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, James Townley, who shares the following guest post originally posted on his Shortwave/Medium Wave blog:
540 kHz to 1700 kHz Loop Antenna (Click to enlarge)
AM Broadcast Loop Antenna
by James Townley
Several years ago, I became interested in medium wave DXing. One of my limitations was the size of my yard, so I developed an interest in tuned loop antennas to compensate, because setting up a beverage antenna was out of the question. I experimented with different sizes of loops, and found that the bigger the aperture, the more gain the loop would have. The tuned loop antenna is also very directional, which allows you to reject, or null out interference from either noise or other stations. Loops are considered bi-directional in that they receive to the front and back, but not to the sides. The tuned loop antenna quickly became my weapon of choice for medium wave DXing.
Recently when the weather began allowing me to enjoy the outdoors, I decided to make another smaller loop antenna from a plastic milk crate I had lying around. I saw the idea on the internet when I observed that someone had used a milk crate for their loop. Click here to see a variety of tuned loop antennas that others have made. Whichever material you decide to make your loop antenna from, just make sure that it is not a conductive material. Wood, plastic, and cardboard seem to be popular materials for loop making. In the photo above, I am using my Sony ICF-2010 to listen to WCCO on 830 kHz. This station is nearly 200 miles south of me, but I am able to receive it with 9 LEDs lit on my signal strength meter while using the loop. There is no direct connection of the loop to the radio, it is inductively coupling with the radio’s own ferrite rod antenna.
If you are interested in making a loop antenna like mine, here are the materials you will need:
120 ft of 18ga insulated wire (I bought a 100 ft spool of cheap speaker wire and pulled the 2 conductors apart):
1 – Plastic milk crate
1 – 15 to 365 pF air variable capacitor (found in many old radios, or a google search to buy one from an internet store)
1 – Tuning knob. Any knob will do as long as it fits the shaft on the variable capacitor.
1 – Tape or wire ties. I used tape to secure the wire while winding, then hot glue when finished.
When you begin to wind your coil, use tape or a wire tie to secure the wire, and leave about a foot of wire. This extra foot of wire will later be soldered to the frame on the capacitor. As you wind your coil, pull the wire snugly and with each turn leave about a quarter inch spacing between each turn. The spacing isn’t critical as long as the spacing is consistent. I wound 21 turns on my crate. This may differ for you, depending on the size of your crate, or the value of you capacitor. If you find that the bottom frequency isn’t low enough, you can add more wire to make a few more turns. This will lower the bottom frequency for you.
After winding the coil, you can solder each end of the coil to your capacitor. The beginning of the loop gets soldered to the frame of the capacitor, and the other end of the coil to the rotor solder lug on the side of the capacitor. If you do not have a soldering iron, you can use alligator clips to connect your loop coil to the capacitor as well. I secured my capacitor to the inside corner of the crate with hot glue. I put a generous amount of the hot glue onto the bottom of the capacitor frame, and held it to the crate until the glue cooled enough for the capacitor to stay on it’s own. I used enough to get the job done, but not so much that it interfered with the plates in my capacitor. The hot glue seemed to adhere very well. I then checked the spacing of my coil turns, and secured them with the hot glue as well.
I was very impressed with the results after spending some time with the loop. It’s small enough to maneuver around easily, but big enough to give it some gain, so I can listen to daytime DX. I may make another tuned loop using two crates to see how much more gain I get with the larger aperture.
Happy DXing,
James Townley
Many thanks, James, for sharing your project with us! This loop appears to be relatively simple and accessible even to those with little knowledge of soldering or homebrewing. I’m now wondering how a loop made of four milk crates might perform!
My good friend, David Korchin (K2WNW), has a knack for finding diamonds in the rough.
He’s been known to find a radio that needs TLC, take it home and restore a bit of its former glory. He’s had some amazing luck in the past.
Recently, DK sent a video of of his recent acquisition: a beat-up GE Super Radio II he purchased for two dollars. This radio will win no beauty contests, but it still plays well.
Many thanks, DK, for allowing me to post this video. It goes to show you that you should never pass up an opportunity to adopt a Super Radio. Even if the telescopic antenna is all but missing, the internal ferrite bar is where the money is!
I’m finally back from a week of travels which included the 2017 Hamvention held a the Greene County Fairgrounds in Xenia, Ohio.
As an inside exhibitor, I was quite busy at Hamvention–indeed, my voice is only now recovering.
