HDTV Forum

Hello,

I appreciate any help someone may be able to offer for this.

I have a small OTA antenna in my attic, then a run of about 45 feet of coax to my TV input (no splitters).

I get good HD reception with the setup, but I've noticed that I get dropout when any electric motors/devices are turned on in the house. Some cause worse problems then others.

1) Halogen reading lamp (5 ft from TV)...when its turned on I completely lose the HD signal

2) Pencil sharpener in the kitchen (20 feet from TV) when its run, I get severe pixelation and dropout

3) Paper shredder (15 feet away)... same as sharpener


You get the idea. Is this an issue with the power to my TV? Antenna (amplifer built in to antenna). Is this an antenna issue?

Any tips on how to best troubleshoot/resolve it would be appreciated!

Thanks

Hello dscalfano,
Wow, that is a strange problem. Richard may, however, know right away what it is. One thing you could do first is try using the electric items while watching a DVD. Do you still get interference? If not, the problem must be in the antenna cable/connections.

What you have going on is noise on your AC power lines and this typically points to an older house with improper wiring or even a new one. Another facet is using different AC receptacles which also are on different circuits. Every breaker or fuse is considered another circuit in your home so you may have your antenna amp on one circuit and your A/V equipment on another. Grounding could be playing a role...

First step is get rid of complexity, best done by disconnecting everything you don't need to see and receive a picture. In this case we need your antenna, receiver and TV powered while also disconnecting all interconnects to any other products. You want to create a stand alone system of these three components with out any association to anything else. Run your gizmos.

If the problem is gone then you need to reflect on what you have. Are all three components using the same AC outlet? That would seem to indicate that your other equipment may not be, inducing your problem. If they aren't on the same outlet then when you hook up the other stuff that may be inducing a problem so yet again, is this other stuff using different AC outlets?

If the problem remains then again, is the antenna or receiver on a different outlet?

Often times problems like this can be resolved with an AC conditioner that removes the trash from the AC line that your gizmos create when you run them. An example would be a refrigerator that happens to be using the same circuit your A/V equipment is on and typically there is little you can do about that except use an AC conditioner. If you go down this road only buy products that you can return in case they do not resolve your problem and you may very well find if this is the solution that you get better picture and sound even when the gizmos aren't running.

AC Surge/Lightning Suppressors
viewtopic.php?t=3497

Grounding - hum, noise bars, interference
viewtopic.php?t=4470

This next thread goes into great depth about all this stuff with an excellent debate on the whole subject. The key point here is to recognize this stuff and your kind of problem is not as straight forward as one might think hence my direction to you on how to start diagnosing this problem rather then just throwing money and product at it.

AC Power: Conditioners versus Synthesizers
viewtopic.php?t=3488

Guys,

Thanks for the tips so far.

I'll definitely have to do more isolation testing.

What I can tell you is this... the picture is only degraded when watching OTA HD, nothing else is impacted by these devices (digital cable: good, DVD: good). So it would seem to me its related to my antenna input, or the power line to the antenna amp.

The thing I found really strange is the severe degaradation due to the halogen lamp. I wouldn't expect that do induce much power line noise (but I am not expert).

The house is new (6 yrs), but I can tell you I have never been happy with the electrical (primarily the use of 14g wire instead of 12).

Any other tips or ideas are appreciated.

I think I'll try a non-amplified antenna first to see if the problem persists... if the problem is fixed, I've nailed it down at least to the antenna. If so... more work to do

The AC power quality is the single most important element in a well designed A/V or home theater system.

14g is not NEC (National Electrical Code) for for branch circuits - only lighting. I would be shocked (no pun intended, that a 6 year old house would have 14G for branch circuits). I would start out by buying one of those plug in circuit polarity testers and insure that all of your outlets are wired correctly. Electricians get sloppy some times and miswire outlets. You may also want to purchase a voltmeter and actually test the voltages. You may have a bad junction in one of the outlet boxes. In the US today, most VAC can go as high as 120V - 125V or more.

