Category Archives: Mediumwave

The Airspy Youloop is a freaking brilliant passive loop antenna

Before I start talking Youloop, I have a little confession to make up front:

At the Winter SWL Fest when I gave a presentation about Portable SDR DXing, not only did I give attendees the wrong name of the Airspy Youloop antenna, but I also configured it incorrectly, hence the poor performance via my Miscrosoft Surface Go tablet PC.

I had assumed the the crossover component of the antenna was the transformer component. I realized the mistake I made when I saw some of the first promotional photos of the Youloop antenna a few weeks ago.

The crossover connects both sides of the loop while the tee junction contains the transformer.

Doh! I’m trying to forgive myself for making such an obvious mistake, but in my defence–and in the spirit of full disclosure–my antenna was a very early sample prototype without instructions, diagrams, etc. so I set it up imagining it being similar to the homebrew loop Vlado and I built. (FYI: When I say “Vlado and I built” it, I really mean, “Vlado built it.”) 

So obviously I made a poor assumption.

Once I assembled the antenna correctly? Wow. Just. Wow!

Youloop: The ideal travel antenna for high dynamic range SDRs

The Youloop, Airspy HF+ Discovery, SDRplay RSPdx, and all cables easily fit in my Red Oxx Lil Roy pack.

The Youloop is truly the travel antenna I’ve always wanted for portable SDR DXing. Here’s why:

  • It’s incredibly portable and can be rolled up to fit in a small travel pouch
  • It has all of the low-noise characteristics of other magnetic loop antennas
  • It’s wideband unlike many passive loop designs
  • It requires no variable capacitor or tuner
  • It’s made of quality components
  • It requires no external amplifier nor power source
  • It takes one minute to assemble
  • It’s affordable (~$35 USD shipped)

The only caveat? To take advantage of the Youloop, you must use a high dynamic range receiver.

Airspy HF+ Discovery SDR

I can verify that this antenna works brilliantly with the Airspy HF+ Discovery.

The AirSpy HF+ SDR

It will also pair well with the Airspy HF+  if you shortcut R3 via the R3 modification.

SDRplay RSPdx SDR

I’ve also used it numerous times with the new SDRplay RSPdx while using SDRuno in High Dynamic Range (HDR) mode. With the RSPdx, I can make spectrum recordings of the entire AM broadcast band. Note that HDR mode is only available on the RSPdx at 2 MHz and below, using the SDRuno app.

I have not tested the Youloop with other SDRs yet. I will soon test it with my WinRadio Excalibur.

So how well does the Youloop perform?

Listen for yourself!

I’m doing a little cargiving family members today. Their home is swimming in RFI (radio interference/noise). In the past, I’ve struggled to make good mediumwave recordings at their home–certainly an ideal situation for a mag loop antenna.

This morning, I wanted to record one of my favorite local AM stations (WAIZ at 630 kHz), so I set up the Youloop in the middle of a bedroom, hanging off a large bookshelf set against an interior wall. In other words: not an ideal situation.

When I plugged in the Airspy HF+ Discovery and loaded the Airspy SDR application, I fully expected to see a spectrum display full of broadband noise.

Instead, I saw signals. Lots of signals:

Sure, there’s some noise in there, but it’s low enough I could even do proper mediumwave DXing on most of the band if I wished.

In fact, if you’d like to experience the HF+ Discovery/Youloop pairing in this compromised, less-than-ideal DXing setup, why not tune through one of the spectrum recordings I made?

Click here to download the spectrum file [885.7MB .wav].

The recording was made on March 30, 2020 starting around 10:50 UTC. You’ll need to open this file in AirSpy’s free application SDR# or a third party SDR app that can read AirSpy .wav files.

I can’t wait to try the Youloop in other locations. Since we’re in lock-down due to Covid-19, I won’t be able to try the Youloop in a hotel any time soon. Almost all of my 2020 travel plans have been canceled.

Highly recommend

If you have one of the SDRs mentioned above, go grab a Youloop. At $35 USD, it’s a fantastic deal.

Click here to check out the YouLoop at the RTL-SDR.com store ($34.95 USD shipped).

