select a splitter with just enough ports. Unused ports need to be terminated, not left 'open' at the far end of a cable run.

John, thanks for clarifying the definition of 'test cable'.

GroundUrMast · 11-Jun-2011, 5:04 PM

Signal metering on consumer grade receivers is generally, 'un-calibrated' and can be based on any combination of RF signal power and digital error rate. I don't know if your set can detect or indicate a higher signal quality value.

I agree, terminating the unused cable run, or the splitter port is the next step.

The cable from the antenna to the splitter is now high on my list of suspects. If water has ever entered the coax, it's done. Coax Seal is a good way to keep water from getting into the connectors exposed to weather.

jc5000 · 11-Jun-2011, 5:12 PM

I have now terminated all of the outputs from the system. I have also removed one length of outdoor cable that was not necessary. There appears to be some slight improvement in reception over my brief observation period but real channel 38 is still unstable.

I agree that the next logical step would be to replace the remaining outdoor cable that feeds into the attic splitter. I will have to evaluate this very carefully as it passes through my roof and I do not want better TV reception at the risk of a water leak.

GroundUrMast · 11-Jun-2011, 5:39 PM

Quote:

Originally Posted by jc5000

I have now terminated all of the outputs from the system. I have also removed one length of outdoor cable that was not necessary. There appears to be some slight improvement in reception over my brief observation period but real channel 38 is still unstable.

I agree that the next logical step would be to replace the remaining outdoor cable that feeds into the attic splitter. I will have to evaluate this very carefully as it passes through my roof and I do not want better TV reception at the risk of a water leak.

Consider abandoning the old coax 'in place'. Can you run from the antenna down to the roof edge and enter the attic from the soffit?

jc5000 · 11-Jun-2011, 10:03 PM

I have now replaced all cable prior to the splitter. I have replaced the 4-way splitter with a 2-way splitter and disconnected the cable going to the room without a TV - so no open connections. Still having trouble on real channel 38. It goes from having a great signal to having a lousy signal and back again (12-28dB according to my TV).

I do not think that anything is wrong with my components, especially since they have all been replaced now and all of the other channels are stable. This is just a crappy signal...thank you digital TV.

I appreciate all the troubleshooting advice, JC and GUM.

jc5000 · 11-Jun-2011, 11:03 PM

Oh, one more thing. My new outdoor cable came with a ground wire. Where do you typically attach the ground- mast and cold water pipe?

GroundUrMast · 12-Jun-2011, 1:15 AM

A thread re. Grounding

If you stand behind the antenna and sight down the boom, does it point into the side of your neighbors house or large dense trees?

Have you inspected the cable and connectors on the cable from the splitter to the TV you are using as a meter?

jc5000 · 12-Jun-2011, 4:47 PM

The antenna is pointed towards a couple trees that are probably about 50 ft away. There are larger trees further away at maybe 100 ft. Nothing is right up on top of the antenna in the direction of the signals.

I have been monitoring the signals on both TVs and i did look at the connections. They are both behaving similarly. Behind the wall cables to the TVs are relatively new (3 - 5 yrs) compared to the other components that were in the system. I think they are unlikely to be the problem since both TVs exhibit similar behavior for all channels.

Do you think this brings up back to the antenna, which is where we started this conversation? Perhaps there are more optimal choices.

Quote:

Originally Posted by GroundUrMast

A thread re. Grounding

If you stand behind the antenna and sight down the boom, does it point into the side of your neighbors house or large dense trees?

Have you inspected the cable and connectors on the cable from the splitter to the TV you are using as a meter?

GroundUrMast · 12-Jun-2011, 5:19 PM

I don't think we have tried installing an FM Trap. They are fairly inexpensive and usually available at local Radio Shack stores, (returnable). The symptoms point toward a possible interference problem.

If I were building from scratch, I would use a modest sized 7-69 combo such as the HBU-22, HBU-33 or HD7694P. All of those antennas should have no trouble powering many more sets than you have at the moment. If we are fighting multipath, the larger Winegard antenna with it's more narrow beam width would be a better choice.

I would not install any sort of amplifier.

jc5000 · 7-Jul-2011, 6:10 PM

I have one more piece of factual information to add. After the frustration of not receiving KIAH (real channel 38) for some time, I decided to reposition the antenna again. When I moved it towards a more southerly direction (just about 180 degrees), the signal improved to the point where it was viewable. Unfortunately, all of the other station signals were lost. I have it back to where the majority of stations are ok and KIAH is passable at times. I was surprised by this behavior as I thought all of the towers were in the same location.

ADTech · 7-Jul-2011, 7:11 PM

While the towers are in the same relative location, the signal doesn't always behave the way we want it to. You are likely experiencing what I call "frequency-specific multi-path". That usually means that you are getting an errant reflection off something on or near your line of sight that is interfering with the "primary" signal in a destructive nature.

The solution is to either try a more directional antenna (hoping to reject the reflection) or to move the antenna to a different location (up, down, left right) and try again, hoping that the new location is not bedeviled by the original reflection or a new one.

No static at all · 7-Jul-2011, 7:22 PM

Same exact situation here (With another channel 38 no less) After much experimentation, the best solution was to aim the antenna 25Â° off axis for RF 38 with a rotator.

Tower Guy · 7-Jul-2011, 10:56 PM

Quote:

Originally Posted by jc5000

I have one more piece of factual information to add. After the frustration of not receiving KIAH (real channel 38) for some time, I decided to reposition the antenna again. When I moved it towards a more southerly direction (just about 180 degrees), the signal improved to the point where it was viewable.

That's a classic symptom of an overloaded amplifier. Your signals are too strong for an amplifier anyway. I'd optimize and troubleshoot the system without the amp and the power supply and try to figure out why you thought that you needed it in the first place.