Category Archives: Portable Radio

Tecsun PL-990x vs. PL-880: Comparing SSB audio characteristics and pre-production/production PL-990 models

A number of SWLing Post readers have been asking about SSB audio characteristics on the new Tecsun PL-990.

Earlier this week, I took a moment while visiting family to make a few quick comparison videos with the PL-880 outdoors and away from RFI.

As I mention in the videos, there are a lot of cicadas singing in the background and you can also hear a bit of road noise–not ideal for audio, but I had to take advantage of a break in the weather!

You should also note that this isn’t a sensitivity comparison. The radios were pretty close together–if measuring sensitivity, I would have spaced them much further apart. Rather, I hope these videos give you an idea of the audio characteristics in SSB (both CW narrow and voice) and one comparison in AM. If you’re curious about sensitivity and how the PL-990x compares, check out Dan Robinsons initial evaluation.

CW Audio: .5 kHz filter on the 80 meter band

CW Audio: .5 kHz filter on the 30 meter band

SSB audio: 75 meter band

AM Audio: 5 kHz filter WWV 10 MHz

My thoughts

While these videos are far from ideal, they should give you a real-word impression of audio characteristics.

Personally, I think the PL-990x is a much better performer in single sideband. The noise floor is lower, but I think that may have more to do with better filter implementation. I’ve always felt that the PL-880 audio sounds “wider” than the selected filter in the more narrow SSB selections.

In addition, the PL-990x exhibits better SSB stability that’s especially noticeable in CW. The PL-880, at times, almost sounds garbled in comparison.

I also mentioned in the last video that the audio sounds better on the PL-880. I should have qualified that statement a bit better.

In general, yes, the PL-880 audio sounds better because its built-in speaker has slightly better audio fidelity that’s most noticeable when listening to music on the FM band, or a strong local AM station. On shortwave, I feel like I actually prefer the PL-990 audio for all but the strongest stations although I do wish the PL-990 filter could be widened to 9 kHz like the PL-880.

PL-990x (pre-production) vs. PL-990 (production model)

Tecsun Radios Australia reached out and kindly sent me one of their PL-990 production model radios to compare with the PL-990x pre-production model from Anon-Co we’ve been testing up to this point. This has been incredibly helpful as I put together my PL-990 review for the 2021 World Radio TV Handbook.

As I’ve mentioned in previous posts, I feel it can be problematic using a pre-production model radio for review only because there can be differences in quality control when a small number of pre-production units are manufactured compared with a proper first production run (remember this case?).

I’ve only had the production model PL-990 for a few days and most of that time we’ve been dealing with the remnants of hurricane Sally moving through our area dumping torrential rains.

Last night, however, a massive tree fell across our road knocking out power for the better part of 5 hours. This gave me a perfect excuse to start my comparison indoors while rain continued outside.

Based on my comparisons last night, it appears performance is nearly identical between the production and pre-production models. I’ve still more testing to do, but my initial impressions are most positive. Very happy quality appears to be consistent.

Many thanks again to Tecsun Radios Australia for making this comparison possible.

Spread the radio love

Mark spots another radio in “Death In Paradise”

Many thanks to SWLing Post contributor, Mark Hirst, who writes:

Another radio turned up in the BBC series, ‘Death in Paradise’.

Set on a picturesque Caribbean island with an infeasibly high murder rate, we see the police interviewing a witness as he listens to the local radio station.

Can SWLing Post readers identify the radio I wonder?

Please comment if you can ID this radio! Not an easy task this time as there’s no close-up shot to pull details from the front panel. Good luck!

Spread the radio love

Tecsun PL-990x Initial Assessment

SWLing Post contributor, Dan Robinson, and I have been evaluating a pre-production model of the Tecsun PL-990x portable shortwave radio–the same model which will be soon sold by Anon-Co.

Dan has just completed his initial assessment and included a long-format video. Many thanks to Dan for sharing the following:


Tecsun PL-990x:  An Initial Assessment

by Dan Robinson

Recently, Thomas Witherspoon posted the first photos of the Tecsun PL-990x – we both received units from Anon-co in Hong Kong for testing.

