Monday, February 15, 2016

T. R. MCELROY'S STREAMLINED TELEGRAPH KEYS

     T. R. McElroy was a blazing fast telegrapher -- any code, any time.  He worked both landline and radiotelegraphy, and set speed records.

     But he was ambitious, too.  In the 1930s, he started manufacturing semiautomatic telegraph keys of his own design, massive, heavy bugs that suited his own style -- and which appealed to plenty of others, too.

     The original Mac bugs were heavy, rectilinear keys with their own style, a little "Arts & Crafts meet heavy industrial" look.  But the times --and the styles -- were changing and shortly before WW II, Mac introduced a series of streamlined telegraph keys unlike any any other, culminating in the S-600 Super Streamspeed semiautomatic key, possibly the most graceful "bug" ever made.

     I own a few Mac keys and recently bought an accessory:
     There's an uncommon Bakelite-based Streamkey at far left, followed by a Telegraph Apparatus Co. (not Inc.) copy* of the wrinkle-finished metal-base Streamkey (you can tell by the bulge in the lever arm at the contact area) and a pair of chrome-plated McElroys.  The Streamkey is at far left, and it handles just as fast and sleek as it looks.  At the very back, the accessory and its box: an Oscillatone code-practice oscillator.  They are not especially rare and this one was offered at a very low price -- how could I pass it up?

     Restoration will be interesting.  The Bakelite is likely to be very brittle.

     There are still McElroys in the electronics business.  They're not making telegraph keys any more, but the name lives on.
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* TACo was a co-venture between McElroy and Hallicrafters.  They built copies of Mac Streamkeys and their own interesting semiautomatic key, sometimes known as the "hole-in-the-wall" bug.

Friday, January 15, 2016

A VINTAGE-SUITABLE CALENDAR

     I needed a calendar for my mostly-vintage hamshack.  1932 and 2016 share the same calendar, but buying an old one in intact shape and ripping each month off seemed too destructive to me.

     So I made one.
     The backing sheet is card stock.  The calendar pages look crooked -- the paper fasteners that hold them are a bit loose in the punched holes.  It straightens out when hanging.  The printer output does not look like hand-set type, but might pass for offset printing or lithography.

     I'm trying to figure out how to post the original as a PDF, if any readers would like their own copy.

Sunday, July 12, 2015

INDIANAPOLIS HAMFEST, 2015

     I had to go solo this year, while Tam stayed home to meet the AT&T tech.  This meant, of course, that I lacked even the modicum of restraint she sometimes adds--
     The two large devices are a 1940s Meissner Analyst, which is a kind of "test bench in a box" for receiver servicing, and a 1950s Harvey-Wells Bandmaster, a 25 to 30 Watt AM/CW amateur radio transmitter.  Both appear to be pretty clean; the transmitter needs an external power supply, 400 V at 200 mA.

     Other neat stuff: a pair of vintage binoculars in good shape -- didn't have anything but toy versions, so for $35, why not? -- a very goof push drill with straight bits and a "Handyman" Yankee screwdriver' a full set of Birnbach ceramic antenna insulators, chassis-mount octal plugs (good for power supply connections), three General Radio mixer knobs, a couple of Dakaware knobs, a National tube socket and 100 pF variable cap, another 100 pF dual variable capacitor, an SW-3 coil form, a 6F7 tube (possibly for a project) and a pair of 6L7s (used in my microphone mixer).  Plus four 1940s/50s QST magazines, three quartz crystals and and assortment of other nice small parts.  Not shown, a short (10'?) desktop rack and a large toroid core to wind a balun on (you want 'em big -- magnetic saturation is lossy and can produce a lot of heat!).

     I met my dear old friend Don H., and several other people I know slightly, including the talented Jim Borgioli,whose ham work includes building very nice AM transmitters that run at or near the legal power limit. And one ham who knew me!  A young man who'd gone looking for info on the Stancor 10-P transmitter and found my postings about it on Retrotchnologist walked up to in the flea market area, asked, "Are you Roberta?" and introduced himself.

     Found but missed a nice balanced antenna tuner.  I should have purchased it at first sight!  But it's a cloneable design and I think I have the parts.

     A fun time!  When I returned home, the phone tech was there -- and pointed out a very large broken limb on the roof and my ham antenna and still loosely attached to the tree.  I climbed up and had a look, but it's too big and too precarious for me.  We've called the singing tree hippie, who does great work at a fair price.

