Tag Archives: Guest Posts

Guest Post: Richard builds a WiFi radio with the Raspberry Pi

Many thanks to SWLing Post contributor, Richard Schreiber (KE7KRF), who shares the following guest post:

Yet Another Internet Radio!

by Richard Schreiber (KE7KRF)

After deciding that an internet radio could be an important source of entertainment in our household, we formulated a few general guidelines:

We opted not to use an aggregator but would pick and choose stations we enjoyed and discover the URL’s ourselves. Also would be satisfied with a couple of dozen stations. Based on a recent decision to pare down the number of TV channels we were paying for, having access to hundreds of stations seemed impractical and unnecessary.
The price had to be affordable, thus eliminating many stand-alone, commercially available internet radios.
We already owned a quality portable speaker (Bose SoundLink Mini) so the internet radio didn’t need to duplicate that component.
Didn’t want to tie up nor be tethered to a laptop, tablet, or netbook. We predicted that would eventually lead to less and less use of the radio.

After some research, coupled with the fact I already had some experience with Raspberry Pi computers, that small device appeared to be our best choice. I had recently purchased the newer 2 B model, which has plenty of computing power, and had installed Ubuntu Linaro as the OS. (As an aside, this OS has not to my knowledge been upgraded for the latest Raspberry Pi 3). There are several other operating systems that will work just as well including the official Raspbian OS available through the Raspberry Pi Foundation.

I installed the MPD music player daemon and its client MPC, which is used to add to and delete station URL’s from the playlist, control volume, etc. An important find was the iPhone app called MPod which provides remote wireless access to the features of MPC. At the moment it is a free app for the iPhone (in my case the iPod Touch).

For portability, my Raspberry Pi is being used “headless”, meaning it is not connected to a monitor, keyboard or mouse. If maintenance is required you can use PuTTY, a SSH and telnet client, wirelessly from a Windows (or MAC?) PC, using a command-line interface. Mainly this is needed to shut down the Raspberry Pi properly before turning off the power, but it boots completely on its own when powered up. The MPod app will then load the playlist of stations and let you start playing the radio without direct access to the Raspberry Pi.

The sound output of my Raspberry Pi is connected to the auxiliary port of our Bose SoundLink Mini Bluetooth speaker. But instead of trying to implement Bluetooth on the Raspberry Pi, I took the easy way out and use a direct connection. The sound reproduction from this setup is very good, though audiophiles might be somewhat more critical.

The above represents a minimal investment if you already have a good speaker on hand. It does require some on-line research and learning at least enough to install the OS and software. The good news is that there are many websites and forums providing step-by-step instructions and helpful hobbyists willing to explain some of the more cryptic aspects. A few of the websites that I found to be helpful:

http://www.instructables.com/id/Arduino-Raspberry-Pi-Internet

http://cagewebdev.com/raspberry-pi-playing-internet-radio

https://learn.adafruit.com/raspberry-pi-radio-player-with-touchscreen

A couple of these also explain how to add a display to your Raspberry Pi internet radio.

Our Raspberry Pi radio is on each evening and has been trouble free. It is worth mentioning that this is a very portable setup, and can even be powered by a battery pack (the kind used for recharging tablets and cell phones) for a few hours. Of course you need to be near a wifi hotspot.

Thank you, Richard! What a great way to use the inexpensive Raspberry Pi. I have a spare Pi2 and an amplified speaker here at the house. Though I don’t need another WiFi radio, it would be fun putting this little system together.

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Guest Post: Revisiting the Realistic DX-440

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RadioShack ad for the Realistic DX-440

Many thanks to SWLing Post contributor, ShortwaveGuy, who shares the following guest post originally published on his blog, Shortwave.me:

Tried And True. . .Revisiting Older Receivers – Realistic DX-440

by ShortwaveGuy

Anyone who knows me, knows I am a fan of the “latest and greatest” when it comes to shortwave receivers. Like most of us involved in the hobby, I am always on the lookout for what newer technology has to offer me in order to pursue my quest of either capturing that elusive DX signal, or whatever will bring my favorites in the clearest. As a result, over the past few years, I have collected an assortment of receivers, each one serving a different purpose. My wife can not only attest to this, but can also relate to this phenomenon, as someone who has far more shoes than she will ever have time or fortune to wear! That’s how I am with my radios!