I was able to spend some time outside my house here in Maryland, running the 990x and comparing it to the older receiver by Tecsun, the PL-880.

Tecsun undertook a thorough re-design of the PL-880, which among other things was known for its superb sound through a large speaker.

The 880 was available both on its own, or in a hard-case kit that also included (or includes assuming these are still purchasable) a separate Tecsun-branded solid state recording device, spare knobs and other accessories including Li-ion batteries.

So, the long-awaited PL-990, which we have been seeing in YouTube videos being tested by various individuals who purchased pre-production versions from Asian sites such as AliExpress, is finally here – or will be in coming weeks and months.

Those who view my videos know that I like to do fairly long hands-on tests of receivers, and this is no exception, at about 50 minutes.  My test did not include medium wave or FM, focusing only on shortwave performance and using only the telescopic whip antenna.

Throughout the video, I do put the 990x up against the older PL-880, which had the well-known issue of poorly-implemented synchronous detection (SYNC was not an official feature in the older receiver).

IMPORTANT NOTE:   On the 990x, hitting the “4” key while the radio is powered on activates DNR (Dynamic Noise Reduction) which then activates auto-bandwidth switching, a feature I found quite annoying in the PL-880 and would no doubt find just as annoying in the 990x.  I can’t imagine why anyone would want bandwidths auto-switching on their own.

I always tell people who come to me for advice about radios that you don’t always have to have the latest receiver to enjoy what’s left of shortwave.

I am a big fan of classic older portables such as the SONY ICF SW55s, 7600GRs, SW100s, SW-07s, SW-1000Ts, SW-77s, etc along with other classics such as the Panasonic RF-B65.  I own one or more of most of these – they’re a joy to use assuming they are in good condition.

One more thing – I did not compare the 990x to the Tecsun S-8800.  I think they are really different radios – the 8800 has that gorgeous remote control and fantastic audio . . . I really don’t put it in the same category as the 880/990s or even the 600 series Tecsuns.

I will leave extensive tests of the 990x on medium wave and FM to others – there are already quite a few YouTube demonstrations online showing this.  In the tuning I did on MW and FM, the radio did seem quite sensitive.  I noted that whereas the 9 kHz bandwidth is not visible on shortwave, it is on MW.

Here is my list of high points and low points for the 990x.  Since this receiver, and the still-to-be-released H-501, may in fact be the last we will ever see from Tecsun, it’s up to the individual to make a judgment as to whether to buy.

PL-990x High Points

  • A thorough physical re-design of the old PL-880
  • Tecsun has mostly fixed the problem with synchronous mode which is now a regular as opposed to a hidden feature.
  • Selectivity options are still excellent.
  • Calibration function retained (but see below)
  • Audio is fairly full and powerful.
  • Sensitivity seems good
  • Tecsun has added mp3 play capability and a microSD slot
  • Tecsun has added bluetooth capability (NOTE:  This is activated by pressing the RADIO/MP3 key in powered off state, and then toggling Bluetooth on or off with the PLAY/PAUSE button).
  • Tuning and other knobs remain of high quality as on the PL-880
  • Bandwidths given their own separate buttons
  • Line out retained and hidden feature can adjust line out level
  • Claimed “Triple Conversion” in AM mode
  • Timer functions
  • ATS (automatic station tuning) retained
  • Nice faux-leather case retained

PL-990x negatives:

  • Re-design appears to have come at expense of speaker real estate.
  • Synchronous mode improved, but there still seems to be some distortion which is more noticeable on some frequencies and in some reception situations than others.
  • PL-880’s wide AM bandwidth of 9 kHz is no more at least on SW, but it does appear when using MW.
  • Sensitivity seems good BUT in some situations, PL-880 sounded better and seemed to bring in stations better
  • MicroSD capability does not provide recording from broadcasts (likely due to copyright issues)
  • Method for re-calibrating radio is puzzling – more information needed on this
  • Birdies are present
  • Top element of telescopic antenna is VERY thin, vulnerable to bending and breaking
  • Number keys seem to be not as good as they could be – the white paint on the keys is certain to fade over time.  On my test unit part of the “W” on the MW/LW key was already beginning to disappear.

