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Old 19-Jun-2016, 5:04 PM   #1
RCBOB
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Phoenix OTA problems??

Recently I have been having problems with receiving Channel 45-1 to 45-3 (KUTP) and Channel 15-1 to 15-3 (KNXV-ABC). At times they would come in poor as the pixels are scramble. I don't know if it's the weather (heat) that is causing this or the stations having xmtr problems. I have no other problems with the other channels that i'm aware of.
Anyone in PHX having this problem??
Or can someone give me answer to what may be the problem??
Bob

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Old 19-Jun-2016, 7:42 PM   #2
rabbit73
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Hi, Bob:

The first thing I see is that mountain in the signal path.

KUTP
http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d5

KNXV
http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d6

Quote:
I don't know if it's the weather (heat) that is causing this or the stations having xmtr problems.
Temperature inversion can affect the signals on their way to your location, by keeping them from bending down by refraction toward your location after crossing the peak. Is it worse during the day?

The affect can vary according to the frequency of the channel.

What antenna are you using and where is it located?

Are you using a preamp?

Any trees in the signal path?
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Last edited by rabbit73; 19-Jun-2016 at 7:44 PM.
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Old 19-Jun-2016, 8:00 PM   #3
RCBOB
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Quote:
Originally Posted by rabbit73 View Post
Hi, Bob:

The first thing I see is that mountain in the signal path.

KUTP
http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d5

KNXV
http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d6

Temperature inversion can affect the signals on their way to your location, by keeping them from bending down by refraction toward your location after crossing the peak. Is it worse during the day?

The affect can vary according to the frequency of the channel.

What antenna are you using and where is it located?

Are you using a preamp?

Any trees in the signal path?
The antenna I have is a CM QUANTUM 1165A about 25 ft high with no trees and yes a mtn is not to far away. I do have a preamp hook up.
When I first tried out this antenna in the cool weather I could not get channel 15. I had to raise the antenna 3-4 ft in order to get it.
In the cool wx the stations come in great.
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Old 19-Jun-2016, 8:03 PM   #4
RCBOB
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The antenna I have is a CM QUANTUM 1165A about 25 ft high with no trees and yes a mtn is not to far away. I do have a preamp hook up.
When I first tried out this antenna in the cool weather I could not get channel 15. I had to raise the antenna 3-4 ft in order to get it.
In the cool wx the stations come in great.
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Old 19-Jun-2016, 8:09 PM   #5
rabbit73
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This what the terrain profile looks like using a different software:



scroll half way down this page to the Example of a path profile diagram and you will see how refraction bends the signal down
http://www.mike-willis.com/Tutorial/PF6.htm

If there is a temperature inversion in the bowl between the transmitter and the peak, the signal can get trapped in a high altitude duct and not be able to bend down to your antenna. Scroll down to An illustration of a high-altitude tropospheric duct.
http://www.dxfm.com/content/propagation.htm

The only thing I can think of at this time would be to tilt the front end of the antenna up to better catch the signal coming over the peak. However, if the antenna is old, it might not be performing as well as when it was new.
Attached Images
File Type: jpg RCBOBTVFp2KNXV.JPG (98.1 KB, 711 views)
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Last edited by rabbit73; 19-Jun-2016 at 11:19 PM.
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Old 19-Jun-2016, 8:33 PM   #6
RCBOB
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Just got on the TV and both channel 15 & 45 are solid as a rock right now. Temp.@115 in the shade. I guess I should add a few more feet??
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Old 19-Jun-2016, 11:04 PM   #7
rabbit73
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It might help. OTA signals constantly vary in strength. You don't seem to have enough Fade Margin to allow to allow for that; you are right on the edge of the "Digital Cliff."



I found the 1165B in the CM 1990 Catalog, so your antenna must be even older.



The 1165B looks like it has a high gain UHF section. I don't know what the difference is between the 1165A and 1165B.

What preamp are you using?
Attached Images
File Type: jpg CM Quantum 1160-65 1990.JPG (98.6 KB, 973 views)
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Last edited by rabbit73; 19-Jun-2016 at 11:14 PM.
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Old 19-Jun-2016, 11:38 PM   #8
rabbit73
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If you want to ask other guys in your area about reception, go to the AVS Forum Local Reception Thread for Phoenix:

Local Reception Master Thread
http://www.avsforum.com/forum/45-loc...nfo-reception/

Instructions
http://www.avsforum.com/forum/45-loc...e-posting.html

Thread Index by Location
http://www.avsforum.com/forum/45-loc...read-here.html

Phoenix thread
http://www.avsforum.com/forum/45-loc...l#post44667425
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Old 19-Jul-2016, 10:36 PM   #9
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That Quantum 1165 has to be more than 20 years old, and the sun has probably taken it's toll on than antenna. You might want to consider using a dual antenna system with a High band VHF yagi, like a AntennaCraft Y5713 and a High gain UHF antenna like an XG-91 antenna from AntennasDirect. Join the two antennas on the same mast, separated by at least 3 feet, using a UVSJ antenna joiner. I think that you'll see a difference in your reception immediately.
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Old 20-Jul-2016, 3:56 PM   #10
RCBOB
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Quote:
Originally Posted by Tigerbangs View Post
That Quantum 1165 has to be more than 20 years old, and the sun has probably taken it's toll on than antenna. You might want to consider using a dual antenna system with a High band VHF yagi, like a AntennaCraft Y5713 and a High gain UHF antenna like an XG-91 antenna from AntennasDirect. Join the two antennas on the same mast, separated by at least 3 feet, using a UVSJ antenna joiner. I think that you'll see a difference in your reception immediately.
We will consider that. I did some repairs on the elements as the doves love it. Have to wait for the cool weather for any changes to be made. Thanks for info.
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Old 20-Jul-2016, 6:32 PM   #11
analogqueen
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I too am in Phoenix and we get a LOT of multipath interference. If a helicopter or small plane goes by... there goes the picture. As I posted today on another thread, one channel went out completely and I spotted a sparrow perched on the horizontal arm of the VHF portion of the antenna. Mine is also 30ft high just like the OP's.

PS- off topic, but about a month ago I turned on TV to no picture- went outside to check antenna and it was GONE- turns out, the manager of the HOA in this gulag- er, "condo complex" took it upon himself to use his man-lift operator to REMOVE my antenna about a month ago, no note, no nothing- no warning! Can you imagine?? I marched right down steaming mad, manager put on fake smile, said he's trying to "improve" the looks of this sh__hole. I advised him of the OTARD federal law, etc- he gets nervous and says oh oh we'll work with you! How bout we put it on the roof?? I got my antenna back, waited a week to cool off - and I have it right back up where it was. I A) should have called the police at first (this is a note to anyone else this happens to- don't hesitate, call the police, don't let the police wave you off, this is burglary and trespass, demand the report be taken as it stands) and B) the fact I am renting, if a landlord removes ANY property from YOUR area (a balcony IS a private area) you are entitled to TWO MONTHS rent in punitive damages, this is Arizona tenant/landlord law I believe in pg 16 of the law pdf)

I was dumb to be "cool" about it and not "make waves". Demand your rights, if you are a renter do NOT! let landlords or whomever dictate how, what, why and where your antenna is- as long as it is not installed on their wall, put it on your own stand or what have you- they have zero say in it. You can install a small dish, any kind of TV antenna and they can't tell you where to put it, or anything- they can recommend where to place it, but if you go along with them they can't make you have to hire an installer, or go up on a hot 120F roof, or make you install it someplace where you get LESS reception.

Anyway, off topic I know, but it might help someone else along the way.
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