In the past few weeks, I’ve gotten a lot of questions from readers who are trying to decide if they should install a magnetic loop antenna or a simple wire antenna at their home. Obviously, most of the questions come from shortwave radio listeners, but some have come from ham radio operators as well.
I realize that there’s a common theme to my answers and I thought it might be useful to share it here on the SWLing Post for future reference. I started to write a slightly more comprehensive article about this, but I quickly realized I want to keep my advice as short and clear as possible. I’ll be painting in broad brush strokes, but here you go:
If you live in an environment with a lot of radio interference…
Magnetic loop antennas are your friend.
By design, mag loop antennas are some of the best antennas for mitigating the radio frequency interference (RFI) that plagues so many of our homes and neighborhoods. When oriented vertically, mag loop antennas can also be rotated to null out unwanted signals on lower frequencies.
Mag loops come in a wide variety of configurations:
The most popular among SWLs are wideband amplified loop antennas manufactured by companies like Wellbrook, Chameleon Antenna, MFJ, DX Engineering, Cross Country Wireless, Bonito, and a number of manufacturers in China. Unlike passive loop antennas, wideband amplified antennas require no manual tuning. These loops do require a power source, typically fed through a Bias-T or batteries.
Passive loop antennas are popular among ham radio operators because they’re easy to build and, unlike amplified loop antennas, one can transmit into them if designed correctly. They’re less popular among radio listeners only because they typically have a very narrow bandwidth and need to be re-tuned (via a variable capacitor) each time you move frequency even a few kilohertz. The NCPL (Noise-Cancelling Passive Loop) which is also known as the Moebius or YouLoop is a bit of an exception and doesn’t require tuning, but does require a receiver with a very high dynamic range.
Loop antennas can also be very stealthy. In fact, Loop on Ground (LoG) antennas are essentially invisible and could be deployed (under the cover of darkness, of course!) in the most restrictive of neighborhoods. Note that since LoGs are horizontal, they are essentially omni-directional. [13dka corrects this in the comments: “This is somewhat ambiguous and not entirely correct: LoGs are horizontally oriented but (somewhat surprisingly) vertically polarized, and even more surprisingly they have the trademark property of verticals”]
As with any antenna, mag loops prefer to be outdoors but can be effectively used indoors if that’s the only option.
If you live in an environment free of radio interference…
Outdoor wire antennas are very hard to beat.
I am a case in point, in fact: I live in a rural, remote location without any meaningful RFI. All of my external antennas are homebrew wire antennas and they serve me incredibly well.
If you’ve been a reader for long, you may note that I don’t personally review amplified magnetic loop antennas often–these are typically published by some of our amazing contributors. This is because I like to do “apples to apples” comparisons and usually don’t have a second compact magnetic loop antenna for comparison here at SWLing Post HQ.
Almost without exception, my cheap homebrew wire antennas outperform wideband amplified mag loop antennas…sometimes, by orders of magnitude.
Many years ago, I tested a Pixel Loop amplified mag loop antenna (now under a different name and sold by DX Engineering) specifically for use on the mediumwave band to null unwanted stations. It was a very capable amplified mag loop antenna, but other than its MW nulling abilities, all of my homebrew wire antennas outperformed it on the HF bands. Reception was, at times, dramatically better on my wire antennas.
Of course, for a wire antenna to perform properly, it needs to be deployed properly. There are excellent resources out there that describe ideal heights and configurations for any given wire antenna design.
Keep in mind that wire antennas can be incredibly stealthy as well. It’s very difficult to see a wire antenna among or in front of a patch of trees, for example. At a previous home, I deployed a horizontal delta loop antenna on my property that–if you knew where to look–was easy to spot from the road. In all of the years we lived there not one neighbor took note, though, because the antenna wire had sky blue jacketing and I deployed it while no one was looking.
This isn’t an either/or choice for most of us. There’s no harm in building a simple wire antenna and trying it at home first. If the local noise floor is high, then consider adding a magnetic loop antenna to your arsenal as well.
