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The antenna is a 10 - 160 meter horizontal loop fed with 450 ohm ladder line all the way into the ham shack to an Palstar AT1500BAL balanced line antenna tuner

HF anf VHF amplifiers made in U.S.A. by Command Technologies, Inc. now acquired by Palstar

Receivers, Antenna Tuners and accessories, antenna analyzers, dummy loads, wattmeters, shortwave radio receivers, baluns, filters

Accurately determining an antenna's feedpoint impedance is crucial for optimal performance, especially when experimenting with new designs or making adjustments. While SWR meters provide basic information, a full complex impedance measurement reveals the resistive and reactive components, which are essential for proper matching. Modern antenna analyzers, like the _Palstar ZM30_ or MFJ259B, simplify this task, but measurements taken through a transmission line require careful interpretation due to impedance transformation. This resource details a calibration method to precisely account for the effects of the feedline. It explains how a transmission line can significantly alter the measured impedance, illustrating this phenomenon with a Smith Chart example where an 80m antenna's [22 + j6] Ohms feedpoint impedance transforms to [82 + j45] Ohms after a 10m line. The guide demonstrates using a transmission line calculator applet, such as the one by W9CF, to reverse this transformation. It outlines the process of calibrating a specific length of RG174 coax, showing how an initial 26ft estimate was refined to **25.85ft** to accurately predict a known 22 Ohm load, significantly improving accuracy over uncalibrated results.

Two receivers compared, Drake R8A and Palstar R30

Italian ham radio dealer for major brands like Icom Kenwood Yaesu HY-GAIN Heil Sound Rigexpert Palstar GAP antennas Diamond SteppIR and others