Smith Chart Tutorial

I paid the big bucks ($7.95 in 1967) for a whiz-wheel version with rotating and stationary dials plus the clear plastic slide with cursor. I still have it but the area around 50R is getting pretty scratched up {;-)

Jim

Only one Russian engineer vaguely remembered what that was but

Jim Thomps>Only "non-linearity" I had to deal with I mentioned before, a hallway

I love it. Forced perspective view.

...and I know of software to print your own blank Smith Charts but not any that wil take input and resolve on the screen.

I've made something like that, for satellite position calcs and other stuff. Very practical tools. Then the CA sun and heat disintergated the plastics, turned tan, then brown, then crumbled :-(

Which reminds me: Where can one buy that hard clear plastic, 12mils or a little thicker, in really large sheets? It is very useful for educational purposes but it needs to be 2'*2' or so in order to be visible in front of a white-board. Many companies don't have projectors anymore but they all do have white-boards. Using compasses on there is frowned upon ;-)

Blank Smith chart:

Geez, Joerg, aren't you going to have to apply to get your home's lot zoning changed from residential to commercial? :-)

Sure you aren't planning on expanding and becoming another Highland Technology? ;-)

Here's the slightly fancier one with admittance and impedance printed simultaneously:

Admittedly if you're not doing a lot of Z/Y conversions it's often easier to use the regular Smith chart and just rotate 180 degrees yourself...

Nope. I think they even changed it so you can have up to one employee in purely residential areas.

If we had less onerous regulations in CA I'd probably do that but in the current climate I prefer to remain on my own.

Joerg wrote:

Places that sell window glass also sell clear plastic sheets. A good hardware store does as well.

The last item here is an indicator:

This stuff doesn't chip or crack--and you pay for that:

Thanks. Didn't know that window glass places sell it. Cool.

Well, I don't need it bullet-proof :-)

Must be able to roll it up, 15mils thick or so.

I used these in aviation work, still have my Picket:

Then I noticed this from FXR:

Not sure if anything like that is still being made.

Jon

Ever hear of a printer? ;-)

That's pretty cool... I'd love to have one like that!

Yeah, but if you have to make an ad hoc design change right then and there the printer would be soiled as well. Design changes such as "Oh dang, there's a pipe and I can't drill there."

r?

Nice story. I think I have had more encouraging comments on this tutorial then all my other ones combined (There are a lot of ham radio operators out there that seem to like the less mathematical and more interactive approach I think)

Brent

Never had to drill (too deep) when laying tile. Generally it's too late for the PC when pipes are found. :-(

Well, then you don't have a house with a mud bed (2" concrete top floor) and radiant heat pipes in there. Murphy says something will show up at the most inconvenient time and location :-)

While there are certainly still plenty of hard-core RF circuits guys in amateur radio, these days you often find such people working on fancy DSP-based SDRs in the ISM bands. I'm thinking of, e.g., the GNU Radio guys --

In southern Oregon, the ham groups I'm familiar with have an average age that's somewhere in the mid-'50 to '60s... and generally creeping upward year after year. To a large extent the whole idea of local clubs seems to be dying off due to the Internet's ubiquity -- web sites like your let people learn things in more depth and over a wider range of topics than local clubs ever did, I think.

Joerg wrote:

I misread your spec as 12mm. The stuff used as rear windows on convertables should be quite durable. Having never had a ragtop, I don't know how exactly stiff that is

--or how tight you need to roll it.

Hey, I am one of them. But I must confess that I've done it, too. Didn't have a 100pF high power cap, took a piece of FR4 and dremeled away until "it fit". We called it "pruning". Then I got my first job and found out that active laser trimming works the same way, just at a higher poshness level.

But SDRs are so boring. Problem is that the HD bands are so polluted from poorly designed switchers, CFLs and so on that that's no fun anymore either.

Then one fine day the big one hits, the infrastructure falls to pieces on account of wide-spread power outages, and dang, got to crack out the old HF transceivers.