Archive for the ‘Uncategorized’ Category

Inspirational YLs

February 20, 2018 Leave a comment

Are you looking for ways to inspire young women to be involved in science and amateur radio? These inspirational women may be the answer.

Female Space Hams

Tamara E. Jernigan (USA) formerly KC5MGF. Jernigan attended Santa Fe High School in Santa Fe Springs, CA. She graduated in 1977. Jernigan attended Stanford University, where she earned a B.S. degree in physics in 1981, an M.S. in engineering science in 1983. At the University of California, Berkeley, she received an M.S. in astronomy in 1985. In 1988 she was awarded a Ph.D. in space physics and astronomy from Rice University.

She entered the NASA Astronaut Corps in 1986 and retired in 2001. Her first trip to space was on June 5, 1991.[1] She flew on five Space Shuttle program missions (three on Columbia and one each on Endeavour and Discovery) and logged 1512 hours in space. In her last mission on Discovery in 1999, she performed an extra-vehicular activity for 7 hours and 55 minutes.


Renata Luise Bruemer (Germany) DB5PL Studied mathematics and physics at the Munich University; Ph.D. in meteorology from University of Miami, Florida, 1986; research scientist at University Corporation for Atmospheric Research, Boulder, Colorado; was selected as backup for STS-55 (D-2 mission).


Born in West Point, New York, Yvonne Cagle (USA) formerly KC5ZSV graduated from Novato High School in Novato, California. She received her bachelor’s degree in biochemistry from San Francisco State University in 1981, and a doctor of medicine degree from the University of Washington in 1985. She completed a transitional internship at Highland General Hospital in Oakland, California in 1985 and received a certificate in Aerospace Medicine from the School of Aerospace Medicine at Brooks Air Force Base, Texas, in 1988. She then went on to complete a residency in family practice at Ghent FP at Eastern Virginia Medical School in 1992 and received certification as a senior aviation medical examiner from the Federal Aviation Administration in 1995.

Cagle retired from the United States Air Force with the rank of Colonel in 2008. As a commissioned medical officer in the USAF Cagle served as Air Force Medical Liaison Officer for STS-30, before she became a NASA astronaut. She worked as medical doctor at NASA’s Occupational Health Clinic from 1994 to 1996. In 1996 she was selected for astronaut training by NASA.

Yvonne Cagle was a member of the Astronaut Class of 1996 (NASA Astronaut Group 16). She is currently assigned to Johnson Space Center’s Space and Life Sciences Directorate.

Dr. Cagle is also an advisor for NASA’s Flight Opportunities Program (originally named CRuSR – Commercial Reusable Suborbital Research Program). Currently Dr. Cagle is on faculty and serves as the NASA liaison for exploration and space development with Singularity University. During the workshop, Dr. Cagle was embedded with the crew as a crew training consultant and advisor, providing insights and feedback to both crew and study team from the viewpoint of an astronaut, flight surgeon, space development expert, and science liaison.

She has recently been selected reserve crew for Hawai‘i Space Exploration Analog and Simulation (HI-SEAS), which is part of a study for NASA to determine the best way to keep astronauts well nourished during multiple-year missions to Mars or the moon. Furthermore, Dr. Cagle is also listed as an honorary member of the Danish Astronautical Society.


Tracy Caldwell Dyson (USA) KF5DBF  born Tracy Ellen Caldwell; August 14, 1969 is an American chemist and NASA astronaut. Caldwell Dyson was a Mission Specialist on Space Shuttle Endeavour flight STS-118 in August 2007. She was part of the Expedition 24 crew on the International Space Station between April 4, 2010 and September 25, 2010. She has completed three spacewalks, logging more than 22 hrs of EVA including work to replace a malfunctioning coolant pump.

As an undergraduate researcher at the California State University, Fullerton (CSUF), Caldwell Dyson designed, constructed and implemented electronics and hardware associated with a laser-ionization, time-of-flight mass spectrometer for studying atmospherically relevant gas-phase chemistry.

