Category Archives: Portable Radio

A review of the Tecsun H-501x portable shortwave radio receiver

I was recently searching for my review of the Tecsun H-501x on the SWLing Post to send to a reader when I realized I had not yet published it here! Let’s fix that…

The following review of the Tecsun H-501x was originally published in the November 2021 issue of The Spectrum Monitor magazine. Enjoy:

A review of the Tecsun H-501x

by Thomas (K4SWL)

Last year [2020], we were treated to a group of new shortwave portables from Tecsun: the PL-990, PL-330, and the H-501.

Although all of these models garnered attention from shortwave listeners, one model in particular seemed to draw the most interest, the Tecsun H-501.

No doubt, much had to do with the H-501’s size––a large format portable––and especially the twin stereo speakers, that no doubt sparked the interest of those of us who owned (or wished we owned) the venerable Grundig Satellit 500 or 700 with its reputation for robust audio.

Tecsun was also very clear during their product announcement in 2019 that the H-501x is the flagship portable for the Tecsun line.

H-501 versus H-501x

Note that the product being evaluated in this review is the H-501x; the latest “export” version of the H-501.

The differences between these two models is fairly modest. The “x” model gives the user a slightly lower frequency floor in longwave and shortwave, and finer FM tuning (50 kHz as opposed to 100 kHz) when the AM tuning steps are set to 9 kHz as opposed to 10 kHz.

The differences are so modest between the H-501 and H-501x, I wouldn’t be worried if you already have the H-501. I would simply encourage you to only purchase from a reputable Tecsun distributor so you can be confident you’re not receiving one of the very early production runs of the H-501 that was only distributed domestically within China. Some of these early domestic models didn’t have all the refinements of the latest H-501 versions. I would encourage you to only purchase the H-501 or H-501x from a reputable distributors like Anon-Co, Waters and Stanton, Tecsun Radios Australia, and Bonito.

Unique features

Besides the large dual speakers of the H-501x, there are a number of other unique features and design choices that truly set the H-501 series apart from other Tecsun models.

Firstly, the H-501x uses two 18650 Lithium Ion batteries housed in two separate battery compartments. Both batteries can be internally charged, but here’s the interesting part: each battery seems to be somewhat independent of the other. When you engage battery charging, you must select, via a mechanical switch on the back of the radio, “Battery A” or “Battery B.” Only one battery can be charged at a time, and thus only one will power the radio at a time.

More than once, I’ve been listening to the H-501x and the battery indicator started flashing, signifying a low battery. I simply switched the battery switch to Battery B, and, voliá: I have a full battery again! This reminds me of a college friend’s VW Beetle that had a spare fuel tank…with this unique feature, when you were running low on fuel, you’d kick in the spare fuel tank and then make plans to refuel the main tank soon. Of course, with the H-501x, both these “fuel tanks” are also generous ones, in that the batteries last for a good while.

I find that the play time of each battery impressive given the size and audio amplification used in the H-501x. I had worries that the unit’s need for two batteries could suggest a short battery life, but fortunately this hasn’t been the case, no matter what mode I’ve used (FM, AM, shortwave, or Bluetooth).

However I will note here that the supplied switching power supply will inject noise if you try listening to AM or shortwave while charging. This hasn’t affected FM reception, though.

The fold-out metal bail on the H-501x is very large. This shouldn’t have surprised me, but it did. The H-501x is tall and wide, but not very deep––only marginally deeper than, say, the PL-880. The bail needed to be low-profile, but also support this mini “wall” of the radio while in use. The metal wire bail is handy and certainly does the trick, although there’s only one tilt position, and when it’s deployed, the radio effectively has a large footprint. This might limit where you can set it if the surface––say, a bedside table––is small. Not a problem for me, but worth noting. Continue reading →

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13dka Reviews: The new 2022 “Belka” (generation 3) general coverage receiver

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The new 2022 “Belka” (generation 3) general coverage receiver

by 13dka

Since its introduction in 2019, the super-tiny Belka (back then called “Belka DSP”) shortwave receiver sure gained an enthusiastic followership among SWLs and hams. The main reason for this is certainly the way how the Belka is incredibly small yet playing in a different league than the various consumer grade, Chinese mass-production radios, particularly the DSP-based ultraportables: The Belka is an all-mode shortwave communications receiver with a completely different (direct conversion SDR) architecture, developed and produced by a radio enthusiast (Alex, EU1ME) in a small mom&pop shop in Belarus.