The other day, however, while listening to some of my favorite stations on what is arguably my best current portable receiver, the Tecsun PL-660, I got to thinking about some of my other receivers, in particular, my Realistic DX-440. I have had this receiver for as long as I can remember and I can remember back a long time! Around the time it came out, the radio most of us had our eyes on was the venerable Sony ICF-2010. Like a lot of people, however, I had no means of purchasing a receiver as expensive as it was at the time. I hoped that somehow, I would be able to afford one and one day, I did buy one, but that’s a story for another time, however.

In the mean time, I can remember perusing the latest Radio Shack catalog, something I did as often as they came out when I saw it. . .a radio with all kinds of wonderful buttons and knobs! The top of the page screamed out at me: “CATCH THE ACTION ON MULTIBAND PORTABLES”. It was the Realistic DX-440! Here is a picture of the ad as it appeared:

Once I saw it, I knew I must have it! While the MSRP on the Sony ICF-2010 was $449, this gem could be had for less than $200! All my previous radios had analog tuning so the prospect of getting a radio with a digital display was quite appealing to me! Try as I may to convince my parents to get me just this one Christmas gift instead of several, it didn’t happen. . . .at that time. But fast forward several years later. . .

I finally got my digital receiver in the form of the Realistic DX-380 from my parents one Christmas. I worked that thing for years, and was mostly happy with it. It didn’t have SSB, which I had begun to understand by that time. I had pulled in a lot of great stations such as HCJB, BBC, VOA, Radio Havana Cuba and many others. However, because it didn’t have SSB, there were several occasions where I would happen upon ham radio operators who were talking back and forth, utility stations or even pirate stations. I could never be for sure, though, because my unit was not equipped to decode those signals. I knew that it was time to finally remedy that.

I purchased a few other radios that would do SSB and most of them worked reasonably well. At one point, I had even managed to procure the much-celebrated ICF-2010, which I loved dearly until it died a slow and unfortunate death that those with the know-how told me was beyond repair. But always, in the back of my mind, I wondered about that near-mystical Realistic DX-440. . .dreaming about what might have been.

I contented myself with the radios I had, still enjoying this wonderful hobby that I have participated in for so many years. I was, with the exception of the now-departed 2010, generally happy with the receivers that I had. I wasn’t looking for a new radio, but one night, mostly out of boredom, I wandered on to eBay and did a search for shortwave radios. I looked at tabletops and ultralights, primarily as I really had neither and had plenty or portables. About two pages in, I saw the Realistic DX-440. It only took about 10 minutes before I decided that this one must be mine. I placed my bid and waited patiently. . .only to lose the auction. “Oh, well”, I thought. If I saw another one, I might try again. . .or maybe not.

Well, the next day, I did a search and found one. This one looked in fantastic shape and had no bids. There was a “Buy It Now” price, but I wanted to get this for as inexpensively as I possibly could. The auction ended in 5 hours. I chose not to bid, not wanting to draw attention to it. I set an alarm on my watch and came back in an hour. . .still no bids. I set another alarm. With only 3 hours left, I began to get excited. Another hour went by and another alarm had been set. 2 hours to go. Any bidders, yet? No! Could this really happen? Maybe!

When I got down to the final hour of the auction, I didn’t bother to set an alarm. Like a watched pot that never boils, I stared at the web page, refreshing it every couple of minutes. With every refresh, it began to seem as if this might come to a happy conclusion. 10 minutes left. . .no bids. 5 minutes left. . .still no bids. I waited until 30 seconds before the end of the auction and placed the minimum bid.

Tick. Tock. Tick. Tock. Tick. Tock.

Auction over.

I HAD WON!

A dream over 20+ years in the making had finally happened! I quickly paid for the radio and then purchased the appropriate “wall-wart” adapter to make sure I had it ready for when the radio arrived. It said it would be 7-10 days for delivery, but it was at my house in 3!

I opened the box and carefully wrapped in old newspaper, was the radio that I had been pining for since my early teens. I quickly checked it out to make sure it was in good condition and was pleased to find it was. My heart sank a little bit when I opened the battery compartment to find 2 AA cells left in for the last 5 years that were supposed to power the clock and the memory functions. Fortunately, they had not exploded and I quickly removed them and replaced the unit with a fresh round of batteries. The only flaw I was able to find was that it seemed that the previous owner had lost the screw on tip of the internal whip antenna and had placed a plastic cap on the end in its place. It didn’t look out of place and was very secure, so I shrugged it off. Now for the moment of truth: I powered the radio on and it worked! I checked all the bands and was able to receive quite well on all of them except LW (which is to be expected, given my geographic location and the lack of stations on the longwave band, in general). All the knobs were there and in place and there were no dirty switches or tuning pots to deal with. I had snagged myself a honey of a bargain!

