Category Archives: Software Defined Radio

Harold’s JA7HJ tower was not your average tower

The following post was copied from my ham radio blog, QRPer.com. I thought that SWLing Post readers would enjoy this article about Harold Johnson (W4ZCB) as well:

Harold's JA7HJ tower (Click to enlarge)

Harold’s 30′ JA7HJ tower (Click to enlarge)

I meet some very interesting people in radio circles.  My friend Harold Johnson (W4ZCB) is undoubtedly one of them.

Last year at my local ham radio/DXer club meeting, members were asked to bring photos of shacks and rigs, and describe our evolution as ham radio operators. In the series of photos that arrived at the following meeting, one in particular stood out: Harold Johnson’s radio tower in post-war Japan.

Johnson’s tower stood almost thirty feet tall and supported a 20 meter Yagi which you can see in the above photo.  Johnson, who at the time operated under the callsign JA7HJ, also had a little ham shack built. The shack materials–including the tower, Johnson recalls–cost him “three bottles of Scotch for the army quartermaster…I paid the Japanese builder $15 or $20 for the complete  enchilada.” This tower was built entirely of wood: the vertical members were 2′ x 4’s, the slats were 1′ x 3’s.

Of course, the tower didn’t have a mechanical rotor; instead, Johnson climbed inside the tower, lifted the wooden boom, rotated it manually, and placed it back on the uprights.

When asked how he powered his station, Johnson pointed to the wheeled generator in front of the radio shack in the photo. “The generator was called a B6B–it produced 24, 120, 240, and 480 volts, and was rated 10 kW.” When I asked how he managed to procure the generator, he replied that he “borrowed it from the flight line, which was about 300 feet away.”

Johnson's Nashville, TN shack, circa 1955/56. (Click to enlarge)

Johnson’s Nashville, TN shack, circa 1955/56. (Click to enlarge)

I always enjoy hearing personal histories in radio and I didn’t doubt for a moment that Harold Johnson’s would be intriguing, so I asked if he’d tell us how his interest in radio began. So, here’s Johnson’s story in his own words:

As a preteen, (and poor as a church mouse during our previous
Depression), I would visit my aunt and uncle in the summer, likely due to the fact that they were farmers and had food to eat. They owned an old Philco radio that had shortwave bands and I was intrigued with the phone amateurs on the 80 and 20 meter bands. Often, I could hear both sides of the conversation, after I found out that they were on various different frequencies, being crystal controlled back then! My…How times have changed.

In high school, I found another afficianado, and can recall melting “Woods metal” in boiling water and floating a piece of Galena on it until it returned to a solid and [thus] made my own crystal set. WWII had started by then, and I would listen to the ground-to-air communications between ships in Lake Michigan and pilots taking off and landing on them. Great DX, perhaps 10 miles away.

In 1943, I had graduated from high school and joined the US Army Air Corps. Went through training and was still in training (…to be a pilot until they counted airplanes and pilots and decided they had enough of each […so instead] turned me into a B-29 gunner). The war was over whilst [I was] still in training and I “retired” in November 1945. Went home and found my high school sweetheart, married, went back to school to finish my education and started the Johnson family. Still married, and
to the same girl. What a sweetheart to have put up with me all these years. [No kidding, Harold!]

Went back in the US Air Force in 1949, this time became a pilot, and just in time to go to Korea for a year. However, during training, had to learn the Morse and if you learned to 13 WPM, you had a free hour and didn’t have to attend class. That overcame my obstacle to amateur radio, and I took the exams in 1950 and became W9PJO. Our rules at that time were that you had to hold a “class B” ticket for a year before you could take the “class A” exams. That year I spent in Korea and Japan and managed to obtain my first foreign call, JA7HJ.

W4ZCBqslReturning home to wife and by that time two children, I took the class A exams and became W4ZCB. I decided that I enjoyed flying, (at least most of the time), and decided to make it a career. The ensuing years, I was always on and in the air, and usually spent the winters in Alaska and the summers in the Canal Zone, anything to practice how to be miserable. Lebanon in 1958, Vietnam in 1968 and by 1969 decided that I should start doing something else before my luck ran out.

During my last 4 years of service I flew an Army four star around the world four times. Fortunately he was Ted Conway, W4EII, and we mutually enjoyed operating under a couple dozen different call signs from a lot of exotic (and several not so exotic) places. Had G5AHB back when the 5 was reserved for foreign nationals. We were good friends after we both retired (on the same day; I always liked to say that he couldn’t stand to serve without me) until his death in 1990.

