wenzeslaus
Member
- Joined
- Aug 30, 2023
- Messages
- 126
a lot of shortwave radios make a squeal noise as you approach a station. the squeal goes down to 0 hz on the station, then as you leave the station it goes back up to a high pitched squeal before it fades away entirely as you continue scanning. anyone who has ever used a shortwave radio knows what I'm talking about.
what causes that?
I have a Grundig FR-200 and around 7 MHz on shortwave, it squeals loudly as you approach a station, and if you put your hand close to the antenna it varies the pitch. it's obvious there is capacitance between your hand and the antenna, so when you move your hand, the C varies, making the frequency vary, and you get the same effect as if moving the tuner. according to the equation f=1/(2*pi*(L*C)^2)
why does this radio do that, when other radios don't? is a capacitor damaged or out of adjustment? antenna improperly connected? or what?
then there's my Grundig Yacht Boy 205, which doesn't squeal at all. why not?
??
what causes that?
I have a Grundig FR-200 and around 7 MHz on shortwave, it squeals loudly as you approach a station, and if you put your hand close to the antenna it varies the pitch. it's obvious there is capacitance between your hand and the antenna, so when you move your hand, the C varies, making the frequency vary, and you get the same effect as if moving the tuner. according to the equation f=1/(2*pi*(L*C)^2)
why does this radio do that, when other radios don't? is a capacitor damaged or out of adjustment? antenna improperly connected? or what?
then there's my Grundig Yacht Boy 205, which doesn't squeal at all. why not?
??