You might find that the wire antenna has an advantage on frequencies where you have less radio interference, and the mag loop serves you well in those portions of the band with thicker RFI and QRM.
I omitted numerous antenna designs that aren’t straight-forward loop or simple wires. Check out some designs by our contributors Grayhat, Giuseppe Morlè (IZ0GZW), TomL, and many others here on the SWLing Post. As always, please feel free to comment!
Many thanks to SWLing Post contributor, Jock Elliott, who shares the following guest post:
There’s a 50-foot antenna in this room. Can you spot it?
Got reception issues? An idea worth considering: the “Horizontal Room Loop.”
by Jock Elliott (KB2GOM)
When my radio room was in the front of the house (on the east side), it was easy to run a feedline to a large RF-hungry SWL dipole with various stubs and feeders.
Now, however, with my “shack” moved to the SW corner of the house, any attempt to mount an outdoor antenna of any significant length raised potential safety issues because of nearby electrical lines.
Monitoring VHF/UHF is no big deal because of high-performance scanner antennas. HF, however, presents challenges.
My main SWL receiver is a Satellit 800, which has the guts of a Drake R8 and also has a large telescoping vertical antenna. It works okay, but I wanted more signal. I had been looking at small loops and got some great recommendations on Radio Reference, but then I had a thought: what if I turned the 8′ x 12′ room into a giant horizontal passive loop?
Here’s a hint.
So I called a ham friend and ran the idea by him. “Sure,” he said, “give it a try.” He gave me 25 feet of 4-conductor phone wire. Before I could use it, I had to strip off the outer insulation so I could get at the four separate insulated wires inside. The better half helped. Once I had the four wires, I connected two of them together and ran the resultant 50-foot strand around the perimeter of the room by taping the wire to the top of window frames and hiding the wire on the top shelves of book cases. As a result, the horizontal room loop is near the ceiling, about 7 feet in the air, and the room itself is on the first floor.
With the loop in place, I hooked the ends to the clip-in terminals on the back of the Satellit 800.
There’s a switch on the back of the 800 that allows me to quickly compare the loop with the radio’s built-in vertical antenna. And . . . it works! It pulls in more signal than the vertical (as measured on the signal strength meter), but I have not noticed a dramatic reduction in noise. On some stations, the horizontal room loop brings the signal up to full scale, and then the sound is very agreeable indeed.
In all, I am pleased with the results.
For anyone who wants squeeze more performance out of their shortwave receiver, I can recommend giving the horizontal room loop a try. It’s not expensive; it’s relatively easy to do (and undo if you don’t like the results), and just might improve your shortwave reception.
If you are not blessed with a bunch of window frames on which you could tape the wire for your room loop, you’ll have to get creative, but with lightweight wire, you don’t need a massive support structure. Tape, map tacks, or even self-adhesive Velcro segments might work for putting your room loop in place.
I don’t claim that this is the “ultimate” SWL DX antenna, but it certainly improved my situation. Perhaps others have suggestions for improving it.
I live here in South Florida and am unable to erect anything outdoors. I do get pretty good reception on my Grundig Satellit 800 and Tecsun PL-880. For these, I use either an indoor slinky antenna I bought on E-Bay; or an active indoor tunable loop antenna. This is one of the models past reviewed by you. It is Australian made, and covers 6-18 MHz. Please comment if you can on antenna usage.
Thank You very much!
First of all, I’m glad you enjoy the SWLing Post, Tim!
Great question: no doubt you understand that the antenna is the most important part of your radio equation!
You’re on the right track with a PK Loop if you live in an apartment and have no way of putting an antenna outdoors. Being a small magnetic loop antenna, the PK Loop should help mitigate a bit of the noise in your apartment building.
What I love about the PK Loop is it’s small enough that you can re-position and rotate it to tweak noise rejection and find the quietest spot in your listening room. When I travel by car and even by air, the PK Loop is a welcome companion.
