The recent schematic puzzle dredged up one of my 'pet peeves' about published schematic drawings. Namely the often inconsistent, occasionally incorrect, use of the drawing conventions for intersecting

And there's a great book published by IEEE Press Crystal Clear – The struggle for reliable communications technology in World War II, Richard Thompson, Jr.; IEEE Press; Piscataway, NJ; 2007 ISBN 978-0

KPH Enigma test ... at 1900 UTC I'm copying KPH on RTTY (45 baud, 170 Hz shift) at 13585.5 kHz, using fldigi About 80% print here in Louisiana, So I'm hoping the 12808.5 or perhaps 17016.8 kHz CW tran

Hi David, The 2N5819 diodes actually have the part number printed on them - but you'll probably need a 5x or better magnifier to see. The polarity is determined by the light colored band around one en

Hi again, David, Thanks for the info. I didn't know for sure that your dummy load had that convenient built in diode peak detector. You are quite right. (Vp)^2 / 100 = power into 50 ohms. The detected

Hi David, I'm still wondering about that voltage. On a hunch I hooked up a dummy load to my K2, then connected a simple digital DMM across the dummy load. Set the rig for 5 W out (confirmed with a QRP

Hi David, If your meter is truly reading RMS volts, the the power formula is just (Vrms)^2/ 50, the same as for DC, where power = V^2 / R If you are using a diode detector RF probe with your DMM, so t

Hi Lisa, I see you found a volunteer to print a case for you. Just in case anyone needs them, attached are STL files to 3D print a case for the Crystal Spotter. Uses about 30 grams of material Often p

Hi Lisa and Brad, One thing to be aware of is that the revB (Blue) Bayou Jumper requires that the keyer's output transistor pass the full TX current of the rig - several hundred mA. The standard BS170

A trick I've used to make LEDs visible when they were on a PCB and wasn't possible to have them poke through a hole. I made a hole or slot in the case. Then placed it so that the outer surface of the

Right - in "662536S" the "S" suffix refers to the small box of the three-box set. You can buy the small box individually in the stores, but online you can only order the three-box set as #662536, curr

Hi Bob, The dimensions of the Hobby Lobby box changed slightly a while back. In response to that the boards for the revC and revD were reduced slightly (0.05") in length and width, and the mounting ho

Hi again Marc, To address your other comment.... it would take a fair bit of cobbling and trace cutting/jumpering to implement the new keying scheme on earlier BJ versions. In my estimation it wouldn'

Hi Marc, Dave, NM0S, developed the new keying circuit. The manual has a scope grab of the keyed waveform at the ARRL Lab testing standard of about 60 wpm (a skosh fast for the BJ's onboard key LOL) On

When y'all get your Magic Box boards, don't forget there is a sub-group for the Magic Box v2.5 <https://4sqrp.groups.io/g/magic-box> Manuals, PCB files, software, 3D print info and other stuff n the F

Should you be heading for the Dayton area for the big 'Fest and/or FDIM, don't forget you're less than 10 miles away from the National Museum of the U.S. Air Force. Open 9am-5pm 7 days a week And if y

The has been some interest popping up in the new v2.5 Magic Box design. details at <https://github.com/ku4qo/MagicBox2.5> Thanks to Jim and Mike for making their design efforts available to us. It won

Hi Tom, Your self-adhesive stickers will probably behave a bit different compared to the water-transfer type. But I'd recommend, as some one mentioned already, applying a couple coats of a clear finis

Thank you so much, Jim and Mike, for making the fruits of all your hard work available to us. I built one of the original MBs, used it with some of my regen receivers, sold it, then had seller's remor

John and Dave are on the mark. A "via" is just a plated through hole that joins the top side copper to the bottom side copper. Sometimes they are used to make transitions along a trace, so that the tr