Category Archives: How To

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

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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Ron’s Bluetooth solution for robust shortwave radio audio

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Many thanks to SWLing Post reader, Ron Wagner, who writes:

Thanks very much for your informative SWL pages. With the, seemingly, shortsighted, contracting world of SW broadcasters, you keep our interest alive!

Recently, you called attention to Jay Allen’s modification and installment of a new speaker for the Satellit 800. Not quite ready to open up my 800, even with a scratchy volume pot, I setout to find another way, not only for the 800, but for all of those older radios that “SWLers” love.

Walla, a Bluetooth TX/RX device (by JETech Designs) which connects to the headphone or external speaker jack of the radios. Then, with a Bluetooth speaker, put the TX/RX device on TX and pair with the speaker, and your off to an audio improvement in all of your radios.

Attached, see the TX/RX with my 800, G3 and ICF 7600 and my outdoor Bluetooth speaker. With today’s Bluetooth speakers, you can spend to suit your budget and ears. Now, I’m on my way to find Bluetooth headphones to pair with the Bluetooth transmitter.

What a simple and relatively affordable idea, Ron. I had been considering the purchase of a Bluetooth receiver for the AUX in port in my minivan’s audio system. If I understand correctly, this one unit can both send and receive Bluetooth audio. Very cool!

I could also imagine someone placing their shortwave portable outside–on a patio or deck–away from indoor radio interference, and using the Bluetooth link to port audio to a speaker inside the house. You wouldn’t have tuning control (and you’d have to remember to bring the radio inside if rain is in the forecast–!), but you would have audio control.

Looks like this JETech receiver/transmitter is available on Amazon or directly from JETech. Thanks again for the tip, Ron!

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Video: Repairing, restoring and modifying a Sony CRF-320

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Many thanks to SWLing Post contributor, Ken McKenzie, for sharing the most comprehensive video you’ll ever find on restoring the Sony CRF-320 receiver:

Click here to watch on YouTube.

Make sure you check out Mr. Carlson’s YouTube channel, Mr. Carlson’s Lab where you’ll find repair videos ranging from solid state to tube gear.

Thanks for the tip, Ken!

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The new LNR Precision LD-11 transceiver is essentially general coverage

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A couple weeks ago, LNR Precision sent me their new LD-11 Digital Direct Conversion QRP transceiver on loan for review.

The LD-11 is basically a small, tabletop SDR transceiver. It’s like a miniature, simplified version of the Icom IC-7300 I’ve also been evaluating.

The LD-11 is an all-mode and all-band transceiver–meaning, it includes SSB, CW, CW-R, Digi, AM and FM modes on all amateur radio bands (160 – 10 meters).

Though the LD-11 isn’t advertised as having a general coverage receiver, it will indeed tune the entire HF band.

You do this by entering the LD-11’s administration mode. LNR describes this in the LD-11 product manual, but suggests you contact them for help the first time you do this. In the admin panel, you’ll find functions that allow you to set the band edges on each amateur radio band.

For a preliminary test of broadcast reception, I moved the lower band edge of the 30 meter ham radio band to 8.2 MHz.

After saving the settings and re-starting the LD-11 in normal operation mode, I could then tune the entire 31 meter broadcast band on the LD-11.

Hypothetically, you could either widen each amateur radio band to include adjacent broadcast bands, or you could simply set one of the ham bands to include the entire HF spectrum. To make it easier to navigate and tune through the bands, I’m choosing the former method over the latter.

Since the LD-11 has a proper AM mode, broadcasts sound great–especially via headphones!

Proper AM filters for broadcast reception!

Better yet? The AM filter width can be widened to an impressive 9.6 kHz! Woo hoo!

The LD-11 has four filter slots: F1, F2, F3 and F4.

The F1-F3 slots can be set to a fixed user-defined widths (common widths are default).

F4 can be altered to any available filter width without having to enter the admin mode of the transceiver. Simply press the “F” (blue function button) and the FILTER button simultaneously and use the encoder/tuning knob to specify the filter width in .1 kHz steps. Pressing the F and FILTER button simultaneously again, will save your filter width for the F4 position.

I’ve been using the F4 filter position for widths between about 8.2 and 9.6 kHz in AM.