Also at CSUF, she worked for the Research and Instructional Safety Office as a lab assistant performing environmental monitoring of laboratories using hazardous chemicals and radioactive materials, as well as calibrating survey instruments and helping to process chemical and radioactive waste. During that time (and for many years prior) she also worked as an electrician/inside wireman for her father’s electrical contracting company doing commercial and light industrial type construction.

At the University of California, Davis, Caldwell Dyson taught general chemistry laboratory and began her graduate research. Her dissertation work focused on investigating molecular-level surface reactivity and kinetics of metal surfaces using electron spectroscopylaser desorption, and Fourier transform mass spectrometry techniques. She also designed and built peripheral components for a variable temperature, ultra-high vacuum scanning tunneling microscopy system.

In 1997, Caldwell Dyson received the Camille and Henry Drefus Postdoctoral Fellowship in Environmental Science to study atmospheric chemistry at the University of California, Irvine. There she investigated reactivity and kinetics of atmospherically relevant systems using atmospheric pressure ionization mass spectrometry, Fourier transform infrared and ultraviolet absorption spectroscopies. In addition, she developed methods of chemical ionization for spectral interpretation of trace compounds. Caldwell Dyson has published and presented her work in numerous papers at technical conferences and in scientific journals.

Selected by NASA in June 1998, Caldwell Dyson reported for training in August 1998. Her Astronaut Candidate Training included orientation briefings and tours, numerous scientific and technical briefings, intensive instruction in Shuttle and International Space Station (ISS) systems, physiological training, ground school to prepare for T-38 flight training, as well as learning water and wilderness survival techniques. Completion of this training and evaluation qualified her for flight assignment as a mission specialist.

In 1999, Caldwell Dyson was assigned to the Astronaut Office ISS Operations Branch as a Russian Crusader, participating in the testing and integration of Russian hardware and software products developed for ISS. In 2000, she was assigned prime Crew Support Astronaut for the ISS Expedition 5 crew, serving as their representative on technical and operational issues throughout the training and on-orbit phase of their mission.

During ISS Expeditions 4 through 6, Caldwell Dyson also served as an ISS spacecraft communicator (CAPCOM) inside Mission Control. In 2003, she made a transition to the Astronaut Shuttle Operations Branch and was assigned to flight software verification in the Shuttle Avionics Integration Laboratory (SAIL) and also worked supporting launch and landing operations at Kennedy Space Center, Florida. Caldwell Dyson also served as Lead CAPCOM for Expedition 11.

Caldwell Dyson was assigned to, and later flew on STS-118, Space Shuttle Endeavour, on August 8–21, 2007, which was the 119th space shuttle flight, the 22nd flight to the station, and the 20th flight for Endeavour. Caldwell Dyson was assigned as Mission Specialist #1 on this flight. During the mission Endeavour’s crew successfully added another truss segment, a new gyroscope and external spare parts platform to the International Space Station. A new system that enables docked shuttles to draw electrical power from the station to extend visits to the outpost was activated successfully. A total of four spacewalks (EVAs) were performed by three crew members. Endeavour carried some 5,000 pounds of equipment and supplies to the station and returned to Earth with some 4,000 pounds of hardware and no longer needed equipment. Traveling 5.3 million miles in space, the STS-118 mission was completed in 12 days, 17 hours, 55 minutes and 34 seconds. Finally, during the flight of STS-118, Caldwell Dyson celebrated her 38th birthday in space.

On April 4, 2010, Caldwell Dyson joined the Expedition 23 crew aboard ISS. She lifted off on April 2, 2010 from the Baikonur spaceport aboard a Russian Soyuz capsule (Soyuz TMA-18). After 176 days duty as part of the Expedition 24 crew, she returned to Earth with the Soyuz TMA-18 landing unit. Together with commander Aleksandr Skvortsov and flight engineer Mikhail Korniyenko, Dyson landed in Kazakhstan on September 25, 2010.

