Tag Archives: Belka-DX DSP

Guest Post: A synchronous detector crash course!

Many thanks to SWLing Post contributor, 13dka, who shares the following guest post:


Revisiting the Belka’s “pseudo-sync detector”: A sync detector crash course!

by 13dka

“It’s usually hard to assess whether or not a sync detector helped with a particular dip in the signal or not, unless you have 2 samples of the same radio to record their output simultaneously and compare.”*

That’s what I wrote about the “pseudo sync detector” in my review of the Belka DSP last year.

Since I was recently upgrading to the Belka DX in order to pass on the Belka DSP to a friend, I had briefly two examples of almost the same radio on the table at the dike. I tuned them to the same stations and recorded some audio clips with one radio on sync detector, the other in regular AM mode, to answer the question whether or not sync has “helped with a particular dip in the signal”. Then I thought that demonstration would be an opportunity to try an explanation on what exactly (I think) sync detectors are all about anyway, hoping to find a middle ground between “technical” and “dumbed down beyond recognition”.

The trouble with sync detectors

Perhaps no component of a shortwave receiver is surrounded by so much misconception and confusion as sync detectors. Full disclosure: Until quite recently, I had an, at best, vague concept on what they do myself. It seems it’s not so much that people don’t know how they work, what they actually do when they work is where the ideas often diverge. Continue reading

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Greg’s Uniden stand works perfectly with the Belka-DX

Belka-DX StandMany thanks to SWLing Post contributor, Greg Hathaway, who writes:

Hi there –

I bought a Belka-DX recently and am really enjoying it! The stand from my Uniden Home Patrol 1 scanner works great with it. The stand is sold separately by Uniden for those who may be interested.

Best,
Greg Hathaway

Thank you for sharing this, Greg. You’re right: that little Uniden stand fits the Belka perfectly!

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Radio Waves: Josh reviews the Belka-DX, Sinclair Fraunhofer DRM Partnership, Clear Net Frequencies Requested, and

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’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors TomL, Alan, Bruce Atchison, and Troy Riedel for the following tips:


Belka DX Shortwave Receiver – Closest Thing To A Spy Radio? (HRCC via YouTube)

Sinclair Launches ATSC 3.0 Test Site; Partners With Fraunhofer On Mondiale Service Integration (ATSC)

HUNT VALLEY, Md.—Mark Aitken, senior vice president of advanced technology at the Sinclair Broadcast Group, flipped the switch on a 100w transmitter to begin broadcasting ATSC 3.0 from atop the station group’s corporate headquarters here with the express purpose of testing reception on small devices like its MarkONE 3.0-enabled smartphone and, in particular, integration of Digital Radio Mondiale (DRM) in its broadcast app.

The launch comes on the same day Sinclair and German technology research institute Fraunhofer IIS jointly announced they are working together to bring audio services using the DRM standard to ATSC 3.0. (Earlier this year, Sinclair rolled out 3.0 simulcasts of its Seattle radio stations with its DRM-based broadcast app.)

“We are actually building the DRM radio service into the [3.0] broadcast app environment,” says Aitken. “That means those [DRM] services will be carried in band and transported just like HEVC [high efficiency video coding] and [Dolby] AC-4.”[]

Clear Frequencies Requested for Net Providing 24/7 Coverage of St Vincent Volcanic Eruption (RAC Newsletter)

For immediate release:
April 20, 2021 –

The Caribbean Emergency and Weather Net (CEWN) has been providing round-the-clock coverage during the La Soufriere volcanic eruption on the island of Saint Vincent and the Grenadines.

Several neighbouring islands are also being affected by the disaster.

When responding to disasters and emergencies such as this, the CEWN utilizes 3.815 MHz LSB and 7.188 MHz LSB. CEWN is requesting that Radio Amateurs not involved in the volcano response to keep these frequencies clear.

