transformerless aerial amplifier

38 transform erless aerial amplifier 9 The omega-antenna, published in the June 1980 issue of Elektor (page 6-08), fulfilled a popular demand. It"s main drawback however, the difficulty to obtain the cores for the broadband transformers, prompted our design staff to come up with a version that does not require these particular components. The "alternative amplifier for the CI antenna", described in the previous summer circuits issue, was primarily intended for direction finding purposes in the 100 kHz to 30 MHz range.The compromise, s the rather circuit, it can still be considered quite low. The gain of the amplifier is determined by the ratio of the collector and emitter impedances and because of the complex nature of the emitter impedance, which also depends on the loop size, it should be stated that this circuit performs almost as well as the original one. The circuit does have one snag, however. Due to the absence of a transformer, the tendency for the am- plifier to oscillate...