LHS Episode #315: The Weekender XXXVIII

It's time once again for The Weekender. This is our bi-weekly departure into the world of amateur radio contests, open source conventions, special events, listener challenges, hedonism and just plain fun. Thanks for listening and, if you happen to get a chance, feel free to call us or e-mail and send us some feedback. Tell us how we're doing. We'd love to hear from you.

73 de The LHS Crew


Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Regulated power supplies, sunspot cycles, ham radio satellites and more

Stories you’ll find in our December, 2019 issue:

Before Radio’s First Century: “Pre-Broadcasting” Activity in North America
By John Schneider W9FGH

For many decades, the prevailing myth has been that broadcasting in the United States first occurred on the night of November 2, 1920. According to this general conviction, no broadcasting took place anywhere before that date, but then, in a brilliant stroke of genius, it was suddenly invented that night by the Westinghouse Corporation when its new station, KDKA, broadcast the Harding-Cox election returns. Nothing could be farther from the truth! By 1920, experimental broadcasting had already been happening around the US for many years. John takes a look at the country’s transition from that early experimentation to formal broadcasting.

Radio’s Role During Pearl Harbor’s ‘Day of Infamy’
By Scott A. Caldwell

Diplomatic relations between the United States and the Japanese Empire had steadily deteriorated in the years that followed the First World War. On May 7, 1940 the US Navy Fleet reluctantly relocated its operating headquarters from San Pedro, California to Pearl Harbor, Hawaii. President Franklin D. Roosevelt considered the redeployment as vital because it represented a significant military deterrent to the growing Japanese bellicosity. However, there was great concern and opposition to this action that was headed by Admiral James O. Richardson, Commander-in-Chief US Fleet, who believed that they would be unnecessarily exposed to attack from the Japanese Navy. Seven months later a price would be paid.

Those Regulated Power Supplies from Heathkit and Others
By Rich Post KB8TAD

In recent columns on testing and restoring the National SW-3, FB-7 and the HRO Senior, Rich initially used metered regulated power supplies in place of the matching “doghouse” power supplies to keep those vintage National supplies from possible overloads and damage before full restoration of the receivers. In his previous column on the HRO, he mentioned replacing the entire HRO power pack with a totally voltage-regulated supply since varying the RF gain control changed the set’s current draw somewhat and thus the B+ on both the oscillator and the mixer. As promised, he takes a second look at that supply.

Novice-era Hamming Today: Still a Thrill
By Cory GB Sickles WA3UVV

Cory’s first amateur radio station consisted of a solid-state Realistic (Radio Shack) DX-150A general coverage receiver and a gently used Heathkit DX-20 transmitter, that incorporated three tubes to produce 20 Watts out. He used a set of house switches in a metal box to swap the antenna between the receiver and transmitter, plus mute the receiver when transmitting. It was not the best solution, but it was cheap, and it worked. If you, like Cory, have a hankering to revisit your old Novice operator days, it can still be done—with vintage gear or even their modern equivalent. Cory explains how you can start your own Novice-era memories.

Scanning America
By Dan Veeneman
Tillamook County, Oregon; Vintage Scanner Crystals

Federal Wavelengths
By Chris Parris
Scanning Projects

Milcom
By Larry Van Horn N5FPW
Monitoring the DoD High Frequency Global Communications System

Utility Planet
By Hugh Stegman
HF Utility in Troubled Ukraine

Shortwave Utility Logs
By Mike Chace-Ortiz and Hugh Stegman

VHF and Above
By Joe Lynch N6CL
Planet Alignment and Sunspot Cycles Linked?

Digital Voice
By Cory GB Sickles WA3UVV
Three Short Subjects for New Hams

Amateur Radio Insights
By Kirk Kleinschmidt NT0Z
A Log-Periodic Tragedy

Radio 101
By Ken Reitz KS4ZR
Free-to-Air Satellite TV Update

Radio Propagation
By Tomas Hood NW7US
Largest Sunspot in Solar Sunspot Cycle 24

The World of Shortwave Listening
By Rob Wagner VK3BVW
Online SDRs: Impacting the Way We Listen to Shortwave

The Shortwave Listener
By Fred Waterer
Shortwave Listening Past and Present

Amateur Radio Satellites
By Keith Baker KB1SF/VA3KSF
Amateur Radio Satellite Primer (Part VI)

The Longwave Zone
By Kevin O’Hern Carey N2AFX
LF Info: 101

Adventures in Radio Restorations
By Rich Post KB8TAD
Helping Dan: A Silvertone 6230A Farm Set

Antenna Connections
By Dan Farber
Feedlines: Getting There from Here

The Spectrum Monitor is available in PDF format which can be read on any desktop, laptop, iPad®, Kindle® Fire, or other device capable of opening a PDF file. Annual subscription is $24. Individual monthly issues are available for $3 each.