I did manage to sneak away from our table on several occasions to visit with vendors, friends, and check out new innovations (thanks to ETOW volunteers Eric McFadden, Miles McFadden and Robert Gulley!). I also attended the NPOTA (National Parks On The Air) forum on Sunday.
I’ve also already started a re-cap/review of the 2017 Hamvention which I plan to post in the next few days. Stay tuned.
In the meantime, though, a number of readers have asked what I brought home from the Hamvention. Though I had no intention to buy stuff this year–seriously–I did manage to come home with a few treasures.
Panasonic RF-2200
If you’ve been reading the SWLing Post for a while, you’ll know I’m a big fan of the ‘2200. On the shortwaves, it’s a great performer even though the analog tuning can be a bit squirrelly.
Where it really shines is on mediumwave, though. It’s easily the best AM portable I own.
My buddy, Eric (WD8RIF), pointed out this RF-2200 (see photo above) in the flea market. Since I already own an RF-2200, I had no intention of buying one.
While taking a photo of it, the seller started telling giving me details. He said he’d never used batteries in it, and only used a small external wire antenna connected on the back (his homebrew connector was still attached). He then mentioned that he also had the original box, manuals, accessories and packing materials.
I put my camera phone away and picked it up to take a closer look. It had obviously been taken care of over the years. The battery compartment was immaculate and the telescoping whip didn’t have any bends or missing sections–it was straight, clean and original.
Out of curiosity, I asked how much he wanted for it.
He wanted $70.
Sold!
With absolutely no hesitation, I reached for my wallet. Sure, I’ve already got an RF-2200, but one can never have too many RF-2200s. Right?
I took a few photos of the RF-2200 this morning:
Without a doubt, this was my exciting 2017 flea market find. .
MFJ-8121 Analog Shortwave Portable
While browsing the inside exhibits late afternoon on Saturday, I spotted this analog portable from MFJ Enterprises.
In truth, I didn’t realize MFJ even had a shortwave portable in their product line.
This particular unit was on the clearance table and was labeled as a “factory second.” The sales person told me it was likely due to the damaged box (the unit inside had no visible blemishes).
At $12, I decided to purchase it.
You see, I get a lot of requests from readers asking for recommendations of simple analog portables. I thought I might eventually review this MFJ unit.
Last night, I popped some AA batteries in the radio and, sadly, it produced no audio. The tuning indicator works, but the speaker doesn’t even produce a hiss. I suspect this is the real reason it was being sold on the clearance table.
I might contact MFJ and let them know about this, or I might simply pop the radio open and see if it’s a broken connection.
HamSource flashlight
And finally–while not a terribly exciting purchase–I did also pick up this CREE LED flashlight at the Ham Source booth. It’s small, bright and runs on one AA battery. It has three settings: high, low and flashing. It appears to be very durable and the beam can be focused. For eight bucks, it’s the perfect flashlight to live in my new Tom Bihn Synapse 25 backpack.
That’s all, folks!
Looking back, I’m quite impressed with my self-control. I really didn’t want to return home with any new finds. If anything, I’m trying to downsize right now.
But a Panasonic RF-2200? I always have room for another FR-2200!
Post readers: Have you acquired any flea market finds recently? Please comment!
Many thanks to SWLing Post contributor, Phil Brennan (VK8VWA), who shares the following:
I spotted this bit of research from the Australian Communications and Media Authority regarding radio listening habits of people living in remote Western Australia.
It shows that radio very much remains a big part of people’s lives in the bush, particularly AM radio. I’m sure these findings would be replicated in the Northern Territory where I live, but as you are only too aware, we’ve had our remote SW radio service axed by the ABC. Anyway, it may be of interest to you and your readers.
Thank you for the tip, Phil. This is a pretty fascinating report. As you mention, the use of AM radio is quite heavy–no doubt due to the vast broadcast footprint. It’s this sort of report that should have been done prior to any decision about axing ABC’s NT shortwave service.
Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes and recordings from an Ultralight DXpedition in Kona, Hawaii:
April 2017 Kona, Hawaii Ultralight DXpedition
The first long-range test of a “Frequent Flyer” FSL Antenna
By Gary DeBock, Puyallup, WA, USA April 2017
Introduction
Ever since the U.K.’s Graham Maynard published his innovative article about the “Ferrite Sleeve” antenna in early 2011 an enthusiastic group of DXers and tinkerers has continually refined and upgraded the design, with most of them going in the pursuit of maximum possible gain. Monster FSL models were designed with weights of up to 38 pounds (17 kg), and considering the size, weight and subversive appearance of the typical model, the general assumption was that this new type of antenna was highly unsuitable for air travel, since it would send airport security personnel into a serious panic.
