Noise filter for ciga lighte rof the car------noise.gif

Noise killer
I go sometimes on the hill in order to make a local expedition with my car. I get a power from the cigar lighter of my car. The power of the car has the noise of the ignition and alternator. These noises are heard on the receiver. Therefore I made noise killer. The transformer is fly wheel transformer of a switching power supply. 0.8mm diameter enamel wire is used in it. Capacitor is 1000 micro farad 24V. The case is a lunch box.

E mail letter between JF1OZL and Darrol

Yes, you have my permission to up link the letter, or to do whatever you want with it. Darrol Draper wrote: > Dear Darrol > Please give me a permission to > up link following your letter on my home page. > Kaz > > ---------- >

From: Darrol Draper[] > Sent: Thursday, October 14, 1999 0:38 > To: > Subject: Comments on "99.noise killer for the car" > > Hi, > > You have one of the most interesting amateur radio websites. I have > been looking at different pages from it, for over a year. I like your > "perverse fellow" attitude, where you do things just to see if it can be > done. I would never have thought of using a 6BE6 for an IF Amp, but it > makes perfect sense, really. > > One of your circuits can be improved a lot. "99.noise killer for the > car" uses two separate choke coils. It would work much better if you > put two windings on one core. Here is why: > (1) You don't need the second core. That cuts the weight. > (2) If the cores saturate because of too high DC ampere-turns, you > don't have a choke, you have a resistor. When you put both windings on > one core, the DC currents on the two wires cancel each other out. The > total DC current then becomes 0 A, and you don't have to worry about > saturation. > (3) If the two wires are twisted together before making the coil, then > you get capacitance between the two wires. (In fact, you get a > transmission line.) This capacitance also works to block out the QRM > from the car's electrical system. This could be important, because the > ESR of the electrolytic capacitors is not good at HF or VHF. > > You have a great web site. > > Darrol Draper


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