In a television interview on the 40th anniversary of the first moon landing, she said she is the first astronaut who was born after Apollo 11.

As Tracy Dyson, she is the host of a series on NASA TV called “StationLife”, which focuses on facets of life aboard the International Space Station.

She appeared on Episode 3 of MasterChef Junior Season 4.

On March 21, 2017, Dyson stood behind President Trump as he signed a bill for NASA to send humans to Mars in 2030s and receive $19.5 billion in 2018 funding. Dyson and fellow NASA astronaut Chris Cassidy presented Trump with an official flight jacket during the ceremony.


You can read about many more inspiring female astronauts who were hams at the following links

Categories: Uncategorized

KRK VXT6 Repair

February 6, 2018 Leave a comment

Some time ago I picked up a powered studio monitor for about $20. The music store was closing down and the speaker had a fault- the tweeter wasn’t working. These studio monitors of this size range in price from about $200 to $400, so I couldn’t pass up the deal, as I was sure I could repair it – one day.

That day finally arrived. I had purchased a spare tweeter which had sat in the parcel unopened for some time. When I unpacked it, you guessed it, it was the wrong part. Given that it had come from the US, the return postage added way too much to the cost of repair, so I decided to repair the existing tweeter.


There isn’t much to a permanent magnet tweeter, basically the only electrical component in it is a super-fine winding of copper. This usually fails to due physical stress or sometimes an over-voltage or over-current fault. All that is required is to solder the broken wire- easy right? Well the wire is quite a bit thinner than a human hair and enamelled and wound very tightly into a place that is difficult to get to. You got the picture?


The good story is that after one repair, a subsequent failure and another repair, the speaker works great


Categories: Uncategorized

My Dad’s 1935 Ultimate Receiver Part 1

January 23, 2018 Leave a comment

Some time back in 2015 I obtained a 1935 Ultimate AU Receiver. I had just recently restored a 1936 Pilot receiver and was keen to do the same for this radio. What I most liked about the radio was that its “birth year” was the same as my Dad’s. Dad’s 80th birthday was forthcoming and I thought that the radio would make the ultimate present. He and my Mum had been loaned a console radio early in their marriage and I know they loved it and were disappointed to see it return to the owner, many years later.

thumbnail_RL AU 34 pix 2

I set about doing as much restoration as I could before my Dad’s birthday, which was to be soon. Unfortunately it was during the worst part of my life, when my gender disphoria had resulted in serious mental health issues and the loss of all that was dear to me. I rushed to get the radio ready for the birthday celebration while dealing with my own demons. One capacitor proved difficult to obtain- a filter capacitor across the DC output of the rectifier, so I left the original there. I left the radio running for many hours as a test and it worked a treat.

When I presented the radio to my Dad, on the day after his birthday, it immediately failed with a loud pop. I left it with him, with the view to getting back to it “one day.” BTW he loved it.

However my life was about to take a radically different path and it would be some time before I saw the radio and indeed my Dad again…… More in Part 2

Categories: Uncategorized

A Different Project- An Audio Amp

August 26, 2017 2 comments

A friend of mine contacted me to ask if I knew someone who could trouble-shoot her valve driven audio amplifier- of course I said I could. The amplifier is an interesting Chinese brand, a Yaquin MC-100B. It can be used in two different modes Ultra-linear or Triode mode. The amp uses a bunch of valves including 2x 12AX7 a pretty common  amplifier found in everything from guitar amps to radios, used in this case as voltage amplifiers. It also uses 4x 6N8P as drivers and cathode followers and finally 4x KT88 valves in the output stage.

My friend complained that the amp had not worked for nearly 12 months but the filaments on all valves glowed. According to her tests, it had no output at all. She dropped it off and I promised to take a good look at it. Since I was lacking any means to connect any kind of music source to it, I got straight down to visual fault finding- a mistake but only a minor one- it simply cost me some time. I was later to find that when I did connect it to a source it worked, though not perfectly.

