TV NOTCH FILTER

Also, " Snooper" & "Bullet"

NOTE: Always have the high side of the coils facing the same direction.

NOTCH FILTER THEORY OF OPERATION

The low frequency version (channel 2 to 6 - 55 MHz to 90 MHz) of this kit has 4 poles. Each pole has approximately 11 to 14 dB of attenuation at the resonant frequency. The high frequency version channels 14 to 22 and channels 7 to 13 (100 MHz to 215 MHz) has 3 poles, each pole has approximately 13 to 18 dB of attenuation at the resonant frequency.

The bandwidth (notchwidth) is approximately 300 to 500 kHz for each pole of either filter design. Since each pole may be adjusted independently the notch depth and width are somewhat variable and adjustable. If all poles of the Filter are set to the same resonant frequency the overall depth will be 45 to 55 dB and the notchwidth will be approximately 0.5 MHz. However, if you set each pole of your filter to a different frequency the overall depth will be approximately 1 5dB and the notchwidth will be 1.0 to 1.5 MHz.

If you want to "trap-out" an unwanted carrier it is normal to adjust all poles to the same frequency. You could "trap-out" a carrier which has been placed within in a TV channel between the color-burst signal and the audio carrier, without any appreciable affect on either of the desired signals. This carrier that you might want to remove normally causes a annoying beeping sound, and causes the picture to be un-watchable. By removing only the unwanted carrier you can restore a good picture.

PARTS LIST

NOTE: The capacitors used in this kit may be disk or monolithic. 
3ea     2.2 pF cer disk cap (2.2, 2R2@ 229)
lea     3.3 -  cer disk cap (3.3, 3R3, 339)
lea     4.7 pF cer disk (4.7, 479, 4R7)
2ea     5.6 pF cer disk cap (5.6, 5P6, 5R6, 569)
2ea     8.2 pF cer disk cap (8.2, 8R2, 829)
2ea     10      pF cer disk     (marked lOD, 100, 10)
2ea     12      pF cer disk     (marked 12 or 120)
2ea     18      pF cer disk     (marked 18 or 180)
2ea     22      pF cer disk     (marked 22 or 220)
2ea     27      pF cer disk     (marked 27 or 270, 27K)
2ea     33      pF cer disk     (marked 33 or 330)
2ea     56      pF cer disk     (marked 56 or 560)
2ea     5 1/2 turn slug tuned coil (alum core) .16 to .24 uH
3ea     3 1/2 turn slug tuned coil (alum core) .06 to .09 uH
lea     2 1/4 turn air coil 5/32" dia.
lea     1 1/2 turn coil 5/32" dia.
2ea     P C mount 'F' connectors
lea     P C board (080-00212A)

SCHEMATICS

CHART OF FREQUENCIES
4 - POLE FILTER FREQUENCIES

 Channel        Video Color           Audio
 2       55.25   58.83   59.75
 3       61.25   64.83   65.75
 4       67.25   70.83   71.25
 5       77.25   80.83   81.75
 6       83.25   86.83   87.75
Bullet 103 MHz to 105.5 MHz Snooper 107.997 MHz

CHART OF FREQUENCIES
3 - POLE FILTER FREQUENCIES

Channel VIDEO   COLOR   AUDIO
7       175.25  178.83  179.75
8       181.25  184.83  185.75
9       187.25  190.83  191.75
10      193 25  196.83  197.75
11      199.25  202.83  203.75
12      205.25  208.83  209.75
13      211 25  214.83  215.75
14      121 25  124.83  125.75
FILTER 
15                      127.25  130.83  131.75
16                      133.25  136.83  137.75
17                      139.25  142.83  143.75
18                      145.25  148.83  149.75
19                      151.25  154.83  155.25
20                      157.25  160.83  161.75
21                      163.25  166.83  167.75
22                      169.25  172.83  173.75

ALIGNMENT

Alignment procedure for removing an unwanted carrier on channels 2 to 6

1. Adjust L1 so the sound starts to clear.
2. Adjust L4 for the best sound the picture the picture should also start to clear.
3. Adjust L2 for the best picture and sound.
Adjust L3 several times, the adjustments are critical and 'touchy' be patient and be careful.

Alignment procedure for removing an unwanted carrier on channels 7 to 22

1. Adjust L1 so the sound starts to clear.
2. Adjust L4 for the best sound the picture.
3. Adjust L2 for the best picture and sound.
4. Repeat steps 1 to 3 several times, the adjustments are critical and 'touchy' be patient and be careful.

Alignment procedure for 'Snooper' and 'Bullet'

The 'Bullet' and 'Snooper’ are best aligned with a sweep generator or spectrum analyzer. You must know the exact frequency that is used on your system, and the filter must be calibrated to that frequency.

BLOCK A CHANNEL

If you want to remove an unwanted channel you would need to use 2 of these filters. One filter would be adjusted to remove the video information and you would use the other filter to remove the audio and color information. most of the video information is contained within a 600 kHz bandwidth, therefore one filter will provide approximately 40 dB of attenuation with a notchwidth of about 600gHz. Typically you will adjust 3 poles of a 4 pole filter or 2 poles of a 3 pole filter for a frequency about l00 kHz above the video frequency of the desired channel and the remaining pole would be adjusted to a frequency approximately 400 MHz higher than the video frequency. (see chart of frequencies for channels 2 to 22).

BULLET; The "BULLET" is a signal used to turn on and off cable services. The signal is used some systems to remotely activate / de activate the premium services supplied by the operator without actually having to go to each location.

Snooper; There is a signal inserted in the cable on some systems that is used to detect cable leaks and unauthorized equipment, to detect this signal you use a device called a Snooper.

PART SELECTION CHART

PART   CHANNEL  CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL CHANNEL BULL
#       2-3     4       5-6     7-8     9-10    11-13   14-16   17-19   20-22   SNOOP
C1      2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2p
C2      33pF    22pF    18pF    8.2pF   8.2pF   5.6pF   18pF    12pF    10pE    27pF
C3      22pF    8.2pF   12pF    5.6pF   4.7pF   4.7pF   4.7pF   3.3pF   2.2pF   8.2p
C4      56pF    56pF    33pF    2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2pF   2.2p
C5      56pF    56pF    33PE    8.2pF   8.2pF   5.6pF   18pF    12pS    10pE    27pF
C6      22pF    8.2pF   12pF    ----    ----    ----    ----    ----    ----    ----
C7      33pF    22pF    18pF    ----    ----    ----    ----    ----    ----    ----
C8      2.2pF   2.2pF   2.2pF   ----    ----    ----    ----    ----    ----    ----
L1      3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3-5Turn 3.5Turn 3.5Turn 3.5Turn 3.5T
L2      5.5Turn 5.5Turn 5.5Turn 5.5Turn 5.5Turn 5-5Turn 5.5Turn 5.5Turn 5.5Turn 5.5T
L3      5.5Turn 5.5Turn 5.5Turn 2 1/4 A 2 1/4 A 1 1/2 A 2 1/4 A 2 1/4 A 2 1/4 A 2 1/4A
L4      3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5Turn 3.5T
J1 & J2 ----- INSERT AND SOLDER J1 & J2 IN PRINTED CIRCUIT BOARD -----

* NOTE: L3...Some coils inL3 location are marked 2 1/4 A or 1 1/2 A this indicates a wire wound air coil 5/32" dia. made with enameled wire.

* **** All capacitors and coils must be inserted into printed circuit board so the body touches the PC board with very short leads.

* **** INSERT ALL PARTS ON FIBER SIDE AND SOLDER ON SILVER SIDE
 

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