Before we talk about investing in a better indoor antenna, let’s make sure we cover a more affordable option first…
External wire antennas
If you have operable windows in your apartment, even fishing a thin-gauged wire out of your window–allowing it to simply hang along the outside of the building–could improve your reception significantly. Of course, if there’s a source of noise outside of your apartment it might only make things worse, but this is at least an inexpensive experiment and the results might impress you.
I had a fantastic opportunity to evaluate how well the PK Loop would perform in a typical hotel room. My buddies Eric (WD8RIF), Miles (KD8KNC) and I stayed overnight in a hotel on Wright-Patterson Air Force Base during our mini National Parks On The Air DXpedition.
The hotel room was indeed dense with RFI.
We hooked my Electraft KX2 to both the PK Loop and to a simple random wire antenna.
Without a doubt, the PK Loop was much better at mitigating radio noise than the wire antenna we hung on the inside of the hotel window.
Unlike most modern hotels, however, this one actually had operable windows, so we tossed the random wire out the window and made another comparison. In this case, the external wire antenna consistently outperformed the PK Loop, no doubt because it had the advantage of being outside the radio noise cloud within the hotel’s walls. It goes to show that outdoor antennas–even if simply hanging from a room window–will almost always outperform comparable indoor antennas.
So, if you have a way to dangle a wire out one of your window, give this a try.
How long should the wire be? I suppose it depends on how much vertical space you have below your window. For starters, I’d try to suspend at least eight feet of wire outside. If I had the vertical space, I’d try as much as 31 feet.
Important: First you must check to make sure your wire couldn’t possibly touch electrical lines. Never lower a wire outdoors if the wind could blow it into an electric service entry point, power line or any other type of line or cable. You should do a thorough inspection of the site first.
With that said, keep in mind: Stealth is key!
Can you spot the wire antenna in this photo? Of course not.
Use a thin wire with a black or dark jacket/insulation. Only lower it when using it–don’t leave it out all day long. Check to make sure your antenna isn’t going to interfere with your neighbors below (like landing in their outdoor grill or flower pots!). One strong complaint from neighbors could shut down your operation permanently.
Now back to loops…
If you don’t have operable windows or a way to deploy a wire antenna outside–or you’ve tried a wire antenna and results were unsatisfactory–then you will be forced to stick with indoor antennas which almost always leads you down the path of larger amplified wideband magnetic loop antennas.
This is a topic I covered extensively earlier this year.
I’m plotting to write a more in-depth article about antennas in the coming months, but it will focus on external antennas and methods of mounting them. When you have no means of mounting an antenna outdoors, in my opinion, your best options are the ones mentioned above.
Post readers: Have I overlooked an indoor antenna option? Please comment if you have experience with indoor antennas!
Let’s face it: SWLers and amateur radio operators are some of the most frugal hobbyists out there. But the good news is that radio is a hobby that favors the frugal. There are many practical and time-tested ways to make radio listening fun and effective–such as improving your shortwave radio reception–that are absolutely free, or that cost very little.
And how do I know this? Among the frugal, I’m the most frugal SWLer I know! Yet there’s a method to my frugal madness: because I simply can’t afford to waste hard-earned radio money on gadgets and accessories that are ineffective, I count my pennies in order to make quality purchases with longevity in mind. Meanwhile, I track down ways to keep my hobby cost-effective.
I’ve gathered here some of my favorite frugal tips and quality purchase suggestions here. So, without further delay, let’s start SWLing–and saving money.
1. Check your shack/home for RFI. Cost: Free
Checking your shack for RFI is vitally important, a procedure every radio listener or operator should undertake.
The truth is, very few of us regularly experience ideal conditions for HF or AM radio listening. Devices like plasma TVs, laptop power supplies, and the ubiquitous AC adapter inject distracting noise into our otherwise peaceful environs, disrupting our hobby. This noise is known as RFI (Radio Frequency Interference).