I began by removing the bottom plate and visually inspecting all components and PC boards for damage, burns, broken tracks, anything obvious- there was nothing. I then began checking all voltages at the appropriate test points. Beware if you are attempting to do the same. There are some KILLER voltages in here; some over 1000V AC. Beware!

I found all to be within specification. I at this time did not check the bias as I wanted to first confirm the amp had no output at all. I connected my audio signal generator to the audio inputs on the front of the amp (labelled 0.6V). I configured the amp switches appropriately for these inputs and connected some speakers. I immediately heard a pretty good tone, so the amp did have output after all. I confirmed with my friend that she had not just inadvertently had the inputs configured wrong, but she advised she had tested all configurations. hmmmmmm …some testing at her place may be necessary to check that the audio source is not the issue.

Continuing with my testing I noticed that one channel was lower output than the other. I began by checking all bias voltages, finding all of them low but one non-existant. I swapped the suspected KT88 with one of the good ones and the bias voltage returned- indicating a failed tube. I then set about adjusting the bias voltages to 0.55V as specified. Even with one channel low, the amp sounds pretty good.

I instructed my friend to purchase her choice of new KT88 or a matched set of four. This amp is not very sensitive to valve changes, so I would just purchase one. I finished up the repair with fixing the cage over the valves, as it had begun to come apart.

Categories: Uncategorized

I Need to Restore Before I Restore

July 31, 2017 Leave a comment

Today I began preparing a list of parts required to restore my Echopone EC-1, and familiarizing myself with the alignment procedure. I also made a list of parts required to interface the test equipment with the radio.  It was at this point that I realized things would be a whole lot simpler if I used a Vacuum Tube Voltmeter for the RF alignment. While I can use my signal generator and my oscilloscope for the IF alignment, I liked the simplicity of using a VTVM for the RF alignment.

There is only one problem. I have a habit of purchasing vintage test equipment that needs restoring, for example my capacitance tester and other items. So it is with my VTVM which is a Heathkit V-5. Made in 1952, the V-5 like all electronics of that era, uses wax and paper capacitors. These capacitors will almost certainly have failed or will fail if I power the unit. So it is that I added to the list of parts, two capacitors required to restore the V-5. Of course it won;t be as simple as replacing the capacitors- I will have to check all resistors and calibrate the unit as well as make a probe for it. But the beauty is, I will have a working VTVM that like my radios is from an earlier time.


Categories: Uncategorized

Echophone EC-1 Beginnings

July 29, 2017 Leave a comment

If you saw my previous posts Echophone EC-1 and The Echophone EC-1 Unboxing you will know that I put off the restoration of this little gem of a radio until such time as I was able to spend some more time on it. As often happens with these tasks, it never really is about the time, but more about finding the headspace to allocate and finding the motivation.

A great deal of organisation and pre-work goes in to any such restoration, even if the final result is not to have it look exactly like it came out of the factory yesterday. So it is that I find, despite having many other things on the go, including moving house, a very busy career, commitments in music and cycling, I have somehow found the motivation to begin.

For those of you who have never undertaken such a task as restoring old radio equipment, I will be pleased to document the process here and via Youtube. The EC-1 is a very simple radio- a variant of the All American 5 chassis. This design is quite simple and therefore very common in earlier radios, but is is not particularly safe- it requires some modifications to make it safer. Restoring valve radios often means dealing with lethal voltages, so if you undertake a restoration yourself, you do so at your own risk. I am not an qualified technician, just a holder of an Advanced Amateur Operators Certificate of Proficiency (AOCP), the highest licence category for amateur radio operators in Australia. I am certainly not an expert. In fact when it comes to radio repair, I am entirely self-taught. If you wish to see someone far more skilled than me restore the same radio model, you can go to the video below.

Screen Shot 2017-07-29 at 8.25.19 PM

The first steps for me after obtaining the radio and inspecting it are now underway.

