XHDATA D-808 modification to allow an external mediumwave antenna

Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

I have added an external antenna capability for mediumwave on the XHData D-808.

Simply add a 27 pF capacitor on the backside of the PCB on C10 to the the ferrite antenna.

The mod causes no loss on FM or shortwave!

I also replaced the Ferrite antenna with a bigger one so I now have more performance on MW!

Longwave is not good in my radio, even with an external antenna, it is not performing well.

Thanks once again, Rolf! I must assume that the Digitech AR-1780 could be modified in the same way as the radios appear to be near identical. Perhaps someone can verify this at some point!

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NY Times on the rise of low power community radio

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When listening to marginal FM signals, the AR1780 can be set to mono mode instead of default stereo mode.

(Source: NY Times via Mike Hansgen)

As Low-Power Local Radio Rises, Tiny Voices Become a Collective Shout

SEATTLE — A knowledge of geography is essential if you are running a tiny, 100-watt radio station. Hills are bad, for example, as are tall buildings. Salt water, though, which lies at this city’s doorstep, can boost a radio signal for miles, like a skipped rock.

For a low-power FM radio station, anything measurable in miles is good.

But on a recent Thursday night, one station, KBFG, was struggling to even get on the air. The station’s signal, audible since November in an area measurable in square blocks, had flatlined. The Ballard High School basketball team was about to take the court and the live play-by-play was in doubt.

“We’re bootstrapping it,” said Eric Muhs, a physics and astronomy teacher. Headphones were slung around his neck, and a mop of unruly gray hair came further undone as he leaned into his laptop trying to fix a software glitch. But Mr. Muhs, 60, one of KBFG’s founders, admitted that the stakes for failure were relatively low. “Almost nobody knows that we exist,” he said.

Low-power nonprofit FM stations are the still, small voices of media. They whisper out from basements and attics, and from miniscule studios and on-the-fly live broadcasts like KBFG’s. They have traditionally been rural and often run by churches; many date to the early 2000s, when the first surge of federal licenses were issued.

But in the last year, a diverse new wave of stations has arrived in urban America, cranking up in cities from Miami to the Twin Cities in Minnesota, and especially here in the Northwest, where six community stations began to broadcast in Seattle.[…]

Continue reading at the New York Times.

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SSB Reception Examples with the XHDATA D-808 Portable Receiver

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In my earlier article on this receiver, I shared reception videos of three weak medium wave stations and a single shortwave outlet, all demonstrated in AM mode.

These two videos are of reception in SSB. The first example is true SSB reception–in lower side band on the 40m amateur band, while tuning a local on-the-air ham radio classifieds broadcast:

https://youtu.be/bXsSBktVZRM

The next video demonstrates “ECSS” reception (tuning an AM mode signal in SSB). In this example I use a strong station so the audio quality and fine tuning accuracy of the XHDATA receiver can be clearly heard. Typically, ECSS is used by SWLs and DXers for AM mode stations that suffer from adjacent channel interference on one side or the other.

https://youtu.be/v7SD4czqHAs

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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The Minerva Tropic Master: a portable WWII era morale radio

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If you’re a regular here on the SWLing Post, you’ve no doubt discovered that I’m a fan of vintage radios.

Lately, I’ve been attempting to let go of some of my vintage gear to give my favorite rigs proper shelf space and dedicated antenna time. To keep temptation at bay when I visit flea markets or hamfests (like Hamvention and the one in Shelby, NC) I now focus on WWII era radios; specifically “morale” radios that were used for troop entertainment. I’ve two morale sets: the Scott Marine Radio Model SLRM (technically, a commercial version of a Navy set) and the Minerva Tropic Master.

I purchased this Minerva set off of eBay a couple years ago. I got it for $50 or $60, if memory serves (the seller originally wanted $180 + shipping!). He claimed it worked, but after I asked him a few questions prior to making an offer and learned that “working” meant the speaker prodeced a noise and the backlight worked. I made a low offer and he accepted.

Last year, I took Minerva over to my buddy, mentor and boat anchor doctor, Charlie (W4MEC). Charlie discovered the radio had many issues and several poorly implemented repairs. Still, in a few short weeks, when parts arrived he brought the girl back to life.

With front cover closed.