Now it was time to use this thing for what I bought it for: to listen to shortwave radio! I usually use a 100 foot longwire antenna when I listen to shortwave, and this time would be no exception. However, I was anxious to pair the DX-440 with the Realistic 20-280 amplified antenna that I had picked up years ago at an auction. I had used it with other radios, but never in conjunction with a longwire antenna. I was ready to change that. I wanted to use the preselector function of the amplified antenna as well as the actual amplifier in order to maximize my ability to pull in distant stations. When the radio was first manufactured, there were a lot more stations on the air to listen to and less of a need to do much more than throw 20 feet of wire up in a tree. Obviously, with many of the powerhouse shortwave stations having gone the way of the internet, I knew that my plan to couple the longwire with the amplified antenna had the potential to pay big dividends. I took a look at the back of the radio, where the external antenna jack was and I was surprised to find not the 1/8? jack I was accustomed to, but in its place was an RCA phono plug. The amplified antenna had an RCA plug on its side, as well, but it wasn’t to connect to a radio, it was for connecting to an antenna. The amplified antenna had the 1/8? plug and accompanying cable that was used to connect to the external antenna jack of nearly every modern portable radio. To be honest, I wasn’t completely sure how I was going to go about handling this issue. I thought about using alligator clips, but wasn’t sure how to integrate this into my coupling scheme. I pondered over this for all of about 3 minutes and than quickly got into my car and headed to my local Radio Shack. I told them I was looking for a 1/8-inch phone plug-to-phono jack and they were quick to accommodate me. They gave me the adapter you see pictured here (Catalog #: 2740871). It would handle either stereo or mono input of a 1/8-inch plug and as a bonus, it says “MOM” on the end, if you are willing to use the input hole as the letter “O”.

I got it home and quickly got it hooked up. As I expected, the “MOM” adapter was a perfect fit. I made sure I had fresh batteries in the amplified antenna, though it would accept an AC adapter if I wanted. I chose to run it on battery, so as to reduce any possible introduction of noise to the signal. And then, I powered on both the amplified antenna and the DX-440. . .the moment of truth had arrived! I tuned to WWV on 15 mHz, which I use as a baseline for most test I conduct on my radios during the time of day I was listening. I must tell you, I was NOT disappointed in what I heard. It was a rather cloudy day weather-wise and I was concerned about a middling solar flux. I needn’t have been worried at all. The signal was robust and clear as the familiar sound came booming in from Fort Collins, Colorado! Not only was the signal strong, but using the separate bass and treble controls and the wide selection on filters, it was actually rather pleasant listening, not fatiguing at all. I pulled up my trusty shortwave schedules app on my phone and began searching for things to listen to.
I heard domestic broadcasters like WRMI and WBCQ with no issues and managed to catch BBC to West Africa, as well! I listened to quite a bit that night and into the morning hours, checking out not only broadcast shortwave, but utilizing the BFO to listen to ham bands, particularly my favorite, the Freewheelers Net on 3.916 mHz, LSB. The BFO was easy to operate and the addition of the Realistic amplified antenna helped to bring in signals with great gusto. As with any amplified antenna that is not a loop, this one amplified not only the signal, but the noise as well. That said, the propagation deities were kind to me and I enjoyed a long night of listening.

I have since given my DX-440 a place next to my bedside and have enjoyed listening to whatever I could find to listen to most nights. While a radio like the Tecsun PL-660 offers newer technology and the addition of an excellent synchronous detector, the DX-440 holds its own against the newer technology. At the end of the day, it’s still a portable and while most portables pale in comparison to tabletop rigs, this one is rather excellent with what it has offer versus its price point. The build quality is solid and ergonomically it is a pleasure to operate. If I had any critiques at all, I would have made the BFO and the RF Gain knobs a bit bigger, but now I am truly splitting hairs. I can see why contemporaneous editions of the Passport To Worldband Radio listed this as an Editors’ Choice radio back in the day.