Geomagnetic storm warning (Spaceweather.com via Southgate ARC)

A CME is heading for Earth and it could spark a geomagnetic storm when it arrives on April 25th.

NOAA forecasters say moderately strong G2-class storms are possible, which means auroras could dip into northern-tier US states from Maine to Washington.

Full story and updates @ Spaceweather.com.

 


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Belka-DX: Installing the new speaker and battery pack from Mobimax

Last month, Mobimax announced a new speaker option for the Belka-DX DSP receiver. This speaker is slightly different from the original Belka-DX speaker in that it has a full-size battery pack and fold-out legs to prop up this pocket-sized receiver.

Mobimax sent one of these speakers to me to install and evaluate at no cost to me–I received it last week and installed it yesterday.

Installation

The installation couldn’t have been more simple: the only tool needed is a small Phillips-Head screwdriver. Note that my Belka-DX already had the original speaker option installed.

All I needed to do was remove the lower two screws on both sides of the Belka chassis.

After doing this, the bottom section of the chassis simply pulls out (do this slowly since there are both battery and speaker jumpers).

Next, I unplugged the speaker and battery jumpers from the original speaker option.

Installing the new speaker section was simply a matter of plugging in the speaker and battery jumpers (each plug is a different size so they can’t be confused), then attaching the new pack to the back of the Belka-DX using the same four screws that had been removed.

The whole process might have taken four or five minutes (mainly because I took photos!).

How does it play?

Since I can’t really do a side-by-side comparison with the original speaker and this one, I simply listened to the original speaker tuned to WWV, WRMI, and the Voice of Greece for a while before installing the new speaker.

Both speakers are obviously very small as the Belka-DX is the most compact shortwave portable I’ve ever laid hands on.

Audio quality

I believe the original speaker has better audio fidelity, likely due to the fact it uses the body of the Belka-DX as an enclosure or resonance chamber. The new speaker has a dedicated enclosure, but it’s maybe 40% the size of the Belka-DX body.

In the end, though? Neither speaker will give you the audio fidelity of a traditional portable. The original speaker is just slightly better than the new one. With the Belka-DX, I see the speaker as a wonderful convenience, but frankly, I reach for earphones or headphones if I want to do DXing or proper broadcast listening.

Battery

The new speaker option allows for a full size battery pack in the Belka-DX. This is probably the biggest selling point of the new speaker. The original speaker option fits both the speaker and a smaller LiIon battery pack on the bottom plate of the radio.

The original speaker and smaller battery pack (top section of this photo)

Since the new speaker option adds a dedicated speaker section, it opens up the full real estate of the bottom plate for a full size battery again.

 

I should also add that the new speaker section matches the original Belka-DX enclosure and speaker in that it’s incredibly durable. Frankly, it feels military-grade and over-engineered. I love it.

Fold-out legs

I really like the fold-out legs on the new speaker. They actually have two indented sections that click into place as you fold them out. This allows for two different stable viewing angles. I prefer having them folded out all the way.

Size

The new speaker option adds a bit of weight and bulk to the Belka-DX.

Again: we’re talking about a wee little radio here, so I can’t imagine someone complaining about the size or weight. The new speaker makes the radio slightly deeper or thicker if you look at it from the side or profile. Frankly, it’s a negligible amount, but worth noting.

Should you buy it?

In my opinion, the main reasons to buy the new speaker option are to take advantage of the longer play time from the full size internal battery and to gain the two fold-out feet.  The Belka-DX is so efficient that even the smaller battery pack in the original speaker option will power this radio for many hours without recharge.

Still, if these two factors are important to you, this is a no-brainer.

I would simply pick the speaker option that best suits your needs.

I must say again that it’s a real pleasure evaluating products that are engineered to the degree of the Belka-DX (and Belka-DSP) and both speaker options. These feel like they’re built to last a lifetime and could really take a beating in my various radio packs and kits.

Many thanks again to Mobimax for dispatching one of these for my evaluation.

Click here to check out the new speaker option from Mobimax.

