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Criminal

204C Oscillator?

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I figured if anybody could answer this, you guys could. I found a HEWLETT-PACKARD 204C Oscillator recently. What is it and what does it do? (Pretend I know nothing at all about sine waves, whatever they are.) How can I tell if it works?

 

EDIT: The pic won't post so go here to see a pic of it.

 

Thanks!

 

http://fp1.centurytel.net/Criminal_Page/

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I don't know much about oscillators either. It strikes me as one of those: "If you don't know, you don't need one" situations.

 

Maybe the guy selling these could tell you what they are for. (If he does, tell me what he says!)

 

migo_sig_logo.jpg

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Try this LINK.

 

It has a frequency range of 5 Hz (5 cycles per second, lo bass audio) to 1.2 MHz (1.2 million cycles per second, mid AM radio area). It sells used for about $100 bucks. Yes, it will make noises in a speaker, and you could hear it from about 30 hz to 16 KHz (16 thousand cycles). From 16 KHz to about 25 KHz, you can drive the neighborhood dogs nuts. I bet you could set up a neighborhood concert, and have a "Howling" good time with the dogs. Above 540 KHz, you can mess up your neighbors AM radio. If you find a microphone to work with it, you can even send them messages. Did that once in the barracks in Alabama. During a thunderstorm, I set mine up to the local storm warning station. I flipped it on, "Interrupted the scheduled broadcast" with a tornado warning, and sent 1/2 the crew running to the shelters. icon_biggrin.gif

 

Normally, they are used for substituting signals in broken equipment, or for doing an accurate alignment on receivers and other equipment. It was TOP GEAR in its time, but now-a-days, it is more of an antique. If it were mine, I would put it on this rack and display it HERE.

 

Hope this helps. Enjoy it.

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

 

[This message was edited by Desert_Warrior on February 13, 2003 at 07:06 AM.]

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KD9KC

OK, I think I get it, well maybe not. There's no antenna so I don't know how it would transmit anything to anywhere. One site said it would be useful for guitar tuning? I'm still not sure it even works.

 

Wow, nice rack! The Collins R390 sounds familiar, I think we had those in the C141 before they were replaced in the late 90's. I was trying to get my hands on one but was told the C-130s were still using them, so they were sending the stock to them.

 

http://fp1.centurytel.net/Criminal_Page/

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What you have is a device used to provide a known input to some equipment for testing purposes.

 

Unless you are testing audio frequency circuits, you have white elephant.

 

If you want to characterize the frequency response of your stereo amp and speakers, it might work.

 

Unfortunately the dial on these 204Cs is not very accurate or repeatable, and the output voltage is not very stable, so you need to monitor the frequency and amplitude with an oscilloscope to get usable results. These are about 20 years out of date for people who actually need calibration standards.

 

You might be able ot get a few bucks for it on EBay.

 

My two cents worth, refunds available on request. (US funds only)

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quote:
Originally posted by Criminal:

KD9KC

OK, I think I get it, well maybe not. There's no antenna so I don't know how it would transmit anything to anywhere. One site said it would be useful for guitar tuning? I'm still not sure it even works.


 

You would put the antenna (a long peice of wire) to the red jack and just hang it out. I do not see any external modulation input on the front panel. If there is one on the back, you would connect the microphone there.

 

If you want to fire it up, a quick check-out wouldn't hurt. Try putting a charge on the power supply caps SLOWLY before you hit it with the full shot. Caps that have been stored a long time need to reform slowly.

 

Good luck.

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

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*BIG grin* DO NOT connect a microphone to the AC power connector. Especially if power is still connected. If there is no other connector on the back, it is not set up for external modulation.

 

Now, having said this.... there IS a way to modulate the power supply, but it is dangerous to attempt unless you are VERY sure of what you are doing. Myself, I would not attempt it, I would just put it with the other antiques.

 

PLEASE - SAFETY FIRST!!! If you are not sure, don't try it. You are betting your life.

 

You know, I am treating this seriously because I am not sure if you are jerking my chain or not. If you are, well... you got me!!! If not, please be careful!

 

Mike. Desert_Warrior (aka KD9KC).

El Paso, Texas.

 

Citizens of this land may own guns. Not to threaten their neighbors, but to ensure themselves of liberty and freedom.

 

They are not assault weapons anymore... they are HOMELAND DEFENSE WEAPONS!

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No No! I wasn't going to connect a mike to the AC jack! I'm saying that there is a jack on the rear, just like the one on the rear of your computer, where you can connect an ac line cord. In other words, there is a jack (or boss) with two prongs inside, and you plug one end of a power cord in there and the other end to the wall.

 

http://fp1.centurytel.net/Criminal_Page/

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quote:
Originally posted by Criminal:

I figured if anybody could answer this, you guys could. I found a HEWLETT-PACKARD 204C Oscillator recently. What is it and what does it do?


 

I'm not reading too attentively today, so forgive me if I'm repeating someone's post.

 

The only time I've personally used an oscilator like this is in circuit analysis class. We hooked it up to an osciliscope so we could see the waveforms and learn how the scope works.

 

In slightly more practical applications, you use the oscilator when you need a solid, known frequency signal to test some sort of system. Examples might be, if you're building a filter circuit that's supposed to block everything below a certain frequency, you can use the oscilator as your test input and see how your filter actually does, or for guitar tuning, you might hook the oscilator up to an audio amplifier, set it to the exact frequency of an "A" note and tune your guitar to it like a pitch pipe.

 

So how can you see if it works? Short of hooking it to an osciliscope, try hooking to the audio amp as above, set it to the frequency of an "A" note, then play an "A" on an already tuned guitar or keyboard and see if it sounds the same pitch!

:-)

 

ApK

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