Selectivity comparison of the PL-990x and PL-880

PL-990x

Selectivity Options on SW:

2.3, 3.5, 5.0, 6.0

Selectivity Options LSB/USB:

0.5, 1.2, 2.3, 3.0, 4.0

Selectivity Options LW/MW:

2.3, 3.5, 5.0, 9.0

PL-880

Selectivity Options SW/LW/MW:

2.3, 3.5, 5, 9

Selectivity Options LW/MW:

0.5, 1.2, 2.3, 3.0, 4.0

Video


Many thanks, Dan, for sharing your initial review with us. As always, your expertise as an experienced DXer is incredibly valuable. 

I’ve tested every function on the PL-990 save some of the hidden features (yes, there will be hidden features). Dan and I are both trying to sort out the calibration sequence so that when these units hit the market, there’ll be a documented procedure in place. 

We’ve been comparing notes along the way and are in agreement on all of the major points with this radio. Still more testing to do, but updated with be posted here with the tag: Tecsun PL-990x


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

Andy builds a genius companion control display for the Yaesu FT-817 transceiver

Many thanks to SWLing Post contributor, Andy Webster (G7UHN), who kindly shares the following guest post:


Yaesu FT-817 companion display

by Andy Webster (G7UHN)

 

Like so many I love getting out portable with my FT-817 but I do seem to spend so much of my operating time fiddling through the soft-keys because my most used functions (CW narrow filter, power and keyer settings to tune an ATU, A/B, A=B, etc.) are spread across different “pages” of the A,B,C assignments. Compared to the sublime experience of using my Elecraft K2 the FT-817 can be a little frustrating!

Last month, inspiration struck and I thought I could cobble together a small microcontroller and a little OLED display with some buttons to provide some extra soft-keys for the radio using the CAT serial port. Nothing particularly original here (I’ve seen articles of people using PICs for this purpose) but it seemed like a nice sized project for me to play with and build some experience doing PCBs (I’ve only done this once before at home). A little bit of discussion with Michael G0POT (FT-817 and SOTA guru), some Google searching and we were looking over KA7OEI’s excellent reference page (http://www.ka7oei.com/ft817_meow.html) and thinking about our favourite FT-817 commands…

 

As it happened I was lucky to have the right bits (Arduino Nano, small OLED display, buttons, prototype board and an 8-pin mini DIN cable) lying around the house to see “first light” from my FT-817’s serial port that evening. The Arduino Nano is a good place to start because it works at 5V so can work directly with the FT-817 levels on the ACC port. What followed next was some late nights of hacking on Arduino code to send and receive the data for my favourite commands and more experimentation on prototype board.

I tried a couple of cheap OLED displays and they look great indoors but weren’t quite up to the job in full sunlight which is fairly typical in my portable operations.

Daytime readability issues with an OLED display

By this point I had also realised the utility of having an auxiliary display on top of the radio as a much easier thing to view than the 817’s own display on the front panel. I’d also experienced some interference from the unshielded prototype board coming through as clicking sounds on the radio’s receiver so it looked as though some isolation between radio and my circuit might be necessary. Guided by many Internet tutorials, I switched to using a Nokia 5110-style LCD for better daylight readability and lower power consumption. Adding an ADUM1201 digital isolator and a B0505S-1W isolated DC-DC converter to the prototype board (modules acquired very quickly from eBay suppliers) gave me some isolation and lowered the interference which I guessed would disappear when I made the design on PCB with good ground planes around the signal lines.

Screen capture showing the schematic (click to enlarge)

With a (mostly) working prototype it was time to hammer the Internet tutorials again, this time to learn how to use KiCad, a free open-source PCB design tool available on Linux, Windows and Mac. I’ve done one PCB for home projects before using Autodesk EAGLE and I found learning Eagle pretty hard going, it seems like it carries 20 years worth of baggage and dogma in the user interface. In fact I started using EAGLE on this project but spent 3 hours on the first evening just trying to change the labels on the ADUM1201 chip that I couldn’t find in an EAGLE library… so I gave up and thought I’d try KiCad which I’d seen some recent good reports on. I’m happy to say after finding an excellent tutorial on KiCad I had drawn the schematic and my PCB layout in about 15 hours working time spread over a few evenings.

