October 2025

The Superflex

A Publication of the Alabama Historical Radio Society October 2025

NOTE FROM PRESIDENT WAG

Members,

Mark your calendars!

The date for next AHRS Business meeting will fall on the usual 4th Monday, Nov 24th, 2025, (just before Thanksgiving) at 7:00 PM. The Exec CMTE will meet in person by invitation only at 6:00 PM.

Join Zoom Meeting
https://us02web.zoom.us/j/86330579924?pwd=ckZLWEJMb0V2ajhBUzh0S2liQnlmZz09

Meeting ID: 863 3057 9924
Passcode: 631140

Mike was such an integral part of AHRS and will be missed on many levels. The Celebration of Life is scheduled for Friday, November 14, 2025 starting at 2:00 PM at the AHRS Shop. Many member of his family will attend. All are welcome.

We are working to transition all his tasks and duties to current members. If a matter that Mike would have handled arises, let me, Steven, or another officer or board member know. As a society, we must search for a new treasurer, and Mike Spanos has volunteered on a trial basis. The position involves some knowledge of Quickbooks, but the number of monthly transactions we deal with, and other duties, are minimal. Steven and I are working to make the transition as seamless as possible:

· We have opened a new checking account appropriate for a non-profit.

· Monthly automatic debits have been migrated to the new account.

· New checks have been ordered.

· Our credit union CD accounts has been updated.

· We can still accept payments on PayPal and hope to have all other financial functions are operational.

We anticipate participating in a celebration of Mike’s life, especially as it related to AHRS; details are being arranged and will be sent as they develop.

In the way of member updates, Grady Shook’s wife required urgent hip surgery recently but is doing well.

It is that time of year to start thinking about several things:

· Yes, dues and membership renewal for 2026 will be coming soon, payable in person at the shop, by mail or by Paypal through our website.

· Our year-end business and board meeting with Holiday get-together, including guests, is on the horizon with a date to be set soon.

· The Nominating CMTE and election of officers and board members: If you wish to volunteer as a member of the committee and/or in AHRS leadership, let John Outland know; he is forming the Nominating CMTE which will develop the 2026 slate of officer and board nominees.

Boyd’s next class is Saturday, Nov 1st, 2025, at 9:00 AM in person and via Zoom; he plans to discuss the following:
1. Project review of the RCA 1050 that had a puzzling hum problem

2. Troubleshooting 'hum'

The following link remains in effect:
https://us02web..us/j/88180351990?pwd=N2lucjB3WVhtR05nTSs5S0xGcURadz09

Let me thank the Technology CMTE and chair Boyd Bailey for holding its first formal meeting via Zoom on 29 September 2025. Topics discussed included adoption of a password manager, AHRS computer backup and integration options, enhancements to our website, and YouTube hosting. The group has promised to provide tech support to other committees and the society (without having to call a foreign country, navigating an automated menu, or waiting for hours on the phone) and plan meet on a quarterly basis. We’ll try to keep the membership aware of the committee’s work as it progresses.

Tom Killian, Grady Shook, and Ray Giles hosted our most recent auction on Saturday, October 18, 2025, which was in person, but members were allowed to bid by proxy. Thanks to Ray for his cleaning the radios and Maurice Hill (and anyone else I might’ve missed) who checked them electronically ahead of time! We have some unsold items on the table at the shop so if you drop by and see one of interest, consider making a donation and it’ll likely follow you home. Also, if you missed the auction and think an item may still be available, contact us.

Save the date! The Montgomery Hamfest (Nov 8^th, 2025, at Alcazar Shrine Temple, 555 East Blvd, Montgomery AL 36117, 8:30 AM-1PM). AHRS is planning to attend so we welcome volunteers! https://w4ap.org/hamfest

The Helena (Shelby Co) Tailgate/Hamfest was scheduled Saturday 25 October 2025 from 8am-12pm but was canceled due to a scheduling conflict at the site; it may be rescheduled, so check for details on its website. https://www.helenahamfest.com/The upcoming Veterans Day parade on November 11^th should not require closing the shop since it starts at 1pm and stages in another area downtown.

Dave Cisco is working on a presentation about the History of AHRS, including pivotal individuals who are no longer active or with us. Hopefully, this will be available at an upcoming business meeting and become a potential forum for the 2026 BirmingHamfest. We have another potential program from John Green on radio astronomy in the works.