Click here to check out the YouLoop at Airspy.US ($29.95 + shipping).

Click here to search for AirSpy distributors in your region/country.

If you don’t have a high dynamic range receiver, note that Airspy is exploring the idea of making a pre-amp for the Youloop. If interested, you might drop them a note of encouragement!

Do you have a Youloop? Please share your comments!


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Radio Waves: Digitizing Pakistan, BBC MW Closures, Lowe HF-250 Review, and BBC News suspends 450 job cuts

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Alan, Mike, and Dave Zantow for the following tips:


Government to fully digitize Radio Pakistan (Radio Pakistan)

The incumbent government, under its vision of introducing modern trends and technology in different sectors, has planned to fully digitize the state-owned Radio Pakistan.

This information has been revealed in official documents during the ongoing week-long national workshop on Digital Radio Migration policy of Radio Pakistan at Pakistan Broadcasting Academy, Islamabad.

The digitization will bring about a revolution in the field of broadcasting in the country, and will capture the audience at home and abroad including South Asia and Central Asia and the Middle East through quality news, current affairs and programs.

Under the plan, the biggest 1000-Kilowatt DRM Medium-wave transmitting station of Radio Pakistan will be set up at Fort Monroe hill station in Dera Ghazi Khan district in South Punjab at an estimated cost of three billion rupees.

It will be the first ever most powerful but digital transmitter of Radio Pakistan that is to be established in center of the country as part of Phase-II of Digital Radio Migration policy and it will help cover the entire population of Pakistan with crystal clear and noise-free waves.

The project has already been approved by the federal cabinet while the Punjab government has been asked to acquire land for the said purpose.

Under Phase-II of DRM plan, five DRM+FM transmitters of 10-kilowatt each will be installed in Islamabad, Lahore, Karachi, Faisalabad and Multan in the existing Radio Stations.

Besides, eight DRM+FM transmitters of five kilowatt each will be installed in Quetta, Peshawar, Gilgit, Skardu, Gwadar, Mirpur (Azad Kashmir), Khairpur and Narowal in the existing radio stations.

The phase-II of the plan would be accomplished in three years with an overall estimated cost of 3,153 million rupees.

And under Phase-III of the plan, four DRM medium wave transmitters of 100-kilowatt each will be installed in Lahore, Skardu, Quetta and Peshawar for strategic purposes.[]

BBC Radio to close more medium wave transmitters (Radio Today)

The BBC says it is closing a further 18 medium wave transmitters across England, Scotland and Wales in the next stage of its plan to cut costs.

Services being closed range from BBC Radio Solent’s two AM frequencies on the South Coast to BBC Radio Scotland’s service in Aberdeen.

Six more BBC Local Radio services will no longer be transmitted on AM – they are Three Counties Radio (630 and 1161 kHz), BBC Radio Merseyside (1485 KHz), BBC Radio Newcastle (1458 KHz), BBC Radio Solent and BBC Radio Solent (for Dorset) 999 and 1359 KHz, BBC Radio Cornwall (630 and 657 kHz) and BBC Radio York (666 and 1260 KHz).

Kieran Clifton, Director, BBC Distribution & Business Development explains: “The majority of radio listening in the UK – including to the BBC – is now digital, and digital listening is continuing to grow.

“This change was planned as long ago as 2011, but we have taken a measured approach to implement it to ensure that as many of you as possible have already moved on to other ways of receiving the services before we make this change. We know that the changes will impact some of you, and that’s why we’re speaking about the plans again now. We want to make sure that people listening to these transmissions will be able to use other methods to hear the same programmes.”[]

Dave’s review of the Lowe HF-250 (N9EWO)

[…]As far as audio quality goes, it’s extremely difficult to beat the Lowe HF-250. Mind you it has it’s share of “bug-a-boos” as well.

In our view it has held up much better in it’s old age vs. the AOR AR7030. Properly operating and in decent condition samples are fairly rare on the used market now (even more so in North America). Most owners know what the receiver is and hang on to them. But once a great while one does show up on the used market. Click here to read the full review.

