Oscilloscope?

[brandon7861]

I wish my oscilloscope could handle a wall outlet on a 1x probe.... Mine can only handle ±20v pk, so if I forget to use the 10x probe and try that on a 12w radio, poof! I've been lucky, came close to smoking it a few times. These new scopes do almost everything mine does for just 1/10 the price, and take much higher voltage. I bought mine too early in the technology boom..

Although the 300v that scope is rated for should handle anything you throw at it, high SWR increases the expected voltage at the coax port. A tuner can also raise the peak voltage at the antenna jack, so unless you are running into a purely resistive load, be careful!

 

[KK4JW]

Well, after fiddling with this thing most of yesterday evening and night, I think I've got it figured out. I've already had three of my radios on it and cleaned thier audio up to some nice symmetrical peaks.

My biggest problem has been getting enough RF into the scope to see a clean and clear picture. I've found out that I can switch the test lead to 10X and basically drop it down inside the radio where the coax connector is and it picks up really good down in there.

Really surprised me how out of whack the audio was on my Cobra 29 and Connex. Getting it adjusted on the Connex was a little bit of a challenge. When adjusted to look nice and uniform, it seemed to kill off about 40% of my audio. I was able to find a happy medium by just barely pinching off the carrier. Still no flat-topping of the peaks though, so I was happy with that.

 

[loosecannon]

LC, this is going to make you think I am an idiot......

You said something about calibrating power meters using your scope.......

Does that old E squared over R work? I mean... if you take the peak to peak and convert it to RMS and divide by 50.... ... does that hold up for this purpose????

Thanks!

here ya go!

Power Measurement with Simple Techniques

www.ab4oj.com

this also helps people figure out just how many watts they can measure safely with their scope before they might need the 10:1 resistive divider described in the article.
LC

 

[Enterprise312ok]

Find an old service monitor like a b&k 1040 and 2040 and you will have attenuation for your scope and a tone generator. be sure to send it to the desert for nist certified calibration.

 

[guitar_199]

Find an old service monitor like a b&k 1040 and 2040 and you will have attenuation for your scope and a tone generator. be sure to send it to the desert for nist certified calibration.

I've got a 2040 and am looking FURIOUSLY for a 1040... so far... to no avail!

 

[guitar_199]

here ya go!

Power Measurement with Simple Techniques

www.ab4oj.com

this also helps people figure out just how many watts they can measure safely with their scope before they might need the 10:1 resistive divider described in the article.
LC

Thanks a million for that. A really nice article.

 

[Eldorado828]

be sure to send it to the desert for nist certified calibration.

Just setting on the bench alone will add quality, value and super powers! If @TheRealPorkchop was reading this he'd surely add to that! Come to think of it, that dude has been absent for a while.