The PDC 1089 was a TVI filter to attenuate harmonics generated by CB or Ham transceivers. The 1089 consisted of a PI network of capacitor and air-core inductors. Capacitor values of 47pf and 150pf at 6KV ratings.
The Para Dynamics PDC 1089 works through the filtering or attenuating of frequencies above the transmitter output frequencies. These frequencies are commonly known as harmonics (whereas the original transmitted frequency is the fundamental) that are created by the transmitter often times due to ineffecient grounding of the station and or possiblities of radio modifications to boost modulation.
Typically, these harmonics can interfere with other audio/video electronic equipment. The PDC 1089 was designed to help eliminate these harmonics before they reach your antenna. The 1089 filter works best closer to the transmitter output, and if necessary a second filter can be used closer to the transmitting antenna. It is recommended to ground the PDC 1089 as well as all your radio gear.
The Para Dynamics PDC 1089 works through the filtering or attenuating of frequencies above the transmitter output frequencies. These frequencies are commonly known as harmonics (whereas the original transmitted frequency is the fundamental) that are created by the transmitter often times due to ineffecient grounding of the station and or possiblities of radio modifications to boost modulation.
Typically, these harmonics can interfere with other audio/video electronic equipment. The PDC 1089 was designed to help eliminate these harmonics before they reach your antenna. The 1089 filter works best closer to the transmitter output, and if necessary a second filter can be used closer to the transmitting antenna. It is recommended to ground the PDC 1089 as well as all your radio gear.
The 1089 would handle 1000 watts PEP (50% duty cycle) and about 250 watts continuous.
The attenuation was as follows:
The attenuation was as follows:
42.17MHz (color IF) -25dB |
45.75MHz (video IF) -25dB |
55.25MHz (ch. 2 vid) -.50dB |
loss @ 27MHz -.13dB |
Reflection @27MHz -18db |
Curve @27MHz -28dB |
Insertion Loss
1.8MHz | -.18dB |
14.3MHz | -.05dB |
7MHz | -.03dB |
30MHz | -.13dB |
As you can see by the table the area around 7MHz seems to have the lowest insertion loss point. Further tuning of the coils can help with harmonic attenuation while decreasing insertion loss to the circuit.
The PDC 1089 has about -50 - 55dB attenuation for channel 2 video.
PDC 1089 Schematic
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