In case you’ve never heard about it amidst all the buzz about more popular brands, here’s the skinny:

The Belka offers true allmode (including NFM and CW) reception with a proper 400 Hz CW filter and individual settings for the low and high filter slopes for AM, FM and SSB. It has an AM sync detector and comes with a 0.5ppm TCXO-controlled local oscillator for absolutely spot-on, calibration-free frequency precision and stability, which makes SSB or ECSS reception of broadcast stations a pure joy. The second iteration “Belka DX” brought a slightly extended coverage down to 1.5 MHz and an I/Q output for panadapter display and/or processing via your favorite SDR software.

All Belkas are quiet and very sensitive radios with a surprisingly robust front end, the filters are better and its AGC works like you’d expect it from a communications receiver, without the artifacts and distortion the DSP radios are infamous for, and of course smooth, non-“muting” tuning in variable steps down to 10Hz.

The Belkas have no built-in speaker (available as option tho) but really excellent audio on headphones and external speakers and they actually give my Icom IC-705 a run for its money in terms of reception quality, and they do that for up to 24 hours on a single charge of the internal Li-Ion battery. This stunning feature set is crowned by the best performance on a telescopic whip antenna ever – the Belkas have a high-impedance (>10 kOhm) antenna input optimized for this whip and taking it on a walk is (really!) like having a big rig with a big antenna in tow…

Despite all this goodness setting the Belka(s) quite fundamentally apart from most (if not all) current and former, even much higher priced portables and simultaneously putting it solidly into pricey tabletop territory, it hasn’t put Tecsun et al out of business for a couple of reasons: One reason is that it can only be obtained from Alex in Belarus, which is now often assumed to be impossible (it isn’t, more on that later). Another reason is that it doesn’t try to compete with aforementioned multiband radios from China, so there is no FM broadcast band and – until now – no AM BC band, but most owners and potential buyers particularly in the US really wished it had at least the latter. Well, Alex obviously heard us! After the Belka DSP and the Belka DX, the new Belka is just called “Belka”, so in order to avoid any ambiguity I’m going to refer to this model as “Belka 2022”.

What’s new?

The most prominent addition to the Belka 2022 is the extended 0.1-31 MHz coverage, the previous version only started receiving at 1.5 MHz. With LW and MW included, its “pseudosynchronous” detector (as featured in venerable radios from Harris, Racal or Drake), the great filtering and the great frequency precision for hassle-free ECSS reception are promising that the “squirrel” is now an ultra-ultraportable companion for MW DXers as well.

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Belka DX updated to now cover mediumwave and longwave

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Many thanks to SWLing Post contributor, Dave Garr, who writes:

I have some interesting news for all of those Belka DX fans, Alex the guy behind this magnificent receiver has just announced the introduction of a new model. Ok so it is still called the Belka DX but it has now got a total frequency coverage of 100KHz to 31MHz so those that have put off buying because of lack of Long wave and Medium wave have now had their prayers answered. There has been no fanfare announcement about this but they have just updated their website with the new added frequency range. I am just waiting for the first review to appear before committing my hard earned cash.
Regards
Dave Gurr

Click here to check it out.

Excellent news. I’m sure this will make the Belka DX even more popular than it already is. I have to assume a ferrite bar hasn’t been added (there isn’t much room for one in the Belka series) so you would need to pair a proper MW/LM antenna antenna in order to fully take advantage of the new bands.

Thank you for the tip, Dave!

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Solid copy: Tom receives JG2XA in the Netherlands on his PL-365

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CountyComm GP5/SSB, aka Tecsun PL-to 365

Many thanks to SWLing Post contributor, Tom Kamp (PA/DF5JL), who shares the following brief report and video:

Today (September 21, 2022) around 2015 UT strong signal on 5006 kHz (CF) from JG2XA beacon from Japan (0.2 kW) near Den Helder, in North-Holland, The Netherlands.