Dave provided this clipping and be sure to check the date. It’s old, so apologies for its being off-kilter.

I wish to thank VP Steven Westbrook in advance for keeping things running whilst I am gone from the end of October until mid-November. We are traveling to Jordan, Cairo, and the upper Nile, a trip I have wanted to do for years. Plenty of antiquities, but no antique radios likely to be sighted… Over the decades, a combination of my day job and unsettled politics in the region precluded a visit. We will be back in plenty of time to celebrate Thanksgiving. 🍗🦃🥘

Respectfully submitted, (mostly) enjoying college football (at this writing, Hugh Freeze is still at Auburn, but Brian Kelly was just fired from LSU), and welcoming cooler temps, I remain,

President Wag, AHRS

Power Supplies

In a previous newsletter member Rick Curl submitted an article on wall want We recently an email from Rick directing us to the article below in all EE World On line.

When I wrote the article about wall warts I touched on the difference between linear and switching supplies. Here’s a short article that expands on that line of thought:

Rick Curl

AC/DC supply shrink illustrates dramatic technology shift

October 24, 2025 By Bill Schweber Leave a Comment

Figure 1. This “workhouse” linear Analog Devices AD956 AC/DC power supply from Analog Devices still delivers a noise-free 5 V/2 A output, despite its nearly 50-year age. (Image: Bill Schweber)

While looking through some of my accumulated AC/DC wall adapters, I came across an AC-line input, 5-volt, 2-amp output linear power supply from “back in the day.” The Analog Devices model 956 encapsulated-brick module is serious business, as it weighs almost a kilogram (just under two pounds). I have used it occasionally as a bench supply when testing or fixing various small products.

According to its date code, it was made in 1997 (it’s nearly 50 years old!), yet it still works fine. Its output is rock solid despite load transients and has no visible output noise. I couldn’t find a data sheet online, even at legacy-documentation sites, but the solid epoxy block (10.2 × 6.8 × 5.1 cm/4.0 × 2.7 × 2.0 inch) seen in Figure 1 reinforces the definite impression that it is electrically and physically “bulletproof.”

The no-nonsense screw terminals for AC input and DC output connections are clearly marked, as shown in Figure 2. It attaches to a chassis or reinforced PC board via #4-40 screws, which go into threaded metal inserts in each of its four corners.

Going to a switching approach

Figure 2. The AD956 has easy-to-use, clearly marked screw terminals; the AC-line terminals need safety protection, which must meet various regulatory mandates. (Image: Bill Schweber)

Thinking again about this supply’s size and weight relative to modern ones with comparable ratings, I started to wonder: we all know that IC feature and transistor sizes have shrunk dramatically over the decades as adjunct of Moore’s “law,” but what about power supplies? While the improvement has certainly not been as dramatic, the development of switching power-supply technology (formally called a switched-mode power supply, or SMPS) and its many variants over the past decades has dramatically shrunk the size, weight, and losses of AC/DC supplies.

I did a quick search for some state-of-the-art switching supplies with the same ratings and found that the fully encapsulated, PC-board mount PSK-10B-S5 (5.08 × 2.54 × 2.1 cm/2 × 1 × 0.83 inch) from CUI/Bel Fuse was a representative 5V/2A AC/DC unit, shown in Figure 3. There are even smaller ones available that operate in the hundreds of kilohertz and into the low-megahertz range, but this 85-kilohertz unit is a good example due to its overall performance specifications.

Figure 3. The CUI PSK-10B-S5 delivers the same voltage/current ratings as the AD956 but uses a linear topology, resulting in a far lighter, smaller, and efficient unit. (Image: CUI/Bel Fuse)

Note that I deliberately chose not to consider mass-market consumer units such as standard USB adapters/chargers, even though they might be even smaller and lighter than the CUI unit. My reasoning was that their quality is usually inferior to a “proper” AC/DC supply in terms of DC output stability and transient response, operating-temperature range, and overall electrical and mechanical ruggedness.

Table 1 shows the numbers for the CUI PSK-10B-S5 compared to those for the AD956, illustrating the reality of a switching supply versus a linear one with the same basic ratings. In a word: the differences in volume, weight, and efficiency are truly impressive.

