? How to stabilize a cheap colpitts oscillator

I can read resistor color codes, and I can read the display of my DMM which confirms the value of the resistor in question (I checked it before using it, just to make sure). So far as the model of the frequency counter, 1252 is what it says on the front, and I can't argue with that.

BTW, I solved the mystery. Problem was where I was feeding the counter from, which was the tank circuit of the active antenna. Moved the input for the counter to the output of the oscillator, and problem is solved. Display is now rock steady. Like I said, I may be ignorant, but I am sincere.

Call me an idiot if you like, but I'm beginning to think you are the troll in this equation. Lots more accusations than answers. I do appreciate your making me think, which is what I needed, but I have grow tired of the body-slams. Sue me. I never claimed to be a genius.

Dave

Dave,

You have to excuse Phil. He gets a little irritable and bloated around this time of every month.

Bob

LOL!!! Thank you. I needed that. (still grinning...)

Dave

"Dave the Drongo "

You have no cred left.

F*ck Off.

....... Phil

"Boob"

....... Phil

Whatever.

Goodnight.

Phil,

You MUST remember to take your Midol, sweetheart.

Bob

Phil Allison a écrit :

Oh, I thought counters should be able to count pulses, square waves... Obviously I was mistaken.

Counters should be able to count any reasonable waveform. A good "universal" counter will have an adjustable threshold, ac/dc coupling, and often a switchable attenuator. Cheaper counters, without adjustments, can get confused by duty cycles, amplitude variation, and things like ringing and noise.

John

Late at night, by candle light, "Dave" penned this immortal opus:

The counter is sensitive to below and above some reference level and counts those transitions. What does it look like on the scope? It doesn't need to be a pure sinewave, as long as there aren't any obvious wiggles or noise. Try checking the counter with a known good generator.

- YD.

Don't worry too much about Phil - sometimes he goes off his meds.

What does the counter say when you clip it to the scope's calibrator?

Thanks, Rich

John Larkin a écrit :

He he, it wasn't your leg I was pulling :-) (unless you were not answering me)

put a simply unity gain follower amp on the output.. something like an emitter follower.

Or a CMOS amplifier (74HCU04 with resistior from input to output).

Thomas

"Fred Bartoli Frog Moron "

Other waveforms with strong harmonics of the fundamental frequency may well exhibit extra zero crossings and these also become added to the count.

Users of frequency counters need to be aware of the problem and check the input signal with a scope if anomalous readings are being obtained.

BTW Fred,

Your mistakes are all too obvious & your asinine ignorance is beyond the tiniest doubt.

F*ck off.

....... Phil

Hey everyone...

Turns out the problem with the counter was where I was taking the input from, which was the tank circuit of the active antenna. Taking the input from the output of the signal generator fixed the wild fluctuations. Rock steady. And rewinding the coils gives me a Q of 231 for the first, which had a Q of 177 last night, and nearly 400 for the second, which previously was something like 4. I honestly find this value hard to believe, but that's what it looks like.

Don't know what else to say right now. Once that problem was resolved, everything else sort of fell into place...

Regards,

Dave

Repeat after me:

IRONY DOES NOT WORK ON USENET IRONY DOES NOT WORK ON USENET IRONY DOES NOT WORK ON USENET IRONY DOES NOT WORK ON USENET IRONY DOES NOT WORK ON USENET IRONY DOES NOT WORK ON USENET

John

Dave, does your tek scope have a "Ch 2 output on the rear panel? If it does, you need to connect your counter there with a BNC cable, to whatever the freq counter's input takes.

On my scope it's CH 1 output. (Hitachi) Mike