Click here to read about the original speaker option and its installation.

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Fenu’s assessment of the Belka-DX

I recently noticed that Fenu (at Fenu-Radio.ch) has added a review of the Belka-DX on his excellent website.

He agrees that the Belka-DX is a brilliant little portable that delivers a lot of performance and features for the modest price.

As with my Belka-DX, Fenu’s unit includes the built-in speaker option.

In a video he posted on YouTube, Fenu demonstrates reception, speaker quality (including a small issue with button vibration at high volume), and how you can connect IQ out to an SDR application like SDR#:

Click here to check out Fenu’s full review.

More on the Belka-DX and Belka-DSP:

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Dan reviews the Tecsun PL-330 portable shortwave radio

Many thanks to SWLing Post contributor, Dan Robinson, who shares the following guest post:


Tecsun PL-330:  The Powerful Mini With One Serious Design Issue

by Dan Robinson

As SWLing Post readers know, I have a huge radio collection – including premium receivers and portables, now nearly 100 in all.

So, these days I am hesitant to add too many, but I continue to take interest in what companies such as Tecsun and Sangean are doing in the way of stuffing the latest chip technology and capabilities into portables radios.

The last receivers I reviewed included the Tecsun PL-990x, which has developed quite an enthusiastic following since its consumer version was released in 2020, and the Tecsun S-8800.

Out for some time now is the Tecsun PL-330.  By now there are many reviews of it on You Tube and elsewhere.

It’s become a familiar observation for many of us – if this were still the 1960’s and 1970’s – even into the 1980’s, which could be considered the golden days of shortwave and we had receiver technology like this, well what a joy that would have been.

When I traveled around the world both before and after college, and professionally for Voice of America in the 1980s and 1990s, wow what a good time I could have had with today’s portables!

Some world band portables radios back then were superb performers.  The Grundig Satellit series 500/700/600/650 come to mind – but these were not exactly what I would call small portables.

Paging through Passport to Worldband Radio from 1990 (wow, that’s 30 years ago!) you see others such as the SONY SW-1, Panasonic RF-B65, and of course, the SONY ICF-2001D/2010 which introduced killer synchronous tuning technology in the 1980s and remains popular today decades after it first appeared.

Also available were the SONY ICF-SW55 and later in competition with the 2010, the SONY ICF-SW77.  Today, I have four SW-55s and two SW-77s and still use them regularly.

Tabletop receivers back in the good ol’ days offered multiple selectivity positions.  One of those was the Lowe HF-225 (and later Europa version) along with the HF-250, Kenwood R-5000 and R-2000, ICOM IC-R71A, and Yaesu FRG-8800 among many others.

But as far as smaller portables go, features such as synchronous detection and multiple selectivity were still pretty limited, and a number of receivers didn’t offer selectable synchronous as was eventually offered on the Drake R8B and later production of the SW-8.

The RF-B65 by Panasonic – which today remains sought after for its amazing sensitivity – was hobbled by having a single selectivity position.  Same with SONY’s SW-1 and SW-100, and 7600GR, though SONY’s PRO-80 had two bandwidths.

Indeed, it wasn’t until Eton brought out the E-1, with its three bandwidths combined with Passband Tuning (though no notch filter) that a portable finally reflected capabilities of some of the better tabletop radios (though lacking a notch filter).

The Grundig Satellit 800 was close in competition with the E-1 (though the earlier Sat 600/650 series also had multiple bandwidths) but was bulky.

Fast forward to 2021 – credit due to Tecsun and more recently to Sangean with its 909X2, for some years now we have enjoyed Asia-originated portables with multiple selectivity and synchronous mode, though sync implementation on some has left much to be desired.

Which is where the PL-330 comes in.  When I look at the 330, I am reminded of one of the now ancient SONY portables, the ICF-4920 which was a super small slide-rule receiver that nevertheless was quite sensitive.