Table 1. This brief comparison provides a sense of the reduction in size and mass, plus an increase in efficiency, that is available using a modern switching AC/DC supply compared to an older linear supply. (Image: Bill Schweber)

Further, like nearly all of today’s AC/DC supplies, the CUI unit must meet a very long list of complicated and detailed regulatory mandates covering EMI/EMC performance, galvanic-isolation voltage, various safety demands, and ROHS, all in addition to protection against adverse thermal and short-circuit conditions. Many of these requirements were not in place in 1977 or were much “looser” then.

Given the many real and critical advantages of switching AC/DC power supplies compared to linear designs, you might think that linear ones are obsolete, but that’s not the case at all. For example, Acopian Technical Company offers several standard families of linear supplies with outputs ranging from 40 watts to 1200 watts, with voltage outputs from 1.5 VDC to 150 VDC; vendors offer even higher power, and custom units are available.

Acopian doesn’t try to convince prospective users that linear supplies are the better choice in all applications. They note that “a 250-W linear power supply would require 600 in³ of mounting space and weighs 26 pounds, while a comparable AC/DC switching power supply would require 60 in³ of mounting space and weighs 2 pounds.” Further, they present a lengthy table with clear numbers comparing the attributes of these two supply topologies. In addition, they acknowledge that switching supplies can be used to both step up and down the input voltage, while linear ones can only provide a step-down output.

Given the many tangible benefits of a switching supply, why would an engineer even consider selecting a linear one? Sometimes, the positive attributes of the linear supply —lack of switching clock, nearly zero noise, fast transient-recovery time, longer hold-up time, and tight line regulation — outweigh the negatives and are critical factors in an application such as high-resolution X-ray machines. As in nearly all engineering endeavors, making a choice requires a balance among priorities.

Once again, designers first look at conventional wisdom, but don’t necessarily exclude unpopular alternatives. Sometimes they must go against the flow when the technical facts require consideration of less-conventional and perhaps even presumed-obsolete alternative solutions. It’s the classic engineering-design conundrum revolving around the trade-offs, technical costs, and realities of the situation.

References

Power Supply Comparisons: Difference Between Linear and Switching Power Supply, Acopian Technical Company
PSK-10B Series Data Sheet, CUI/Bel Fuse

Battle of the Beams

The Battle of the Beams was a period early in the Second World War when bombers of the German Air Force (Luftwaffe) used a number of increasingly accurate systems of radio navigation for night bombing in the United Kingdom. British scientific intelligence at the Air Ministry fought back with a variety of their own increasingly effective means, involving jamming and deception signals. The period ended when the Wehrmacht moved their forces to the East in May 1941, in preparation for the attack on the Soviet Union.

The idea of beam radio navigation was developed during the 1930s, initially as a blind landing aid. The basic concept is to produce two directional radio signals that are aimed slightly to the left and right of a runway's midline. Radio operators in the aircraft listen for these signals and determine which of the two beams they are flying in. This is normally accomplished by sending Morse code signals into the two beams, to identify right and left.

For bombing, the Luftwaffe built huge versions of the antennas to provide much greater accuracy at long range, named Knickebein and X-Gerät. These were used during the early stages of the Blitz with great effect, in one case laying a strip of bombs down the centerline of a factory deep in England. Tipped off about the system's operation by pre-war military intelligence, the British responded by sending their own Morse code signals so that the aircraft crew believed they were always properly centred in the beam while they flew wildly off course. The Germans became convinced the British had somehow learned to bend radio signals.

When the problem became widespread, the Germans introduced a new system that worked on different principles, the Y-Gerät. Having guessed the nature of this system from a passing mention, the British had already deployed countermeasures that rendered the system useless almost as soon as it was used. The Germans eventually abandoned the entire concept of radio navigation over the UK, concluding the British would continue to successfully jam it.