I should add that the 15 hours of KiCad time did include several hours of agonising over the choice of slide switch so a PCB can be done much quicker than that once you’ve got your favourite parts sorted!

That’s pretty impressive for my first go with KiCad as a near-beginner to PCBs, I heartily recommend it, it was so much easier than EAGLE and quite an enjoyable tool. Right, PCB design done and uploaded to JLCPCB for manufacture. 5 PCBs with DHL shipping cost me less than £20 and arrived from China within 5 calendar days. Other PCB fabs are available… 🙂

Click to enlarge

So that brings us to today, pretty much. The PCB was assembled very quickly (!) and there is no sign of noise from the serial data lines creeping into the 817’s receiver now it’s on PCB. Some lessons have been learned through the construction (e.g. brown 6mm push buttons are less “clicky” than the black ones and that’s a good thing!) and I now have my companion FT-817 display/buttons in field trials. I’ve no plans to sell this, it’s a trivially simple design, but it does make a great home project to polish your skills in microcontrollers, PCBs and construction. I’ll post a write-up on my website in due course.

In use, the device works just as I’d hoped, I can do everything I want to on my FT-817 without having to fiddle through the awkward button presses. The frequency display is also in a much better position for me now (as most FT-817 owners will know as they jealously eye the KX2, KX3, etc…!) and I think I used it for the whole session when I took it to the field on Saturday. If only my CW had been so slick!

Next steps are to work on the Arduino code. My code is pretty rubbish (my coding style involves a lot of Stack Overflow and copy/paste!) and not safe for public consumption. There are also some health warnings to be noted in manipulating the FT-817’s EEPROM (required for some of the functions I wanted), explained on KA7OEI’s page but there have been a few volunteers on Twitter to help with the software which is great. Also I may do a “Rev 2” board with an Arduino Pro Mini to lower the drain on the FT-817 battery before sharing the PCB files. Other than that it’s now time to get back outdoors and enjoy the new improved interface to my smallest radio! 😀

73
Andy G7UHN


Andy, I absolutely love this project! A wonderful addition to the FT-817/818 and I’d hardly call it a “trivial” design–!

I purchased the original FT-817 shortly after it was introduced. At the time, I was living in the UK and travelled extensively throughout Europe. I loved the ability to simply throw this little rig into my carryon and play radio pretty much anywhere my work travels took me. In the end, I did less ham radio work with the FT-817 and more SWLing.

Still, I eventually sold my FT-817 for the very same reason that motivated you to build a companion display: the front panel is too small and my most used functions require too much menu digging. 

Your companion board is an elegant homebrew solution. I love the Nokia LCD screen–superb readability in the field. 

Thank you again and once you do a write-up on for your website, we’ll be sure to link to it on the SWLing Post!


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

Any advice on compact Lipo batteries, in-ear earphones with volume control, and portable amplified speakers?

The MTR-3B 3 band transceiver is about the size of a pack of playing cards.

SWLing Post readers: I originally published the following post on QRPer.com. I thought I might share it here on the SWLing Post as well since we’ve so many readers who regularly use compact battery packs, earphones, and portable speakers. I’m looking for some advice as I build a super-compact SOTA/POTA field kit around the Mountain Topper MTR-3B. If interested in helping me sort this out, read on:


I received my Mountain Topper MTR-3B last week, and I’ve already taken it on a POTA activation.

POTA Park Hampton Creek Cove

Last weekend, I decided to break it in on a POTA “two-fer” site: Hampton Creek Cove State Natural Area (K-6246) and The Overmountain Victory Trail (K-4577) in Tennessee. Hampton Creek Cove was actually an ATNO (all time new one) so it was a trial by fire!

