Category Archives: AM

Review of the SSTRAN AMT3000 AM transmitter kit

Regular SWLing Post readers know that I’m a sucker for vintage radios––especially those of the WWII era. Indeed, I’m pretty much a fan of anything from the 1930s and 40s. I love the technology of that era and have an affinity for the culture and history, especially film and music.

Last year, I acquired a beautiful Scott Marine Radio Model SLR-M––a receiver that quickly became the centerpiece of my modest vintage radio collection.

Scottie (yep, I call her Scottie) produces beautiful, rich audio from her internal speaker. It’s truly an amazing piece of over-engineered technology that still sounds this good after 70 years.

Edythe Wright

Only a week or so after plugging Scottie into an antenna, my wife and I picked up a $1 CD at a church yard sale. The CD featured big band music from the late 30s/early 40s. Though we already had much of the music on the CD, we bought it anyway to keep in our car. One beautiful fall day, I was driving down a rural road and had the CD playing when a Tommy Dorsey recording of “The Music Goes Round And Round” with Edythe Wright on vocals, began playing. It had been ages since I heard this song…I then wondered how many GIs might have heard this song during WWII via GI Jive or the Armed Forces Radio Network. Perhaps they heard it on the Navy version of my Scott Marine radio, the Navy REH?

It was then I decided to finally pull the trigger and order a proper low-power AM transmitter for our home––something with which I could broadcast period music via my vintage gear.

There are a number of AM transmitters on the market, but the one that always stands out from the crowd is the SSTRAN AMT3000. My buddy, The Professor, has one and uses it to consume much of his digital audio content including podcasts and Internet radio stations. He sang the AMT3000’s praises, and I trust the Prof; he’s something of a medium wave guru.

Thing is, the AMT3000 only ships as a kit. In the past, this had stopped me from ordering the transmitter as I figured it was more than my beginner kit-building skills could manage. But after building David Cripe’s Ozark Patrol regenerative receiver, and loving the experience, I felt confident enough to make the order.

And, boy, am I glad I did!

The SSTRAN AMT3000 kit

The kit arrived within a few days of ordering it. Upon unboxing it, I felt like I had gotten my money’s worth, as it was packaged carefully in a quality box: components were clearly labelled in their own poly bags, the board was clearly marked with component numbers and the assembly/instruction manual was in a plastic binder, all clear and straightforward.

SSTRAN suggests taking your time building the kit, as there are a lot of components to solder, and you risk making mistakes that aren’t necessarily easy to remedy if you rush through the process. I tried to follow this advice––well, I intended to follow this advice. Thing is, I find it very difficult to put down a kit once I’m in the zone, so I zipped along a bit more quickly than I intended.

But it helped that SSTRAN took out a lot of the head-scratching and guesswork; the process couldn’t have been more smooth. I carefully checked and double-checked each component and marked it off the assembly list. First, you install all of the resistors, then capacitors, and on to other components. Other than having to hunt for some of the component locations on the board, it really was quite simple.

I started building the kit on a Friday afternoon and actually finished it the following Saturday morning. Much to my delight, after performing the tuning procedure, the transmitter worked on the first go. Whew!

Powerful (low power) broadcasting

The AMT3000 can be configured to work with the supplied simple wire antenna, which will essentially broadcast AM to radios throughout your home, or it can be configured for a Part 15 compliant outdoor base-loaded vertical antenna which will extend your range up to 3/4 of a mile, should your shack be down the road or in an outbuilding.

For the moment, I have my transmitter set up for in-house broadcasting only. If I ever want to build the base-loaded vertical, I only need to make a simple modification to the board to do so.

The supplied manual does a great job of explaining the best ways to maximize your signal, reduce any electrical hum and tweak your audio fidelity.

I’ve been using the AMT3000 nearly every day since I finished building it in mid-November. It seems to have a 100% duty cycle, does not overheat, and has no drift.

It produces high fidelity audio with a flat frequency response––and of course, with modulation and compression controls, you can tailor the audio to your particular taste.

Result? It sounds amazing piping WWII-era tunes through my Scott Marine SLR-M, Hallicrafters SX-24, and SX-99 and my Hammarlund SP-600.

As a bonus, I can hook my shortwave receivers up to the AMT3000 and listen to received audio via other radios throughout my house. Many times, I’ve listened to live broadcasts of ERT Open on 9,420 kHz via my kitchen AM radio…Very cool!

I also hook the AMT3000 up to my shack PC and stream my favorite internet radio station: the UK 1940s Radio Station via TuneIn radio. Absolutely brilliant!

I set my transmitter to 1410 kHz, and have left it there. You’ll need to do a medium wave (AM) survey to find the clearest spot on your AM dial. I’m sure results will vary, depending on the level of medium wave broadcast activity in your area.

Here’s what my Scott Marine SLR-M sounds like playing “March of the Toys” by Tommy Dorsey and his Orchestra via the SSTRAN AMT3000 (note that this was recorded with just an iPhone, so audio fidelity is somewhat lacking):

Conclusion

If you’re looking for a high-quality, low-power legal AM transmitter, I highly recommend the SSTRAN AMT3000. Even if you’re a novice kit builder, with time and patience, you can successfully construct the AMT3000, too. If I did it, you certainly can!