BBC News suspends 450 job cuts to ensure Covid-19 coverage (BBC News)

BBC News has suspended plans to cut 450 jobs as it faces the demands of covering the coronavirus pandemic.

The job losses were announced in January and were part of a plan to complete a £80m savings target by 2022.

Outlets due to be hit include BBC Two’s Newsnight, BBC Radio 5 Live and the World Service’s World Update programme.

Director general Tony Hall gave staff the news on Wednesday, a week after the broadcaster delayed the end of the free TV licence scheme for all over-75s.

Lord Hall said “we’re suspending the consultation on those saving plans”.

He told staff: “We’ve got to get on with doing the job that you’re doing really brilliantly.

“It would be inappropriate. We haven’t got the resource to plough ahead with those plans at the moment, so we’ll come back to that at some point.

“But for the moment we just want to make sure you are supported and you’ve got the resources to do the job that you and your colleagues are doing amazingly.”[]


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Radio Waves: WNPV Off Air, Privat-Ear, End of Radio, and China COVID-19 shut-ins tune-in

(Source: JamesButters.com)

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Ron, Tracy Wood, and Dennis Dura for the following tips:


WNPV Radio preparing to go off air April 30 (The Reporter)

TOWAMENCIN — When April ends, the airwaves above the North Penn valley region will be emptier, and so will a little brick building on Snyder Road in Towamencin.

Sitting below five 165-foot-tall radio antennas and one cell tower, that brick building has been the home for six decades of WNPV, the local radio station found at 1440 AM and 98.5 FM.

“We’ve been at it for 60 years, and our mission and our core values are really no different today than they were in October of 1960. It literally is to serve the community,” said Phil Hunt, the station’s General Manager.

“It’s gotten to the point where it’s not sustainable for us to continue to do that. It takes resources to do it properly; those resources, primarily, are people, and we were having trouble making ends meet,” he said.

Hunt announced Wednesday that WNPV will go off the air on April 30, bringing an end to an era of live, local news that began on Oct. 17, 1960. The station’s coverage of local sports, politics, breaking news, and key issues have earned dozens of awards, a handful of which greet visitors as you walk past an old teletype machine through the station’s front door.[]

Privat-ear Subminiature Tube Pocket Radio (JamesButters.com)

The Privat-ear pocket radio was manufactured in the USA and released onto the market by Electronics Systems Corporation in 1949 (1a, b, c). Although small enough to fit in a shirt pocket this is not a transistor radio; it owes its small size to the use of subminiature tubes developed during WWII and was designed as an earphone only model. It predates the first commercially available transistor radio by five years and was an innovative, but ultimately doomed, attempt at realizing an American cultural objective; the creation of a portable shirt pocket radio with mass appeal.

The Privat-ear was invented by Frank L Stuck, a Minister of Lakeland Florida. Born in Washington, Pennsylvania on October 13 1904 to William and Maise Stuck, he was the second youngest of four children (1d, e). He studied Theology at Bethany College, West Virginia from 1924 – 1927 and received a Doctor of Divinity degree from the American Theological Seminary at Wilmington Delaware (1f). Whilst attending College he was one of the founding members of Alpha Pi Alpha, was a member of the Student Volunteers and met and married Iva Myrtle Driggs.[]

IN CASE YOU MISSED IT – The End Of Radio. Really? (Radio Ink)

(By Mike Bustell) I try to keep my head down and quietly work behind the scenes helping our salespeople make a killing for our advertisers and our company. However, I had to react to Roger Lanctot’s “Technology Tyranny and the End of Radio” LinkedIn article published in last Friday’s Radio Ink headlines.

How Tesla and Silicon Valley (and other tech giants) feel about local radio is not much different than what our salespeople hear when talking with their local garden center or auto dealer group — that local radio is no longer relevant to bother putting it on their 2020 dashboards.

All these objections are happy opportunities to educate, bond, and sway hearts, minds, and advertising budgets. We have to be happy well-armed warriors with targeted customer-specific information every time we ask for a decision-maker’s valuable time. Once we earn an advertiser’s business we can never stop educating, bonding, or working on helping them grow their business.

