Tag Archives: How to eliminate RFI

Guest Post: More Anti-Noise Ideas

In a previous guest post, SWLing Post contributor TomL, shared his “Evolving, Morphing, SW Listening Station” where he detailed the many ways he’s trying to fight heavy radio interference at his listening post. The following post is TomL’s update:


More Anti-Noise Ideas

(Continuing the hunt for better reception in a foul RFI environment)

by TomL

toml-radios

I have made the following changes:

  • Created a prototype mini-loop based on a crossed-parallel idea from VE1ZAC (Jeff).
  • Added a balun from LNR Precision (Parfitt’s EF-SWL) in an experimental configuration.
  • Added to the balun, an outdoor amplifier – Wellbrook ALA-100M.
  • Added a noise canceling unit (MFJ-1026).
  • Added 2 preselectors, an old Grove TUN-3 connected to the main loop feed and an MFJ-1046 connected to the ground connection of the balun. Both feeds go into the MFJ-1026.
  • Added BHI Compact In-Line DSP filter and two switch boxes to cut it in/out as needed.
  • Added a medium wave noise canceling unit that I have not figured out how to use yet. (Quantum Phaser). The MFJ unit does not work on medium wave without modification.
  • Purchased from eBay a used Grundig Satellit 800, a somewhat more robust fixed-station receiver to replace my aging Sony ICF-2010.
  • Other non-related (not shown): Whistler digital scanner + UHF over-the-air TV + FM broadcasts + an AM/FM HD digital radio + high pass filters from MiniCircuits.com – (audio from all these sources is passed to an existing high fidelity stereo power amp and NHT Super One speakers on the computer desk for near-field monitoring). Associated antennas are also hidden on the outside deck (shhhhh!).
  • Large charge card balance!!

So, here are some pics for the crossed-parallel loop. VE1ZAC web site has all the references if you want to explore further or google him. Mine is purely a prototype and not finished. And should eventually be placed on a rotor (but how to keep my Nazi-like condo association from finding out?!?!?!?).

loops

It is three 14 inch quilters hoops from Joann Stores plus some 1-inch copper strips cut from a small 2 meter roll of thin copper from eBay. Then, it is wired in parallel with silver-plated aviation wire on each side with a feed in the middle. Not an optimal placement of the feed, (should go straight down along the pipe). Will fix things up whenever I get some more time.

loops-closeup

loops-closeup2
Seems to be an efficient way to prototype small loops. It is now mounted on a short ¾” inside diameter PVC pipe into a cheap plastic sand-filled deck-umbrella stand. Loops are light and somewhat flimsy, so I mounted the three loops on a plastic triangle ruler and dowel sticks glued to the sides for some extra strength. Good enough for now.

The EF-SWL balun is also in an experimental configuration. Since I read somewhere that loop antennas have a very low impedance at the feed point (like, 10 ohms or lower), I thought I might try a balun that is meant to lower the impedance and mount it backwards. I don’t have a picture of it but the SO-239 output is facing the loop and the screw terminals are facing the direction of the radio. My feeble brain thinks since it is a passive device of coils on ferrite, it should work bidirectionally for receive only applications like this. It seems to work but I have the excuse that I really don’t know what I am doing! 🙂

bhi

BHI unit in action.

The BHI DSP filter is useful in some circumstances but I find it fatiguing to listen to. The audio from the Sattelit 800 is so nice, I mostly like it without the DSP. The DSP narrows the bandwidth significantly, somewhere around 4 kHz or less from my hearing. I like that the Grundig has two tone controls. And it also has a stable SSB and on very strong signals with clear audio, I like to listen with SSB lower or upper sideband. But the DSP is useful at times for hash-like noisy signals; it is not quite as good on buzzing noise and I wish the Satellit 800 had a noise blanker, but that would have been a more costly purchase, like a Drake R8A.

So, in a nutshell, I have a discovery about noise here: it is all around me and ubiquitous, like the air I breathe!

I find it hard to null and also worry about peaking a station signal at the same time. However, I do have a lower noise floor with the experimental loop sitting outdoors, especially on medium wave (the Wellbrook amp + loop works great on the lower frequencies – am able to get eight different medium wave stations carrying Major League Baseball games at night – it would be nine to get WFAN for the New York Mets but the local Chicago Cubs station covers the adjacent frequency with horrible digital hash! ***Bleeping*** digital junk!).

