Westinghouse NT-33 Antenna Ammeter

From my stash of interesting stuff. I know very little about measuring antenna current, I’ve never seen it covered in a Radio Amateur Handbook or the like. Not even my 1948 edition.

The meter face (note the non-glare glass) reads “USE 3 AMP 17.5 M.V. 2 M.A. EXT TH’C’PLE. F.S. WITH .166 OHM LEADS = 17.5 M.V. STYLE N-635226 TYPE NT-33 FS = 2 M.A. 25 CY TO 9 M.C.

It has three terminals and I have no idea what “L” means.

Turns out “L” is connected to the back of the meter face. Still don’t know what it stands for.

Anyway, it’s a non-linearly calibrated d’Arsonval movement with a (measured) internal resistance of 8.5 ohm and an FSD of 2mA. 17.5mV over 8.75 ohm is 2mA, so depending on whether the 0.166 ohm lead resistance is for one or both wires, the internal resistance should be 8.58 ohm or 8.42 ohm so yea, the complete meter spec is written on the meter face if you know what to look for.

It should look good in some retro kit, even if I have to interface a PIC to the back of it to get the calibration right.

John Prine

It’s been three years.

From the comments:

Will Cayemberg
One of my coolest musical experiences involved this song. Long horrible divorce that very nearly ended me I ashamed to say. I began running at night in the dark on lonely country roads “trying to change the shape I was in” both physically and mentally. This song was in my ear buds most nights. Then I got a chance to see John in a tiny Manitowoc, Wi. theater and after a few songs I yelled out “Clay Pigeons” and he looked right at me and said “Yeah, I know that one.” The whole place cracked up. The next song he started Clay Pigeons and looked right at me and I yelled “Thank You.” I was thanking him for more than just a song request I think he helped me keep my sh#t together.

Spencer Mason
Rest In Peace, John. Music won’t be the same without you.


Spaghetti and Cabbage. Strange combination.

So I looked in the fridge. We had carrots, cabbage, sandwich ham, and cream. Yea, with the kids out the house we have what they refer to as a “sauce fridge”.

And I felt like pasta.

Google to the rescue.

Boil some† spaghetti. Water, salt, ‘cmon you don’t need instructions for that.

Fry onions and cabbage (recipe calls for a head of cabbage, I have no idea how big a Napa cabbage is, I used about a third of a Cape Town cabbage). This takes longer than you might think. Pasta was al dente and I was still frying cabbage.

Add ham and more seasoning than the recipe calls for. Add the cream. Add the spaghetti. Add some reserved spaghetti water to make a sauce.

I didn’t have parmesan but I did have mozarella in the freezer.  I left the carrots for another day.

† Technical Term

Silicon mumbo-jumbo

So this thing crossed my path.

I suppose that’s as much of a disclaimer as you’re going to get.

Because it’s pure snake oil.

Of course I took it apart and reverse-engineered it.

The battery was a bit dodge so I disconnected it.

Someone else had been here before.

The schematic is very similar to the one on the cs.cmu.edu web page. The power supply is… interesting. Unless there’s an external transformer that I don’t have?

I lol’ed

Note to Groom: This is where you GTF away. Seriously. Most people don’t get this good a Hint. You won’t get another one this clear.

Welcome Distopia

Sol stopped pedaling and the whine died away to a moan, then vanished. He disconnected the wires from the electrical generator that was geared to the rear axle of the bike, and carefully coiled them up next to the four black automobile storage batteries that were racked on top of the refrigerator.

— Harry Harrison, Make Room! Make Room! a.k.a. Soylent Green

The novel was set in 1999, the movie in 2022. Reality is lagging a tiny little bit behind.