Below is the most up-to-date look at the audio sources that $100K+HHI purchasers and lessees for new hybrid and electric vehicles are using. Like Mike Bloomberg taking the salt shakers off of New York City restaurants’ tables, Tesla’s removing easy access to local AM/FM radio stations on their new vehicles’ dashboards shows a similar out-of-touch-with-the-people attitude. Ninety-four and a half percent of $100K+ Age 25+ adults who plan to buy or lease a new hybrid or electric vehicle in 2020 listen to Local AM/FM radio every week — nearly three times that of Spotify, the second most-listened-to audio source every week used by these consumers.[]

China COVID-19 shut-in tunes in to the world via radio (Marketplace)

The battle to contain the COVID-19 virus in China has kept most people at home since the end of January.

Life is slowly returning to streets in cities like Shanghai, but face masks are now required in nearly all public spaces, even though they are not recommended for the general public by the Centers for Disease Control or World Health Organization.

Since there is a shortage of masks, most people are still effectively forced to stay home. As Marketplace’s China correspondent, this includes me. My window to the world for a better part of a month has been through radio.[]


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A Compact RSPdx & Wellbrook Loop Kit for the Beach — My Approach

I have enjoyed three to four medium wave and shortwave DXpeditions per year since 1988, to sites on the Washington and Oregon coasts. I love the chance they give to experiment with antennas in a (hopefully!) noise-free location, and concentrate on catching stations that might not be heard from home.

All of my DX trips have been via car–until now! I’ve just returned from nine vacation days in Hawaii (Waikoloa Beach, on the Big Island), and I thought others might like to see the radio related items I chose to take along for air travel. I’m pleased to report that everything worked as planned, and I have five days of SDR IQ WAV files of the MW band for review, all recorded in the time frame surrounding local dawn.

My goal was not the smallest, most compact portable setup, but one with high performance and modest size. Fitting everything into a day pack was another requirement. A simple wire antenna and an even smaller Windows tablet or laptop than the one I’ve used (and a smaller SDR like the HF+ Discovery, for that matter) would make a much smaller package. However, the items I’ve assembled worked excellently for me during my enjoyable Hawaii vacation. The directional loop antenna provided nulls on medium wave of 30 dB during preliminary tests indoors, a less-than-ideal test situation.

Waikoloa Beach–just one of a zillion picturesque scenes in Hawaii.

Here is a list of what I’ve put together for my DXing “kit”:

    • SDRPlay RSPdx receiver
    • Short USB cable for receiver<>PC connection, with two RFI chokes installed
    • Lenovo X1 tablet— a Windows 10 device with magnetically attached keyboard; this model is a competitor to Microsoft’s Surface Pro tablet
    • Wellbrook Communications’ ALA1530 head amp module, modified for female SO239 connectors enabling use of large diameter LMR-600 coaxial cable as a 2-turn loop element. My antenna setup is similar to Wellbrook’s commercial flexible loop
    • Wooden base for the antenna (ALA1530 is bolted to the base)
    • 20 feet of lightweight RG-174 coax
    • Wellbrook DC interface module for the ALA1530
    • 3.0 Ah LiFePO4 rechargeable battery for the Wellbrook antenna
    • 15 foot long section of high grade “Times Mfg.” LMR-600 coax cable with PL259 connectors (bought from Ebay already assembled/soldered)
    • Fold-up beach mat
    • Small day pack to hold everything

All the contents of this DXing setup fit a standard size day pack.

You’ll note the absence of headphones in the list. This is because my intent from the start was to record all the DX (MW band) as SDR WAV files for DXing post-vacation. That said, I did have headphones in my travel luggage for later spot checks of a few frequencies. That’s how I found 576 kHz Yangon, Myanmar lurking at their 1700 sign-off with national anthem and English announcement. The remainder of the DX to be uncovered will have to wait until I’m back home near Seattle!

The LMR-600 is a very thick and stiff coax cable, whose diameter approaches that used in the standard aluminum tubing ALA1530 series from Wellbrook. It has the benefit of being self-supporting in a 2-turn configuration and will also coil up into an approx. 12-inch package for transport. It just barely fits within the day pack I’m using. As I understand it, magnetic loops with tubing or large coax as the active element, versus simple wire, are more efficient in operation. Whether or not this holds true in practice remains to be seen.