These “wall wart” type adapters can create a lot of RFI
A number of times, I’ve received a message from one of my readers on the SWLing Post claiming that their new shortwave radio can “only” hear strong, blowtorch stations. My simple advice? Put batteries in your radio, turn it on to an unoccupied frequency in your favorite shortwave meter band, go to your circuit breaker box, and turn off everything in your house. (Warning: Do warn your housemates beforehand, to avoid any loud protestation! And do reset your clocks and check your refrigerator/freezer after this test.)
Did the noise level on your radio decrease? If the decrease coincided with the power cut, then one or more electronic devices in your house are generating RFI. RFI often sounds like static–very loud static–and is often so wide in bandwidth that it can cover several megahertz. RFI can overwhelm your portable radio and basically “deafen” it to anything but the loudest stations that break through the elevated noise floor.
Next comes the process of elimination: systematically turn on circuit breakers until you hear the noise return. If you’re fortunate enough to have accurately-labeled circuit breakers, you will at least know what area in your house holds the infamous disruptive device. Here’s a short list of the usual RFI culprits:
If you live in a condo, high-rise, or high-density neighborhood, my first suggestion may be of little use to you. In this case, your neighbor(s) may be causing RFI; turning off your own power may have little to no effect. Fortunately, there’s an easy–albeit modestly inconvenient–way to deal with neighborhood RFI. Leave the neighborhood! No, not permanently; just for a fun afternoon outing (with radio, of course).
If you live in a city, grab your radio, and head for a park or other area with wide open space and no buildings. Listeners who live in urban areas frequently enjoy radio listening via headphones on a park bench; some even have a favorite bench for their fair-weather pastime.
The benefits in this case are two-fold: firstly, you’re removing yourself from the vicinity of RFI, but secondly–and the icing on the cake–is that you’re taking your radio, and its antenna, outside. Antennas always function better outside. Walls and even windows attenuate HF signals. Plus, outdoor settings nearly always equal fun.
By the way, if you have no local parks to which you can escape, consider taking your radio in the car and driving to a national park. Better yet, combine camping and SWLing. I like to do this, although I don’t have an RFI problem where I currently live.
3. Make a simple wire antenna. Cost: Free (or, at most, $10-15)
Most shortwave portables radios on the market today have a telescopic whip antenna that will suffice for casual listening. But often you can increase the antenna gain by simply adding more length in the form of a simple thin wire. Keep in mind that many radios actually ship with a clip-on antenna wire. Check your original box and make sure you haven’t overlooked it, as it’s fairly easy to do.
An alligator clip offers serious bang-for buck–especially if you already have the parts lying around
If you didn’t receive a factory-supplied clip-on antenna, no worries! They’re a breeze to make and quite cheap: indeed, if you have a junk box of electronics parts like so many hobbyists I know, you may already have what you need. Simply obtain a 20 foot length of jacketed (insulated) wire–gauge is not important, just something thin enough that you can easily roll up to transport. Next, strip ¼ inch of insulation off the end of the wire. Solder and/or crimp an alligator clip to the end of the wire, making sure you have a solid, stable connection.
Now, stretch out this wire and attach it to your antenna. You will most likely find that this improves antenna gain. The effectiveness of the wire varies with the receiver. When I’ve made clip antennas in the past, I’ve simply made them longer than I thought I might need, then later cut it off at the optimum length based upon signal strength.
If you live in an RFI-heavy environment, adding a wire antenna at home may only increase your noise level (after all, it will make the radio better at “hearing” the noise).
Some receivers are susceptible to overloading and electrostatic discharge (the Tecsun PL-600, Grundig G5 and G3 come to mind). To be on the safe side, do not attach any wire to your portable that is in excess of twenty feet in length. Twenty feet should be more than sufficient length to increase antenna gain without any negative repercussions.
4. Use batteries––preferably rechargeable ones. Cost: $5- $20
Not all rechargeable batteries are created equally. Lean toward name brand, higher quality cells. Dollar store batteries lack longevity.
Why rechargeables–? First and foremost, with rare exception, shortwave radio manufactures give little thought to the AC adapters they include with a portable shortwave radio; they’re simply an accessory that is expected, so they deliver. Indeed, the AC adapter that came with my Tecsun PL-880 (Tecsun’s latest flagship portable) came with an AC adaptor that does a great job charging the internal batteries, but injects copious amounts of RFI in the process. Running the radio off of batteries solves the problem instantly.