This situation continued for a full 6 years, during which the FSL antenna became a star performer in the related new niche of ocean cliff transoceanic DXing. But was there another possible application for the antenna’s compact performance advantage? What if a very lightweight, high-performing model could be designed which would not only provide a huge boost in DXing gain, but fit inside a hand-carry suitcase, and routinely pass airport security screening inspections around the world? This was a tough design challenge, but well worth the effort if successful!
Since the new antenna would need the maximum possible performance for its small, lightweight size, the use of the Russian surplus 100mm x 20mm x 3mm ferrite bars was mandatory. Every possible effort would be used to make the antenna as compact and lightweight as possible, although the choice of the highest-sensitivity 1162/46 Litz wire was critical for best performance. The PVC frame would be shrunk down to the smallest practical size. Finally, in a major experimental effort here over the winter season, the first of the new 5 inch (127mm) “Frequent Flyer” FSL’s became a reality. The finished antenna had a very non-subversive appearance, and could fit inside a custom-sized plastic tote within a hand-carry suitcase. Most importantly, it could still deliver a serious amount of inductive coupling gain– roughly similar to that provided by a 4 foot (1.22m) air core box loop, but with the advantage of somewhat lower noise reception.
Because the Russian surplus 100mm x 20mm x 3mm ferrite bars are extremely scarce (without any current supply source) only five of these original “Frequent Flyer” models would be made, although alternative models using the commonly available 140mm x 8mm ferrite rods were also designed. These antennas would be somewhat heavier and larger, but these “Baby FSL” ferrite rod models could be easily assembled from parts available on eBay, fit inside the hand-carry suitcases, and still deliver a lot of DXing performance (while routinely passing airport security screening). Finally, an economic model using the commonly available 62mm x 12mm x 4mm Russian surplus ferrite bars was also designed. This lightweight FSL can be constructed for around $65 US, and can still provide a serious DXing gain boost to a stock Ultralight radio. For want of better terms, these three classes of “Frequent Flyer” FSL antennas are called the “first class,” the “business class” and “coach class” models, with FSL sensitivity scores (ferrite length x coil diameter) of 585, 490 and 300 respectively.
From April 9-12 a Mini-DXpedition was conducted on a 6th floor oceanfront room at the Royal Kona Resort Motel in Kona, Hawaii. This was the first of many long-range DXing trips based upon the performance boost provided by the compact new antenna– which was specifically designed to easily pass through airport TSA security checkpoints. A 5 inch (127mm) “Frequent Flyer” FSL antenna was packed inside a matched-size plastic tote within a hand-carry suitcase, and breezed through TSA security screening in both the Seattle and Kona airports (without even a single question ever being asked). This was one of the “first class” Frequent Flyer models described previously, and was used to boost DX station gain on a 7.5″ loopstick C.Crane “Skywave” Ultralight radio. This combination was effective enough to track down many exotic Pacific Island stations (540, 621, 1440, etc.) at S9 levels during transmitter-site sunset skip propagation into Kona, as well as Asian TP-DX of varying strength around local sunrise.
This Kona trip was primarily designed as an anniversary celebration with my wife, so before we took off I had (somewhat reluctantly) agreed that DXing would have a secondary priority to sightseeing over the four days. Because of this there were many frequencies that could not be investigated in Kona, but I knew very well which Pacific island stations were tough challenges in both North America and Japan, and I was determined to go after them with a vengeance. 540, 621 and 1440 would all receive serious attention in Kona– not because they were great challenges in Hawaii, but because most DXers in both North America and Japan needed all possible information about them if they were to have any chance of reception at all. Besides this I was eager to try my long-range luck chasing exotic Asians around local sunrise with the innovative FSL antenna, but I knew that east-west propagation was almost totally dependent upon solar activity– and as it turned out both the A and K indexes shot up after our arrival.
Overall the Kona MW propagation to the Pacific islands was exceptional around local midnight (as expected), but the sunrise propagation was somewhat challenging for long range Asians. Perhaps the biggest success of this entire trip was the interest and excitement that the “Frequent Flyer” FSL antenna series (the major experimental project here this past winter) has inspired among DXers who routinely travel to foreign countries and other faraway venues. As I write this Craig Barnes of Wheat Ridge, Colorado is conducting his own 5 inch “Frequent Flyer” FSL- based DXpedition to Hawaii. Good luck, Craig!