Countermeasure

Efforts to block the Knickebein headache were codenamed "Aspirin". Initially, modified medical diathermy sets transmitted interference. Later, local radio transmitters broadcast an extra "dot signal" at low power on nights where raids were expected. The German practice of turning on the beams long before the bombers reached the target area aided the British efforts. Avro Ansons fitted with receivers would be flown around the country to find the beams' location to be reported to nearby broadcasters. The low-power "dot signal" was initially transmitted essentially at random, so German navigators would hear two dots. This meant there were many equisignal areas, and no easy way to distinguish them except by comparing them with a known location. The British transmitters were later modified to send their dots at the same time as the German transmitters, making it impossible to tell which signal was which. In this case the navigators would receive the equisignal over a wide area, and navigation along the bomb line became impossible, with the aircraft drifting into the "dash area" and no way to correct for it.

Thus the beam was seemingly "bent" away from the target. Eventually, the beams could be inclined by a controlled amount which enabled the British to fool the Germans into dropping their bombs where they wanted them. A side effect was that as the German crews had been trained to navigate solely by the beams, many crews failed to find either the true equisignal or Germany again.^[19] Some Luftwaffe bombers even landed at RAF bases, believing they were back at base.^[20]

Y-Gerät Countermeasure

The British were ready for this system even before it was used. By chance, the Germans had chosen the operating frequency of the Wotan system badly. It operated at 45 MHz, which happened to be the frequency of the powerful, but dormant, BBC television transmitter at Alexandra Palace. All Jones had to do was arrange for the return signal to be received from the aircraft and then sent to Alexandra Palace for re-transmission. The combination of the two signals modified the phase shift, and thus the apparent transit delay. Initially, the signal was re-transmitted at low power, not powerful enough for the Germans to realise what was happening, but enough to spoil the accuracy of the system. Over subsequent nights, the transmitter power was gradually increased.

As Y-Gerät's use went on, the aircrew accused the ground station of sending bad signals and the ground station alleged the aircraft had loose connections. The whole scheme appealed to Jones as he was a natural practical joker and remarked that he was able to play one of the largest practical jokes with virtually any national resource that he required. The gradually increasing power conditioned the Germans such they did not realize that the system was being interfered with, but believed that it suffered several inherent defects. Eventually, as the power was increased enough, the whole Y-Gerät system started to ring with all the feedback.

The Luftwaffe, finally realizing that the British had been deploying countermeasures from the very first day that the system was used operationally, completely lost faith in electronic navigation aids as the British had predicted, and did not deploy any further system against Great Britain, although by this time Hitler's attention was turning towards Eastern Europe.

Wikepedia (edited)

Quote of the Month

“I know a man who gave up smoking, drinking, sex and rich food. We was healthy right up to the day he killed himself.”

-Johnny Carson

We meet every Saturday (unless a Holiday weekend) at 8:30 A.M. until around 11:30 A.M., at the one-story AHRS Shop at the corner of 8th Avenue North and 18th Street, (1801 8th Avenue North, Birmingham, AL 35203). Please use the rear (Southeast) entrance.

The Shop is open on Tuesdays at 8:30 A.M. until around 11:30 A.M. Note that parking can be a problem on Tuesdays, so you may have to find street parking occasionally.

Regular monthly members meetings are on the fourth Monday night starting at 7:00 PM with the Executive Meeting starting at 6:30 PM

Please come join us!

The electronics classes are generally on “Zoom” and “in-person” at the AHRS Shop, typically the first Saturday of each month (except when something special is taking place, then we agree on an alternative Saturday)

Check your emails for the schedule and how to participate.

We start from the beginning Ohms Law, inductors, resistor and Capacitors color codes, as well as what each component does within the radio circuits. We also teach how to use test equipment used in the repairing of radios. We teach troubleshooting radio troubles, as well as how to read a radio diagram.

Currently the class is studying advance topics relating to troubleshooting and project radio repair. We are retooling our website in hopes of archiving prior classes for those who may have missed a prior class. Email will provide timely details on date, topics & links.

There are coil winding classes, and one-on-one repair help. Come join these classes!

Membership dues are $25.00 a year, payable beginning in January. If you have questions about your dues, you can contact Treasurer Mike Woodruff at 205-823-7204. Dues can be mailed to AHRS at P.O. Box 131418, Birmingham, Alabama 35213 or paid on-line at https://alhrs.org

Be sure and check out our website at https://alhrs.org, which has copies of all newsletters from 2006 to the present (click on News), videos, photo galleries, museum, Old Time Radio columns, Projects, Reading Rooms, Archives, and Contact Information. Within the next few months we hope to update our website and add additional content and new capabilities