Many radio manufacturers now include rechargeable batteries with the purchase of a radio. Some of these batteries are AA cells, others are slim packs resembling cell phone batteries. Consider purchasing an extra battery if you’re worried yours might die away while you’re listening to your favorite program; a quick switch, and you scarcely miss a beat. If your portable comes with rechargeable batteries, most likely the radio even has a built-in charge control circuit.
I should add that I’m a fan of the traditional AA battery, even though they’re bigger than other battery types. After all, they’re nearly always accessible. If a radio takes AA batteries, I never use the radio’s built-in recharger, instead I prefer a MAHA brand battery charger, as they condition and give a longer life to the rechargeable cells.
Sure, buying rechargeable batteries and, potentially, a good battery charger require an initial outlay of money, but the rewards are a quieter receiver and a more earth-friendly approach than heavy-duty or alkaline batteries can deliver.
5. Listen with headphones or earphones. Cost: $0 – $100
Sony MDREX10LP in-ear headphones are inexpensive and effective.
Why headphones? Ask any serious DXers (amateur radio or SWL) and they’ll tell you headphones are an indispensable tool. While armchair listening is great with your radio’s built-in speaker, headphones give you better sound isolation, and your radio’s audio is equally balanced. Digging a weak station out of the ether is easier with headphones.
Almost every portable you buy today will come with a complimentary set of earphones. Quality varies amongst these, but in my experience, the headphones included tend to be of the lowest quality; for shortwave listening, these may suffice.
Though AM and shortwave radio is not considered a “high-fidelity” medium, thus not requiring a wide frequency response, I still prefer listening with quality earphones/headphones. As long as your headphones have a decent frequency response–I usually aim for 8 – 22,000 Hz–you’ll be pleased. And do make sure your headphones or earphones are comfortable to wear for extended periods of time.
Yamaha CM500’s are a worthwhile investment if you’re an amateur radio operator.
One of my favorite pair of in-ear earphones for SWLing are the popular Sony MDREX10LP series. They’re comfortable, responsive, isolate noise, and are available from a number of retailers for about $10 USD per pair.
For over-ear headphones, I like the Panasonic RP-HTF600. They’re large, comfortable, and deliver amazing fidelity for about $30 USD.
If you also happen to be an amateur radio operator, the Yamaha CM500 headphones have a built-in boom mic that works amazingly well. At $50 USD, they are a steal. When I received mine, I opened the package, plugged the headphone and mic jacks into my Elecraft KX3, and I was on the air with them in seconds.
6. Learn to use use Exalted Carrier Reception (ECR/ECSS). Cost: Free
“Exalted Carrier Reception” (ECR) a.k.a. Exalted Carrier Single-Sideband (ECSS) is just a fancy way of saying that an AM broadcast carrier is tuned in while in single-sideband mode. This is most useful when you’re trying to listen to weak broadcasters.
This (ECR) is, in a sense, the frugal listener’s version of synchronous detection. Why does it work? As my knowledgeable ham buddy Mike (K8RAT) explains: ”You’re removing any selective fading problems by filtering away one of the sidebands, and injecting a carrier of steady amplitude which eliminates the ‘tearing’ heard when a broadcast carrier is varying in amplitude.” Got that?
Even if you don’t understand it exactly, here’s how to use ECR: Simply find a strong AM station on your radio. Next, turn on the BFO or SSB mode on your radio. As you adjust the tuning knob, you’ll hear an audible whine, the pitch of which will change with every increment of tuning. “Zero-beating” the carrier follows next–this is simply tuning in the signal until that whine is gone, and the AM station can be heard as clearly as if the radio were in AM mode.
The fidelity of ECR/ECSS is typically not as good as AM–mainly because SSB filters are usually narrower than AM filters–but it does lower the noise floor, increase the stability of the received signal, and make this signal “pop out” a bit more.
