loopantennas@groups.io | File /MODIFIED AMRAD PREAMP

Group Notification #21219 The following items have been added to the Files area of the [email protected] group. /MODIFIED AMRAD PREAMP - 20 MARCH 2025.docx By: W0LEV <davearea51a@...> Description: Build and technical evaluation with measurements of the Modified AMRAD high-Z input preamp for E-Field probes. Dave - W?LEV
W0LEV All Messages By This Member #21230 I couldn't agree more, Fred.? Audio, yes. ... RF, likely not.? But what about below 100 kHz where most of my application lands?? I'm primarily interested in "DC" through 100 or so kHz. Dave - W?LEV toggle quoted message Show quoted text On Fri, Mar 21, 2025 at 7:53?AM Fred M via <dl4zao=[email protected]> wrote: I doubt, that paralleling FETs in an reactance driven HiZ? application is worth the effort. The noise figure of an Hi-Z FET Amplifier ist primarily dominated by the thermal noise of the Gate bias Resistor of 22 Megohm which is much higher, than the FET noise. It may make sense in Low-Noise Audio applications, where the source impedance is low, but IMHO not as an e-field probe for RF-reception. ? regards Fred -- Dave - W?LEV
Fred M All Messages By This Member #21231 @Dave, Martin ? i am on a weekend trip. Will be back soon and try to answer your questions. ? regards, Fred ? ?

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