I wanted one from the day I saw it those many years ago, and I can say unequivocally, that it was worth the wait!

–ShortwaveGuy

Thank so much for writing about the DX-440–that radio has a special place in my heart. The ‘440 was my first digital shortwave receiver–it revolutionized my shortwave listening.

As I’ve mentioned before, I also travelled with the Radio Shack DX-440 while studying French and living in Grenoble, France. The DX-440 delivered my daily dose of the Voice of America (the only English language news I allowed myself to listen to at the time). Since the VOA broadcast often coincided with meal time at the Université Stendhal cafeteria, I left my voice-activated Micro Cassette recorder in front of the DX-440 which was, in turn, set to turn on one minute prior to the VOA broadcast. It was an amazingly reliable arrangement.

I’d better not wax too nostalgic, though, else I’ll start searching eBay for a 440 just like you did! Hang onto that DX-440–I wish I would have never given mine away!

Visit ShortwaveGuy’s blog by clicking here.

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Guest Post: Remembering our Elmers

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Photo: Mario Filippi (N2HUN)

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), for the following guest post:

‘Tis the Season to be Jolly and to Remember Our Elmers

by Mario Filippi (N2HUN)

At this time of year when we gather with friends, family, coworkers and acquaintances to share the bonhomie and joys of the holidays let us fondly remember those who brought us into this hobby, our dear Elmers, those individuals who’ve given of their time teaching us the basics of ham radio, answered our endless questions, inspired us by their shacks, guided us through the difficulties of radio theory and good operating practices and proctored us through our first examinations. If it weren’t for these selfless individuals, who followed a time-honored tradition of mentoring budding hams, the hobby would not continue on and most of us might have taken other paths and missed out on a life-long, very rewarding hobby.

To start the ball of reminiscences rolling, take a seat with me in the time machine of memories and go back to the early 1970’s, to the suburbs of White Plains, NY, the home of my Elmer, may he rest in peace, George Buchanan, WB2FVX (SK).

George held Novice classes once a week in the basement of his home where he tutored a gaggle of ham wannabes consisting of grammar school kids to those of advanced age, some of whom were old railroad telegraphers schooled in the use of sounders. We’d have an hour of lecture, followed by code practice, then the class would end with general socializing amongst the students as to what transpired along with our future plans for our “shacks.”

You know, George did not quit his day job to train us through our larval stages of the hobby; as a matter of fact he commuted to the city every day and still found the time once a week to start his 7:00 PM class for his eager students, and always had energy after a long day’s work to stand in front of his chalkboard and work out the numerous electronic calculations (OHM’s Law, parallel and series circuits of resistors and capacitors, antenna resonance and impedance ) and list important regulations that would be included in our FCC Novice exams. At the conclusion of the three month course, George sat through our Novice exams and mailed them off to the FCC Office in Gettysburg, PA. Back then it took a few months before you’d get your license and hold in your hand the fruits of your (and your Elmer’s) labors.

George has been a silent key for decades now, and he frequently comes to mind, especially during the holiday season, when thoughts of Christmases past and all of the pleasant memories of almost forty years in the hobby occupy my mind. Indeed, George and all the other Elmers out there, living and deceased, have bestowed upon us one of the greatest gifts of all – Amateur Radio.

Think back on your Elmer and do so with fondness and when the opportunity presents itself, take an inexperienced ham under your wing, guide them, inspire them, show them your shack, answer their questions, help them pick out a rig or accessory, have a QSO with them, help them with troubleshooting, accompany them to a hamfest, share the joys with them when they purchase a piece of equipment, and most of all, be there for them.

Merry Christmas and Happy New Year to all!

Thank you, Mario, for sharing these special memories with us! George was an ideal Elmer indeed–he had the ability to share his enthusiasm and passion with others and helped them obtain their license during a time when study materials were not so readily available (and the test was much more challenging!).

Thank you, Mario!

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Guest Post: An Unusual Night for CB

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Many thanks to SWLing Post contributor, Mario Filippi (N2HUN) for the following guest post:

An Unusual Night for CB

by Mario Filippi (N2HUN)

December 2nd was an unusual night for CB (Citizen’s Band) radio, as the band was open late (0030 GMT) when I turned on the President Washington CB radio just to see who was on. First stop was Channel 19 (27.185 MHz), the trucker’s channel, where the QRM was high, due to the skip from the many truckers on the channel. Earlier in the day this channel was very quiet as was the rest of the band. The fact that Channel 19 was pinning the S meter after dark was a big hint that the band might be open. And it certainly was!

