4O3A SERIES XL (4,500W) POWER BAND-PASS FILTERS
Official Distribution and Import by HamRadioShop Italy
OUR PASSION AT YOUR SERVICE: 4O3A OFFICIAL DEALER
It is with sincere enthusiasm that we share a new milestone with you: HamRadioShop becomes the official reference point in Italy for the prestigious 4O3A brand. For us, it is not just a commercial agreement, but a commitment to bring the technological excellence we have always admired to your stations.
THE NERVE CENTER OF HIGH-POWER RF MANAGEMENT
The 4O3A Series XL band-pass filters are designed to be the fundamental pillar of RF management in top-level contest and DX stations. Unlike traditional filters operating at low signal levels, the Series XL are dimensioned to withstand heavy loads up to **4,500W ICAS** and are to be installed directly on the output line of the linear amplifier. This strategic configuration allows not only for the reduction of canonical harmonics but also the broadband noise generated by the amplification stage itself.
STRATEGIC APPLICATIONS IN THE STATION
-- MULTI-STATION CONFIGURATIONS
Drastic and systematic reduction of intra-station and inter-station interference during crowded contests or with teams operating simultaneously.
-- RECEIVER SHIELDING AND PROTECTION
Total isolation of the sensitive input circuits of your receivers against the concrete risk of permanent damage caused by strong adjacent RF fields.
-- DAILY OPERATIONS
Drastic reduction of intermodulation phenomena, both incoming and outgoing, clearing the spectrum of extraneous mutual interference.
-- FULL DUPLEX OPERATION
Allow perfectly simultaneous transmission and reception on different bands if the station's equipment architecture is predisposed.
SIGNAL ENGINEERING: 5-POLE TOPOLOGY
Where standard filters on the market (such as classic W3NQN or 3-pole modules) typically stop at around 40 dB of rejection, the sophisticated **5-pole architecture** developed by 4O3A guarantees uncompromising performance:
- Typical rejection greater than 55 dB, with attenuation peaks reaching **75 dB** on geographically or spectrally adjacent contest bands.
- Dynamic Example: The Series XL filter dedicated to the 20-meter band attenuates signals on the 40m and 15m bands by more than 55 dB, increasing the protection factor as one moves away from the center band frequency.
- Certified Calibration: Each individual unit is manually tuned in the laboratory by 4O3A technicians. The actual performance of each filter is validated and documented through precise VNA (Vector Network Analyzer) instrumental graphs.
OPERATIONAL AND ECONOMIC ADVANTAGES
• Streamlined Cabling: Compared to cumbersome and delicate low-power matrices requiring multiple sets of switched filters in SO2R configuration before amplifiers, the Series XL works directly in-line downstream of the PA, drastically simplifying signal routing.
• Long-Term Reliability: Fewer coaxial switches, fewer switching relays, and fewer patch cables mathematically translate into a drastic reduction of potential failure points (improved MTBF).
• Investment Optimization: Installing just one Series XL filter for each operating band is sufficient to make it available to all transceivers in the co-located station, eliminating the need to purchase expensive complete sets dedicated to each individual radio.
CONSTRUCTION ARCHITECTURE AND DISSIPATION
The materials and active thermal management are calculated to keep inductance and capacitance parameters stable even under prolonged use:
| Active Cooling | Standard integrated fans powered by 12V DC (40mA). Essential for keeping filters stable during intense high-duty-cycle contests or in the presence of impedance mismatches (SWR). |
| Insertion Loss | Extraordinarily low values (typical attenuation of just **0.5 dB**). Minimizes internal heat generation and maximizes useful power transferred to the antenna. |
| Premium Materials | High-Q coils made of special copper tubing with **pure silver plating**. Each element is firmly anchored on solid **Teflon support pillars** to prevent any geometric deformation or thermal drift. |
ADVANCED TECHNICAL SPECIFICATIONS
- Power Handling Capacity: Up to **4,500 Watts ICAS** (smaller variants of 100W and 200W are also available for standard uses).
- Structural Safety Margin: Engineered to tolerate up to 3 times the maximum legal power allowed in amateur radio.
- Connectivity: Equipped as standard with robust SO-239 (UHF) connectors. N or DIN 7/16" type interfaces can be ordered upon specific request.
-
Dimensional Development:
- Models for 160m and 80m bands: 62 x 15 x 15 cm.
- Models for all other bands: 62 x 15 x 11 cm.
- 160m Band Engineering: For obvious reasons of spectral purity and harmonic optimization in the Top Band, the specific model for 160 meters adopts a **5-pole low-pass** topology, ensuring maximum attenuation of higher frequencies.
TYPICAL INSTRUMENTAL MEASUREMENTS (WORST CASE)
The values reported below indicate the minimum guaranteed performance under the most critical and demanding working conditions:
CLASSIC HF BANDS & 6 METERS
| BAND | Insertion Loss (dB) | Input Match (dB) | Upper Band Rejection | Lower Band Rejection |
|---|---|---|---|---|
| 160 m | ≤ 0.35 | ≥ 20 | ≥ 60 dB | N / A (Low-Pass) |
| 80 m | ≤ 0.47 | ≥ 22 | ≥ 51 dB | ≥ 52 dB |
| 40 m | ≤ 0.42 | ≥ 23 | ≥ 56 dB | ≥ 56 dB |
| 20 m | ≤ 0.46 | ≥ 25 | ≥ 66 dB | ≥ 66 dB |
| 15 m | ≤ 0.40 | ≥ 25 | ≥ 60 dB | ≥ 51 dB |
| 10 m | ≤ 0.45 | ≥ 20 | - | ≥ 65 dB |
| 6 m | ≤ 0.28 | ≥ 20 | ≥ 65 dB @144MHz | ≥ 58 dB @28MHz |
EFFECTIVE WARC BANDS
| BAND | Insertion Loss (dB) | Input Match (dB) | Upper Band Rejection | Lower Band Rejection |
|---|---|---|---|---|
| 30 m (10 MHz) | ≤ 0.56 | ≥ 20 | 45dB @14MHz 60dB @18MHz |
40dB @7MHz 70dB @3.8MHz |
| 17 m (18 MHz) | ≤ 0.58 | ≥ 22 | 37dB @21MHz 55dB @28MHz |
46dB @14MHz 50dB @10MHz |
| 12 m (24 MHz) | ≤ 0.54 | ≥ 25 | 33dB @28MHz | 40dB @21MHz 60dB @14MHz |
YOUR OFFICIAL 4O3A REFERENCE IN ITALY
HamRadioShop offers you specialized technical support for the correct sizing of your station's power filters, the official warranty, and all the necessary assistance to protect your equipment fleet.
Request Information or Technical Support for 4O3A XL Filters4O3A, Antenna Genius, Tuner Genius XL and XL Series Filters are registered trademarks of SkySat DOO — Authorized Distribution, Sales and Service via HamRadioShop
HamRadioShop | Official 4O3A Italy Dealer Partner