I fashioned a wooden disc 3/4″ thick to attach the ALA1530 head amplifier, as I didn’t want to bring along a tripod or other support stand. The Wellbrook antennas all work well near or at ground level, so I was able to get great reception with the antenna right on the beach. The diameter at two turns of the coax is only a few inches smaller diameter than Wellbrook’s aluminum tubing loops. Three strips of strategically placed Velcro straps help keep the turns together when deployed as well as during storage.

In theory a two-turn loop should give 5 dB less gain than a single turn version; however, my older ALA1530 module has 5 dB more gain than the newer “LN” type, according to Andrew Ikin of Wellbrook Communications. The net result is that my two-turn antenna should have equal gain to the larger one-turn variety. Future experimentation with this DIY coax loop antenna is in order!

The Wellbrook loop antenna, RSPdx receiver, and Windows 10 tablet on the beach in Waikoloa, Hawaii.

Another view of the DXing position. Being this close to the water with my radio gear was unnerving at first, but the wave action on a calm Hawaii beach is totally different from the Oregon/Washington beaches with waves that can move in and out by a hundred feet or more.

The Wellbrook “DIY FlexLoop” works fine at beach level, and is less conspicuous this way, too.

The ALA1530 module is bolted to the 11-inch wooden disc for support. I’ve modified the module’s sockets to securely hold SO239 female connectors.

The commercial Wellbrook FLX1530LN is a fine product, and worthy of your consideration as a compact and high performance travel antenna. Full details can be found at this link.

SDR WAV Files for Download

One of my goals from the start for my Hawaii trip was to bring back SDR “IQ” WAV files for sharing with others. These approx. 900 Mb files cover the entire medium wave band as heard from my beach location in Waikoloa.

The overall page is: https://archive.org/details/@4nradio   Clicking on any of the entries will bring you to a details page. From there just right click on the “WAVE” link, and choose “Save as…” to download. For a few of the recordings I also posted the file that precedes the one that goes across the top-of-the-hour, because things seemed a bit more lively prior to 1700 (which  was at local sunrise, give or take a couple of minutes).

The IQ WAV files are only playable with suitable SDR radio software: SDRuno is first choice (but you need a RSP receiver connected). The files are also is compatible with HDSDR and SDR-Console V3. It may also play on Studio 1 software.

I hope other DXers enjoy the chance to tune through the MW band, as heard from the Big Island of Hawaii.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

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KKOH 780 kHz off the air tonight

Many thanks to SWLing Post contributor, Paul Walker, who writes:

If you know any DXers out in western US… pass the word:

Saturday night/Sunday Morning, at 12 AM Pacific KKOH 780 will be off the air for about 6 hours to do some maintenance.

Thanks to Chief Engineer Daniel Appellof for letting me know well ahead of time so I can pass the word

[…]Listen after the off air time is done because KKOH will come back on at 50KW non directional and will have 10-30 minutes of dx test material…. sweep tones, morse code, telephone dial tones and telephone off hook noises and such.

[UPDATE] We’re going to get about 15 to 20 minutes of DX Test material at 50kw non-directional tonight at 12 midnight before he shuts it off.

Thanks for the tip, Paul.  I’m sure west coast US DXers will certainly enjoy this opportunity!

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A Look Back: Memories of the Panasonic RF-2200 and its sibling, the National Panasonic DR22

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


A Look Back: Memories of the Panasonic RF-2200 and its Sibling, the National Panasonic DR22

by Mario Filippi, N2HUN

All photos by author unless otherwise noted

One of the preeminent AM/FM/SW portables of all time is the venerable Panasonic model RF-2200 receiver that was sold in the USA starting in the mid-1970’s for around $165.00 US.

