Poor television reception

[[email protected]]

A couple of months ago, I installed a new Terk TV38 antenna, an antenna
rotator and new coax cables. But the reception is very poor for most
of the channels, even when I rotate the antenna thru the entire 360
degrees.

All of the connections from the antenna to the TV are good.
I've even run a new coax cable directly from the antenna to the TV.
But the reception is still poor.

(I have two TV sets and both get bad reception so the TVs are NOT the
problem).

My house is in Riverside, CA (about 60 miles east of Los Angeles).
Almost all of the stations broadcast from transmitters on Mt. Wilson
(49 miles northwest of my house).

On a scale of "1" (extremely snowy picture and very garbled sound)
to "10" (crystal-clear picture and sound), here are the
"reception"-ratings for the channels I watch:

Channel Rating
2 3
4 4
5 3
7 7
9 8
11 4
13 6
24 2
28 7
56 8
58 8

Any suggestions?

 

[Ken Weitzel]

A couple of months ago, I installed a new Terk TV38 antenna, an antenna
rotator and new coax cables. But the reception is very poor for most
of the channels, even when I rotate the antenna thru the entire 360
degrees.

All of the connections from the antenna to the TV are good.
I've even run a new coax cable directly from the antenna to the TV.
But the reception is still poor.

(I have two TV sets and both get bad reception so the TVs are NOT the
problem).

My house is in Riverside, CA (about 60 miles east of Los Angeles).
Almost all of the stations broadcast from transmitters on Mt. Wilson
(49 miles northwest of my house).

On a scale of "1" (extremely snowy picture and very garbled sound)
to "10" (crystal-clear picture and sound), here are the
"reception"-ratings for the channels I watch:

Channel Rating
2 3
4 4
5 3
7 7
9 8
11 4
13 6
24 2
28 7
56 8
58 8

Any suggestions?

Hi...

Wrong cable impedance? (59/75/300, etc)

Don't know the antenna, but no balun at the head end?

Ken

 

[[email protected]]

What is a "balun"?
What is the "head end"?

 

[Ken Weitzel]

What is a "balun"?
What is the "head end"?

Hi...

Balun is silly talk for balanced/unbalanced... the little
transformer that connects the 300 ohm antenna to the (hopefully)
75 ohm coax.

The head end is silly talk for the antenna proper...

Ken

 

[[email protected]]

The antenna has a 300-ohm matching transformer to which is attached the
75-ohm round coax cable.

 

[Art]

Sounds like you need a better antennea with preamp installed professionally.
A deep fringe antenna should do a work.

 

[[email protected]]

Hi, Art:

According to the support-people at Terk (the manufacturer of the
antenna) "The TV38 is more than enough antenna for where you are".

The coax cable runs from the antenna to an antenna amplifier (about 20'
away) then out to the TV.

Gary

 

[Mark]

are there hills or mountains in the 50 mile path to Mt Wilson?

what kind of reception do your neighbors get and what kind of ant are
they using?

what kind of reception do you get with the rabbit ears?

How is your FM radio reception from Mt Wilson in the car or at home?

Mark

 

[Deke]

The antenna has a 300-ohm matching transformer to which is attached the
75-ohm round coax cable.

First, replace the 300-ohm transformer. Half of the baluns that come in
antenna kits these days are bad (Channel Master, Jerrold, Winegard...rotten
quality baluns)
Second, bypass the amp. If signal/picture improves, the amp is toast. You
can get 75 0hm barrels at Rat Shack, or any electropnics store.
Third, if you wired the cabling up, make sure you havent shorted out the
coax connector. Check all coax connectors. LOOK CLOSELY! One tiny strand
of wire, between the center (copper) conductor, and the wire mesh shield,
and its toast, and everything goes to hell. If someone else wired it up, or
you bought it refab, check the connectors anyway.
Fourth, if you have a small, portable television, and a long extension cord,
take it up and hook it directly to the antenna, and see how much snow you
have.
Fifth, how is the cabling run? Has some moron put a staple thru it?
Staples will not only kill your signal, but they could short out the power
to the amp, and blow up the power supply.
Sixth, is the amp a two piece unit? If so, is the power supply, usually
down in the house, plugged in?
Seventh, take the Terk back, and buy a real antenna.

 

[[email protected]]

Here is a homemade balun page link...

http://users.tns.net/~bb/balun.htm

It gives you an idea. Try looking up more on baluns on google.

 

[Franc Zabkar]

Hi, Art:

According to the support-people at Terk (the manufacturer of the
antenna) "The TV38 is more than enough antenna for where you are".

The coax cable runs from the antenna to an antenna amplifier (about 20'
away) then out to the TV.

Gary

The best location for a masthead amp is on the mast. ;-)


- Franc Zabkar

 

[NSM]

The best location for a masthead amp is on the mast. ;-)

How much do you lose in 20' though?

 

[Franc Zabkar]

How much do you lose in 20' though?

http://www.epanorama.net/documents/video/videocoax.html

Attenuation data for RG-59 B/U:

MHz dB/100 feet
----- -----------
1 .6
10 1.1
50 2.4
100 3.4
200 4.9
400 7.0
700 9.7
900 11.1
1000 12.0

At 500MHz the attenuation is about 8dB/100'. Over 20' there would be a
1.6dB loss. This doesn't sound like much, but in my case a 3dB loss
means the difference between an excellent picture and an unwatchable
one. This 3dB loss results when I try to add a second TV to an
unamplified antenna feed via a 2-way splitter.

In any case, the question has to be asked, if the loss is
insignificant, then why aren't all antenna amps installed behind the
TV, or under the roof away from the weather?


- Franc Zabkar

 

[NSM]

In any case, the question has to be asked, if the loss is
insignificant, then why aren't all antenna amps installed behind the
TV, or under the roof away from the weather?

Cos you're in Oz mate, not in the US. Sometimes people have to put the
antenna on a mountain 2000 feet away. Other times you have to snake cable
down 300 feet of wiring closet in some building. You have to choose the way
to do the job.

 

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You can cut those losses in half with Belden 1694.
Freq MHz loss dB/100'
1 0.24
3.58 0.45
5 0.54
10 0.72
100 1.84
540 4.25
750 5.00
1000 5.89
1500 7.33
2000 8.57
2250 9.14
3000 10.67
This is a partial copy from the Belden catalog.

If there are no mountains blocking the line of sight path, 50 miles
shouldn't be a problem for a good antenna. Personally I'm partial to
Winegard units. For 50 miles I'd use an amplifier directly on the
biggest antenna I can install/afford to boost before the cable losses.
The 1694 was the lowest loss cable I found in RG-6 size. I use it for
my OTA HDTV. I'm only 35 miles out so I can use the SquareShooter (DTV
is all UHF in LA).
GG