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Avid_Nerdlinger · 21st May 2019, 4:00 pm

I got HX207 to tune to Radio 4 on 198kHz by adding a 82pf to the osc side of the tuning cap and a 1nF measuring 910pF to the antenna side. This HX207 was also a bit of a howler before I modified it but it is worse now. I can stop the howling by turning the volume down but that makes it too quiet to be useful. The same tuning cap appears to be used on X921, probably also the HX108-2 on order so I might try this on them at some point.

"Mostly, it appears, that the stages, specifically the IF stages, are unstable and are oscillating." - isn't it more likely the audio stage?

21st May 2019, 4:00 pm	#146
Avid_Nerdlinger Pentode Join Date: Apr 2019 Location: Durness, Sutherland, UK. Posts: 108	Re: More Chinese AM radio kits I got HX207 to tune to Radio 4 on 198kHz by adding a 82pf to the osc side of the tuning cap and a 1nF measuring 910pF to the antenna side. This HX207 was also a bit of a howler before I modified it but it is worse now. I can stop the howling by turning the volume down but that makes it too quiet to be useful. The same tuning cap appears to be used on X921, probably also the HX108-2 on order so I might try this on them at some point. "Mostly, it appears, that the stages, specifically the IF stages, are unstable and are oscillating." - isn't it more likely the audio stage?