Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
Many thanks to SWLing Post contributor, Bill Hemphill (WD9EQD) who shares the following:
I went to the Warminster Amateur Radio Club (WARC) hamfest [yesterday] in Bucks County, PA. For some time, I have been thinking about making a loop antenna for AM DXing. It was my lucky day. When I walked to the inside tables, on the very first table was this homemade loop antenna gentleman was selling from an estate.
I snatched it up for $40.
Attached are some photos of it. It’s 25” by 25”, with a swivel base. There are 23 turns of wire and I have no idea what size the capacitor is. I did some preliminary tests and it tunes from 280 kHz to 880 kHz. So it’s the covers the high half of the long wave band and the low half of the AM band.
It’s very well made and I fugue I can modify it to cover the entire AM band.
[…]I hooked the SDRplay RSP2 to it and was getting good signals of major stations all the way to 15 mHz.
That’s with it sitting on my dining room table. Of course the capacitor wouldn’t peak the signals.
So it was a great day at the hamfest!
Indeed that was a great find, Bill! Someone spent a decent amount of time building that furniture-grade loop support. Indeed, it’s very reminiscent of 1920s-30s mediumwave loops!
What I love about your loop (and that of Thomas Cholakov) is that one can see how simple these antennas actually are to build. The only complicated bit is the support, but even that’s simple if you use the shield of a heavy coax or flexible copper tubing.
Thanks for sharing and enjoy logging DX with your new-to-you loop!
Checking out transoceanic DX propagation at an exotic ocean beach site can provide the hobby thrill of a lifetime– if a DXer is lucky enough to choose the ideal time, place and gear to make the chase. All of these fell into place in an amazing way during a 5-day trip to Aitutaki Island (2600 miles due south of Hawaii) with Ultralight radio gear, resulting in the reception of MW stations in India, Bangladesh, Mongolia and Cambodia– all at over 6,800 miles.
Because of extensive QRM from Australia and New Zealand the total number of Asian stations received was limited, but it was definitely a case of quality over quantity. Phenomenal gray line propagation around sunrise shut down Japanese signals almost completely, but boosted up those from the exotic countries in east and south Asia. Korean station reception was limited to the big guns, which was also primarily true for Chinese signals. Except for the ANZ pest QRM, the conditions seemed custom-designed for a west coast DXer to go after the exotic stations which rarely– if ever– show up in BC, Washington or Oregon (even though the Cook Islands’ distance to them is greater).
7.5 inch loopstick C.Crane Skywave SSB Ultralight
Ocean beach propagation at sunrise was strong enough to bring in both 693-Bangladesh and 1431-Mongolia at S9 levels almost every morning on my Ultralight gear, and allow both 657-AIR and 918-Cambodia to break through ANZ QRM on April 12th. No doubt many more of these exotic stations could have been logged except for Australian QRM on 576, 594, 872, 883 and 1566, but this only added to the thrill of the chase. The overall results were exceptional for a DXer using only a 7.5 inch loopstick Ultralight radio and 5 inch “Frequent Flyer” FSL– all designed to fit within hand-carry luggage, and easily pass through airport security inspections. Thanks very much to Alokesh Gupta, Hiroyuki Okamura, Jari Lehtinen, Chuck Hutton and Bruce Portzer, who all assisted in the identification of these stations!
657 All India Radio Kolkata, India, 200 kW (8,075 miles/ 12,995 km) Recorded by accident during a sunrise check of the Korean big guns at 1641 on April 12, reception of this longest-distance station went unnoticed until file review after return to the States. The female speaker (in the Bengali language) is the third station in the recording, after the female vocal music from Pyongyang BS and the Irish-accented male preacher from NZ’s Star network. Her speech peaks around 40 to 50 seconds into the recording. The isolation of the Star network at the 55 second point was done by the Ultralight’s loopstick, not by the propagation. Thanks to Alokesh Gupta for the language and station identification:
657 Pyongyang BS Pyongyang, N. Korea, 1500 kW Like most east Asian signals the N.K. big gun sounded pretty anemic in the Cook Islands. Its female vocal music at 1641 on April 12th shared the frequency with NZ’s Star network (Irish-accented preacher) and AIR’s female Bengali speaker:
693 Bangladesh Betar Dhaka, Bangladesh, 1000 kW (7,960 miles/ 12,810 km) Probably the biggest surprise of the DXpedition, with S9 signal peaks on 4 out of 5 sunrise sessions. Frequently snarling with the Oz pest 3AW, it usually managed a few minutes on top of the frequency each morning from 1630-1700 UTC. Exotic South Asian music was the usual format, and was very easy to distinguish from the talk-oriented format of 3AW (and other Oz co-channels). This first appearance at 1652 on 4-10 featured a “Bangladesh Betar” ID by a male speaker at 8 seconds into the recording (thanks to Chuck Hutton for listening):
