Oscilloscope monitor

[KE7DDQ]

Can anyone give me ideas how to hook up an oscilloscope to monitor output waveform? (HF bands up to 800w) Thanks!

[AF6LJ]

What kind of scope?

[KE7DDQ]

It's a Tektronix 5110. Bandpass is DC to 2mhz. I have a dual trace vert amp.

[AF6LJ]

The scope you have should have access to the vertical deflection plates in the rear of the scope.
What you will have to do is build a sampling device such that goes in line with your transmitter.
This isn't the most sensitive way to accomplish the job at hand but it works.
It is limited in terms of the upper frequency this will be useable in part due to the scope, and the pickup device. You will most likely be able to make it work up to 30MHZ, however I wouldn't expect it to work very well beyond that.

Here are some articles on the subject.....
http://www.cleanrf.com/applications.html

http://www.icycolors.com/nu9n/scope_your_audio.html

http://www.ab4oj.com/test/peptest.html

[KL7AJ]

The traditional way to do this is to connect an R.F. sample directly to the vertical deflection plates. This is described in several older ARRL handbooks. Another method is to use a simple downconverter to shift a sample of the R.F. signal down to a low frequency, say 500 kHz, which is well within the bandwidth of the scope.

By the way, at Dayton this year, a feller had 6 MINT condition Heathkit waveform monitors. I wanted to buy them ALL....but alas....shipping to Alaska would have been horrendous. Which is why Alaska starts with Alas!
Eric

[KE7DDQ]

Thanks for the info; I'll see if I can find my old handbooks.

[K7MEM]

Thanks for the info; I'll see if I can find my old handbooks.

James,

I am attaching two JPG schematics for a Heathkit HO-10 monitor. This may give you an idea of how they go about viewing the signal and the circuitry needed. I have the manual for my HO-10, but I have not scanned it in yet. The manual describes how to hook it up and what to expect to see. I will see if I can find the manual and scan in the technical stuff.

HO-10_page1.jpgHO-10_page2.jpg

Martin - K7MEM

p.s. How do you attach a PDF in this forum? I tried one but is said "invalid format" so I went with the bigger JPGs.

[KA5S]

Depends what you need to do. I use a 100 MHz 'scope and high power directional couplers able to display the RF waveform as well as its envelope, and even a 15 MHz B&K scope works through 10 meters if I don't need to know the real voltage.

Probably simpler to use directional couplers, rectify the RF and feed that to your scope via potentiometers. Good enough for envelope monitoring, anyway.


Cortland
KA5S