If you’d prefer buying a pre-assembled AMT3000, they do occasionally turn up on eBay. Click here to search.

As for me, I’m happy to have achieved my modest goal of being able to broadcast 1930s and 1940s music to vintage radios of the same era.

SSTRAN sells the AMT3000 directly on their website. Click here to view.

SSTRAN AMT3000 Models and Prices (via SSTRAN)

AMT3000
10 kHz channel spacing for use inside North and South America. Includes enclosure and 120 Volt AC Adapter. The single surface-mount IC is pre-soldered on the board.
Price: $92.95

AMT3000-9K
9 kHz channel spacing for use outside North and South America. Includes enclosure and 120 Volt AC Adapter. The single surface-mount IC is pre-soldered on the board. *
Price: $92.95

AMT3000-9KNT
Same as AMT3000-9KSM, except the US-standard 120 Volt AC Adapter is not included. **
Price: $88.95

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Medium Wave DXer, Johnny Bråtveit, interviewed by Oregon Public Broadcasting

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Check out this excellent in-depth interview with medium wave DXer, Johnny Bråtveit, via Oregon Public Broadcasting (OPD):

“About a month ago, our station received a fascinating email. It came from a Norwegian man named Tore Johnny Braatveit. He wrote: “I am one of those people who still really enjoys hunting for long-distance radio signals on the AM band. I am glad to tell you that I was able to pick up the AM signals of KOAC in arctic Norway.”

Braatveit sent us a recording of what he heard, and there’s no mistaking our litany of OPB stations beamed more than four thousand miles away.

Braatveit, who said we can call him TJ, says the serendipity of the search is what makes collecting radio signals appealing. “It’s the same as for a hunter or a fisher,” said Braatveit, “They know what they want, but they don’t know what they will get.”

Braatveit has been DXing – a hobby to receive, record and identify faraway broadcasts – since the early 1980’s. DX-ers use receivers along with computer software to collect the signals before reaching out to the stations with “reception reports” to verify what they picked up, hence the email he sent us.”

Listen to the full interview via OPB’s SoundCloud:

Tore Johnny Bråtveit also maintains a blog where you can listen to many of his medium wave audio samples. Click here to visit his site.

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A Photo Tour of the National Capital Radio and Television Museum

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On Tuesday afternoon, I made a pilgrimage the to the National Capital Radio and Television Museum in Bowie, Maryland, USA. The museum is located in a modest and beautiful historic house on the corner of Mt. Oak and Mitchellville Roads in Bowie.

Museum Curator and volunteer, Brian Belanger, kindly gave me a private tour of the museum collections (the museum is closed on Tuesdays).

Many thanks to Brian for taking time out of his day for the tour, and for allowing me to take some photos for the SWLing Post!

The museum has a number of display rooms with radios broadly grouped by style and decade. The first room offers examples of some of the earliest radios produced–including the venerable crystal radio (below).

[Click photos to enlarge.]

Like Brian, numerous volunteers work to keep the collections in working order. This isn’t a place where vintage radios come to die; they actually come to life here.

Even examples of some of their earliest radios are on the air and can be tuned to local and international stations.

This RCA “portable” (below), housed two batteries on either side of the center faceplate. Note the ad on the wall above–a couple enjoy the RCA as they recline on a beach.

Speakers of the day were pretty amazing, too–check out this hand-painted 1927 Air Chrome Double Cone Speaker, below.

The museum also has an extensive collection of studio and off-air recordings that can be played over an AM carrier throughout the building.

By the late 1920s and early 1930s, radio manufactures built gorgeous console radios, features in the living rooms and parlors of many lucky homes.

This E.H. Scott All-Wave 23 console (above and below) sported not only twenty-threee vacuum tubes, but a large, robust internal speaker. Radio collectors consider the All-Wave 23 to be one of the finest performing radios of the vacuum-tube era.

The museum also features the Zenith 12-S-232 tabletop radio with working shuttle dial–a futuristic band-switching mechanical wonder with a stunning dial.

A number of tabletop and portable radios that span the decades have found their homes in this museum. No doubt many SWLing Post readers cut their teeth on these classics!

I love the design of the Garod Model 5A2–wow! And I’m sure many kids of the fifties wished they had an official Hopalong Cassidy AM radio (below).

The museum, of course, also houses a large number of classic televisions.

Radio stations and benefactors have also donated many items used in the industry, both in broadcast and retail.

Brian was also kind enough to take me to the building, next door, where they repair radios and store others for eventual rotation into the collection.

Museum volunteers also teach radio repair and restoration classes.

The number of classic ham radios, home brew receivers and transmitters was simply amazing. Indeed, I felt like a kid in a candy shop!

By the end of the tour, I had decided to become a member of the National Capital Radio and Television Museum. Even though I live a few states away, I like knowing that my membership funds not only help preserve vintage radios and televisions, but also provide me members-only access to many of their scanned archives. Click to view a full list of benefits for a modest $25 membership.

