FM Filter Graphs
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Graph 1: CATV Wide FM Bandpass ( 90-108 MHz, reject ch.6)
Graph 2: Antenna System FM bandpass (general purpose)
Graph 3: Narrow FM bandpass Filters
Graph 4: Sharp FM Notch (3 dB BW ± .5 MHz)
Graph 5: Ultrasharp FM Notch (3 dB BW ± 0.15 MHz)
Graph 6 .......Antenna System FM Bandstop ( 40 dB Attenuation)
Return to FM Products
Graph 1: Wide FM Bandpass - BP7-FM/6: (Pass FM, reject ch. 6)
Frequency response of model BP7-FM/6
- Allows FM carriers from 90 -108 MHz to pass. Passband Loss: < 2 dB. Band-edge loss: < 4dB at 90 MHz and <3dB at 108 MHz.
- Stopband Attenuation: >40 dB on ch.6, >50 dB from 5 to 83 MHz and 115 to 750 MHz.
BP7-FM/6: ( Pass FM, reject ch. 6)
| Mkr | Freq (MHz) | Attn (dB) |
| 1 | 90.000 | -3.845 |
| 2 | 108.000 | -2.337 |
| 3 | 83.250, 6 pix | -47.301 |
| 4 | 87.750, 6 snd | -52.273 |
| 5 | 115.000 | -54.687 |
| 6 | 99.000 | -1.606 |
Order as: model BP7-FM/6, or BP7-FM
Graph 2: Antenna FM Bandpass - CF7-FM
CF7-FM - master antenna system bandpass
- Designed to allow reception of FM band
- Passband Loss: <1.5 dB
- Stopband : >30 dB from ± 6 MHz
- Non-adjacent operation (pass ch.6)
- Use to block TV signals from FM antenna
Antenna FM Bandpass - CF7-FM
| Transmission | Return Loss | |||
| Mkr | Freq (MHz) | Attn (dB) | Freq (MHz) | Attn (dB) |
| 1 | 88.000 | -1.269 | 88.000 | -21.577 |
| 2 | 108.000 | -1.269 | 108.000 | -24.351 |
| 3 | 82.000 | -33.632 | - | - |
| 4 | 115.000 | -33.318 | - | - |
| 5 | 99.000 | -0.759 | - | - |
Order as: model CF7-FM (indoor), or CF7X-FM (outdoor)
Graph 3: Narrow FM Bandpass - NF7-FM-HQ and VF7-FM (Tunable)
NF7-88-HQ
- NF7-88-HQ allows only carrier at 88 MHz to pass. Passband: < 1 MHz (± .5 MHz Fc)
- Attenuation >20 dB at frequencies ± 1.5 MHz Fc (see Mkr 2 & 3), >30 dB ± 3 MHz Fc
- Factory retunable to any FM frequency
* Frequency span of NF7-88 HQ graph is 6 MHz
| Mkr | Freq (MHz) | Attn (dB) |
| 1 Fc | 88 | -2.67 |
| 2 | 86.5 | -20.61 |
| 3 | 89.5 | -20.34 |
VF7-FM
- VF7-FM pre-tuned to pass 100 MHz
- Attenuation > 20dB at frequencies 3 MHz Fc (see Mkr 2 & 3)
- Passband tunable from 88 to 108 MHz
- Model NF7-FM is similar, except, frequency fixed and is trap enhanced at ± 3 MHz Fc for greater attenuation.
* Frequency span of VF7-FM graph is 20 MHz
| Mkr | Freq (MHz) | Attn (dB) |
| 1 Fc | 100.000 | -3.062 |
| 2 | 97.000 | -26.151 |
| 3 | 103.000 | -25.380 |
| 4 | 93.000 | -41.621 |
| 5 | 108.000 | -41.267 |
Order as:
- NF7-(Fc) HQ Fixed Bandpass - < 1MHz passband: Specify Fc (88 to 108 MHz)
- NF7-(Fc) - Fixed Bandpass - < 2 MHz passband: Specify Fc (88 to 108 MHz)
- VF7-(Fc) - Tunable Bandpass < 2 MHz passband: Specify Fc (88 to 108 MHz)
Example: NF7-100 HQ (Fixed FM bandpass, Fc at 100 MHz, < 1 MHz passband)
Sharp (HQ) Notch: FM Trap: Graph : CR7-HQ 88.3 (25)
- Graph depicts FM notch with >25dB rejection at 88.3 MHz (Fc)
- Used to reject FM interference on TV ch.6
- 3dB Bandwidth is ± .5 MHz (Mkr 2 & 3)
- Passband (not shown) is 10 to 860 MHz
- Traps 88.3 MHz with low impact on ch.6 audio ( 87.75 MHz - Mkr 2)
- Prevents 88.3 carrier from affecting ch.6
Graph : CR7-HQ 88.3 (25)
| Mkr | Freq (MHz) | Attn (dB) |
| 1 Fc | 88.300 | -36.55 |
| 2 | 87.750 | -2.37 |
| 3 | 88.800 | -2.73 |
| 4 | 87.300 | -1.03 |
| 5 | 89.300 | -0.87 |
Order as:
- CR7-(Fc) HQ (25): Frequency fixed, 25 dB attenuation, 3 dB BW = ± .5 MHz*
- CR7-(Fc) HQ: Frequency fixed, > 50 dB attenuation, 3 dB BW = ± 1.25 MHz*
- VR7-(Fc) HQ: Frequency tunable, > 40 dB attenuation, 3 dB BW = ± 1.5 MHz*
* Specify Fc. Fc = any frequency between 88 to 108 MHz
Graph 5: Ultrasharp FM Notch: CR7-HQT
CR7-HQT 99 - FM system notch
- Graph depicts FM notch with >30dB rejection at 99 MHz (Fc)
- Used to reject FM interference on any adjacents
- 3dB Bandwidth is ± .15 MHz (Mkr 2 & 3)
- Passband (not shown) is 40 to 250 MHz
Graph : CR7-HQT 99
| Mkr | Freq | Attn |
| 1 | 99.000 | -34.392 |
| 2 | 98.900 | -3.465 |
| 3 | 99.100 | -3.622 |
Antenna FM Bandstop: Model CR7-FM
CR7-FMU-40 non-adjacent antenna FM bandstop
- Stopband: > 40 dB (88 to 108 MHz)
- Passband: 5 to 82 MHz, 115 to 900 MHz
- Non-adjacent operation (attenuates ch.6)
- Stopband can be shifted so that passband includes ch.6. Ex: CR7-FM (92-108 MHz)
Model CR7-FM
| Mkr | Freq (MHz) | Attn (dB) |
| 1 | 88.000 | -51.303 |
| 2 | 108.000 | -44.464 |
| 3 | 82.00 | -2.414 |
| 4 | 115.00 | -2.622 |
CR7-FM (indoor), or, CR7X-FM (outdoor)
- Specify Attenuation: 20 or 30dB or custom attenuation: from 15 to 45 dB
- Specify passband: VHF (40-220 MHz) standard, Affix "U" for UHF pass
- Example: CR7X-FMU-20 (20 dB FM trap - outdoor UHF signal pass)