A Crummy Commercial

I was looking for something in various junkboxes and found this board: From the bad old days when I liberated chips from sockets and didn't write down the date or name the boards.  It appears to use a 14 pin quad op amp due to the power supply connections.  There are three sets of wires, power/gnd, input and output ?  There is an LED, also a Radio Shack 1n34 diode. I *think* it might be a tone detector for Morse code ?  Since it was never boxed I assume it didn't work that well so I'll probably put it back in the junkbox.  The moral of the story:  don't rely on your memory, write it down ! Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm

I read these very interesting blog posts from VE7SL: http://ve7sl.blogspot.ca/2014/08/your-lf-stations-best-friend-scopematch.html http://ve7sl.blogspot.ca/2014/08/your-lf-stations-best-friend-scopematch_5.html Although they are from a decade ago I had never seen this Scopematch design before.  M0BMU came up with a very simple, elegant design which allows the user to see the phase relationship between the RF current and voltage on a transmission line.  Why didn't I ever think of that ?  (the answer:  I'm not too bright) The photos took me back to when I was in college studying the transmission of electrical power.  Similar to the RF waveform, 60 Hz power (in the US) waveforms for current and voltage can be out of phase just like the RF on a transmission line.  The cosine of the phase angle between the voltage and current is called the power factor.  The power factor for a resistive load like a toaster or an incandescent lamp would be 1 (the cosine of zero degrees where current

The Keyall HV was mentioned yesterday: https://wb9kzy.blogspot.com/2024/10/kit-re-assurance.html Here are a few more comments on the Keyall HV kit and keying.  I received email today asking about the Keyall - unfortunately it was from a DX ham so I wasn't able to try to sell him a Keyall HV.  But I did try to mention commercial alternatives to the Keyall designs.  Also I presented a little information about Solid State Relays (SSR). In general for ham radio applications a relay is used to switch DC voltages/currents.  A mechanical relay will handle either DC or AC - I've never seen a mechanical relay with polarity indicated on the output contacts.  However SSRs often DO have restrictions on what can be switched.  AC voltage/current is usually switched using a Triac, a 4 layer device.  But a Triac isn't useful for switching DC because once a 4 layer device goes on it stays on until the current goes to zero.  There may be ways to get around this (commutation) but in general a

kit means that it must be assembled by the customer From time to time I get emails from customers or prospective customers about a kit.  Usually it's something along the lines of: "will this kit work with my rig ?" And I usually try to answer promptly with an informative email.  First a disclaimer is included if I have no first hand experience with the equipment in question.  For example, I've never used an amplifier on HF so I'll mention this when fielding a tube amp / rig compatibility question for the Keyall HV.   I recently heard from a buyer of the original Keyall.  I wasn't sure if he had already been using the Keyall but he wanted to know if it would work with a solid state Kenwood rig and a Yaesu FL2100b amplifier.  I downloaded the manual for the Yaesu and saw that it used grid-block keying - the two amplifier tube grids were biased with a negative voltage which appeared to be less than the absolute value of -25 volts since that was the rating on the

I used to sell the Touch Paddle kit: notice the inter digital traces on the left http://wb9kzy.com/touchp.htm It was later replaced by the Touch Switch II and then the current PICPADL kit: http://wb9kzy.com/picpadl.htm The original Touch Paddle kit was a resistance based, skin conductivity circuit - a very low active power circuit which could be phantom powered via the dit/dah pullups. The Touch Switch II and PICPADL were capacitive sensing circuits which work better as paddles but at the cost of higher standby/active current. Getting back to the Touch Paddle circuit, it was very simple, just the 40107, an 8 pin CMOS IC, along with some caps/resistors and diodes.  The user made contact between the inter-digital fingers on the circuit board to "press" a dit or dah.  I used to fabricate a plastic sandwiched sleeve which fit over the fingers.  I discouraged the user from touching the fingers directly as they had solder-based tinning.   But I had a thought:  maybe this same circu

Per Ars, Archive.org data has been breached: https://arstechnica.com/information-technology/2024/10/archive-org-a-repository-storing-the-entire-history-of-the-internet-has-been-hacked/ This is what it says on the site on Friday, October 11, 2024: Per the Ars article I did check that site and found this: I didn't even know about 2022 Question Pro breach - I *think* that is the way Kellogg's does it's surveys for Kitchen Insiders or at least the way it used to do them. Best Regards, Chuck, WB9KZY http://wb9kzy.com/ham.htm

I had a problem with my Nikon 500 mm mirror telephoto lens.  It came with a lens hood built in (a cylinder of aluminum less than an inch high) into which a lens cap was screwed.  But over the years of non-use the lens cap could NOT be removed - it seemed like the cap and the lens hood had been welded together. Luckily the lens works OK without the screw in hood, so when I wanted to use the lens I just had to unscrew the lens hood. None of the other Nikon or other vendor lenses I own have screw-in lens caps so I've never had this happen before. I didn't want to use any kind of lubricant or penetrating oil on the cap and lens hood because I was worried that any residual oil might get on the lens and affect the coating. So I finally decided to try heating up the lens hood in a shallow pan of water heated on the stove.  But since the cap and hood were joined so tightly it was impossible to heat just the lens hood. Anyway, after 5 minutes or so I took the hood/cap out of the water,