But don’t take my word for it–let your ears be your guide! In this recording, I tune in a low-power station on my receiver in standard AM mode, but at 15 seconds into the recording, I switch to the upper-sideband (SSB) mode, zero-beat the frequency, then open up the SSB filter a little wider. Then, just before I end the recording, I switch to lower-sideband–something you can do if there is interference in the upper-sideband, for example:
It’s amazing how much background noise ECR removes.
If you’re lucky enough to have a tabletop radio, chances are it has an SSB mode (although there are some very rare exceptions). Less than a third of portables on the market, however, have SSB. Here is a list of the most popular portables with SSB that are, or have recently been, in production.
If you live in an area with frustrating RFI, but want to listen to the shortwave bands from home, try an online web-based receiver. Sure, it’s not quite like tuning a radio at your fingertips, but it’s the next best thing, and also a handy tool for checking propagation or verifying your own signal (if you’re an amateur radio operator).
My two favorites site are:
Global Tuners which has a number of remotely-controlled radio receivers all over the world. You must register before you can participate, but registration is free. Global Tuners even has a free Android app that permits remote receiver control via your smart phone or tablet.
The University of Twente Wide-band WebSDR is an amazing resource. Not only can you control this receiver, but so, too, can a few dozen other web guests––all at the same time! I’ve used U Twente’s receiver on a number of occasions to listen to European pirates. Cost? Again, it’s free.
8. Finally, practice listening. (Cost: Just some time)
My final bit of “free” advice sounds a little philosophical, but rest assured, it isn’t.
I’ve always likened radio listening to another of my interests, astronomy–an entirely different hobby that, unless you’re a radio astronomer, relies on an entirely different sense.
Why the comparison? I’ve known some talented astronomers that, with just a basic pair of binoculars, can see much more in the night sky than I ever could. Are their eyes better than mine? Not necessarily. Their eyes are just experienced in the field of stargazing; they know what to look for, and most importantly, what to appreciate. Their brains decipher the images of bright or faint stars, subtle variations in color or shape, and focus on what they consider important. In short, this is not an ability you can pick up overnight; it takes patience, experience–and true passion.
Radio listening is, in that sense, much the same. Though I’m by no means a good example, I do wish I could go back to the days of my youth with the ability to listen that I have developed over the decades. There must have been so many jewels of stations hidden in the ether that I completely skipped over…My ability to, for example, pick out the ID of a faint station, to tune accurately and quickly, and to cope with adjacent noise, have all been honed since then, a result of time spent just listening.
My good friend Vlado (N3CZ) is a case in point: he is one of the most capable ham radio DXers I know. His extraordinary ability to pull intelligible conversations and CW (Morse code) out of the static, even in crowded radio conditions, is simply astounding. Vlado’s main transceiver is nearly two decades old, and by no means a benchmark technically. If you ask Vlad if he uses filters and digital signal processing, he will wisely tell you, in his Macedonian accent: “Your best filter is between your ears.”
The same goes for SWLing. I have spent enough time listening to shortwave and weak DX that I can now pull conversations out of the noise that my (non-radio) friends can barely detect. I’m convinced this is healthy exercise for the old grey matter.
David Goren, good friend and the highly-creative radio producer behind Shortwaveology.net, describes how shortwave listening enhanced his career:
“When I first discovered shortwave, I’d strain my ears through the static and all the layers of jumbled up sounds trying to hear as far around the world as I could. Years of this kind of intensive listening tuned my ears in such a way that allows a laser-like focus on the sonic details when working in the production studio making radio stories.”
Indeed, I’ve heard and can certainly appreciate the results of his remarkable “laser-like” listening ability; check out Shortwaveology.net for your own experience of David’s talented ears. You’ll be glad you did.
No doubt you enjoy listening already; my contention is that it has more benefits for your brain than Sudoku puzzles, and iis even more fun. Plus, did I mention that it’s free? You don’t need to pay a subscription to listen to the radio. There’s no real trick to this: it just takes time…interest…and a pair of ears.
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