Uniden President Washington AM/SSB Base Station

Being a CB’er from back in the 70’s (call sign KBN-8387), this band was my first serious introduction to two-way radio communication, and after 40+ years it’s still an enjoyable experience to listen in to the local, and sometimes DX chatter. For the most part the CB band mimics 10 meters, basically open during the day (except when sunspot numbers are low) and closed at night. That’s the usual drill, but Mother Nature doesn’t always go by the playbook and sometimes the band is opened at the darnedest times, sometimes even after midnight!

So this evening around 8:30 EST the President Washington CB base station was fired up and CB operators were heard in Maine, Illinois, and as far as Wisconsin, definitely what would be considered out of the ordinary range of CB, which is generally several miles. Now FCC rules still state that it’s illegal to communicate over 155 miles but it’s a non-issue when the band’s open. For the most part, AM is used on most of the channels but you’ll find LSB activity on Channel 36 (27.365 MHz). And when the band gets busy and crowded, you’ll hear LSB QSOs from Channels 36 – 39 (27.365 – 27.395 MHz) as sidebanders spread out among the channels so that they can work each other through the QRM.

To get a better idea of what the CB band “looks” like during a band opening, a spectral scan of the band (26.965 – 27.405 MHz) would be useful. This can be achieved using an SDR dongle, such as the RTL-SDR.com version which is a diminutive broadband receiver with an analog to digital converter and covers from about 26 – 1670 MHz. Used in conjunction with an up-converter (from Nooelec), software such as SDR# (SDR Sharp) and a computer (Smartphone apps are available also) you’ll be able to put up a spectral scan of the band as well as hear what’s happening.

RTL-SDR.com dongle – a small broadband receiver covering all modes

Nooelec’s Ham It Up RF Upconverter expands dongle’s receiving range to the entire HF and MW band

As the old adage goes, “a picture is worth a thousand words” so tonight the SDR dongle, along with SDR# software was fired up to get an idea of how many stations were on during the opening. The antenna used was an S9 43 foot vertical, the same one I use for HF. Using the dongle, it’s an easy feat to visualize the entire CB band on the spectral scan, which is a plot of frequency (X axis) versus signal strength (Y axis). The top half of the screen is the spectral scan and the lower half is the “waterfall” which is a time lapse recording of the spectral scan.

Screenshot of CB Band (wide red stripe) during tonight’s opening.

Normally at this time of night a spectral scan of the CB band would be flat-lining, but as you can see there are plenty of stations conducting QSOs, with the stronger stations having higher peaks and more intense tracings on the waterfall. Seeing the entire CB band visually gives one lots of information such as what channels are active, how many stations are on, what stations might be running higher power (limit is 4 W AM, 12W PEP SSB output), whether outbanders are active or whether DX stations outside the US are partaking of the opening.

Over the years I’ve heard the CB band open beyond midnight and on a winter’s night during a snowstorm. Some openings have lasted for hours. Last year, using the mobile CB, operators from Europe, the Caribbean, and as far away as Australia were heard during my commute to work. At the opposite extreme some days all you’ll hear is ignition noise, hihi. It’s a lot like 10 meters and even a bit like 6 meters; you never know what surprises Mother Nature has in store. Spin the tuning dial over to the CB band and take a listen one of these days.

Thank you so much, Mario!

Only a few weeks ago, I noticed on my SDR’s wideband spectrum display that the 11 meter band was very active. I started listening around and was absolutely amazed at how organized some of the nets were and how reliable skip was. Signals were blanketing all of the eastern US and even into the west. Sometimes I think there are openings on the 10 meter band, for example, but there are so few users there in comparison, no one notices. The CB frequencies are pretty much always active, when conditions are favorable for DX, everyone instantly notices!

Many might not realize that even their portable shortwave radio can tune the CB frequencies. Thank you again!

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Guest Post: More Anti-Noise Ideas

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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

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?!?!?!?).

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.

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 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

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

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.

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?).

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.

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.