Again, many thanks to Brian Belanger for the amazing tour of this wonderful museum! Brian, I’ll be back next year…

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Radio Taiwan Test transmission

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Many thanks to SWLing Post reader, David Iurescia, who relays this translated message from Radio Taiwan International:

Frequency test for South America between 5 – 7 March, 2015

Looking for alternatives to transmit our programming to South America, Radio Taiwan International will carry out test transmissions frequency to the region from Thursday March 5 until Saturday March 7, 2015 through 11920 kHz frequency in the 0200-0300 UTC .

We request the cooperation of our listeners friends who are in the South American countries , to verify that signal and send us reports of listening to the new test frequency to our e- mail soon: [email protected]

Many thanks for your help!

Source: http://spanish.rti.org.tw/whatsNew/?recordId=8357

Many thanks, David! Perhaps some of listeners can help RTI by sending a listener report and also record a broadcast for the SW Radio Audio Archive.

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Video: Chris reviews the Tecsun 2P3 AM radio kit

Video: 1940s-era holiday treat from Tommy Dorsey (c/o a vintage rig)

The Spectrum Monitor: only $24 for a year’s subscription

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On occasion, the things you enjoy most, you forget to share with your friends. Not sure why this happens, but this is certainly the case with the Spectrum Monitor magazine (TSM). I’m long overdue to properly pitch TSM to my readers, which I feel is an absolute bargain at just $24 per year.

Why? Many of you may recall that it was only July of last year when we learned about the closure of The Monitoring Times magazine. I had always loved the magazine–not only were the management and editors a great group, but the magazine content was some of the best in the communications business when I began writing features and reviews for MT. But the owners of MT, Bob and Judy Grove, were ready to retire; ultimately, they decided to close their magazine down rather than sell it off.

Shortly after the announcement, MT‘s managing editor, Ken Reitz (KS4ZR), decided to make a go of a new publication. Albeit wholly digital, this magazine was to cover the same scope and content depth as MT, and would be known as The Spectrum Monitor (TSM).

In January of this year, TSM launched, and like many SWLing Post readers, I was eager to see if the content met the benchmark MT had set for so many years.

I needn’t have worried. Ken had corralled many excellent contributors, in many cases drawing upon previous writers for MT. And in the past year, I don’t believe it’s a stretch to say that in many respects, TSM not only met that benchmark, but has actually even exceeded it. TSM is now–unquestionably–a good, solid, thoroughly enjoyable publication.

Each issue is packed with topics covering the radio spectrum: shortwave, ham radio, vintage radio, pirate radio, scanning, public service, satellite, AM/medium wave and host of digital/mobile technologies, as well. Really, everything a listener could hope for.

Initially, I had my doubts. I frankly wasn’t sure whether I’d like reading a “digital-only” radio publication, or whether other readers would. I confess to being a bit “old school;” as a radio listener, I like to hold a radio in my hands, to physically tune it; as a reader, I prefer holding a printed publication in hand, to turn the (paper) pages…How would I feel with an e-reader or laptop, instead? Would reading that way feel like work?

But TSM soon swayed me toward the digital as both reader and as a columnist. As a writer, there was less stress on word count. If it was a bit short, or lengthy– as my October column was–I soon found it mattered less. In a digital publication, page count is comparatively irrelevant as long as content is worthwhile and captivating for the reader. And as a reader, I appreciated that the columnists that I was reading would have the freedom to write at length, too.

Secondly, a digital publication gave its writers an opportunity to infuse columns with a multi-media element–something I’d become accustomed to as a blogger here on the SWLing Post. When I published a review of a radio, I could include actual audio clips in the article. If I wrote about pirate radio, for example, I could embed actual pirate radio recordings. Brilliant! And, again, more fun for the reader.

Also, including links or references to external websites is a cinch in a digital format, and quite easy for the reader to check out. Instead of copying a long gangly URL from a printed page, you simply click on a link as you would on a website, such as on this one. Second nature, really.

Finally, in a digital publication, I found writers could use more full-color images in their articles. I really enjoy the addition of the images; they make articles come to life…

So, I soon learned to relax with the e-reader just as I had with the printed Monitoring Times. No pages to turn, but then again, not so different from reading…well, a blog like this. I’ve received excellent feedback from TSM readers, too, many of whom admitted their initial bias against a “digital” magazine had since been withdrawn completely.

I continue to enjoy reading TSM every month. And although–due to time constraints–I’m no longer TSM‘s primary shortwave radio columnist, I still enjoy writing for TSM when time permits, so you will see my reviews and features pop up in TSM now and again.

But why take my word for it? Check it out for yourself–it’s one of the best magazines for the radio enthusiast, digital or print…And at only $24 annual cost, it’s a terrific and affordable last minute Christmas gift for a friend, family member, or–let’s be honest–for yourself.

Afraid to commit to a one year subscription? Individual issues of TSM are available online for $3 each. If you like what you’re reading (you will), you can then purchase a one year subscription, and the cost of your issue will be refunded.

If you’re lucky enough to receive a subscription to TSM in your stocking, I can assure you that you’re in for a real treat. Happy reading!

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