Like the 4920, which you could easily slip in a pocket, the PL-330 is a perfect travel portable.  Only the Belka-DX SDR and still wonderful SONY SW-100 compete in terms of performance and size.

The 330 is basically a PL-990x in miniature:  smaller speaker obviously, shorter antenna, no bluetooth capability or card slot.  But as many people who frequent the Facebook groups have observed, pretty much anything the 990x can do, so can the 330.

This radio has ETM/ATS tuning, synchronous detection, multiple bandwidths in AM, SSB and MW, FM mono-stereo speaker control, alarm/timer functions, external antenna jack, display light, and other features.

Tecsun decided to go with a BL-5C battery here – the same with the new PL-368.  I think this is unfortunate, since it requires one to obtain a number of those flat batteries if you want to travel and not have to re-charge.  On the other hand, this is not a crippling design decision.

What is an unfortunate design problem, in my view, involves the simple question of tuning the receiver.

The main and fine tuning knobs on the right side of the PL-330 are embedded into the cabinet just far enough as to make easy rapid finger tuning of the radio nearly impossible.

In fact, in my testing it’s impossible to thumb tune the radio more than 10 kHz at a time.  The same applies to using the lower knob which controls volume.  When in FM mode, this issue make tuning just as frustrating almost forcing one to use rapid scan mode.

Another puzzler:  Tecsun limited bandwidths in AM SW to three, while in SSB you have 5 bandwidth options.  In AM mode, you have a 9 kHz bandwidth, another puzzling choice.  Longwave too is limited to 3 bandwidths.

But overall, none of these problems really knock the PL-330 down very far.  This is one mini powerhouse of a radio, one that makes you think “wow, if I had just had this back in 1967 or 1973 or 1982.

Some additional thoughts.  My particular PL-330 was supplied by Anon-co but is a pre-production version and so does not have the latest firmware.  Thankfully, I have not experienced the issue of SSB tuning running in reverse as others have.

NOTE:  As most users know by now, but some newer users may not, you cannot charge one of these radios – whether Tecsun or Sangean – using the mini-USB port and use them at the same time. . . there is just too much noise introduced from the charging process.

This little mentioned feature:  just as the Tecsun 909x has a re-calibration function, so does the PL-330.  Tecsun itself initially declined to acknowledge this, but finally confirmed through Anon-co.

The procedure: Switch to LSB/USB.  If the station is not zero beat, hit STEP button once and then quickly again to move the flashing display down arrow so it’s above the far right digit.  Then fine tune the station for zero beat.  Hold LSB or USB in for a couple of seconds.  The LCD blinks.  You then have zero beat – but be sure to repeat the process for LSB and USB.

I should mention that just like on the 990x, the re-calibration process doesn’t mean the receiver is then zeroed up and down the shortwave bands.  You will likely have to repeat the process from, say 25 meters, to 19 meters, to 49 meters, etc.

I have come to enjoy using the PL-330 here in my house, though like other portables in my collection I need to position it in one particular corner of my home away from incoming cable TV lines.

Belka-DX and Tecsun PL-330

The PL-330 and the Belka DX are currently king of the pile when it comes to my smaller travel portables.

I fully expect there will be no further receiver development by Tecsun after the PL-330/990x/H-510 radios – but that company will certainly have left us with some great receivers as the days of shortwave approach an end.

Video

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A new Belka-DX DSP Speaker from Mobimax

Many thanks to SWLing Post contributor, Markku (VA3MK), who shares a link to this new Belka-DX speaker option from Mobimax:

This speaker option is similar to the one we featured a few months ago, but keeps the larger 2200 mAh battery pack and has fold-out legs. The compromise is the case will be a bit thicker/deeper than the speaker option without the larger battery and fold-out feet.

We’re talking about a pretty small radio, though, so I think this will be another great option for the excellent little Belka-DX.

I will plan to check out one of these in the near future.

Thank you for the tip, Markku!

Click here to check out this product at Mobimax.

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