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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Guest Post: Communications Service Monitors – A Radio Hobbyist’s Perspective

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Many thanks to SWLing Post contributor, Mario Filippi (N2HUN) for the following guest post:

Communications Service Monitors – A Radio Hobbyist’s Perspective

Mario Filippi, N2HUN

(All photos courtesy of author)

Over the past few decades I lusted after a communications service monitor for my radio hobby but prices were always prohibitive; several thousands of dollars for a new model and tens of thousands for high-end ones. Not being a working professional in the communications field made it difficult to justify purchasing a piece of equipment whose price tag rivaled a down payment on a house. So, fast forward a few decades later and now life and times have fortunately changed for the better; the house is paid for, the job is secure, the income is finally steady, life is good financially, and to boot many of these older service monitors manufactured by Ramsey, Motorola, Wavetek, IFR/Aerotek, Cushman etc., are currently being sold on the pre-owned market at a fraction of their original decades-ago hefty prices. These service monitors are finally in financial reach of electronics hobbyists who will find many uses for these former electronic workhorses that toiled many years in the industry and now, in their golden years are being retired and becoming available for a second life via reuse/reincarnation/repurposing/reinvention.

Work of Art: Author’s Ramsey COM3 Service Monitor

So what exactly is a communications service monitor, or “service monitor” as the folks in the trade refer to? Well it is an instrument for servicing AM and FM radio equipment, although some units also have the ability to service SSB equipment. The service monitor is basically a highly accurate and precise receiver and low-power signal generator all in one allowing a technician (or electronics hobbyist) to perform service, repair, or alignment of radio equipment. Most of us have had the experience of owning a malfunctioning radio whether it is an AM or FM broadcast radio, two-way radio such as a CB (Citizen’s Band) radio, pager, or a ham radio transceiver, and that is where a service monitor proves its value and utility because now you, the hobbyist, can perform the work yourself.

My Friend’s Ramsey COM3010 Service Monitor, Big Brother of the COM3

As a radio enthusiast (shortwave, ham radio, satellite communications) for over half a century, I’ve definitely owned more radios than shoes; everything from AM, FM, shortwave receivers to CB radios to ham transceivers, all in different stages of health and vintage. For years I relied on standalone RF signal generators, audio generators, frequency counters, and CTCSS decoders to aid in rehabbing, troubleshooting, and aligning each of the many units that paraded past my radio shack. Then one day a friend showed me his service monitor, the Ramsey COM3010, another venerable workhorse still in production, and it was a defining moment; the time had come to invest in one.

Aligning a Uniden President Washington CB Radio Prior to Owning a Service Monitor

My Ramsey COM3, purchased second-hand from an Internet auction site for $400.00 is a no frills, basic unit without the features found in more sophisticated service monitors having built-in oscilloscopes, spectrum analyzers, frequency sweeping ability, and frequency scanning ability. The COM3 was in production from the late 1980’s to around 2003 at a price of around $2500 (ca. 1989) and was considered a workhorse in its time, weighed 13 pounds with the internal battery, and was easily luggable from site to site. It covers from 100 KHz to 999.999 MHz and has become an invaluable tool in my radio shack for measuring a transmitter’s operating frequency and deviation, measuring receiver sensitivity, S meter calibration, and checking CTCSS tones on my two way VHF/UHF radios. My unit evidently had an easy former life as the only needs were to replace the internal battery, perform an external cleaning, check transmitter and receiver accuracy and check accuracy of the internal audio generator. Interestingly, Ramsey Electronics (www.ramseytest.com) still services and calibrates COM3s.

Vintage Tempo One Transceiver Restoration Was Made Easier with the COM3 on the Bench

So, if you’ve been dreaming of owning your own communications service monitor either as a hobbyist or small repair radio shop proprietor then start looking as there are plenty of used units out there; you’ll pay top dollar when buying from a commercial vendor but at least you’ll get some form of warranty. If instead you travel the same road I did, via an Internet auction site, there’s lots more risk involved, but the plus is you’ll save big if you do your homework by checking past auctions, seller feedback scores, and determining what price the market is bearing by looking at the winning bids. In closing, the COM3 owner’s manual is available on line by doing a simple search, and a review of the Ramsey COM3 by Larry Antonuk which appeared in the August 1989 issue of 73 Amateur Radio Magazine is also available as a free download.

Mario, thank you for another brilliant guest post! I always learn something new from your articles. By the way: I have that same Nye Viking straight key–it obviously pairs beautifully with the Tempo One!

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