  • obtain circuit diagram (done)
  • if possible obtain alignment procedure (done)
  • Make a list of components to replace- all capacitors other than silver mica and possibly some resistors depending on how they test
  • construct several pieces of test circuits such as impedance matching circuits for connecting test equipment to the radio

As I work my way through the process of restoring this radio, I will post updates here.


As they are wired from the factory, these radios are deadly dangerous and you shouldn’t even plug them in until they have been made safe.  These radios have what is called a “hot chassis,” and that makes them very dangerous to work on or even to plug in.  Do not attempt to test or repair them until you or a skilled technician have rewired them as I will describe below.  I can not emphasise too strongly how important it is that you follow my advice because over the years, many people have been killed by “hot chassis” radios and many others have received painful shocks.  The fact is, the modifications I shall describe are not only very effective, but are quite easy to do and will cost you less than $10, so there is no excuse for not doing the work.

Why are these radios so dangerous?  Depending on which way their original unpolarized plug is plugged into the wall socket, the chassis of these sets have a 50/50 chance of being “hot” if turned on and a 50/50 chance of being “hot” if simply turned off.  On or off, the chassis will be hot at some point and you will get a bad shock if you simply touch the insides of the radio.  To make matters really deadly, if the grommets that insulate the chassis from the outside case are in bad shape, you will get electrocuted just touching the radio.

How did Hallicrafters and other manufacturers of  “hot chassis” radios get UL approval to manufacture and sell such dangerous radios?  Back when these radios were new, there were no polarized wall sockets and power plugs so radio manufacturers made them safe by insulating the case from the chassis with rubber grommets or by putting the chassis in wooden/plastic cases.  All these radios had Masonite rear covers that prevented probing fingers from touching the chassis and they all had bold warning labels telling you NOT TO TOUCH THE CHASSIS OR CHANGE THE TUBES WITH THE BACK OFF AND THE SET PLUGGED IN. The warning labels said that the set was to be worked on only by a Trained Radio Technician (who knew what a “hot chassis” was).

We can’t trust the old safety devices anymore because the insulating grommets have deteriorated with age and the Masonite backs of most of these old radios are now missing.  Even if they were still there, the warnings that were printed on the backs of these radios are equally useless because The Trained Radio Technician profession has been extinct for decades.  Today we have to be our own “Trained Radio Technician” and the truth is, most of us aren’t “trained” and most of us don’t even know what a “hot chassis” is.  The whole idea of this essay is to give you the training you need to make your radio safe before you try to fix it or use it.

73 de VK2KMI

Categories: Uncategorized

The Echophone EC-1 Unboxing

March 21, 2017 3 comments

The Echophone Ec-1 has arrived. I had to carry it in it’s box from my work to home, on the train, no mean feat when also carrying a handbag, but I did get it home in one piece. I should say that it was not as well packed as I would have liked but it seemed to have survived the journey from the US nonetheless.

This radio known as the morale radio was commonly used by GIs to stay in contact with news of home. Like all radios of this era, I bought this one, fulling expecting that it would need extensive work, despite it possessing a sticker stating major modifications (1994). I am not sure what the modifier considered major modifications, I imagined a recap, I hoped not a major departure from manufacturers specifications.

At the point of unboxing, it is unclear what those “major” modifications may have been. Looking at the wiring, there is little evidence of significant change other than attempt to fit a polarised mains plug. The fitting of this seems to be non-standard. Typically when modifying an “all American 5” one would fit a fuse and ensure that the polarised mains chord had the neutral wire connected to the chassis and one would fit safety capacitors where necessary. One would also remove all wax paper capacitors and replace with modern poly units.

Whoever modified this radio, has connected the mains chord in a non standard way, with both wires going to the first valve in the series of five. No fuse is fitted. The mains chord is retained in the case by a knot which has resulted in the insulation being cut by the case- a common if deadly error. Not a single wax paper capacitor has been replaced and a large electrolytic is clearly leaking.

Another project for a cold, rainy day or two.

Categories: Uncategorized