Ken Reitz, KS4ZR, is publisher and managing editor of The Spectrum Monitor. Contact him at [email protected].

30m FT8

A shot from PSK reporter of my signal FT8 signal on 30m. No problem getting into Europe and I am very pleased with my Endfed antenna set up at only 20 feet off the ground. The power is set to 30 watts. My go-to software for FT8 is JTDX alongside JT-Alert. I am also running the Win4icom suite as well as AClog software.

Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

Hans Solves Exploding Power Transistor with Siglent’s Help! And a New Product…

Exploding power amplifier transistors! Hmm…that’s not a good start to any ham’s operating session. But it happened to Hans Summers G0UPL as he was doing development work on the firmware (version 1.03) designed to accompany his very popular QCX transceiver sold through his company, QRP-Labs. Hans, the recipient of the 2019 Homebrew Heroes Award, was doing some firmware enhancements for CAT control of the QCX (version 1.03) to drive an external amplifier when the amplifier’s power transistor …. well, see for yourself.

RF510 power transistor blown apart

But what on earth caused the explosion? Here’s where a product donated to our Hero for 2019 came to the rescue. Siglent Technologies donated their SDS1202X-E oscilloscope to Hans as part of their sponsorship. He documents how he used the Siglent oscilloscope to diagnose the power spikes that led to the complete component failure in certain circumstances on his blog.

I had switched the QCX off and on again with the toggle switch on the my front panel, rather fast. There was a bright flash and a loud bang. My QCX is connected to a 0-30V 0-20A linear-regulated bench power supply, capable of supplying a lot of power. Investigation revealed that one of the IRF510 power transistors had blown up quite spectacularly. This photo shows the result. Note that the explosion did not blow the IRF510 pins off; my safe removal strategy for replacing components, is to CUT the component out then remove the pins one-by-one from the board by de-soldering them.

Hans G0UPL

Hans explains his diagnostics further, “Investigation with my nice new Siglent SDS 1203X-E oscilloscope (thanks to kind donation by Siglent, sponsors of the Homebrew Heroes award 2019), revealed the following different power-up characteristic, depending on whether the QCX is switched on by turning on the power supply, which is what I normally do, or by switching it on at the toggle switch.

The Siglent SDS 1203X-E oscilloscope has storage features where the display can be frozen by pressing the Run/Stop button at top right. So it is possible to capture an event in “human scale time” with the horizontal timebase running at something like 100ms/div or 200ms/div; then with the display frozen you can scroll it left/right using the horizontal position control, then zoom in on the feature to be investigated, using the Horizontal Zoom knob. Once the display shows the section of waveform of interest, you can use the cursors to make precise measurements of time difference, voltage difference etc. This is very useful to examine and understand features which happen too fast to be seen or captured normally. Screenshots can be captured easily by plugging in a USB flash drive and pressing the “Print” button.”

Siglent SDS 1203X-E in action on Hans’ Workbench
“…this is what the voltage at the PA supply connection pad looks like, when I press the On/Off button on the 0-30V 0-20A bench power supply. It rises nice and gently to 20V, reaching 90% of its final supply voltage after about 56ms and the full 20V supply voltage another 20-30ms after that.”
“(This) is what happens when the toggle switch on the QCX enclosure front panel is switched on (with the power supply already on). The combined effect of the smoothing capacitor in the power supply and the 2200uF capacitor in the QCX enclosure, is that the voltage at the Power Amplifier pad rises extremely fast, and with a significant overshoot; the trace shows a rise to 33V 364us after power-on. There’s another very short spike 2ms after switch-on.”
“Here is a zoom of the first spike with the overshoots. Pretty nasty!”

Hans gives more technical details behind his diagnosis on his blog post but the “nasty” spikes were detected through bench testing and then diagnosing the issues producing it using his new Siglent SDS 1203X-E oscilloscope. This provides a cogent illustration of how our Hero for 2019 goes about his development and testing work for his product line. Like a fine wine, it takes time to ensure that the finished product, whether it’s hardware or a firmware update like in this instance, is working as the higher level block diagrams are intended for it to.

