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
Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20
I'm in the club too, with my 465B!
ReplyDeleteI 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"
ReplyDeletehttp://www.youtube.com/watch?v=8ZKMrzTGxLQ
well worth a look
Francis DL7FP
Thanks Francis - that was me teaching that class!
ReplyDelete