CHA 80 SHORT EXT

Put 80/75 meters into a site that cannot support the full 130 ft CHA LEFS 8010 wire. The CHA 80 SHORT EXT replaces the normal 67 ft 80-meter extension with a compact loaded Standard assembly approximately eight feet long. This is an accessory for the CHA LEFS 8010. It is not a standalone antenna and it does not replace the LEFS transformer or the 63 ft parent radiator. Current Standard production unit We received 100 Standard units for the current production offer. Standard and PRO have identical electrical behavior; their difference is cosmetic. The product supplied by this page is the Standard construction shown in the current Standard documentation. Required parent antenna CHA LEFS 8010 Overall accessory length 7 ft 11 in Standard tail length 6 ft 11 in Loading Fixed 120 uH series load after the 63 ft parent section Field-adjustable range 3.5-4.0 MHz Approximate 2:1 bandwidth 80 kHz after adjustment Factory starting point Approximately 3.520 MHz Approximate weight 7 oz Important: 3.5-4.0 MHz is the range in which the resonant segment can be placed by adjusting the tuning stub. It does not mean one adjustment covers the entire 500 kHz allocation below 2:1 SWR. Production SWR sweep The September 25 production check reached approximately 1.45:1 near 3.50 MHz in the recorded installation. The full sweep also shows the parent LEFS 8010 system's higher-band responses. This is measured impedance at the analyzer reference plane for that setup—not a guaranteed curve for every installation. Height, ground, coax, nearby conductors, wire tension, and weather can move the result. Installation and tuning Deploy the documented 63 ft CHA LEFS 8010 section. Connect the CHA 80 SHORT EXT at the extension point normally used by the 67 ft 80-meter wire. Use the Standard coil-body strain-relief holes for the carabiners and the internal wing nuts for the electrical spade terminals. Tighten the wing nuts finger-tight. Support the low end approximately 3-5 ft above ground with some sag in the wire. Sweep 3.5-4.0 MHz at low power before trimming. If the intended frequency is already 2:1 or lower, stop. To move resonance upward, fold back or shorten only the tuning stub. Trim no more than one inch, restore the same geometry, and measure again. Never cut the loading coil or the 63 ft parent radiator. If the extension will not tune, remove it and verify the LEFS 8010 parent configuration near 7.075 MHz before changing the tail. Governed 2D and interactive 3D NEC patterns Two reviewed Standard models are available at 3.750 MHz. These are NEC simulation values for exact modeled geometries, not guaranteed installed gain. Configuration Band Frequency Peak NEC gain Standard sloper 80 m 3.750 MHz -2.15 dBi Standard horizontal 80 m 3.750 MHz 0.90 dBi Open the complete 2D and interactive 3D pattern library The NEC model uses an ideal 120 uH series load. It does not include measured coil loss, transformer loss, feed-line current, installed mismatch, nearby structures, vegetation, real terrain, or field correlation. The measured SWR sweep and modeled radiation patterns answer different questions and must not be treated as interchangeable evidence. Documentation CHA 80 SHORT EXT Operator's Manual Standard Quick Start Standard flysheet CHA LEFS 8010 field guide in the Chameleon Knowledge Base The Operator's Manual controls if a shorter document conflicts. Keep the complete antenna and supports clear of overhead power lines and public access. Use the lowest applicable power, duty-cycle, feed-line, connector, transformer, support, and completed-system limit.