Also, the signal level is noticeably lower using the loop. Then, add in the effect of the MFJ Noise Canceling unit, the usable signal gets even weaker.

The bottom line is, I can now finally enjoy listening to many SW broadcasts, BUT only the strongest signals. Anything else is still hopelessly lost in the noise. So, gains are limited.

On the other hand, and something else I learned by doing is that, any 1 or 2 dB signal/noise ratio improvement will help with the final audio output in the end product. Using low-noise amps, loops, noise canceler, preselectors, grounded connections, ground isolators at the input of every receiver, high quality stereo amplifier and speakers, tone controls, SSB vs. AM Sync, weird antenna configurations, etc, etc. It all helps in the end to some degree.

Tinkering is an art that involves a lot of thinking/doing iterations! And high quality parts must be used all along the chain or it could degrade the signal.

Below are some audio samples, not very well recorded, but can give some idea of the incremental improvement with each enhancement (turn up the volume). NOTE: other people may get better or worse results depending upon individual situations, type of antennas used, etc, etc.

Recording 1: R. Marti. First 10 seconds an indoor antenna with no noise reduction, second 10 seconds the outdoor loop without the MFJ-1026, the third 10 seconds with the MFJ-1026, then switched off and on to hear the difference.

Recording 2: R. Marti. MFJ -1026 is ON. Last 15 seconds is SSB, very thin sounding. Really only good for strongest signals. I liked the AM Sync better (Satellit 800 is really a Drake SW8 in disguise with a quality AM Sync). But, SSB can sound excellent with very clear voices with a steady and strong signal (The Satellit 800 does NOT have IF-shift or a BFO to fine tune an SSB reception, so the station must be exactly transmitting on the kHz mark, which most are nowadays).

Recording 3: R. Marti. MFJ-1026 is ON. Last 20 seconds you hear me switch in the two audio switches and the BHI DSP is on its lowest setting. Narrower and clearer with some reduction of background noise. I find I only like going up to about 4 on the DSP dial, after that the audio fidelity starts getting more choppy with digital artifacts that sound like dripping water. I tend to like higher fidelity. One nice thing about the BHI DSP is a faux-stereo that helps a little with voice intelligibility by helping the brain naturally filter the noise. Faux-stereo is ON even when the noise reduction circuit is manually turned off (power must be on and bandwidth still sounds narrowed).

Recording 4: R. Nacional Brazilia. First without MFJ-1026, then ON, then OFF, then ON, then with the BHI kicked for the last 20 seconds.

Recording 5: Greece. Switching the MFJ-1026 on and off every 5 seconds. In this particular case, the signal was weak and fading a lot. The MFJ OFF was also weaker than with it turned ON. That is interesting behavior, usually it is opposite. It pays to play with the settings a little. At other times, and less frequently, the MFJ unit turned OFF sometimes sounds better than with it ON and tuned for less noise. Go figure!

After all the tweaking is done, and I cannot get any more performance out of this, I will probably have to move to a nice, quiet neighborhood and setup a nice antenna farm!!

In the meantime, I do enjoy listening to the stronger stations from North America, Cuba, Brazil, Europe, and Australia with less noise than before.

73’s

TomL from NOIZEY Illinoiz


Once again, Tom, thanks for sharing your RFI elimination journey!

I love how you take on this noisy problem by experimenting and seeing it more as a challenge than an obstacle to enjoying your hobby.  Great job! 

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Guest Post: My Evolving, Morphing, SW Listening Station

Many thanks to SWLing Post contributor, TomL, for the following guest post:


Sony-2010

My Evolving, Morphing, SW Listening Station

by TomL, May 26, 2016

My interest in radio listening has been rekindled after a long hiatus in parallel to my dwindling interest in Mainstream Media.  It is now about 8 years without cable TV and I seriously do not miss it, especially with the evolving nature of discovery with respect to other forms of media.  SWL radio was important to me in my formative years during the Cold War; fascinating were the many ways governments used shortwave radio to influence populations, each with their own brand of propaganda!  Young people today know nothing about the endless (and entertaining) tirades of East German editorial commentaries denouncing the evil, decadent West.  Or, of the free, large-sized envelopes full of travel and promotional brochures, pennants, bumper stickers, and booklets sent from the government broadcasters such as Poland, Hungary (yes, communist countries!), Australia, Netherlands, etc. just for sending in one simple QSL report!!!