Hans G0UPL diagram of why the IRF510 self-destructed

Hans states, “My theory is, that the first PTT signal, at power-up, when coincident with all those nasty spikes at switch on (via the toggle switch), and with the PA circuit not yet settled down (all its capacitors charged up, solid state Rx/Tx switching in stable state, etc), creates the right conditions for catastrophic positive feedback in the PA to set up a huge spurious oscillation which is sufficient to self-destruct, via the explosion of one of the transistors. This does NOT occur in my normal power-up sequence via the on/off button of the power supply. Neither does it occur if I switch off with the toggle switch, wait a second, then switch on again. It only occurred when I switched on and off quickly.” The hand diagram above illustrates his theory of the self-destructing PA transistor.

This does NOT occur in my normal power-up sequence via the on/off button of the power supply. Neither does it occur if I switch off with the toggle switch, wait a second, then switch on again. It only occurred when I switched on and off quickly.

Hans G0UPL

The solution? He says it’s an easy fix. “This situation can be resolved very simply by adding a 10K resistor (value entirely uncritical) between the RX signal and +5V. When the processor pins are floating while the processor is starting up, the RX signal is therefore pulled to +5V, until the processor has started and is ready to take over the job. In this fragment of the schematic (below) the additional resistor is shown in the yellow box. I simply soldered it between IC3 pins 13 and 14 which is convenient and easy.” The diagram below illustrates the remedy shown in yellow.

Hans told me by e-mail that, “The QCX + 50W PA is now back in order and I had 9 nice QSOs this morning, with YL Elvira ZA1EM, then E74LZ, UR5MUY, IK7XJA, LZ1HDA, OM3CAZ, R7BW, EW8CP and RW3KE.” So a 10K resistor plus the workbench savvy with a new modern oscilloscope came to the rescue.

Psst…New Product!

The 50W Power Amplifier is a new product that QRP Labs has in very late development. No, it’s actually almost ready to announce with this final change. Hans wrote me today, “Yes, This 50W PA is a new product…This 50W amp is designed as a low cost single-band amplifier for the QCX (which is my flagship 5W CW transceiver http://qrp-labs.com/qcx ).”

New 50W Amplifier Kit to be announced soon!

The description of the new 50W amplifier was sent to me earlier today and should approximate what will be on the QRP Labs website (always subject to last minute changes, of course). Hans says he is finalizing the manual now and expects an official announcement in a week or so from today. So watch his website for the official announcement. The description is in Hans’ words to me by e-mail earlier today.

This 50W Amplifier includes the Low Pass Filter. It can be built for any of 40, 30 or 20m using the supplied components in the kit and therefore covers 95% of QCX owners. Any other bands would be possible too if suitable inductors and capacitors were substituted in the Low Pass Filter.

Inside the box

The amp kit also includes two substantial heatsinks, which are the same design of custom-made heatsink I use in my 10W Linear kit http://qrp-labs.com/linear. Each heatsink is black anodized aluminium and sized 130 x 28mm, with 25mm fins. ALL the connectors are also included in the kit.

A key feature of the amplifier kit is that it has solid state PIN diode Transmit/Receive switching, which is fast, reliable, low cost and silky smooth quiet… it enables full break-in operation (QSK) which is very important for many CW operators (hearing the band during the tiny gaps between your own dits and dahs). Perfecting the transmit/receive switching took 80% of the development time of the kit.

Front panel board

I have used the prototype for over 500 QSOs over the summer on 40m, working from US to New Zealand, Japan, Northern Europe to Middle East. With band conditions in the doldrums they are, or if people wish to have a sked with a friend at a particular time and location, that little extra power can be very useful! QRP has its place, QRO does too.

The custom-manufactured enclosure kit is extruded black anodized aluminium, size 130 x 63 x 25mm and the heatsinks bolt on the top. On the rear are BNC in and out connectors, DC power connector, and a jack for the PTT signal from the QCX. It is designed to match the QCX but could easily be used for other QRP CW rigs too; it may even work well in Linear operation (with the bias adjusted correctly) but this remains to be seen and tested.

50W amplifier rear view

Conclusion

This is the type of bench work that great designers go through, largely unbeknownst to amateur radio operators who purchase their products. Of course, there are issues that get by even the most careful workbench. But here’s a case of precisely why the corporate donors to the Homebrew Heroes Award program have chosen to participate: to give our recipient tools to help that person to do their best work on what they do in the homebrew maker space. To see more of Hans’ illustration of this episode in homebrew development, see his website for a forthcoming video.

Here’s to you, Siglent! And, to Jason Chonko who believed in the HHA program immediately and signed his company on as a sponsor. To see this 200 mhz oscilloscope in action, go to this link.

If you’d like your company’s equipment on the workbench of our next Homebrew Heroe, contact us through the HHA website. We are accepting sponsors for the 2020 HHA now and will announce a new one soon.


Frank Howell, K4FMH, is a regular contributor to AmateurRadio.com and writes from Mississippi, USA. Contact him at [email protected].