It’s still early days with the LD-11, but I’m enjoying this little transceiver immensely. It reminds me of one of my favorite QRP transceivers of yesteryear: the Index Labs QRP Plus (though the LD-11 is much smaller, more versatile and has a much better front end than the QRP Plus!).

LNR Precision sold out all of their first run LD-11 units within moments of having announced availability. I’m willing to bet they’ll bring a few LD-11s to the upcoming Dayton Hamvention, though.

Check inventory status and view LD-11 details on LNR Precision’s website.

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SDRplay: Updated ADS-B for Raspberry Pi 2 and Pi3

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Image Source: FAA.gov

Many thanks to Jon Hudson with SDRplay who shares the following announcement:

We now have an updated beta version of ADS-B for both the Raspberry Pi 2 and 3. This is based upon the 16bit Mutability version of dump1090 developed by Oliver Jowett and unlocks the full 12 bit performance of the RSP1. People should see a significant performance improvement over the dump1090_sdrplus version, which was based upon 8 bit code. The latest beta version can be downloaded in binary form from http://www.sdrplay.com/rpi_adsb.html .

Should anyone have questions or feedback, please contact [email protected]

Section 1 is how to load a brand new image onto an SD card

Section 2 should be straightforward – 2 commands – one to get the software and another one to run it.

Though I don’t live in a metro area with a lot of air traffic, I am often in the flight path of a couple major airports. I’ve been looking for a simple way to try ADS-B (and ACARS). As soon as I locate a dedicated monitor and keyboard for my Raspberry Pi 3–and a little dedicated time–I will give the ADS-B app a go. Thanks again, Jon!

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Have you ever installed a covert shortwave radio antenna?

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The Hammarlund RBG CHC-46140 (Photo by Rich Post, KB8TAD)

Yesterday, in a comment thread, SWLing Post reader Dan described a covert antenna he once installed in a student apartment:

I’m waxing nostalgic now, but I had a great set-up for a couple of years back in the ’70s. The receiver was a black WW2 Navy surplus Hammarlund RBG CHC-46140. (I still have it).

I was a student living in an apartment on top of a two story, wood-framed apartment building. The attic access for that building was from the ceiling of the wardrobe closet.

During a Christmas break I was probably the only occupant of the building. I snuck into the attic and installed a set of five switchable dipoles. I had a good 60′ of space to work with and the antennas were broadside to the southwest. This was quite a memorable listening post.

When I moved out, I cut the coax to the dipoles and used toothpaste and borrowed pieces of “cottage cheese” to fill the five holes in the ceiling. Those antennas are probably still there.

Indeed, I bet they are still there, Dan!

In reply to Dan’s comment, Walt Salmaniw, noted:

Dan, reminds me when I was stationed in Germany in the early 80’s.

We lived in old French officer’s quarters. Basically, 4 story buildings with the upper floor/attic uninhabited.

The Kenwood R-2000 (Photo: Universal Radio)

I put up some nice 60 m dipoles in that space, with a goal of hearing a lot of tropical band DX, which I did using my Kenwood R2000 receiver.

Those were the glory days of dxing!

Thanks, Dan and Walter, for sharing those stories. The thread reminds me of a post we published sometime back where one young listener installed a wire antenna in his home while his parents were away. (I can’t seem to locate that post at the moment for a link!).

Though not nearly as elaborate as Dan and Walter’s antennas, I did install a small covert antenna once myself.

In the early 90s, I lived in Grenoble, France, in a four bedroom house in which three bedrooms were occupied by university students. The landlord was a rather fussy elderly woman who lived on the ground floor. I never dared ask her if I could string a random wire outside my top floor bedroom window. Though she was mostly fair and even sweet at times, I knew what the response would be if I asked for permission: a firm “Non.”

One night, I opened the bedroom window and carefully connected a short wire antenna to a nail on the side of the house, above and slightly to the side of the window. I had to stand on the window and hang out of the house to do it.

The Realistic DX-440

The antenna dangled there the whole year I lived in that room and served me quite well. I’d simply open the window and clip it to my Realistic DX-440. I did remove the antenna before before I moved back to the States, but it was virtually undetectable against the exterior wall of the house.