JG2XA transmits continuously at 200 W on 5006 kHz and 8006 kHz. The type of radio signal is H2A (amplitude modulation with coded tones in the single sideband).

Received with the Tecsun PL-368 and the built-in telescopic antenna! The dBm display of the unit is very inaccurate (in USB), yet S5-S7 should be rated appropriately. Top signal, top RX ?

73 Tom Kamp PA/DF5JL

That’s quite a catch for the PL-365. Thanks for sharing this, Tom!

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Treetop Antennas: Featured with my friend Wlodek (US7IGN) on BBC Radio 4 Short Cuts

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I’m very honored to be featured with my good friend Wlodek (US7IGN) in a short radio documentary on BBC Radio 4 today.

Wlodek is long-time reader and subscriber here on the SWLing Post and QRPer.com. Wlodek lives in Kiev, Ukraine and we keep in touch these days over email. Like me, he is passionate about field radio work and before the Russian invasion, you’d often find him in nearby forests experimenting with some pretty impressive field antennas.

Sadly, when Russia invaded Ukraine earlier this year, it very quickly brought an end to all of that for Wlod. Not only were amateur radio operators not allowed to transmit under the state of emergency, but it’s no longer safe to venture into nearby forests.

Radio producer, Cicely Fell, learned about our love of all things field radio and put together an audio piece that airs today on BBC Radio 4:

BBC Radio 4 Short Cuts

From the forests of North Carolina, USA to the city of Kyiv, Ukraine – two ham radio enthusiasts seek each other out and a voice from the past prompts a dialogue on listening between a rabbi and a radio producer.

Click here to listen via the BBC Radio 4 website (note that the audio can be streamed shortly after the program airs today).

Many thanks to Cicely and her talented team at Falling Tree Productions for spending a little time with us in the forest and on the air! Truly an honor.

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Small Unidirectional Loop Antenna (SULA) Part 2: Construction Notes

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Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us Part Two of a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. This second article focuses on construction notes. The third and final article will essentially be a Q&A about the SULA antenna. All articles will eventually link to each other once published.

This wideband unidirectional antenna is an outstanding and innovative development for the portable DXer. I love the fact that it came to fruition via a collaboration between Grayhat and 13dka: two amazing gents and radio ambassadors on our SWLing.net discussion board and here on the SWLing Post. So many thanks to both of them!

Please enjoy and share Part 2:

Part 2: SULA Construction notes

by 13dka

The drawing [above] has all you need to know. You basically need to put up a symmetrical wire diamond starting with a balun at the one end and terminating in a resistor at the other end of the horizontal boom, the sides are supposed to be 76cm/29.92″ long so you need to make yourself some…

Support structure:

I used 0.63″/1.6cm square plastic square tubing/cable duct profiles from the home improvement market to make the support structure. You can use anything non-conductive for that of course, broom sticks, lathes… The plastic profiles I used had the advantage of being in the house and easy to work on with a Dremel-style tool and everything can be assembled using the same self-tapping screws without even drilling. The profiles are held together with 2 screws, for transport I unscrew one of them and put that into an extra “parking” screw hole on the side, then I can collapse the cross for easy fit into the trunk, a rucksack etc.

These profiles are available in different diameters that fit into each other like a telescoping whip. This is useful to make the support structure variable for experiments and to control the loop shape and tension on the wire. The booms end up at 1.075m each, the profiles come in 1m length, so that’s 4 short pieces of the smaller size tube to extend the main booms by 37mm on each side

On the resistor end of the loop that smaller tube isn’t mounted in the “boom” tube but to the side of it in order to keep the wire running straight from the balun box on the other side.