I quickly realized that those days are gone forever, consigned to a period of history where radio was THE main method of disseminating copious amounts of government propaganda to very large swaths of humanity.  Now, the internet and cable TV fulfill that function in a much more CONTROLLED manner, both technically and socially (Big Brother like).  So, I have diversified my interests and have an unusual listening station.  It is multiple things in one small space.  You see, I live in a very small condo in a noise-plagued environment with only a 2nd floor wooden deck (owned by the Condo Association!) in which to put up any outside antennas.  Only a single “Dish” type antenna is allowed.  So my shortwave antenna needs to be well hidden.  Same for the TV antenna, since I also have a north-facing deck, I cannot have any line-of-sight to the Southern sky for a Dish.

The first wire antenna strung from the top and brought inside was a dismal failure receiving nothing but noise.  I gave up for a couple of years.  I built a loop TV antenna and mounted an FM antenna instead since those were less susceptible to noise issues.  Also recently added to this station are two cheap 4G antennas with wires into a single Verizon USB aircard plugged into my computer and getting up to 14 mbps performance.

But, I still wanted to try shortwave radio again (and medium wave too) but the noise issues were very, very discouraging.  S9 noise on some bands.  Tried preselector, a noise “phaser”, different lengths.  Nothing worked.  However, I read something from an amateur radio operator in Northern California who had a space problem.  He put up a helically-wound-vertical (HWV) antenna with radials for 160 meters (John Miller HWV antenna).  I also read about various “broomstick” antennas.  So, I tried my own version with an old RF Systems Magnetic Longwire Balun I still owned and NO radials.  Put it together with a 2 foot long, 4 inch schedule 40 PVC pipe wrapped in 200 feet of 18 awg magnet wire.  Well, still noisy but, at least now I had a portable antenna!

So, I went camping in March of this year!  Holy Cow, was it cold out but the helical antenna performed well enough to hear All India Radio for my very first time, a small 1kw Mexican station in the 49 meter band, and various others from Asia that were elusive for me in the distant past.  I was finally encouraged again to continue my research.  I did this a few more times and finally got tired of going camping just to listen to a radio!  NOISE at home was still the big bugaboo to kill (and it still is).

I read up on Common-mode noise travelling on ground and shield components of antenna systems.  So I bought a bunch of toroid ferrites of different types to cover different frequencies (something about initial permeability….) to make my own homemade “Super RF Choke” to cover all frequencies made on a Home Depot Homer bucket lid, winding the coax 5 or 6 times through all the toroids, the full diameter of the lid.

Measurements by Jim Brown published on the web (RFI-Ham.pdf), pages 32-33) indicate good choke performance using coax with these larger-sized coils.  I still hoped to salvage the use of the HWV antenna.  So, added the choke and noticed some improvement across most bands (less noise).  Medium wave broadcast was not effective and decided that I did not want to keep tuning an antenna that HAD to sit outside to get away from the noise inside my listening station.

I also shut off the power to my condo and found out which noise sources were mine vs. other noise that came from all the neighbors (very important step to do!!!).  For instance, I did not know before that USB charging adapters are PURE RF-NOISE EVIL in an innocently small package?!?!?!  I rearranged wiring to shut off certain devices and power strips when I want to listen to the radio!

So, I kept reading.  Found out about another magnetic balun from Palomar.  Tried it but not impressed –  performance was too lossy compared to the good old RF Systems MLB (what a great product that was back then!).  Kept reading and found out good things about the EF-SWL from PAR electronics (product is now made and sold by LNR).  The ground connections on it (and the Palomar) intrigued me.  So, I decided to go to Hamvention for the first time, even though I was skeptical of finding anything useful, I told myself, I could at least buy the EF-SWL on sale (which I did).

