Category Archives: AM

Many thanks to SWLing Post contributor, Thomas Cholakov (N1SPY), who shares his latest video explaining the operation of a simple homebrew AM loop antenna:

Click here to view on YouTube.

Brilliant video, Thomas! I love the fact you included a demonstration with your SDRplay RSP1A as well. Via the spectrum display, it’s easy to see the the loop’s bandwidth and also the gain it provides when tuned to a station.

I love your AM loop antenna as well–such a simple design and ideal for demonstrating the mechanics of a passive loop antenna since all of the components are visible. I’m willing to bet you built this antenna for less than $10. Smart design as it’s both portable and effective! Keep up the excellent work, Thomas! We look forward to all of your future videos.

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Puerto Rico: AM Radio makes a comeback post-hurricane

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(Source: Columbia Journalism Review)

ON SEPTEMBER 19, 2017—the day before Hurricane Maria made landfall in Puerto Rico—the evening news team at WORA-TV in the coastal city of Mayagüez broadcast its final program before shutting down the station ahead of the storm.

“If Maria was going to be the monster everyone was predicting,” says Carolina Rodriguez Plaza, the news team’s production manager, “we knew the power could be cut off for a long time. We decided to shut down the station and send everyone home.”

Plaza told her team of 12 reporters not to worry, their salaries would be paid during the downtime and their jobs would be waiting for them when broadcasting resumed. Plaza retreated to her parents’ home, where she spent the night of the hurricane watching updates about the storm on cable TV. Then, as happened in homes across Puerto Rico, the lights flickered and the power went out. Hurricane Maria’s 150-mile-per-hour winds toppled power lines and torrential rains grounded out the island’s power grid.

Desperate for news about the disaster befalling her island, Plaza turned on a battery-powered radio and found that a local radio station, WKJB 710 AM, was maintaining its broadcast. The station’s managers had learned a lesson about disaster preparedness in 1998, when Hurricane Georges blew down their radio antenna and cut off the power. Since then, staff had equipped the station with a backup power generator and a reinforced antenna that could withstand hurricane-force winds.

“Maria erased the world of journalism in Puerto Rico,” Plaza says. “It reemerged in a new form, with radio playing an important role.”[…]

Click here to read the full article at the CJR.

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WTPF’s former site: A “Time Capsule from the 1940’s”

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(Source: ABC11.com via Mike Hansgen)

Photo source: WTPF.com

The distinct Art Deco style clearly defines the WPTF radio station as a 1940’s classic.

With rounded windows and curved edges, the building looks tiny on the outside, but cuts deep underground into a shelter that allowed announcers to broadcast through wars and hurricanes.

Today, it’s hidden behind tall shrubs, a chain-link fence, and a set of train tracks – it often goes unnoticed, a relic from a long past era of Raleigh history.

Decades ago, this station was staffed 24-hours a day, which means it provides amenities like a kitchen and shower. However, this enticing building has been closed to the public, mostly forgotten, for decades. Nearly 80 years old and sealed to most of the outside world, it harbors dust-coated secrets that time forgot, like a living time capsule.[…]

Click here to read the full article and view photos of the site.

Also, check out the following photos of WTPF courtesy of this imgur.com account:

Former WPTF 680 AM art deco studio – Cary, NC

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Guest Post: The Prof finds a Nova Tech Pilot II RDF receiver

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Many thanks to SWLing Post contributor, The Professor, who shares the following guest post:

A 1960s Signal Sniffer

by The Professor

I just recently purchased a radio that on eBay that looks very intriguing, especially if you happen to DX AM Radio. It’s a mid-60s portable made in Japan – a Nova Tech Pilot II . However, wasn’t just a grab ën go to the beach kind of transistor set. This radio has a serious side. It’s actually an RDF – a “radio direction finder.”

I have seen these kinds of radios before, somewhere. Only the ones I’ve noticed were older and had more of a military look. Although I’ve never actually attended a hamfest, I’m sure these types of receivers might be found at a gathering like that.

But this is a smaller and frankly more stylish version of RDF. Not to go into too much detail about something I know little about, but before GPS became ubiquitous, devices like this would commonly assist in the navigation of ships and aircraft by pinpointing “beacon” transmitters at specific known locations.