Monday, June 1, 2015

CARBON MICROPHONE CHECKING

     I went through most of my collection of carbon mics tonight.  The old ones are nearly always non-working when found: they pick up humidity, the carbon packs solid, and that's it; or the carbon granules dribble out over time. 

     Not all of them.  I found several that still work, and a couple that I'd thought were dead (a Shure Brothers 3-A and a 3-B) aren't.  Here are the working ones:
      Two are telephone-types, the T-32 (a pretty common desk mic around WW II) and an odd old telco one from the wood-wall and candlestick era next to it.  The Universal X1 in its nice stand was a complete surprise; I assumed from condition it was a goner.  Nope!  And the little Philmore lapel mic next to it had been sealed up.  The Stancor 10-P -- which needs a carbon mic to do AM -- is behind them.

     Here's my test set-up.  The mic cable goes to a little mixer.  It's isolated with 0.68 uF series condensers, looking at current across a 150 Ohm resistor in series with the mic, a 1.5 V battery and an added resistor to limit current -- I used 820 Ohms and it worked okay for checking.  In practice, you trim microphone current for best fidelity with a carbon -- usually the lower, the better, but there's a point where it stops working.
     Mic cable to mixer at left, connections to carbon mic under test at top right, battery terminals and added current-limiting resistor at bottom right.  I think you can trace it from the photo.

Thursday, March 26, 2015

STANCOR 10P TRANSMITTER: UPDATE 12

     A very long time in coming, I did make progress on the Stancor 10P, getting as far as power supply:

     Rectifier heaters and HV, filter caps, filter choke and bleeder.  It's a little crowded and I struggled to solder the capacitor and resistor to the chassis, even with the big iron.

     That work had it almost done, so tonight I added a few more things:
     Installed output feedthroughs and connected the output, wired up the primary power and the meter.

     Top view:

     Rear view:

     Front view:
     Initial tests -- just power-up, check for excessive current draw, check B+ -- went okay.  Hoping to try more by the weekend.

     Update: Tuned the transmitter up on 40m with a 100 Watt lamp in series, and it made a little power (4:1 balun to a Bird Wattmeter and 50 Ohm load.  Tried it without the lamp and blew the fuse instantly.  So....bigger fuse, and/or 150 and 200W lamps.  Maybe a little Amprobing..

     Update 25 May: Yesterday, I finally brought the transmitter up without a light bulb in series with the 120V AC and it worked. Last time I tried this with the wrong fuse (fast-blow) and it popped immediately -- at which point, I set the transmitter aside for awhile. I didn't have the balun and wattmeter for this test, just a 40W light bulb across the output, which is a bit low-resistance for the link coupling to match to. Plenty more to do but this was a big step.

Thursday, January 29, 2015

YANKEE RADIO TOOL KIT, #106

     Some time ago, I chanced on a nice Yankee No. 100 tool set.  Readers suggested I keep watch for a No. 106 boxed set of "radio tools," which, other than a soldering iron or copper, contains about everything you'd need to build a 1920s-type radio -- and is plenty useful on later equipment.
     I have seen a few come and go at princely prices, including a lovely store display version.  They are fine tools but not on my budget.  Or not until some months ago, when a slightly-grubby one showed up on a well-known auction site.  The serious collectors weren't after it but many of the tools were there; it was hard to figure out what was going on with the little drill, which appeared to have been taken apart.  The wooden case is the most difficult part to find -- the No. 105 kit offered all the tools except the drill, at half the price and in a cardboard box -- and the case was certainly there.
     It arrived in disappointingly worse shape than the original listing showed, due to a poor packing job.  Adjustments, as they say, were made.
     The mystery of the disassembled drill was simple enough: it was the wrong drill.  This proved no hardship; the little Yankee "Radio Drill," No. 1431, is commonly found and inexpensive.

     At present, I am repairing the case, starting with the badly cracked bit holder.  The two long screwdriver blades are missing, as is the uncommon Ratchet Tool Holder No. 230.  They may be a very long while in the finding.
     The incorrect drill is nevertheless a treat: a No. 1530 Ratchet Drill, which can be set to operate in five different modes: plain, left-handed ratchet, right handed ratchet, right-hand double, or locked.  The last is handy when tightening or loosening the chuck, the simple ratchet modes only respond to one direction of turning the crank -- but "double" turns the chuck clockwise no matter which way the crank is turned! 

Thursday, May 29, 2014

OLD-STYLE COVER FOR A MODERN LOG

     It is modeled after one published by Bud in the 1930s:
     I'm not too unhappy with how it came out.