Weighing in at a hefty 7 pounds, 13 ounces and vital statistics of 12” x 7” x 4” it came equipped with a robust shoulder strap to schlep from the radio shack to alfresco listening sites and was basically a completely self-contained entertainment center for the radio enthusiast.  My first RF-2200 was purchased in the late ‘70’s from Grand Central Radio Shop in New York City, now just a memory and long gone, but back then they sold a bevy of shortwave and ham radio equipment.

Photo 1. Author’s favorite portable of all time, Panasonic RF-2200

It was love at first sight when I saw the RF-2200 in the store’s gleaming glass display case way back when. The ‘2200 possessed all the bells and whistles to guarantee a good time for the SWL such as a rotatable ferrite AM broadcast band antenna, BFO (Beat Frequency Oscillator) for SSB reception, AM /FM/SW (3.9 – 28 MHz) bands, a D’Arsonval “S” meter that doubled as a battery status indicator, large four inch front mounted speaker, switchable coarse/fine tuning speed, base/treble/RF gain pots, 125/500 kHz crystal markers to calibrate the VFO, wide/narrow bandwidth switch, dial/S meter lights, earphone/recorder jacks and telescopic antenna for SW and FM. Plus it sported the renowned Panasonic trademark.

Photo 2. RF-2200’s rear: exposed battery compartment, screw connectors for external antenna, AC plug lower right. Rectangular earphone storage compartment is above batteries. Battery cover’s gray foam pad is dry rotted and needs replacement.

Part of the 2200’s ample avoirdupois can be attributed to the unit’s four “D” battery power plant, but Panasonic also supplied an AC cord to plug into the house mains and an earphone (located inside the battery case).  It runs forever on those four stout dry cells, one of the many positive features of this vintage gem.

Back in those days portable radios generally were not judged and valued based their diminutive size and weight but on the array of features geared to the end-user. Front panels were festooned with an array of controls rivaling an aircraft’s cockpit.  Knobs, analog dials, meters, large front-mounted speakers, switches and lots of black plastic were the order of the day. These all contributed to the beauty and practicality of portable shortwave radios back then.

One thing missing though was built-in memory channels; those existed in the operator’s brain and not yet delegated to memory chips.

Photo 3. Pack of four “D” cells, at 1 lb 4oz, weighs more than some of today’s portables!

One of the features long gone and missing in modern receivers these days is the “recorder out” jack that looks identical to an eight-inch earphone jack and yes the ‘2200 has one. It was used to plug in a tape recorder to memorialize an op’s favorite radio show. Of course back then there were many more shortwave stations broadcasting.  Gone also are those tiny incandescent bulbs, sometimes described as “grain of wheat” lamps that were used on S meters, dials, etc. The RF-2200 sports ample illumination for the S-meter and tuning dial which makes it a perfect bedside table radio for late night DX’ers and insomniacs.

Speaking of DX, the ‘2200’s rotatable AM ferrite antenna is one of the main virtues this radio possesses.  As an avid AM DX’er and faithful disciple of AM radio in general, the ‘2200’s rotary directional antenna nulls out noise and routinely pulls in stations as far away as Nashville (WSM), Chicago (WBBM), St. Louis (KMOX), Atlanta (WSB), Boston (WBZ) and Toronto (CJBC) when the sun goes down. Look closely at the antenna mount’s base and you’ll even see compass-like degree markings that’ll help when retrieving a favorite local or DX AM station.

Photo 4. Operating manual copy is available on-line

Shortwave coverage is approximately from 3.9 – 28 MHz as per the service manual, but I’ve checked the actual coverage of my unit using a calibrated service monitor and found it to be 3.47 – 28.9 MHz which makes sense since I’ve tuned to W1AW’s code practice on 3.581 MHz with no problem and have also heard the Volmet station on 3.485 MHz. That’s good news for hams wanting to receive 80m CW.  It gets a bit tricky though using the fine tuning option for CW hi hi.

AM broadcast band coverage is only from 525 – 1610 kHz as per the specifications; the AM band had not yet been extended to 1710 kHz at that time.  The ITU approved the extension in 1988. With that in mind I wanted to determine what the actual band coverage of my unit was. Again, using an IFR service monitor it was found to be from 514 – 1720 kHz; that’s good news for those who listen to stations at the top of the band.  It also explains why I can hear YWA, a non-directional radiobeacon (NDB) from Toronto, Canada just below the AM band on a frequency of 516 kHz. If you own a RF-2200 or DR22 tune to the bottom of the AM band and listen for it. You may also hear the warbling sound of NAVTEX stations on 518 kHz.  Switch on the BFO and wait for dark, you might get lucky like I have.

