Scope your Ham Radio

Here are a couple of videos that show a couple of ways that you can used your oscilloscope to monitor and measure the output of your ham radio transmitter.

This first video shows how you can make a simple RF sampler and RF detector for your scope, and what the waveforms look like on the scope.

http://www.youtube.com/watch?v=y4Zt_LJX1Tc

This next one shows how to setup a simple 2-tone test for the SSB transmitter.

http://www.youtube.com/watch?v=3DxBg6h4Fc8

Oscilloscope looking for infrequent glitches

Here's a video showing how some scopes can, and some scope can't, see an infrequent glitch on a signal.

http://www.youtube.com/watch?v=Rsj8tHA1it0

My ESR meter project

I recently used my ESR meter to locate some bad electrolytic capacitors in the power supply of an LCD monitor that I'm repairing, and thought it might be worth a quick video. I built the ESR meter in 2006, based in large part on various circuits that I found online in various places. The front-end and amplifier were based heavily on the design that is shown here:

http://members.shaw.ca/swstuff/esrm­eter.html

I slightly modified the oscillator circuit, chose note to include the charged-cap protection, and then changed the backend to a dc-corrected half-wave rectifier and peak detector. Here's the link to the video:

http://www.youtube.com/watch?v=bmYAgat-sOQ

Two more scope videos...

I've posted two more videos on YouTube. Both of these are centered around looking at signals inside of a TenTec 1254 Shortwave Receiver. The first video is brief tour of the RF signal path in the radio, and a look at some of the signals (LOs, IF, audio). The second is another short look at the 2nd IF output and demodulated audio on a live shortwave signal.

Tour: http://www.youtube.com/watch?v=dZNN5RnOdt8

Live Signal: http://www.youtube.com/watch?v=pzLA_lRdmPI

73 de Alan W2AEW

Delayed Timebase operation example

I was asked by a friend to post a short video that shows how to use the Delayed Timebase feature on an older analog oscilloscope. The delayed timebase feature can be thought of as a "zoom" function - allowing you to zoom in on a portion of the waveforms that you are looking at with the main timebase. I used a pulsed sinewave output from a function generator as the signal of interest, and Tektronix 485 oscilloscope to demonstrate the setup and operation of the delayed timebase. Other scopes would be similar.

The video is posed on YouTube and can be found here.

Scopes for Dopes class

I helped teach a class on the basics of oscilloscopes to the New Jersey Antique Radio Club. This club is dedicated to the restoration and preservation of antique radios - mainly from the golden age of broadcasting. The class was geared entirely around analog scopes, since that's the type of scope that these guys would most likely come across or have access to for their radio restoration projects. We affectionately called the class "Scopes for Dopes", and it was a great success.

Fortunately, the session was videotaped. We had two projectors going - one with presentation slides, and one with a video camera feed that was focused on a few scopes on a table for demonstration. The videographer did a great job editing the final product, which has now been posted here:

http://www.njarc.org/scopes4dopes/

Note that the first 15 minutes features the history of oscilloscopes by Al Klase, the Technical Coordinator for the NJ Antique Radio Club, then the next two hours features yours truly… So, if you'd like to throw away 2 hours of your life that you'll never get back - take a look at the video… …and enjoy, or laugh, or…