Copper wire has a tendency to "cold flow" and the connections may be loose in the subpanels. Have a licensed electrician do this if you are not completely sure about working with 120VAC (240VAC is often present in subpanels as well). Turn OFF your main electrical service before working on sup panels. You also need a grounding rod for each sub panel and the main panel.

I have a 55 year old house, OTA antenna, my circuits are terribly overloaded, have halogen lamps, dimmers, air compressor and tons of other electronic, electrical gear and have no interference problems (and I also have a ham operator a block away). I have no interference problems with my HD system in the older part of the house.

My new home theater was built from the ground up and I installed a sub panel with more circuits than my entire house. I also upgraded the main electreical service panel to 200A.

Other things I would try are replacing all of the coax with RG-6. Find a good quality coax that has foil and braid shielding. Use crip connectors that screw on. Use waterproof ones in damp locations. Make sure that the coax goes right up to the antenna and the impendence matching transformer is located on the antenna. Insure that all of the "f" type connectors are tight. Also make sure that you don't have a staple through the coax. If you are using couplers replace them with new ones. You should also use have a grounding block. If you don't - get one - if you do replace it. Make sure it is grounded to a cold water pipe but only if your entire plumbing system is copper. If not, you'll have to ground it to the grounding strip in your sub panel. Grounding clamps are available at most hardware stores.

As has been mentioned, insure that the antenna amplifier is on the same circuit as all of your other gear. Try subbing it as well. The signal may be too hot and may need to be attenuated or the amplifier may be defective.

Try moving your noise inducing equipment to other parts of the house on different circuits.

Invest in a minimal, surge protected power conditioning power distribution box. Monster has one at Radio Shack for under $100. If you have had a power surge, like due to lightning, replace it. The atual surge protection devices are typically only good for one shot under those conditions.

'Morning Richard -

Would it not be also be worth a trial to move his antenna outside & eliminate that powered amplifier altogether? The increase ( by avoiding the roof losses ) in gain might make it unnecesary , thereby avoiding any A/C contamination. Of course, if the 6 year old home is actually wired w/ 14 ga, then, there are bound to be additional horrors (code violations) as well, as has been mentioned.
Eli Whitney .... edited @ :28 am to add.....

Just re-read about antenna w/ built-in amp - so, it would require a different antenna, unfortunately. A (p.s.) thought - somewhere in our manual, I believe it was suggested that
an entirely separate power feed & breaker be utilized - whose correct polarity, grounding, etc. could be assured -

Amplifier is part of this antenna so nothing to do there. For the problem he has it is unlikely such a test would make a difference but ya never know...

Ham guys have antenna filters - that's another avenue you might approach. It is a process of elimination.

dscalfano...

Neither of these are 'free', unfortunately. It sounds like a stronger (more gain) signal would certainly be a step in right direction. At www.antennadirect.com among their models, there is a DB-2 for $49 plus a 50' package of their Quad Coax and NO amp, mounted outside, unless you are very close to towers.

If you put in your ZIP code, etc., they'll recommend which would be best fo you, too.

If you are 'comfortable with doing so', I'd run a new 120V 12-2 w/ ground romex directly from the breaker box on a new breaker to serve only that HDTV surge strip. Sounds like you couldn't do any worse than the original contractor !
Eli Whitney

Hi All,

I appreciate all the comments / suggestions.

Last night I replaced the antenna with a different one (the new one also has an amplifier). WIth the new antenna, I get no interference from the halogen light, pencil sharpeners, etc. I noted via the TV that the signal strength is better as well, so I seem to be moving in the right direction.

The new antenna is nothing special either, but seems to be working ok for now. I'll test it for a bit, and if the results aren't satisfactory... I'll take it back and upgrade again.


Regarding the 14g wiring... unfortunately for me, where I live 14g is perfectly up to code. That's what I get for deciding to move out to a more rural area.

Doug