Contest stations operating in SO2R and multi-operator configurations will frequently have dedicated antenna systems for each HF contesting band.  Installing Series XL bandpass filters in the antenna line after the linear amplifier and antenna switch means the right filter will always be in circuit on the band/antenna combination in use and the operator will never have to worry about switching filters between transceiver and linear amplifier.

  • Designed to be installed between the linear amplifier and antenna, filtering out not only harmonics but also broadband PA noise
  • Mitigates intra- and inter-station interference during contests and protect receiver circuitry from damage
  • Reduces RFI egress and ingress during everyday operation
  • Enables full-duplex operation (transmitting and receiving simultaneously) on capable transceivers such as the FlexRadio 6000 Series
  • High power handling capability: 4.5 kW ICAS (vs. 100 to 200 W for the other guys), full legal amateur power with a 3x safety margin
  • High power handling means that the BPFs can be placed between the linear amplifier and antenna
  • Filtering is in line after final amplification allowing maximum reduction of transmitted broadband noise and harmonic energy
  • Station signal routing and switching are greatly simplified vis-a-vis systems that switch low power filters (multiple sets in an SO2R or multi-op configuration) inline between transceivers and amplifiers; less complex means more reliable
  • Simpler signal routing systems cost less and will substantially offset an investment in a set of Series XL filters; additional expense offset comes from needing only one Series XL BPF per band available to all station transceivers whereas other BPF systems require a complete set of BPF for each transceiver
  • Contest stations operating in SO2R and multi-operator modes will frequently have dedicated antenna systems for each HF contesting band. Installing 4O3A Higher Power Band Pass Filters in the antenna line after the linear amplifier and antenna switch means the right filter will always be in circuit on the band/antenna combination in use and the operator will never have to worry about switching filters between transceiver and linear amplifier
  • Exceptional out of band rejection, typically > 55 dB and sometimes as high as 75 dB on adjacent 'contest' bands thanks to the five pole filtering (vs. three poles typical elsewhere); for example, the 20 meter Series XL BPF reduces transmitted and received signals on the 40 and 15 meter bands by approximately 55 dB with higher rejection figures on bands further removed from the primary band.  Series XL filters are hand tuned, thus there are small variances between units)
  • Carefully designed for low insertion loss (0.55 dB or less is typical) to avoid overheating and power loss.
  • Balance between each of the five poles of the filter is carefully engineered using high-quality high-voltage components to ensure many years of reliable, safe operation.
  • All Series XL BPFs now come with 12 VDC 40ma cooling fans standard, generally, no additional cooling is needed at amateur power levels, however, transmit duty cycle, ambient room temperature, humidity, and antenna VSWR all factor into the heat dissipation formula, see the Power Derating chart below for guidance on VSWR related power capability
  • Robust components and construction includes silver-plated high-Q coils, high-current military grade capacitors, and heavy-duty aluminum enclosures with mounting flanges for secure installation on your bulkhead system or elsewhere in your shack
  • Note: the 160m Series XL filter is a five pole LPF (low pass filter), not a BPF
  • All 4O3A devices come standard with SO-239 (UHF) female coax connectors with N and 7/16 DIN connectors available on special order - please contract us for more information
  • Oversize shipping rates are applied to this item in shopping cart

4O3A Series XL bandpass filter - 1.8 MHz

4O3A Series XL bandpass filter - 3.5 MHz

4O3A Series XL bandpass filter - 7 MHz

4O3A Series XL bandpass filter - 10 MHz

4O3A Series XL bandpass filter - 14 MHz

4O3A Series XL bandpass filter - 18 MHz

4O3A Series XL bandpass filter - 21 MHz

4O3A Series XL bandpass filter - 24 MHz

4O3A Series XL bandpass filter - 28 MHz

4O3A Series XL bandpass filter - 50 MHz

"With the 4O3A filters our station to station and site to site interaction was negligible across 83,300+ QSO's.  We ran six stations 24/7, and I don't recall ever seeing a station not manned.  The only time anything was heard was on the exact harmonic and just tuning 5 kHz off that frequency to set the split allowed operation to continue with no impact." - Jay, W2IJ, T33A DXpedition team

"It is indeed a good feeling when you transmit on one band and can listen even to the weakest signals on the other band, without getting annoyed by the interference." - Ivo, 5B4ADA

4O3A BPFs made the trip to T33A, were used on the highly successful FT5ZM DXpedition, and were on board for the recent TX3X and VP8STI / VP8SGI operations. Some of the well-known contesters and DXers who are using 4O3A Signature gear include 5B4ADA, 5B4AGD, 9A1A, 9A1P, 9A5MT, A71CO, AA7XT, CR2X, CX6VM, DJ5MW, DJ6ZM, DK5QN, DL2ARD, DL4NER, DL8ZAW, DR1A, E73A, EA2AFL, EA5FX, EA7AEY, ED1R, EF8M, EI2FG, EI7M, ES5TV, HA1TJ, HA5JI, HB9BJL, JA1BPA, JE1CKA, JF2QNM, JK1MZT, K3LR, K3WW, LA6FJA, LP1H, LU8EOT, LX2A, LZ2BE, LZ9W, N6PEQ, OH2BH, OH6RX, OH8X, ON4AMX, ON4HIL, OZ5E, P49X, PI4DX, PJ2T, PY2ADR, PY5EG, S50A, S50K, S51TA, S52X, S53M, UA3AB, W0YK, WW4LL, WX3B, YO3JR, YU1EXY, YU1EW, YU5R, and many more.