POTA Park Overmountain Victory Trail

In short, the MTR-3B was marvelous. I’m so impressed.

As I mentioned in a previous post, I’m building a full SOTA/POTA activation kit for the MTR-3B. I already have a kit built around my KX2 and I don’t want to “borrow” any items from it (so I’m not surprised later in the field when an item is missing).

The TalentCell Rechargeable 12V 3000mAh Lithium Ion Battery Pack is the little black box.

For this activation, I powered the MTR-3B with this inexpensive 12V battery pack a friend recommended on Amazon.com (affiliate link). The battery pack is almost identical in size to the MTR-3B and works perfectly. The battery, charger and cable all set me back a whopping $25.

I also used my Whiterook paddle (which needs new paddle arms at this point) but that will soon be replaced with a set of N0SA portable paddles I recently ordered.

Since the MTR-3B has no volume control, I used a pair of 20 year old Sennheiser earphones I bought when I lived in Munich. These have been in a drawer for ages because I now prefer using in-ear earphones with silicon earpieces for better comfort and sound isolation. But the Sennheisers have one thing none of my other earphones sport: in-line volume control.

While the earphones worked well for this activation, I’d still prefer a set of in-ear earphones with in-line volume control. Any suggestions from MTR-3B owners? Also, I’d like a compact amplified speaker with volume control to carry as an option when needed. If you can recommend one, please comment!

I’m writing an article for The Spectrum Monitor magazine about portable power later this year. I noticed that a number of MTR-3B owners swear by 11V rechargeable Lipo cells that are used in the RC and drone markets. Many have a similar compact form-factor as the common 9V battery. I understand, however, some of these cells need special chargers and equipment to balance them.

I would appreciate any and all information about these batteries.

In the meantime, Rich (N8TGQ), recently shared a pic of his Mountain Topper portable pack. Check it out:

MTR Kit

I think it’s brilliant how he’s mounted everything on a compact plastic cutting board inside the case. Rich says that what he loves about this set-up is that everything is there, ready to go–simply plug in the antenna!

Please comment or contact me if you have any suggestions as I build out a compact MTR-3B kit!

Spread the radio love

Photos of the lab599 Discovery TX-500 in the field

Many thanks to SWLing Post contributor, Don (W7SSB), who shares the following photos of the new lab599 Discovery TX-500. Don notes that all of these photos were taken in Russia–where the TX-500 is manufactured–and include a number of Chameleon resonant field antennas.

Thanks for sharing these, Don.  The thin form-factor of the TX-500, paired with a resonant antenna, certainly makes for a lightweight portable field setup!

Spread the radio love

Adding CW mode to the EA3GCY DB4020 Dual-band 40 and 20M QRP Transceiver Kit (Part 2)

Many thanks to SWLing Post contributor, Frank (ON6UU), who shares the following guest post which expands upon his previous DB4020 article:


The EA3GCY DB4020 transceiver now has CW mode

by Frank Lagaet (ON6UU)

After telling you all about the DB4020 SSB build I’m here with the CW part of the kit,  let’s say this is part 2.  At a certain moment Javier let me know the CW interface kit was ready for shipment and some week later it was delivered to my QTH.

Again, a well packed kit arrived in a brown envelope, components and boards well packed in bubblewrap.  I found even a board I did not expect which can hold a push button,  a switch and the connector for your morse key.  Javier thinks of everything it seems!

Unpacking the bubblewrap gave me this result,  all components in 2 bags.  In the bigger bag another 2 bags with 2 printboards,  one for the CW interface,  one for the CW filter.  Great !!  Checking the material bill resulted in all components there,  another thumbs up.

I started, of course, immediately building it because I wanted CW in the transceiver as soon as possible.  I don’t do much in SSB mode anymore and I already started missing CW on the DB4020,  so I started my KX3 to listen to while I was populating the boards.  I never thought CW was going to have this impact on me! …. ..

I started building the CW interface,  again starting with all small items.  I soon saw that the 2 relays which need to be soldered in were ideal to protect all components when the board is upside down, so I soldered them in very quickly.  I then soldered in all other components ending with the elco’s.