As you might imagine, this type of technology was (and probably still is) a strategic tool for military purposes. In fact, one of more “infamous” incidents of using radio direction finders was when they were utilized by the Japanese in the bombing of Pearl Harbor. Their bombers just honed in on the signal of a Honolulu AM station (KGU at 760kHz) as their beacon.

So, this radio has three bands which were traditionally used by beacon transmitters. Besides the medium wave band, it also has a section of the longwave spectrum, and the VHF airband. Other models included the old marine band (around 3 to 5MHz). A later model also included the CB frequencies, and another included a VHF police band (called the Nova Tech Action!!).

So, no shortwave on this one. No FM either, but I have plenty of radios with those bands (like almost all of them). Of course, there’s not much to find on this side of the world on longwave these days, and listening to aircraft communications has its fans but it’s not something I’ve done much. But this thing has a unique toolset for medium wave DXing. And after doing a little research online I’ve discovered that the big rotating double ferrite on top is only one of the attributes it offers for AM DXing purposes.

For one, it has an RF amplifier in the front end to help pull those weak signals up out of the noise floor. For another, it has a pure RF gain function called “DF” (direction finder), which when turned on shuts down the AGC (automatic gain control) and allows you to tweak the RF gain any way you like. And it also has a very accurate tuning meter. That all sounds good to me.

So, I haven’t actually seen my Nova Tech in the flesh yet, and it will be probably a couple of weeks before I get a chance to give it a test drive. But I’m pretty confident in my purchase at this point. More than a few people have spoken glowingly of the AM DXing capabilities of this set. But one of the reasons I decided to go ahead and bid on this device was that not only did the dealer have an excellent eBay rating, but he says he also fully serviced the radio electronically and physically restored most of its original beauty. Apparently, it was cleaned up, recapped, and even a transistor was replaced. And he also aligned the AM band IF and re-peaked the antenna trim for AM and the airband.

Although this radio is still a twinkle in my eye at this point, I thought I’d mention it here in hopes some of the fine readers of this blog might have something to say about DXing with direction finding radios. And I was especially hoping that a few people might have personal experience with these 60s era Nova Tech receivers. I also noticed online that there are U.K. versions of these RDFs that were branded as “Bendix” radios.

All insights offered as comments are appreciated, and once I spend some time with this radio I’ll be sure to offer some of my own.

I always find it so much fun to await the arrival of an interesting old radio I’ve purchased on eBay, especially one that I’d never heard of before.

Thanks for sharing your find, Professor! I was not at all familiar with the Nova Tech Pilot II. I love the Transoceanicesque design! No doubt, it’ll be a handsome addition to your collection, and I’m willing to bet a MW DX machine as well!

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A taste of Gary DeBock’s Cook Islands (Aitutaki) Ultralight DXpedition

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Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes from his Cook Islands Ultralight DXpedition:

Cook Islands (Aitutaki) Ultralight DXpedition from April 8-13

A gorgeous environment, with thrilling long range DX! Ruth and I took this trip as the 38th anniversary of out first meeting at Victoria Peak in Hong Kong (April 10, 1980).

DXing highlights were the reception of 693-Bangladesh, 918-Cambodia and 1431-Mongolia on the 7.5 inch loopstick C.Crane Skywave SSB Ultralight and 5 inch “Frequent Flyer” FSL antenna (designed to provide inductive coupling gain equal to that of a 4 foot air core box loop, but in a much more compact size).

693-Bangladesh 1652 UTC April 10 (mention of Bangladesh at 8 second point; thanks to Chuck Hutton for listening):

Download: 693-Bangladesh-1652z041018CCSWANR

918-Cambodia 1659 UTC April 12 (Khmer female speech, National Anthem with “Cuckoo Clock” time pips at 1:41; thanks to Hiroyuki Okamura for listening):

Download: 918-Cambodia-1659z041218CCSWANR

1431-Mongolia 1631 UTC April 11 (BBC Korean service interval signal at 46 seconds; thanks to Hiroyuki Okamura for listening):

Download: 1431-Mongolia-1631z041118CCSW

Location: Tamanu Beach Resort ocean shore, Aitutaki, Cook Islands (in the South Pacific)

Amazing catches, Gary–thank you for sharing! It seems your modified CC Skywave SSB is serving you well. Looks like you were chasing amazing DX from an amazing part of our planet!

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