Other covert antenna installations?

Please comment if you’ve ever installed a hidden antenna as well. (I love this stuff!) Besides…who knows…your antenna might benefit someone in need of a hidden antenna today!

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Guest Post: Tracking High Seas Pirates on Shortwave Radio

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Suspected pirates surrender to crew members of the CGC Boutwell. (U.S. Coast Guard photo)

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

Tracking High Seas Pirates on Shortwave Radio

by Mario Filippi (N2HUN)

(All photos taken by author–click to enlarge)

Ahoy! After spinning a radio dial for over a half-century, shortwave listening still provides a source of adventure and interesting intercepts. While major broadcasters continue to move to the Internet and dwindle in number, there nonetheless remains plenty of utility intrigue to be had; you just need to know where to look, and be comfortable with other modes of communication such as RTTY (Radioteletype).

RTTY remains on HF (3 – 30 MHz), albeit mostly encrypted, but there are some stalwarts of this mode that transmit important and interesting information for ships at sea. The information can take the form of weather broadcasts, hazards to navigation, information on ships lost at sea, and pirate activity. Yes, pirate activity but not radio pirates; real honest-to-goodness modern day pirates looking to loot, plunder and prey upon commercial ships making an honest living or other leisure watercraft just out having fun.

Who knows what dangers lurk behind that dial? Trusty AOR AR-3000 receiver and SignaLink™.

Has your interest been piqued? When avast mateys as I spin ya’ a yarn on how to find out where these sea-faring scoundrels lurk from the Caribbean all the way to the South China sea!

Pirate activity is not something of the past; it exists today and is a threat conducted by ragtag armed ragamuffin groups. To keep abreast of the action you’ll need the following gear: a shortwave radio with single sideband (SSB), a decent antenna, a means of decoding RTTY, and WLO, a station from Mobile, AL that transmits information to ships at sea.

You’ll do well to add WLO’s frequency to your receiver’s memory list as it’s a pretty active station that faithfully serves the sea-faring community and is one of the gems on HF.

First, tune your receiver using USB (Upper Side Band) to around 8.472 MHz and listen for that warbling sound. You will also need a way to pipe the audio from your shortwave receiver to a computer (I use a SignaLink™ USB) and a decoding program for RTTY, such as MMTTY.

To decode you’ll need to set the baud rate (45.45) and shift (170 Hz) on MTTY (or software program of choice) and tune your radio slightly up and down frequency until the software starts decoding.

You may have to press the “Reverse” or “Rev” selector at times. MMTTY is my favorite for RTTY decoding, and a picture of it is below.

WLO, Mobile AL, with RYRY idling loop, MMTTY decoder, 45.45 bauds, 170Hz shift, “Rev.”

MMTTY is available as a free download from Makato Mori, JE3HHT. I’ve used his program for over a decade and it performs well.

You can also use MultiPSK or FLdigi to decode RTTY so it’s the user’s choice as to which is a better fit.

Anyway, what are these pirates up to? Well the next few screenshots (click to enlarge) show some interesting activity as per WLO’s RTTY transmissions:

Pirates use element of surprise with guns and knives as armaments.

Somali pirates reportedly armed with automatic weapons and rocket-propelled grenades. Yikes!

Give ‘em hell boys! An alert bulk carrier crew aborted hijacking with teamwork and water cannon.

Ships are encouraged to report pirate activity via FAX or phone.

Well mateys that’s enough high seas adventure for now, so first shove off to the galley for some grub (or grog) and then head to the radio room, turn on that rig and get ready for action on HF, you’ll find plenty to choose from, it’s out there for you.

I would like to thank the operators of WLO for providing such a valuable service to mariners and for providing us radio aficionados with interesting reception! And thanks readers!

P.S. Note that WLO alternates from RTTY to Sitor B so just make sure you are listening to the RTTY broadcast. If the transmission is in Sitor B then you can use a NAVTEX (e.g. YAND) decoder instead.

Thank you so much, Mario, for sharing yet another fascinating aspect of our radio world! FYI: I’m planning on purchasing a SignaLink USB at the Dayton Hamvention this year.

Readers, you can read all of Mario’s posts by clicking or bookmarking this link.

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