Next phase was the CW filter.  This board is small and came together in a blink of an eye, no problems there, the long legs of the 3 and 4 pin headers went in last.

The following day, I made all wire connections and soldered a 13pin connector,  leaving one pin out since I want to have the option to choose the width of the CW signal I’m listening to.  By cutting the FL CW + pin and adding an additional switch, I have now 500Hz or 2400Hz.  Great option, for very little effort and simple.  Another thumbs up here.

Now it was simply a matter of inserting the sub boards in the main board and all should be working.  And it did!  Hurray!  The 500Hz filter works perfectly,  filtering away all above or below stations nearby my operating frequency.

This is the result of the soldering work,  2 small boards which need to be inserted in the main board:

The CW interface still needs the 13pin header of which I cut one pin and mounted a switch to have the 2400Hz width.

The IC you see in the middle of the CW interface is the KB2 keyer which gives you several functions like 4 memories and beacon mode.  The 4 potmeters are used to set the level on 40 and 20 meters,  to set the delay between TX and RX switchover and to set side tone monitor level.   The keyer also provides functions as keyer mode A or B,  straight key function and can be set for speeds between 1 and 50WPM.   WPM speed can be set in 2 different ways.  Handy!

Here a picture of the CW filter inserted on the main DB4020 board.

The CW interface is inserted at the side of the main board,  notice the 2 wires which go to the switch to allow switch-over between 500 and 2400Hz.

(Wiring still needs to be cleaned up in this picture.)

Finally, the result:  a good working multimode QRP transceiver with 2 bands.  It should be possible to make close to medium range with it as well as DX,  even with QRP power.

And while I was building I also made a new key for this radio,  it is made out of a relay and cost nearly nothing,  looks good doesn’t it ?  hihi.

Homebrew key

The key, when in practiced hands (fingers hi), can do 50 WPM without a problem. My friend HA3HK does without blinking an eye at 40WPM with this kind of key and tells me that he can go faster if needed.  Me? I’m going it a bit slower.

Battery pack

As this radio is only using little power (0.4A in RX,  1 to 2A in TX depending the power you set it) I thought,  let’s make a battery pack for the radio.

The first plan was installing it in the box.  I did not do that because the batterypack is also powerful enough to feed my KX2 and other QRP transceivers. Since I can use it with all of them, a loose battery works out better for me.

I started with an old laptop which had a broken screen and some other malfunctions,  but still had a good battery,  although I needed the battery connector of course.  A piece of wood to mount the connector on was my next goal.  And since I still have another laptop using the same batteries, I can charge the battery without problems.  Simple, but good and it weighs much less than a gel cell battery.

The battery provides me with 12.5V and some 5Ah.  Enough to last for hours on RX and for sure good enough to activate 2 SOTA sites in one day.   It doesn’t look great but works great– that is what matters and to test it was more then good.  Next will be getting the battery pack in a nice box.  Better to re-use stuff than throwing it away I’m thinking.

I need to do something about the cover of the OLED display,  there is still some work there to make it look nicer.

Some video can be seen on YouTube :

Finallym I’d like to thank you all for reading my articles about the DB4020. I had big fun soldering, tinkering with the box, making the key, and batteryholder/batterypack.  My Hungarian friend HA3HK told me it looks a bit like a spy radio. …. ..

I also include one more time the link where you’ll find this kit :

https://www.qrphamradiokits.com/

73 TU ee

Frank

ON6UU


Thank you so much, Frank. No doubt, you had a lot of fun putting this excellent little kit together.

Implementing a filter switch was a fantastic idea and, obviously, not terribly difficult to do.

Based on the videos, the DB4020 has a low noise floor and very good receiver characteristics. I’m impressed that the CW portion of the radios has so many features as well, such as a memory keyer and beacon mode.

I also love how you reused that 5Ah laptop battery! I think that could almost give you a full day of SOTA activations at those consumption levels!

Thanks again for sharing this with us, Frank! We look forward to your future articles!

Spread the radio love