Recordings
[Note: a selection of audio files have been embedded in the post below, but all audio is available to download and stream via the links provided.]
531 6DL? Dalwallinu, Australia Presumably the one with the same-sounding announcer and program as the one on 630-4QN at the time (at 1547 on 4-9; see MP3 for 630-4QN), but it didn’t seem to be exactly parallel (maybe a time zone delay?)
https://app.box.com/s/7bg1hruxrufccuys5axc4yzumexr3q36
540 2AP Apia, Western Samoa This station features a lot of Samoan music (with both male and female announcers), and dominates the frequency in Kona at night as long as it transmits. Unfortunately it doesn’t follow the listed PAL sign off time of 1000, but runs past this time routinely, which made it tough to track down an exact sign off time during my limited sessions. My guess is that it signs off sometime between 1030 and 1100. The following MP3 is of S9+ level Samoan Christian worship music at 0931 on 4-9. This overwhelming signal was one of the most awesome recorded during the entire DXpedition:
558 Radio Fiji One Suva, Fiji Somewhat of an underperformer considering its South Pacific location and (nominal) 10 kW power level. My guess is that the station has some transmitter and/ or antenna issues. Here is some fair level male speech with island music at 1001 on 4-9, which was the strongest signal it managed during the entire trip
558 UnID-TP Once again, this weak signal sounded a lot like the 630-4QN program at the time (1548 on 4-11), so my guess is that 6WA in Wagin, Australia is the most likely possibility
603 HLSA Namyang, S. Korea One of the common Asians which ran the gauntlet of dicey solar activity. It was fairly good at 1521 on 4-12, but was MIA during a couple of days
621 3RN Melbourne, Australia This LR network station would start to fade in just when Radio Tuvalu was about to sign off (around 1000), although it never provided any serious competition for the exotic station. This MP3 was made just after Tuvalu’s sign off at 1006 on 4-9
621 Radio Tuvalu Funafuti, Tuvalu A very tough station to track down on the mainland, but certainly a “piece of cake” in Kona. Routinely has sign off at 1003 UTC, preceded by island choral music and the national anthem (sung by the same choral group). Around 0950 a female announcer begins the routine by giving a monolog news broadcast about 5 minutes long, typically followed by an island music song right before the fixed 5-minute sign off routine. The latter two features are included in the following 8 minute recording (at near S9 strength) made at 0955 on April 10
The usual female announcer with her 5 minute news broadcast at near S9 strength at 0955 prior to the sign off routine on April 11. The lady giving the correct pronunciation for “Tuvalu” is at the 11 second point
630 4QN Townsville, Australia This 50 kW station was far and away the strongest Australian signal heard throughout the trip. Unfortunately it wasn’t in the same time zone as fellow LR network stations on 531 and 558 in Western Australia, making parallel checks seem dubious. Here is a typical signal at 1543 on 4-9
657 Pyongyang BS Pyongyang, N. Korea This bizarre station was far and away the strongest Asian heard during the trip– almost like it was a South Pacific semi-local. When solar activity cooled off it could blast in with serious power, such as at 1555 on 4-9
693 UnID-TP This mystery signal showed up at 1604 on 4-9, after NHK2 (JOAB) sign off. Obviously there is male speech and some kind of backup music at various times, but I’m totally unfamiliar with stations on this frequency (except for JOAB). Any hints or suggestions? This station only showed up on 4-9; rising solar activity brought in only 690-Honolulu splatter on the other three days
1035 Newstalk ZB Wellington, NZ Received late in sunrise enhancement at 1611 on 4-12, this was a rather modest signal from the Kiwi big gun, which never seemed to get anywhere close to its Oregon cliff strength during the entire trip
1098 V7AB Radio Marshalls Majuro, Marshall Islands One of the regular Pacific island stations received in Kona, and one of the best bets for Mainland reception. The frequency has very little QRM, although Newstalk ZB could be weakly received in between the island music songs after around 0900.
Strong island music at 0955 on 4-9 (its best performance during the trip)
1098 Newstalk ZB Christchurch, NZ Heard only once in between island songs on V7AB (at 0957 on 4-9); and never really strong enough to compete for the frequency with Radio Marshalls
1440 Radio Kiribati Bairiki, Kiribati Because of its domestic frequency this obscure station is another of the toughest Pacific island stations (and countries) to receive on the Mainland, but some very helpful identity clues were discovered in Kona (where the station is a breeze to hear). The station routinely signs off at 0936 UTC each evening, with a very loud 1000 Hz audio tone right before it cuts power. The sign off routine includes station ID’s in both the local language and English around 0932 prior to the choral music national anthem, although because of her heavy accent the fact that the female announcer is talking in English might well go unnoticed. The full sign off routine is included in the following MP3, preceded by an Island music number (during which a 1440 Spanish pest attempts a run on the frequency, only to be immediately drowned out)
The American country music format can be heard prior to the 4-bong time signal.