My apologies for not being an FM broadcast band listener so all I can state is the few times I’ve listened it sounded absolutely great.  The specs state a FM broadcast band frequency range of approximately 87.5 – 108 MHz. Mine measured from 86.8 – 108.9 MHz but I’ve yet to realign my unit so these ranges may vary among the population.  Note that I have undertaken the labor intensive task of aligning my National Panasonic DR-22 which is almost the exact same unit as the ‘2200. You can search this blog for my results that were kindly published by Thomas previously (click here to read).

Photo 5. Side by side comparison.  Panasonic RF-2200 on left, National Panasonic DR22 on right.

For those not aware, the RF-2200 was also marketed in Europe as the National Panasonic DR22 and in other parts of the world as the Cougar 2200. My DR22 was an eBay purchase, and that’s the best place to find either model.

DR22s are rather rare compared to the ‘2200 though. First off, one of the major differences with the DR22 is that it runs on either 110 or 220V, and that’s accomplished by a switch on the back of the unit.

DR22 runs on 120 or 240V via switch on rear panel

The DR22’s front panel stenciling is slightly different too, as shortwave bands are labeled “KW 1 – KW 6” in addition to “SW1 – SW6”.  Not sure what “KW” means though. Perhaps some reader can enlighten us.

Well, that’s about it, if you want a RF-2200, or DR22 then window shop on eBay.  Lately they have been selling from $40.00 US (parts only) to $455.00 for pristine units. That’s a pretty wide price range and even I’m surprised at the high prices being gotten for clean units.  All I can say is that the two I have now are staying right here in the shack with me.

Thanks for reading and 73’s.


eBay searches (note these eBay partner links support the SWLing Post):


Thank you so much for sharing this excellent post, Mario. Like you, I’m a massive fan of the Panasonic RF-2200; in fact, I own two of them! It is, in my opinion, the best AM/MW portable ever made. 

Post Readers: Any other RF-2200 and DR22 owners out there? Can anyone explain why the DR22 labels shortwave bands as “KW1 – KW6”–?  Please comment!


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Guest Post: Radiofreunde NRW’s DXpedition-grade signal distribution system


Many thanks to SWLing Post contributor, Joachim von Geisau (DH4JG), for the following guest post:


Signal distribution at SWL camps: The new JK-1000 HF distributor

by Joachim von Geisau (DH4JG)

The Friends of Radio NRW – an independent group of shortwave listeners and radio amateurs in Germany – have been organizing 2-3 SWL camps per year for a number of years, where they meet as far away as possible from electrical noise in order to listen to shortwave together.

To distribute antenna signals, we have previously used an RFT AVV01 antenna distributor.

At an SWL camp there are high demands on signal distribution. Both very weak and strong signals should be distributed well, un-distorted, without noise and other interference. The signal levels are approximately between 0.2 ?V (S1) to over 5 mV (S9 + 40 dB), with a frequency range of at least from 150 kHz to 30 MHz, thus broadcast bands from LW to SW are covered, also all amateur radio bands from 160 m to 10 m.

Popular among listeners are RFT AVV01 RF distributors from the former GDR, at least 30 years old. However, the use of an AVV01 has several disadvantages: high power consumption, difficulties in getting spare parts, high upkeep with corroded contacts and the like. In addition, the transmission of the LW/MW range drops, which is a disadvantage especially for MW listeners. The NV-14 system from Rohde & Schwarz from the late 1960s has the same weaknesses.

Two years ago, the desire arose to develop a concept for the replacement of the RFT system.
The following aspects were important:

  • Frequency range at least 100 kHz – 30 MHz, as linear as possible
  • frequencies below or above desirable
  • Running on 12 V DC or integrated noise-free power supply
  • Remote power supply for active antennas
  • Robust structure
  • Versatility
  • Hobby friendly budget

The amateur radio market offers several products for RF signal distribution (e.g., ELAD, Bonito et al.), but no solution to distribute 6-8 antennas to 10-12 receivers. It was clear from the beginning that DIY development was inevitable.