Mast/mounting:

You can use anything non-conductive to bring it up to height. On second thought that is indeed bad news if you were planning on putting that up on your metal mast…and we have no data on what happens when you do it anyway. I don’t know if the smallest (4m) telescoping fiberglass poles would suffice for portable operation, but I’m a fan of just using the big lower segments of my 10m “HD” mast for the stiffness they give me (3 segments for the height, the 4th collapsed into in the base segment for easy rotation). Telescoping masts also give you easy control over…

Height:

The published patterns are for 3m/10′ feedpoint height over “average” ground. Increasing height further has no expectable advantage, instead it will deteriorate the favorable directional pattern of the loop. Flying it lower, or even a lot lower in windy weather on the other hand is causing a surprisingly moderate hit on performance.

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Introducing the amazing SULA: An affordable unidirectional DX-grade loop antenna that you can build!

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Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. The second article will focus on construction notes. The third and final article will essentially be a Q&A about the SULA antenna. All articles will eventually link to each other once published.

This wideband unidirectional antenna is an outstanding and innovative development for the portable DXer. I love the fact that it came to fruition via a collaboration between Grayhat and 13dka: two amazing gents and radio ambassadors on our SWLing.net discussion board and here on the SWLing Post. So many thanks to both of them!

Please enjoy and share SULA Part 1:

Introducing the Small Unidirectional Loop Antenna (SULA) 1-30MHz

A small and simple, unidirectional and DX-capable loop “beam” for SWLs!

by 13dka

In early June, Andrew (grayhat), SWLing Post‘s resident antenna wizard suggested a variation of the “cardioid loop” on the SWLing Post message board: The original “cardioid loop” is a small loop receiving antenna deriving its name from a cardioid shaped (unidirectional) radiation footprint. The design is strikingly simple but it has a few downsides: It relies on a custom preamp, it needs a ground rod to work and it is unidirectional only up to 8 MHz.

Andrew’s version had the components all shuffled around and it did not only lose the ground rod, it also promised a nice cardioid pattern over the entire shortwave, from a small, diamond shaped loop. Wait…what? It can be made using parts available on Amazon and your DIY store:

You need some 3m wire and PVC tubes to create a support structure to hold the wire, a 530 Ohm resistor and a 9:1 balun like the popular “NooElec One Nine”. Since it’s a “lossy” design, adding a generic LNA like the NooElec “LANA HF” would help getting most out of it. When you put that all together you have what sounds like an old shortwave listener’s dream: a small, portable, tangible, and completely practical allband shortwave reception beam antenna with some more convenient properties on top, for example, it is a bit afraid of heights.

That sounded both interesting and plain crazy, but the .nec files Andrew posted were clearly saying that this antenna is a thing now. Unfortunately Andrew suffered a little injury that kept him from making one of those right away, I on the other hand had almost all the needed parts in a drawer so I ended up making a prototype and putting it through some of its paces, with Andrew changing the design and me changing the actual antenna accordingly, then mounting it upside down. Let me show you around:

Small, diamond shaped wire loop (with 76cm/29.92″ sides), needing as little space as most other small loops.
Unidirectional with a ~160° wide “beam” and one pronounced minimum with a front/back-ratio of typically 20dB over the entire reception range 1-30MHz.
Moderate height requirements: It works best up to 3m/10′ above ground, where it gives you…
…a main lobe with a convenient flat takeoff angle for DX
Antenna is comparatively insensitive to ground quality/conductivity.
Wideband design, works best on shortwave and is pretty good up to 70cm.

A functional small beam antenna for shortwave reception that’s just as small and possibly even more lightweight (prototype:~250g/9oz) than your regular SML, that can be easily made out of easy to obtain parts and easily carried around for mobile/portable DXing and due to its cardioid shaped directional pattern also for direction finding, a “tactical” antenna that’s also doing DX? Unlike conventional, Yagi-Uda or wire beams it can achieve a low takeoff angle at only 3m/10ft height or less, the front/back ratio is typically better than that of a 3-element Yagi, with a particularly useful horizontal pattern shape. That it’s rather indifferent to soil quality could mean that more people get to reproduce the good results and being a real wideband antenna is making the SULA an interesting companion for multiband radios and SDRs. Really? A miracle antenna? Is it that time of year again? If I had a dollar for every….

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