Installed EF-SWL to the HWV but no difference compared to the RF MLB. The antenna did perform better outside on the deck in the far corner, so there it still sits.  Then, I hooked up the wire they gave me with the EF-SWL to the ground and it resulted in MORE noise.  Then, took off the jumper (which connects the coax shield to the ground side of the balun) and connected only the middle post (balun ground) to the ground wire and a lot LESS noise resulted along with a small reduction in radio signal level!!!  Finally some progress – the wire seems to be acting like an old-fashioned “counterpoise”, which is misunderstood these days.  Apparently, back in the 1930’s-1950’s, people involved in radio knew the differences between an “earth ground”, a “radial system”, and a “counterpoise”.  Technically, they are all different and their use is different as a result.  Now, people moosh all these concepts together interchangeably which risks creating very ineffective antennas.

Photo of installed EF-SWL at the bottom of the HWV with coax at the output, the red magnet wire input on top, the middle post for the counterpoise wire, and the coax shield post is unused. 

Photo of installed EF-SWL at the bottom of the HWV with coax at the output, the red magnet wire input on top, the middle post for the counterpoise wire, and the coax shield post is unused.

The HWV antenna now has 600 feet of 26 awg teflon wire on the outside PVC, an inside 3 inch PVC “sleeve” with 102 Russian ferrite rods, a 56 inch stainless steel whip at the top, and one inch hole through the center to accommodate the 7 foot PVC mount to my carbon fiber photo tripod when I take it camping again.

So, I am on a new quest to understand counterpoises, how to actually TUNE them and, hopefully, how to use them to increase the performance of shortened antennas like my HWV (something about reducing the dB loss incurred by shortening….).  A second result I hope will be how to use the counterpoise to keep signal-to-noise ratio high at the same time (maybe with this used $100 Dentron Super Tuner bought at Hamvention?).

Transmatch

Also bought at Hamvention (thanks Thomas W. for the tip!!) and installed Bonito’s Galvanic Antenna Isolator GI300.

If input directly to the input of the radio, led to more reduction in noise and signal!!  Too much actually, so I took off my Super RF Choke and now I had a better result compared to the EF-SWL with the RF Choke (slightly cleaner sound with less hissy noise).  Apparently, the GI300 completely isolates the coax shield, better than my homemade choke!  The requirement is to use coax from the feedpoint and not bare wire.  I then placed a few clamp-on ferrites I bought from eBay to help with slightly higher frequency choking of the shield at various places on the feedline.

Bonito-Galvanic-Isolator

Photo of GI300 on radio with NO extra coax lead into the radio at right (Thanks to Dennis Walter of Bonito for that tip)

Before Hamvention, I wanted to try out AM broadcast.  I wanted to know more about this “FSL” antenna a well-known eccentric from Ireland (Graham Maynard FSL) developed before he passed away a few years later.  So read up and bought a whole bunch of ferrite rods and tried different configurations.  Well, my particular design did not work all that well because I did not follow directions for winding wire into a balanced design.  So, I added all those ferrite rods to the 2 foot HWV (inside a 3 inch thin-walled sewer PVC pipe).  The antenna is louder down to about 3 MHz with a stronger signal (including noise) than without.  I do not have measurements, and find it too time consuming to document.  Maybe one day, I will compare and document by sliding the ferrites out on the 3 inch PVC and measure actual signal levels.  The ferrite sleeve seemed to pick up MORE noise and radio signal than without it.  So, if you need more signal strength in a small package below 7 MHz, then the idea seems to have merit.  But since it increased noise as much as radio signals, it has limited usefulness to me.  I do have another project where I will put ferrite bars onto a tuned medium wave loop antenna (Tecsun AN100) that is much more portable and directional.  The bars and loop were both relatively inexpensive from eBay.  The ferrites change the tuning lower, so I have to figure out how to make it tune higher again…….

Photo of unfinished MW loop project.

Photo of unfinished MW loop project.

Summary

Evolving understanding of dealing with major problems like overwhelming noise and limited space have led to unexpected additions to my SW Listening Station:

  • A 2 foot long, 4 inch diameter helically-wound-vertical antenna (HWV) with way too much wire on it (and now inserted with 102 160mm Russian ferrite rods on a 3 inch diameter “sleeve”). Originally built because of its portability.  Can now be mounted on a carbon fiber photo tripod with a 7 foot 3/4” PVC pipe through the center length
  • A magnetic balun from LNR (designed by Parfitt) attached at the feedpoint of the antenna
  • A proprietary galvanic isolator from Bonito attached right at the radio’s antenna terminal
  • A “boat anchor” Dentron Super Tuner attached to the HWV feedline to help tune it
  • An unfinished MW loop antenna with more ferrite bars
  • An unused, homemade toroidal Super RF Choke
  • Clamp-on ferrites everywhere in proximity on wires and power leads
  • Re-arranged power strips and wires as needed for easier shutoff in functional groups

