Hi John,
The K3/K3S "RF Gain" control doesn't control any RF stage at all... It actually controls the gain of the 8.215 MHz IF amplifier immediately following the 8.215 MHz roofing filters which then controls the 8.215 MHz IF signal level feeding the 2nd mixer. See the K3 RF Board schematic, page 4 of 4. The 8.215 MHz IF amplifier is Q1. IF amplifier gain is controlled the front panel "RF Gain" control (labelled as VIF Gain on the schematic) via U3. This is why its so critically important to select the correct Preamp setting (Preamp1, Preamp2 (in the K3S) or OFF) and proper attenuation level because those are the only gain controls in the RF path of the K3/K3S. If you select Prramp or attenuation incorrectly you've inserted excessive signal levels into the roofing filters and IF amplifier. 73 Frank W3LPL ----- Original Message ----- From: "John Reilly" <reill...@gmail.com> To: Elecraft@mailman.qth.net Sent: Sunday, May 17, 2020 9:40:06 PM Subject: [Elecraft] [K3/K3s] RF Gain Control Where in the K3/K3s Block Diagram is the RF Gain control located? We're having discussions concerning whether is is better to reduce the RF Gain, or turn on attenuation to increase dynamic range, especially on 40m and below. Thanks, - 73, John, N0TA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to donov...@starpower.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
