4O3A High Power Band Pass Filters are intended for installation on the output side of a linear amplifier, filtering out harmonics as well as broadband noise from the power amplifier.

All 4O3A bandpass filters are equipped with either UHF Female SO-239 or Type-N coaxial connectors as standard. For specific connector details, please refer to the short description provided for each part number.

Please Note: The photos provided are for representation purposes only and may not accurately reflect the actual product description.

Typical Applications:

• Mitigating intra and inter station interference during contests.

• Protecting receiver circuitry from damage.

• Reducing RFI egress and ingress during everyday operation.

• Enabling full duplex operation (transmitting and receiving simultaneously) on capable transceivers.

• High power handling capability – up to 4,500 Watts ICAS.

• Exceptional out of band rejection, typically > 55 dB and sometimes as high as 75 dB on adjacent ‘contest’ bands thanks to the 5 pole filtering.

To illustrate, the 20m Series XL filter reduces transmitted and received signals on the 40m and 15m bands by approximately 55 dB or more with higher rejection figures on bands further removed from the primary band.

Note: XL Series band pass filters are hand tuned and there are small variances between units.

High Power:

4O3A Bandpass Filters are capable of full legal limit power handling within a 3x safety margin ensures that stations fitted with a linear amplifier can safely place these filters between the linear amplifier and antenna.

Advantages:

First, filtering is in line after final amplification allowing maximum reduction of transmitted broadband noise and harmonic energy.

Secondly, station signal routing and switching is easier, compared to systems that use multiple low-power filters between transceivers and amplifiers in SO2R or multi-op setups, which translates to less complex and more reliable installations. Additionally, straightforward and uncomplicated signal routing systems cost less and will substantially offset an investment in a set of quality XL Series filters. Additional savings comes from only needing one Series XL filter per band available to all station transceivers, whereas other bandpass filter systems require a complete set of filters for each transceiver.

Low Loss:

The XL Series bandpass filters are carefully designed for extreme (0.5 dB is typical) insertion loss 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 and safe operation.

Design:

A few words about bandpass filter specs. First, 55dB is a lot and 75dB is, well, incredible! The 5 pole 4O3A band pass filter designs yield significant additional filtering over its competition.

Cooling:

All XL Series bandpass filters now have 12VDC 40mA cooling fans standard at no extra cost. Typically, additional cooling is not necessary at Amateur power levels, however, transmit duty cycle, ambient room temperature, humidity and antenna SWR all factor into the heat dissipation formula.

Note: the 160m Series XL filter is a 5 pole low pass filter, not band pass.

XL Series Bandpass Filters – Mechanical Design:

Robust components and construction employing 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.

All bandpass filters and combiners are designed for maximum mechanical stability. This is an important aspect because mechanically unstable coils often get deformed, which causes the filter to become detuned.

The coils which are made from hard copper coated wire are the most common mistake in filter design – they are elastic and easily deformed. Each coil in the 4O3A XL Series Bandpass Filters is mechanically supported by three Teflon pillars that keep them mechanically stable. Additionally, each coil is made from special alloy copper tubes, custom created for 4O3A products are then coated in silver to decrease losses.

Simplicity:

Contest stations operating in SO2R (Single Operator / 2 Radio) and multi-operator modes will frequently have dedicated antenna systems for each HF contesting band. Installing 4O3A High Power 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 the transceiver and linear amplifier. Contest stations using Triband antennas to cover 20m, 15m and 10m can use the 4O3A High Power HF Triplexer/Combiner in conjunction with the XL Series Bandpass Filters to operate simultaneously with a high level of isolation on all three bands, with multiple stations sharing the same antenna!

Dimensions:

• 160, 80M Filter Dimension: (WxHxD) 24.41 x 5.91 x 5.91 in. (62 x 15 x 15cm)

• All Other Filters: (WxHxD) 24.41 x 5.91 x 4.33 in. (62 x 15 x 11cm)