Pass/Reject FiltersBPBR 2/4 / BRBP 2/4

Band-Pass/Band-Reject Filters for the 2m Band

Description

  • The BPBR 2/4… and the BRBP 2/4… are 4-cavity pass-reject filters, which pass one frequency or frequency band and reject another in immediate vicinity of the pass frequency.
  • The filters are delivered in two basic models: The BPBR-types have the reject range on the high side of the pass frequency and the BRBP-types have the reject range situated on the low side of the pass frequency.
  • These filter types can be used to protect a receiver against interference from a nearby transmitter. The filters are tuned to reject the interfering signal. Pass-reject-type filters are applied when the spacing between the utility signal and the interfering signal is so small, that the slope steepness of normal band-pass filters or notch filters are not sufficient enough to provide adequate rejection.
  • These filters are primarily intended to pass and reject two single frequencies, but the filters can also be tuned to pass and reject several single frequencies or to having a certain pass and reject port bandwidth. In these cases, factory-tuning is recommended.
  • Both the BPBR 2/4… and the BRBP 2/4… are delivered in a high-band and a low-band version tunable within 136 - 154 and 152 - 175 MHz, respectively. These models are again divided into submodels, each dedicated to work with a certain spacing between the pass frequency and the reject frequency. See “Ordering information” below.
  • The filter has very small physical dimensions owing to the use of high-Q, temperature compensated helicalresonators.
  • The housing is made of extruded aluminium, the chassis of passivated steel, and teflon insulation has been applied in the rigid coaxial cables and in the connectors.
  • The filter is black vinyl coated to prevent corrosion.

Specifications

Electrical
Model BPBR 2/4 / BRBP 2/4
Filter Type Band-pass / band-reject filters
Frequency 136 - 175 MHz
Max. Input Power 50 W
Pass Band Insertion Loss Single-channel tuned ≤ 1.0 dB
Multi-channel tuned, 1.5 MHz BW ≤ 1.2 dB
Impedance 50 Ω
Pass-Reject Spacing 4 - 10 MHz (see table)
Reject Attenuation Single channel tuned > 90 dB
Multi channel tuned, 1.5 MHz BW > 60 dB
VSWR ≤ 1.5:1
Mechanical
Connection(s) BNC(f)
Dimensions 210 x 104 x 33 mm / 8.26 x 4.09 x 1.29 in.
Weight Approx. 0.6 kg / 1.32 lb.
Environmental
Operating temperature range -30 °C to +60 °C
Frequency Stability Approx. 10 ppm / °C

Diagram and Mounting

TYPICAL RESPONSE CURVES @ 4.5 MHz DUPLEX SPACING

TYPICAL RESPONSE CURVES @ 4.5 MHz DUPLEX SPACING

Ordering Designations

Model Product No. Description Frequency
BPBR 2/4 L-4/6 200001349 SPACING: 4 - 6 MHz 136 - 154 MHz
BRBP 2/4 L-4/6 200001474 SPACING: 4 - 6 MHz 136 - 154 MHz
BPBR 2/4 L-6/8 200001350 SPACING: 6 - 8 MHz 136 - 154 MHz
BRBP 2/4 L-6/8 200001478 SPACING: 6 - 8 MHz 136 - 154 MHz
BPBR 2/4 L-8/10 200001351 SPACING: 8 - 10 MHz 136 - 154 MHz
BRBP 2/4 L-8/10 200001479 SPACING: 8 - 10 MHz 136 - 154 MHz
BPBR 2/4 H-4/6 200001345 SPACING: 4 - 6 MHz 152 -175 MHz
BRBP 2/4 H-4/6 200001468 SPACING: 4 - 6 MHz 152 -175 MHz
BPBR 2/4 H-6/8 200001328 SPACING: 6 - 8 MHz 152 -175 MHz
BRBP 2/4 H-6/8 200001463 SPACING: 6 - 8 MHz 152 -175 MHz
BPBR 2/4 H-8/10 200001337 SPACING: 8 - 10 MHz 152 -175 MHz
BRBP 2/4 H-8/10 200001465 SPACING: 8 - 10 MHz 152 -175 MHz

Typical response curves @ 4.5 MHz Duplex Spacing

BPBR 24 BRBP 24 curve GB

BPBR 24 BRBP 24 curve 2 GB

Ordering Information

If pass and reject frequencies are stated when ordering, the filters are delivered factory-adjusted. Ordering example : BRBP 2/4…, LOW : 149.5 MHz, HIGH : 154.0 MHz. In this case, further information is not required.

When ordering untuned filters please use the model selection table above to select the appropriate ordering designation for the desired filter type.