774 JOUB Akita, Japan, 500 kW Oddly enough, this was the only Japanese signal making it to the island during the entire trip. Mixing with a goofy-sounding 3LO announcer at 1613 on 4-11, the Japanese female speech concerns a “doobutsuen” (a “zoo” in Japanese, similar to what the frequency sounded like with the 3LO announcer):
819 KCBS Pyongyang, N. Korea, 500 kW The N.K. big gun managed a potent signal for its 3+1 pips across its “TOH” at 1630 on 4-12 but never could shake off RNZ’s Tauranga transmitter:
909 CNR6 Quanzhou, China, 300 kW Strong signal with CNR ID (1:08) and Mandarin speech by male and female announcers. NZ’s Star network was apparently off the air at the time, since it was a real blaster when transmitting:
918 RNK Phnom Penh, Cambodia, 600 kW (6823 miles/ 10,981 km) Breaking through the Shandong and Oz QRM at an ideal time to dominate the frequency, its sign off transmission with the National Anthem peaked just before the 1700 TOH on April 12. Female speech in the Khmer language and exotic music are featured just before the anthem (thanks to Hiroyuki Okamura and Jari Lehtinen for listening, and identifying the National Anthem):
918 Shandong RGD Synchros (Multiple) The dominant Asian signal on the frequency, it rarely allowed Cambodia to sneak through. Here it is with female Mandarin speech at 1647 on 4-11:
Shandong RGD’s transmitters were poorly synchronized, resulting in the two-tone time pips at the 1700 TOH on 4-12 (during Cambodia’s National Anthem at 1:40, in the MP3 linked below). Although actually from two different transmitters, the sound effect sounds similar to that of a “cuckoo clock,” resulting in some initial confusion about their source:
972 HLCA Dangjin, S. Korea, 1500 kW The South Korean big gun played the part on most mornings, including this S9+ Korean female speech at 1631 on 4-12:
981 CNR1 Synchros Changchun/ Nanchang, China, 200 kW/ 200 kW The first of three CNR1 frequencies which usually produced strong signals, this music // 1377 was received at 1624 on 4-12:
1377 CNR1 Synchros (Various) Overall this was not only the strongest Chinese frequency on the band, but was the strongest Asian station on the band as well. Awesome S9+ signals were typical each morning, as with this male speech and music at 1622 on 4-12:
1431 Mongolia (Relay Station) Choibalsan, Mongolia, 500 kW This station was easy to receive on the first attempt, with very little competition on the frequency. It typically managed an S9 signal after 1630 daily with the BBC’s Korean service, which seemed to be broadcast during the peak sunrise enhancement time in Aitutaki’s ocean-boosted propagation. Here is BBC’s Korean male announcer at an S9 level at 1632 on 4-11, with the BBC interval signal at 47 seconds into the recording:
1566 HLAZ Jeju, S. Korea, 250 kW A very poor signal was typical during this trip, with the Chinese service barely showing up under 3NE and two other DU English stations (probably 4GM and Norfolk Island). Whenever 3NE was in a fade it had a chance, since other two co-channels were running very low power. Here is the latter situation, with the weak Chinese barely audible under the DU English snarl at 1641 on 4-12:
1593 CNR1 Changzhou, China, 600 kW This was another Chinese blaster, with S9 signals typical every morning. Here it was at 1641 on 4-12 with male Chinese speech and music at 1377:
Amazing, Gary! Thank you for taking us along on your excellent Ultralight DXpedition. With a modest portable radio and a little antenna ingenuity, you’re enjoying some outstanding DX! You’re living proof of the point I was trying to make in a post yesterday!
Many thanks to SWLing Post contributor, Gary DeBock, who shares the following note about his recent Cook Island DXpedition:
The farthest DX received during the Cook Island DXpedition (on Aitutaki island) was 657-All India Radio in Kolkata, India, at 8,072 miles (12,991 km). Recorded by accident during a sunrise check of the Korean big guns at 1641 on April 12, reception of this longest-distance station went unnoticed until file review after return to the States.
The female speaker (in the Bengali language) is the third station in the recording, after the female vocal music from Pyongyang BS and the Irish-accented male preacher from NZ’s Star network. Her speech peaks around 40 to 50 seconds into the recording.
The isolation of the Star network at the 55 second point was done by the Ultralight’s loopstick, not by the propagation. Thanks to Alokesh Gupta for the language and station identification!
Many thanks to SWLing Post contributor, Thomas Cholakov (N1SPY), who shares his latest video explaining the operation of a simple homebrew AM loop antenna:
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.
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.”[…]
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!
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):
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!
Spread the radio love
Please support this website by adding us to your whitelist in your ad blocker. Ads are what helps us bring you premium content! Thank you!