For shortwave, I still pick up mostly noise on many bands.  With the uncalibrated S-meter on the ICF-2010 – 49 meters is around S1 (before about S3).  31 meters is MUCH improved and is now listenable to stronger stations (S2 instead of S7 noise!).  Even 19 and 16 meters is improved from S6 to S7 down to about S3 now – noise still too annoyingly loud to understand any language being spoken however.  And forget about DXing from this location!  Will have to go camping again soon.

BUT, listening now to Voice of Greece, Radio Nacional Brasilia, or Radio Romania International is a much cleaner sounding experience than just a couple of months ago.  They are there to re-discover and appreciate, even though many speak a foreign language and I do not understand a word they are saying!  Also, there is the odd observation (like just this morning), that I can actually learn to enjoy listening to Country Music if it is the unique sounding Australian flavor!!

Do I miss cable TV??  Not a bit!!

Future investigations

  • Employ the Dentron Super Tuner in various configurations to find any improvements (currently attached to the coax of main feedline from the EF-SWL, it is helping tune different SW bands (not sure why it helps, does not make sense, must be a mismatch between coax and balun)
  • Obtain old book(s) on counterpoises
  • Get a Linear DC power supply for use with all the EVIL RF-spewing devices that use 5 volts. Maybe this one:  (Tekpower 3Amp Linear)
  • Replace any cheap/old RG58 cables with LMR-240 or similar
  • Finish the AM loop w/ferrites so I can take it places
  • Perhaps an ultra low-noise outdoor amplifier for the HWV, depends on counterpoise experiments: (Wellbrook ALA100M-2)  (I don’t want to spend that much money now)
  • Somehow use a noise antenna with a better phaser: (DX Engineering NCC-1) (gulp, don’t want to spend THAT much money now also!!!)
  • Get some relief from background noise using a really robust noise blanker. I don’t want to spend on the portable radio, would rather get something like the Bonito 1102S or an ELAD model both supposed to have excellent audio quality and excellent DSP noise blankers.  But that means getting a cheap laptop to run it and replacing the Sony.  MOAR big bucks…. but not right now
  • Maybe a real loop antenna, BUT it has to be remotely tunable and remotely turnable and small enough to HIDE. MOAR big bucks, sigh….

TomL from noisy Illinois, USA



Many thanks for sharing your experiences, Tom! Also, it was great meeting you at the Hamvention this year.

I must say that there is something to be said for brute-force experimentation when it comes to mitigating radio interference. I hope you keep us posted as you continue to experiment and improve upon your unique listening system.

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Frugal SWLing: Investing little, but getting a lot out of your radio

This article originally appeared in the April 2014 issue of The Spectrum Monitor Magazine.


RadioDialLet’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

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:

  • the ubiquitous AC adapter (aka, “wall wart”)
  • laptop power supplies
  • flat screen TVs: especially Plasma TVs
  • heating devices like electric blankets
  • external hard drives
  • lamp dimmers
  • touch lamps

Good luck tracking it down!  Chasing RFI can be complex.  Check out this list of RFI resources on the ARRL website for methods and ideas to cope with RFI.

2. Take your radio outside. Cost: Free

ParkListeningIf 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.

Want some inspiration? Check out how this SWL plays radio in central London.

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

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.

Two caveats:

  1. 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).
  2. 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.

Not all rechargeable batteries are created equally. Lean toward name brand, higher quality cells. Dollar store batteries lack longevity.

This is one suggestion that may require a modest investment, but will pay off in more ways than one. I honestly can’t think of the last time that I listened to a portable radio while it was plugged into mains/grid power via an AC adapter. Since at least 2007, I have been powering my portables exclusively with good-quality rechargeable batteries.

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.

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.

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

ECSS-PL-660“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.

7. Use a web receiver.  Cost: Free

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:

  • GlobalTunersGlobal 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.
  • utlogo4bThe 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)

SP600Dial3My 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.

Happy listening!

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