The Tropic Master is a portable eight tube receiver that covers both the AM broadcast band and shortwave bands from 5.5-18 MHz. It can be powered by AC or DC. It was “tropicalized” to withstand extreme heat and humidity. The internal speaker produces mellow, full-fidelity audio and the volume can be increased to room-filling.

To give you a taste, this morning I tuned the Tropic Master to my in-house AM transmitter on 1570 kHz which was being fed audio from The UK 1940s Radio Station (my favorite Internet radio station). This particular clip features Jay Lawrence’s excellent show, From Stateside:

Click here to view on YouTube.

The Tropic Master is portable and even has a fold down handle on top of the chassis. Though substantial, it must be the lightest of all of my vintage metal chassis radios.

Tuning isn’t exactly precise, but it does the job and is a pleasure to use. It’s quite sensitive on both shortwave and mediumwave. Last night, she was tuned to the Voice of Greece on 9420 kHz–I probably listened to two hours of Greek music while her eight tubes warmed the shack.

Who could turn down a radio with this speaker grill?

If you ever find a Minerva Tropic Master at a flea market or hamfest, I say adopt one! It’s a beautiful receiver and like all good vintage radios has a story and history of its own.

Post readers: Any other Tropic Master owners out there or do you have a morale radio? Have you ever spotted a Tropic Master in the wild? Please comment!

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MDZhB featured in BBC Future’s “Best of 2017”

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Many thanks to SWLing Post contributor, Golan Klinger, who shares the following article which was elected “Best Of 2017″ on the BBC Future website:

“MDZhB” has been broadcasting since 1982. No one knows why.

In the middle of a Russian swampland, not far from the city of St Petersburg, is a rectangular iron gate. Beyond its rusted bars is a collection of radio towers, abandoned buildings and power lines bordered by a dry-stone wall. This sinister location is the focus of a mystery which stretches back to the height of the Cold War.

It is thought to be the headquarters of a radio station, “MDZhB”, that no-one has ever claimed to run. Twenty-four hours a day, seven days a week, for the last three-and-a-half decades, it’s been broadcasting a dull, monotonous tone. Every few seconds it’s joined by a second sound, like some ghostly ship sounding its foghorn. Then the drone continues.

Once or twice a week, a man or woman will read out some words in Russian, such as “dinghy” or “farming specialist”. And that’s it. Anyone, anywhere in the world can listen in, simply by tuning a radio to the frequency 4625 kHz.

It’s so enigmatic, it’s as if it was designed with conspiracy theorists in mind. Today the station has an online following numbering in the tens of thousands, who know it affectionately as “the Buzzer”. It joins two similar mystery stations, “the Pip” and the “Squeaky Wheel”. As their fans readily admit themselves, they have absolutely no idea what they are listening to.[…]

Click here to continue reading the full article on the BBC Future website.

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Short Videos: the XHDATA D-808 Portable SSB Receiver on MW and SW

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I recently received a new XHDATA D-808 SSB portable receiver, after AliExpress had a $69 USD introductory sale. I’m intrigued by this new model, as it uses the SiLabs Si4735 DSP chip, the same “brains” that powers the Eton Satellit (and Executive version), and C. Crane Skywave SSB. I believe the same Si4735 is found in Tecsun’s PL-880 and the CountyComm GP-5/SSB. A key feature found in all of these radios is USB/LSB modes and 10-Hz tuning step in SSB.

It would be a mistake to assume that all portable DSP receivers with the same SiLabs chip will perform equally; quite the opposite! They all have reception differences that owners will notice. I certainly noticed differences in sensitivity, AGC action, audio quality, and (to some extent) variations in adjacent channel (splatter) rejection between receivers using the same bandwidth. I made these observations when I owned the PL-880 and GP-5/SSB radios. Differences in the circuitry surrounding the SiLabs chip, as well the sizes of MW ferrite loopstick antennas and SW/FM whip antennas contribute to each receiver’s personality.

Below are four videos showing the D-808’s reception of three weaker daytime medium wave stations from indoors at my suburban Seattle-Tacoma (WA) home, plus one video of a shortwave reception in the 41 meter band. The XHDATA D-808 is compared to C. Crane’s newest Skywave radio, the SSB model, and the Eton Executive Satellit. Although brief, these tests show how the new XHDATA portable is a welcome competitor to the field of modern, compact SSB-capable radios:

https://youtu.be/Ef0n5i2UNbo

https://youtu.be/UL6akqUbYMw

https://youtu.be/p41L-ena5rg

https://youtu.be/Wrt6WQ54BTo

What about single sideband? These four videos show reception in AM mode only, but rest assured the D-808 is very capable on the SSB modes of LSB and USB! A separate fine tuning rotary wheel on the right side of the radio’s case offers adjustment in 10 Hertz increments. The effect feels very similar to tuning CountyComm’s GP-5/SSB “walkie-talkie” style receiver. The plus or minus (+/-) offset is displayed in multiples of 10 Hz steps as “-1”, “-2”, “-3”, and so on.