Prior to the sign off routine this station also uses its female announcer to give a final news update (like 621-Tuvalu). This recording is of such a news update at 0925 on 4-11, with several mentions made of the American president
1566 HLAZ Jeju, S. Korea Fairly regular with its Chinese Christian service around 1530 each morning in Kona, but never at very great strength (possibly due to unfavorable solar activity). Here at 1609 on 4-9 it is the music station playing the Chinese version of “I Would Rather Have Jesus,” in a mix with the (presumed) Mainland Chinese Yanbian Jammer
1566 Yanbian, China (Presumed location, Jammer) Because of Chinese inflection this is the apparent co-channel of HLAZ in the same recording at 1609 on 4-9; it was also received at 1600 on 4-10 with Chinese 5+1 time pips (thanks to Chris Kadlec for his assessment)
“Arctic Radio Club in Sweden celebrates the 2017 Convention in Jönköping, Sweden May 6 & 7th. Our radiostation ( the radiovan above) will be on the air with many different type of programs, mostly in Swedish. The transmitter will have a power of 250 W (ERP) on 1593 kHz and the antenna is located on a high hill near lake Vättern. In the evening of May 5th we will start tests. There will be station identifications in English, too.
The official start will be May 6th at 1900 UTC and the programs will be running until 1100 UTC on Sunday noon
On the 7th there will be a program dedicated to the local SR P4 Radio Jönköping that celebrates its 40th year of broadcasting. this year. This program starts at 1000 UTC and will be in Swedish. Until the station signs off at 1100 UTC.
Reception reports are appreciated and a special QSL-card is issued, if you enclose return postage in your letter. Reception reports by e-mail will be answered by an e-QSL. Address: Ronny Forslund, Arctic Radio 1593, Vita Huset, SE-17995 Svartsjö, SWEDEN. E-mail: info(AT)rock.x.se”
Hi there, subscribers to the Oxford Shortwave Log YouTube channel and regular readers of this excellent website will be aware that I have been using a Bonito Boni whip E-field wideband antenna for a couple of months now. You may have seen my previous post here, detailing some excellent initial DX results achieved with the Boni Whip. What makes this antenna so compelling for a DXer such as myself is simply that it’s so light and compact; I can literally take it anywhere. Currently it lives in a small flight case (see above & below) on the back seat of my car, with either my Sony ICF-SW55 or Eton Satellit, a home-brew battery pack (that literally cost pence) and some peripheral bits and pieces; spare batteries, cables etc. I think it’s probably already clear that if you consider the Boni Whip’s performance as a function of portability and price, it’s out there on its own – I’m not aware of another antenna that can match it. Of course, there are H-field antennas, such as the excellent Wellbrook active loops that will effectively reject QRM, if that’s an issue for the user, but at a significant cost delta.
Since my last posting, I have continued to use the Boni Whip regularly on my DXpeditions and upload the reception videos to my YouTube channel. I have been nothing but totally impressed with this antenna, to the point that I’ve actually been surprised by the signals I’ve caught and recorded with it. Recent catches include a number of low-power stations from Brazil, including Radio Bandeirantes – Sao Paolo, Radio Voz Missionaria – Camboriu (on the 49 and 31 metre broadcast bands) and Radio Aparecida. Some of these signals are incredibly difficult to hear in Europe at all, let alone well and yet the ultra-compact Boni-Whip running off AA batteries, coupled to the (equally brilliant) Eton Satellit managed it with aplomb. Other catches include Zambia NBC Radio 1 – Lusaka and a signal from Bangladesh Betar that sounded as if the transmitter was 5 miles down the road!
All-in-all, I’m extremely satisfied with the performance of the Bonito Boni Whip and highly recommend it to those DXers requiring a high-performance, compact antenna, for use at home in electrically quiet environments or on any DXpedition. You certainly won’t be disappointed.
Please find embedded reception videos below and text links that will take you to the Oxford Shortwave Log YouTube channel. Thanks for reading/watching/listening and I wish you all great DX.
Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.
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!