LHS Episode #314: Epic Pie

Welcome to the 314th installment of Linux in the Ham Shack. In this short-topics episode, the hosts discuss Open Source and the government, YOTA in IARU Region 2, microwave transverters, Docker, the Linux 5.5 kernel, Y2038, JS8Call and much more. Thank you for listening and have an excellent week.

73 de The LHS Crew


Russ Woodman, K5TUX, co-hosts the Linux in the Ham Shack podcast which is available for download in both MP3 and OGG audio format. Contact him at [email protected].

Weekly Propagation Summary – 2019 Dec 02 16:10 UTC

Weekly Propagation Summary (2019 Dec 02 16:10 UTC)

Here is this week’s space weather and geophysical report, issued 2019 Dec 02 0130 UTC.

Highlights of Solar and Geomagnetic Activity 25 November – 01 December 2019

Solar activity was very low. No sunspots were observed on the visible disk. No Earth-directed CMEs were observed in available coronagraph imagery.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached high levels on 25-28 Nov and decreased to moderate levels on 29 Nov – 01 Dec.

Geomagnetic field activity was mostly quiet. A single isolated period of unsettled was observed late on 29 Nov in response to a prolonged period of southward Bz.

Forecast of Solar and Geomagnetic Activity 02 December – 28 December 2019

Solar activity is expected to be at very low levels throughout the outlook period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to range from moderate to high levels. High levels are expected to be reached on 20-25 Dec in response to CH HSS influence; moderate levels are expected for the remainder of the outlook period.

Geomagnetic field activity is expected to be at quiet to active levels. Active levels are expected on 18-19 Dec due to interaction with a positive polarity CH HSS; unsettled levels are expected on 03 Dec and 20-21 Dec; quiet levels are expected for the remainder of the outlook period.

Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/

Live Aurora mapping is at http://aurora.sunspotwatch.com/

If you are on Twitter, please follow these two users: 1. https://Twitter.com/NW7US 2. https://Twitter.com/hfradiospacewx

– – – – – – – – – – – – –

Be sure to subscribe to our space weather and propagation email group, on Groups.io

https://groups.io/g/propagation-and-space-weather

Spread the word!

– – – – – – – – – – – – –

Links of interest:

+ Amazon space weather books: http://g.nw7us.us/fbssw-aSWSC
+ https://Twitter.com/NW7US
+ https://Twitter.com/hfradiospacewx

Space Weather and Ham Radio YouTube Channel News:

I am working on launching a YouTube channel overhaul, that includes series of videos about space weather, radio signal propagation, and more.

Additionally, I am working on improving the educational efforts via the email, Facebook, YouTube, Tumblr, and other activities.

You can help!

Please consider becoming a Patron of these space weather and radio communications services, beginning with the YouTube channel:

https://www.patreon.com/NW7US

The YouTube channel:
https://YouTube.com/NW7US

..


Tomas Hood, NW7US, is a regular contributor to AmateurRadio.com and writes from Nebraska, USA. Tomas is the Space Weather and Radio Propagation Contributing Editor to 'CQ Amateur Radio Magazine', and 'The Spectrum Monitor' magazine.

Potential Astron power supply failure solved!


One of my blog readers informed me regarding the Astron linear power supply that the outer case on the pass transistors at the rear of the supply are live with about 24 volts.  These pass transistors are isolated from the case and the heat sink so the potential is there to inadvertently via a PL259 connector, USB cable or any other conducting item at the rear of your setup to short the pass transistor and destroy them.  This morning I once again was searching the internet to see if anyone had devised a solution for this very issue. I came across a web page . This individual has the RS-35A power supply and came up with a great solution using a 3D printer. Now I am not at all up on the whole 3D printer thing but click on the link  above (web page) and have a look at the pictures they posted. The covers look great and are very professional looking. It would look to me the plans are available to those who have access to a 3D printer to produce the guards them self.  I would really like a set of these for my RS-25 but just short on the 3D printer part of things.
To my fellow bloggers have a look at the above link and do post any 3D printer info you may have as well.

As a side note below are some links to great information regarding Astron power supplies.

http://www.wb1gof.org/files/AstronPDF.pdf

http://www.repeater-builder.com/astron/pdf/astron-troubleshooting.pdf

http://www.repeater-builder.com/astron/astron-repair/astron-repair.html

https://www.ecse.rpi.edu/courses/CStudio/ham_radio_docs/astron-repair-index.htm

Mike Weir, VE9KK, is a regular contributor to AmateurRadio.com and writes from New Brunswick, Canada. Contact him at [email protected].

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