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Old 16-Sep-2014, 7:19 PM   #1
Vorkosigan
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1 Problem Channel

http://www.tvfool.com/?option=com_wr...d2432b80bb6aba

I have 2 antennas mounted in the attic. Typical plywood and shingle roof. An old VHF antenna that was there when I moved in and a simple homemade UHF antenna. The VHF can't be aimed because of it's size and the construction of the attic, but that's ok because it works great. The UHF might have a little play in the direction it's aimed, but not much at all. I would say that it's currently aimed at 300.

There are trees to the SE in my yard, but hardly any trees towards where the antennas are aimed. Quite a few houses down. I am sort of at the bottom of a hill and the hill is on the SW side of the house.

I'm using a UVSJ to combine their signals. From there I am running quad shield RG6 about 30 feet where it splits off to feed the other locations in the house. The longest run from there is no longer than around 50 feet.

I am using the following amp for distribution.
http://www.amazon.com/gp/product/B001EKCGT8/

I am feeding 2 tv's, a Hauppauge 2250 tuner card, and a SiliconDust HDHR4.

The two tv's don't seem to be having any problems. Maybe a bit of pixellation on a couple of channels now and then, but not bad at all.

My problem is that both the 2250 and the HDHR4 are having problems with KFXA. Sometimes it comes in good with some minor pixellation. Other times the signal seems to drop out for a few seconds. Other times it just won't come in at all.

The software fort he 2250 shows a small SNR meter that goes up to 30. With the distribution amp, most channels are at 30 or close to it. KFXA is usually less than that and will drop down to about 23 and then at times it will drop to 0.

The software for the HDHR4 shows Signal Strength, Signal Quality, and Symbol Quality. On most channels Signal Strength shows around 98-100%. Signal Quality is usually around the same with a couple of channels showing between 70 and 80%. Symbol Quality shows 100% most of the time, but does show a drop that coincides with pixellation.

KFXA on the HDHR4 shows a Signal Strength of around 84%. The Signal Quality is usually around 65-80%. Symbol Quality fluxuates a great deal.

I made up another homemade antenna that I could take outside to see if that would make a difference. The signal seemed slightly improved, but the dropouts were still happening. I tried aiming it many different directions.

I am at a loss for what I should try next.
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Old 17-Sep-2014, 5:04 AM   #2
rabbit73
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Quote:
I am sort of at the bottom of a hill and the hill is on the SW side of the house.
Quote:
I made up another homemade antenna that I could take outside to see if that would make a difference. The signal seemed slightly improved, but the dropouts were still happening. I tried aiming it many different directions.
Have you tried aiming the antenna slightly up (upward tilt)?
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Last edited by rabbit73; 17-Sep-2014 at 5:27 AM.
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Old 17-Sep-2014, 1:39 PM   #3
Vorkosigan
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Hey rabbit... I assume you are the same rabbit73 that responded to my thread on AVS.

Yes, I did try it with a slight tilt.
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Old 18-Sep-2014, 11:25 PM   #4
Vorkosigan
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I made up a new antenna based on a link that rabbit posted on AVS. (The 10" x 9 1/2")
http://m4antenna.eastmasonvilleweath...0Drawings.html

I put the antenna outside aimed in the same direction as the antenna in the attic, about 300.

I hooked it up directly to the HDHR4 and checked KFXA. The Signal Strength showed around 50%, sometimes a bit less. Signal Quality was about the same as it is with the attic antenna, but it doesn't seem to move around as much. The Symbol Quality was staying steady at 100%. Seems to be a much more stable signal. However, it's hard to say because the signal seems to be more stable with the attic antenna as well.

I then connected the new antenna directly to the Hauppauge. The SNR shows between 17 and 28. I have not noticed any of the random dropouts. When connected to the attic antenna just before I switched the feed, there were some long dropouts happening.

I checked the other UHF channels and KGAN and KRIN seem to come in ok, but KWKB and KPXR seem to be having problems. I have not tried adding an amp into the equation yet, though.

It would be nice if I could just switch this antenna with the one in the attic, but I don't think this antenna will fit up there.
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Old 19-Sep-2014, 12:12 AM   #5
Vorkosigan
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I put a cheap GE amp I have at the antenna and on the HDHR4 that brought the Signal Strength up to 100%, the Signal Quality up to 98% and the Symbol Quality up to 100% for all of the UHF channels. It didn't affect the numbers much on the Hauppauge, but all of the channels seemed stable.

If the antenna won't fit in the attic, I guess that tells me that I really need to mount an antenna outside and that I need to use a preamp. Is there a problem with using a preamp and a distribution amp? I still need to feed 4 sources currently and I'll be adding another HDHR4 in the near future as well.
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Old 19-Sep-2014, 1:34 AM   #6
Vorkosigan
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That might have been a lot of work for nothing... I went up into the attic and found that one of the V's on the antenna had loosened up and was pointing downward. Doh!

I fixed it and the numbers seem decent for the moment. I'll have to give it a few days to see if the signal stays good.
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Old 19-Sep-2014, 1:57 AM   #7
StephanieS
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Greetings,

KXFA is already in 1-edge conditions and at 38db, while your other major affiliates are in LOS conditions and are right at 50db or stronger.

Combine KXFA's weaker signal and 1-edge situation with an attic install and you are losing quite a bit of signal as it arrives through your roof. I'm not surprised you have some difficulties with it.

I'm glad you seem to have it partially stabilized. Moving the antenna around might help to test if there is a sweet spot.

It goes without saying though, the true solution is to get the antenna outdoors where it can provide the best possible signal reception for you.

Cheers.
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Old 19-Sep-2014, 11:18 PM   #8
Vorkosigan
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I was having issues on all UHF channels today and so I did a bunch of things. I took the second antenna I had made and tweaked it a bit to make it better. This one was able to fit in the attic. I moved it around to a couple of different places and tried with and without an amp up there.

It seemed like it was getting worse the more I tried. Then I realized that the cheap Radioshack transformer I used was coming apart. Luckily I had another one that wasn't from Radioshack that I could switch it out with. I also replaced the coax from the antenna to the UVSJ because I didn't trust that the one I was using was any good.

Currently my setup is the same as it was except that I mounted the second antenna I built in place of the first antenna I built.

KFXA is coming in much better now. Signal Strength of around 90-95% and the the Signal Quality is better and more stable. I haven't noticed any dropouts yet, but I'll need to give it a few days to see if it stays that way.

The funny thing is that now KPXR is the one channel that has issues. Similar to the ones I was having with KFXA. It's not a priority channel, luckily.

Stephanie, I think an outdoor antenna is in my future. However, even if I bought one now, it would be awhile before I had help to install it. I think if there was more room in my attic, a better antenna up there would work just fine.

I am open to suggestions on UHF antennas that would work good for me. I'm thinking one that doesn't need a reflector so that I can pick up KWKB on the back side like I am doing now?
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Old 19-Sep-2014, 11:26 PM   #9
StephanieS
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If mounting outdoors, you don't need a high horsepower antenna. Your signal is pretty good across the board.

A good, inexpensive and easy outdoor setup would be an Antennacraft HBU11k mounted on the included J-pole and orientated to about magnetic 250 or so.

I would expect in a clear unobstructed location (trees, buildings) that the little Antennacraft would be all you'd need.

Cheers.
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