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Sunday, April 22, 2012

Club 465

I mentioned on the podcast that a generous friend sent me a Tektronix 465 scope. It now seems like every day I'm discovering new and interesting things about this magnificent piece of gear.   I've also discovered that there a LOT of guys out there who are loyal and enthusiastic users of Tek 465s.   George Heron, N2APB, and Joe Everhart, N2CX, have been putting out an excellent podcast called "Chat with the Deigners." They recently talked about oscilloscopes with our friend Alan Wolke, W2AEW:  http://www.njqrp.org/teamspeak/Apr10.html
George mentioned that he has a 465.  Our friend Farhan, VU2ESE, is using one.  Who else is in Club 465?  Send us your names! 


Preston. WJ2V, up in the Big Apple sent me a very interesting message about a feature of the 'scope that I was unaware of.  Thanks Preston!

Bill,

I am caught up and just listened to number 142.  The podcasts continue to be new and interesting each issue.  I too have a 465 workhorse in the shack.  I have one suggestion that will turn it into an even more valuable instrument.  Note that you have an amplified output in the back with the vertical signal presented at a BNC connector.  This is made for connection to a frequency counter.  In fact, some of the military versions of this scope came with a frequency counter.  If you have a counter in the shack, just connect it to the vertical output in back of the scope.  This will faithfully report the frequency of any wave you see on the screen.  Since the signal is amplified, the counter will be able to read small signals in receiver stages, while you view them on the scope.  Amazingly helpful in setting up and troubleshooting receivers.  I leave a dedicated counter connected to the 465 all the time, as it enhances the usefulness of the scope many times.  I also am lucky enough to have an early Steve Weber ("Melt Solder") SASA II device available for connection to the scope whenever needed.  This is a 100 MHz spectrum analyzer adapter, with a built-in calibrator.  It gives a great view of the output of transmitters.  But, of course, you can see the quality of a clean sine wave with just the scope.  The SASA II will just help you to see where in the spectrum the junk is coming from.  Sadly, I don't think Steve made more than about a hundred of these terrific kits.  Also, it did not have provision for a tracking generator, which would have made it an ideal instrument for designing and checking IF filters.  Steve and I talked about this, and he said he might revisit this someday.

As to seeing your QRP (or even higher) signals on the scope, of course you would not connect a transmitter to the input of the scope--that would burn it out in short order.  But a proper bypass/attenuator connected to a proper 50 ohm pass-through termination at the input to the scope would give the ability to see why your SWR meter is showing an abnormally high SWR with your homebrew transmitter that's generating spurious stuff.  There is a very practical article for building the two pieces you need on simple PC board "cabinets"  (more like half-cabinets) in the wonderful Drew Diamond books, I think in volume II.  These simple devices will give you the ability to see what you're doing with your transmitters, using the scope--

72,

WJ2V



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3 comments:

w2aew said...

I'm in the club too, with my 465B!

DL7FP said...

I too enjoyed the talk about scopes. There is a really interesting 2 hour video on scopes from the New Jersey Amateur radio club with the suitable title of "Scopes for Dopes"

http://www.youtube.com/watch?v=8ZKMrzTGxLQ

well worth a look

Francis DL7FP

w2aew said...

Thanks Francis - that was me teaching that class!

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