Uploaded June 2018 | Updated September 2026, 2 weeks ago
Designed in the 1970's the HW104/SB104 tranceiver was Heathkits Solid state HF tranceiver with slide in circuit boards for easy adjustment and repairs . I like these rigs I can still work on them . I started on testing various Microphones and increasing the gain of the microphone preamp in the Hw104/SB104 a few months ago and this is the final setup it is very simple to do . I have tested changing the 2 resistors for months now in my other HW104 but just changed this one yesterday . I comment on this because what I say about this in the video seems confusing to me
anyway . My demo here shows the increase in transmitted signal from this MOD. Care must be taken to set the MIC LEVEL not to high the modulated RF waveform peaks should just come up to the same level as the CW wave form on a monitor scope such as the Heathkit SB610 my demo here shows the increased microphone gain of the microphone preamp but the level was not checked on the monitor scope which I will do before putting it on the air OR follow the modulation instructions in the HW 104 or SB104 operating manual so you do not get the MIC level to high and get distorted output . 73
HEATHKITS FOREVER ! Bob
Designed in the 1970's the HW104/SB104 tranceiver was Heathkits Solid state HF tranceiver with slide in circuit boards for easy adjustment and repairs . I like these rigs I can still work on them . I started on testing various Microphones and increasing the gain of the microphone preamp in the Hw104/SB104 a few months ago and this is the final setup it is very simple to do . I have tested changing the 2 resistors for months now in my other HW104 but just changed this one yesterday . I comment on this because what I say about this in the video seems confusing to me
anyway . My demo here shows the increase in transmitted signal from this MOD. Care must be taken to set the MIC LEVEL not to high the modulated RF waveform peaks should just come up to the same level as the CW wave form on a monitor scope such as the Heathkit SB610 my demo here shows the increased microphone gain of the microphone preamp but the level was not checked on the monitor scope which I will do before putting it on the air OR follow the modulation instructions in the HW 104 or SB104 operating manual so you do not get the MIC level to high and get distorted output . 73
HEATHKITS FOREVER ! Bob