I hope to post some future videos showing SSB usage of the D-808.

Soft mute. The dreaded soft mute is present in AM and SSB mode to some degree, but I do not feel it is excessive. Like most radio hobbyists I’m not a fan of soft muting and prefer uninterrupted tuning with no sign of “chuffing” or lowering of noise or audio. The amount of soft mute on this radio seems the same as the Eton Executive Satellit in my opinion.

What else to like? My take–

Audio. I find the D-808’s audio quality to be slightly more mellow or warmer…I like that, especially on FM! Audio on the MW and SW bands still has a crispness that aids in DXing on those bands, however.

18650 Li-Ion battery. Not all may agree, but I like this style of battery. The D-808’s internal circuit shuts off when the battery is fully charged, or after 10 hours of charging. The radio comes with a 18650 battery and a USB cable; the owner supplies a common 5V USB charger.

RDS on FM. This is a feature lacking on the Skywave SSB, but it is present and performs as expected with the D-808. The XHDATA radio lacks the Skywave SSB’s NOAA weather presets, however.

AM filter bandwidths. Interestingly, this receiver supplies two additional narrow AM mode bandwidths lacking in the Executive Satellit: 1.8 kHz and 1.0 kHz. It’s good to have options, although such narrow filters in AM mode sound a little muffled (offset tuning helps). The Skywave SSB does offer 1.0 kHz in AM mode, but has a 2.0 bandwidth in place of 1.8 kHz.

Backlighting. If desired, the D-808’s easy-on-the-eyes white backlight for the display can remain illuminated continually. Bravo, XHDATA! Now, if we could persuade more manufacturers to add backlighting to the keys themselves (a la the Degen DE1103/Kaito KA1103/Eton E5), we’d have more choices use in low light conditions like camping or bedside use.

Handy size. Probably a third larger than the diminutive Skywave SSB, the D-808 is still a very handy size that will fit most coat pockets, and is a smaller receiver than the Eton Executive Satellit. As you can tell from my videos, reception doesn’t suffer due to the smaller size.

Design. OK, this one’s very personal! As a graphic designer I have a real soft spot for any receiver that looks as good as it sounds, no matter what the technology or vintage. The D-808’s look really appeals to me and adds to my enjoyment while operating it. There are no unnecessary protrusions, ridges, or visual do-dads on this XHDATA model. In fact, I seem some design clues from the stylish Tecsun PL-880 in the D-808. The radio also has a quality feel to the plastic case and buttons, giving it a more “upper class” impression during use.

Antenna jack. The D-808 has the standard 3.5mm antenna port on the left side of the receiver. This is an addition I appreciate, and wish that C. Crane had included one on their Skywave SSB model. I tried this external antenna jack with an amplified PK Loops’ shortwave antenna and the combination performs excellently.

Minor annoyances

So far, the list is short! As a sacrifice to style, the manufacturer has kept all front panel buttons almost flush with the case. The effect looks great, but they are almost too low and close to the front panel. Those with larger fingers may find operation awkward or frustrating. Also, entering a shortwave frequency with less than five digits (i.e., below 10,000 kHz) requires a trailing push of the Frequency (FREQ) button.

I encourage other new owners of XHDATA’s D-808 to leave their comments below. Where does this portable rate among other radios you may own?

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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Rolf’s LED backlight mod for Sony ICF-SW35

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Many thanks to SWLing Post contributor, Rolf Snijder, who writes:

This is a simple LED backlight modification for the Sony ICF-SW35.

Simply add a 120K resistor and a bright LED:

Overview of resistor placement. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of resistor. (Click to enlarge)

Detail of Pin 10 (Click to enlarge)

Detail of LED placement–replacement of capacitor is not necessary. (Click to enlarge)

When you push the backlight switch, the light stays on.

When radio is turned off, the light goes off–then push light switch and backlight will stay on for 15 seconds or so.