I started a small company manufacturing electronic test equipment for public utilities; spent the next 20 years doing that (and enjoying a much more stable life with family and radio.) Managed to work all the countries (entities these days) there are, win a few contests from a contest station I built and operated for 10 years. (80, 40, and 20 in the front room, 15 in one bedroom and since 160 and 10 were seldom open at the same time, they shared the other bedroom. To change bands, you just changed chairs. Five big towers and Yagis, a VERY  high maintenance hobby in the lightning prone state of Florida. (Let’s not mention hurricanes!)

Retired again to the beautiful mountains of North Carolina in 1986. A much more modest station these days, but active on all the HF bands. I really enjoy building homebrew radios and maintaining daily schedules with friends worldwide. Can be found daily on 21.203 with G3XJP and often joined by other builders of the magnificent PicaStar transceiver designed by him. Sixty-three years a ham, still enjoying it. It’s guided my careers and interests. What a wonderful hobby!

W4ZCB's shack today is based around his home brew SDR transceiver, the PicaStar. (Click to enlarge)

W4ZCB’s shack today is based around his home brew SDR transceiver, the PicaStar. (Click to enlarge)

Over the past few years, I’ve gotten to know Harold Johnson; I must say, he has to be one of the very few hams I know who knows the inner workings of tube/valve radios as well as he does the highest tech radios on the market, a rare talent indeed. If you’re trying to learn a bit more about the BC-348 series of radios and trying to diagnose a problem with it, Johnson’s your guy. If you’re trying to build an SDR from scratch, he’s also your guy.  And clearly, if you want to hear a fascinating account of a life influenced by radio, this is most definitely your guy.

Thanks, Harold, for letting me share your story!

Check out Harold Johnson’s website by clicking here.

Ragnar’s review of the RFspace NetSDR

The RFspace NetSDR wideband receiver

The RFspace NetSDR wideband receiver

A few weeks ago, I posted a link to Universal Radio’s used receiver page which featured a used RFspace NetSDR. Ragnar Daneskjold (of Pirates Week fame) jumped on the deal. Ragnar had been contemplating an SDR purchase for some time, and the NetSDR fit the bill.

Now that Ragnar has had some time to play with the NetSDR, he posted some of his impressions which began with this statement:

A few weeks ago I purchased a Net SDR from RF Space. I have to say that I love it. Its just a black box that resides in my basement but it has revitalized shortwave listening for me.

Ragnar evaluates the NetSDR using three different SDR applications: CuteSDR, sdrDX and SDR-Radio.

Click here to read his full post which also includes instructions on how to listen to his Internet-connected NetSDR.

Thanks for sharing your thoughts on the NetSDR, Ragnar!

CommRadio CR1 is now available for purchase

The CommRadio CR-1

The CommRadio CR-1

You can now purchase the CommRadio CR1 (we recently mentioned) for $500 plus $12 shipping on CommRadio’s website.

Don Moore (N0HDX), founder of CommRadio, placed the following statement on the CR-1 order page:

As the lead designer of the CR-1, I am pleased to offer this new radio to you. It draws on my experience as a kid building Knight Kits, from my paper route earnings through currently owning a classic Drake 2B and a Zenith Transoceanic; my benchmarks for enjoyable, high quality short wave listening. I added a smooth machined aluminum tuning knob and minimized the number of buttons to provide you (and me), an intuitively obvious and enjoyable radio to operate. This radio is solid as a brick, looks cool and sounds great. The tall feet have a purpose besides good-looks: rest your hand on the tabletop to spin the knob and for the bottom- speaker to bounce the sound to you instead of going straight up into up in space. The military ‘black box’ people who visit us see it sitting on the shelf with the bright OLED display and they all say: “I want one!” Well, here it is. Let the CR-1 draw you into the wonderful hobby I’ve enjoyed throughout my life.

I do love the look of this little radio–its simplicity reminds me of the Palstar line of shortwave radios.

SDR Touch: An Android-based software defined radio

SDRtouchThough not available for the shortwave bands, Google Play reviews are mostly positive for the new software defined radio application that will run on your Android phone or tablet: SDR Touch.