The starting point of the considerations was to integrate remote power supply for active antennas, an amplifier stage and a distribution network.

Such a distributor is able to distribute an antenna signal to several receivers; several antennas require several such distributors, which led to the decision to implement the project in plug-in technology.

With OM Frank Wornast DD3ZE (www.dd3ze.de), known e.g. for his converters, filters and the like, a well-known RF developer could be won, who took over the implementation of the concept based on the detailed specifications. OM Wornast first produced a prototype without remote power supply, which already did an excellent job of RF signal distribution.

A “hardness test” at an SWL camp showed that this distribution module easily fulfilled our requirements: Frequency range 10 kHz – 50 MHz (also usable with a few dB loss above 50 MHz). Supplemented by a switchable remote power supply and a 90V gas discharger at the antenna socket, the final PCB layout was created, representing the core of the new HF distribution system of Radio Freunde NRW

The distribution block consists of the following components:

  • Input with 90V arrester & 100 kOhm MOX resistor to dissipate static interference
  • Remote power supply, switchable, 10-14 V, max. 350 mA
  • Amplifier stage with 14-14.5 dB
  • Resistor network for distribution

The device is characterized by a very smooth frequency response and has a very low inherent noise. It offers the possibility of using levels of -120dBm with very good SNR
to process up to strong levels of up to + 14dBm. In addition, the reception on VLF is now possible, which did not work with the previous system.

 

The PCB is designed in a very practical way: series resistors for LEDs are integrated as well as fixing points for coaxial cables. The remote power supply can be switched separately, but can also be used permanently by means of a jumper.

With this concept, the distribution block can be used universally: use on an active or passive antenna with distribution to several receivers, by means of a step switch in front of it also for several antennas; if you leave the remote feed path unconnected, the block can also be used as a simple distributor, so it is almost universal for hobby purposes.

For use on SWL camps, we decided to install them in 19 “rack-mount technology. A standard rack can thus accommodate 4 distributors and a power supply, allowing  distribution of 4 antennas to 12 outputs each. An example of the installation is shown in the following picture: Parallel to the input is another BNC socket, which is connected via a C 100 nF where the input signal can be used DC-free for measurement purposes or the like. The distribution unit is installed in a transport case. The components themselves are mounted in slide-in housings which are provided with a corresponding front panel: Such front panels might be obtained from CNC manufacturers.

On the back + 12V DC must be supplied as operating voltage. For the power supply units, we opted for linear power supplies because we have made the best experience with these without interference. For a distribution unit with 4 slots, a power supply with 12V 1A is sufficient – each distribution block takes about 55 mA, an active antenna up to 150 mA, so even with “full load” a power supply with 1 A is sufficient. The distributor was tested with various well-known active and passive antennas, including a PA0RDT MiniWhip, active loops, long wires and T2FD.

Due to the wide input voltage range, the module can handle nearly any antenna. The cost for a distributor for 4 antennas amounts  (depending on the version: housing, sockets, switches, power supply, etc.) to about 700-1000 €. That may seem a lot at first glance. However, taking into account that a simple 5-gang distributor from mass production costs already around 250 ¬, the cost of the distribution of 4 antennas to each up to 12 outputs are not that much. The Friends of Radio NRW use two of these distribution units for SWL camps.

If you are interested in building one, please contact the author (dh4jg@darc.de) for further information. The development history of the distribution unit is also available at www.dx-unlimited.eu.


Wow!  What a beautifully engineered antenna distribution solution, Joachim!  I love how you worked together to sort out all of the requirements for your system then build it for ultimate performance and flexibility.  No doubt, you and your colleagues at  Radiofreunde NRW posses a lot of design and engineering skills!  Simply amazing and thank you for sharing your design with the radio community!

Contact Joachim for more details and check out notes and discussion at www.dx-unlimited.eu (may require registration).

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