According to the Google Play page, SDR Touch covers 50 MHz to 2.2 GHz and demodulates WFM, AM, NFM, USB, LSB, DSB, CWU and CLW signals. It requires an inexpensive USB rtl-sdr compatible USB DVB-T tuner. Click here to search eBay for RTL-SDR receivers. You then connect to your Android device via a USB OTG cable and SDR Touch should control the receiver.

SDR Touch’s Google Play website has a list of supported receivers–make sure to check the model number from eBay against this list before purchasing. Additionally, you should install their free demo SDR app to make sure your Android device is compatible.

This video shows SDR Touch in action on the FM broadcast band:

SDR touch claims that crashes should be expected as this app is still considered somewhat experimental.

Would be great if SDR Touch could support the HF bands some day.

CommRadio is introducing the CR-1, a new tabletop shortwave receiver

The CommRadio CR-1

The CommRadio CR-1

US-based CommRadio is introducing a new tabletop, SDR-based, shortwave receiver this year: the CR-1. Their website has a few specifications and the video I’ve embedded below.

The CR-1 receives the full medium wave and shortwave spectrum (.5-30 MHz), plus some portions of VHF and UHF (FM broadcast band, Aircraft, Marine, NOAA weather radio, GMRS and FRS services).

The receiver architecture is a dual conversion super-heterodyne design with low-IF , I-Q digital sampling, 16 bit DSP with digital audio CODEC.  Their website also mentions DSP algorithms for all demodulation: DSB-AM, SSB, CW, WBFM, NBFM and channel filtering.

Other impressive features:

  • Can be powered from USB or a 6-18 VDC power source (from a separate 2.1mm jack).  The CR-1 possibly has the most flexible power source I’ve ever seen in a shortwave receiver!
  • The knobs are black anodized machined aluminium and front panel is powder coated machined aluminium; case is 20 gauge powder coated steel
  • Three antenna inputs
    • BNC for HF/MW
    • 3.5 mm audio jack (rated at 1000 Ohm, for roll-up antennas or telescoping whip),
    • BNC for VHF and UHF
  • Very portable size!

Full specs are available on their website: commradio.com

We will also keep you posted with any future updates.

Shortwave Radio Recordings: All India Radio on the Bonito RadioJet

The Bonito 1102S RadioJet IF receiver

The Bonito 1102S RadioJet IF receiver

After posting my latest All India Radio recording, SWLing Post reader, Pete, suggested that I check out their broadcasts starting around 21:00 UTC on 11,670 and 9,445 kHz, as they are quite strong into North America. He was right.

On Thursday afternoon, I tuned the Bonito RadioJet to 9,445 kHz, where I was greeted with a strong signal from AIR’s Bengaluru, India, transmitter site (over 8,500 miles from my home). I compared the signal on the RadioJet with that of my trusty WinRadio Excalibur to find that the RadioJet’s audio was somewhat fuller and richer. In situations where AM sync detection is not needed, I may start using the RadioJet for recordings. I’ve been using it strategically over the past few months for DRM reception and digging weak stations out of the static–something I typically don’t record, but probably should, as the RadioJet deserves even more air and recording time!

AllIndiaRadioLogo1I recorded this AIR broadcast on Thursday January 10th–around 21:30 UTC–on 9.445 MHz. This particular broadcast features news, commentary and the wonderful music I’ve come to expect from All India Radio. You can download the MP3 by clicking here, or simply listen in the embedded player below. Enjoy!

WinRadio Excalibur owners take note: 2013 may require a software update

WinRadioExcaliburFullScreenYesterday, when I attempted to start my WinRadio Excalibur software, I received an error message from Windows 7. No matter if I restarted my PC, re-installed the control software or the USB driver, I simply could not get the Excalibur software to launch.

I navigated to WinRadio’s software download page and found that on December 20th, 2012, they made a new version of the Excalibur software available to download: version 1.61.  This is the first official upgrade I have seen in months.

I uninstalled my old version (important: being careful to tell WinRadio not to remove my shared libraries!) and installed 1.61. I restarted my PC, launched WinRadio and all was back to normal (save, back to default settings, of course).

I then received a message from my buddy, Dave, describing the same problem with his Excalibur and noted that other users had complained about this in a WinRadio discussion group. This morning, I received a comment from a user on the SWLing Post describing the same problem.

I think it’s safe to assume the previous version of the WinRadio Excalibur control software could not deal with the year changing from 2012 to 2013. Not exactly Y2K, but a bit odd.

If you own the WinRadio Excalibur, I would encourage you to visit WinRadio’s software download page and upgrade to version 1.61.