Many thanks to SWLing Post contributor, Dean Bianco, who has written a review of the FLEX-6400M SDR transceiver from the point of view of an SWL DXer.
Dean’s review has been posted on Dave Zantow’s radio website. Click here to view!
Many thanks to SWLing Post contributor, Jaap de Goede, for the following guest posts:
by Jaap de Goede
Inspired by my father, I like listening to radio transmissions for the last 60 years. That includes listening to shortwave transmissions. In my collection there are a number of radios including computer based SDR-receivers. The TECSUN PL-330 is a shortwave portable radio with SSB and digital readout.
I’d like to share my operating experience of the PL-330 and throughout I will now and then compare this radio to similar radios in my collection: Eton Satellit, XHDATA D-808 and CountyComm GP5-SSB (AKA Tecsun PL-365).
To be clear the PL-330 used here is a Chinese domestic version, probably manufactured in July 2020. An English manual was not available at the time of writing. In the meantime, the English manual of the Tecsun PL-990 helped to figure out a number of the features of the PL-330. Newer manufacturing batches might contain other firmware and that could change the way of operating.
With a volume of about 18 cubic inches the PL-330 is less than 20 cubic inches. It easily fits the pocket of my jeans. 20 cubic inches (unofficially) classifies it as an Ultralight DX radio. The smallest radio of the four is the GP5-SSB with 14 cubic inches. The Satellit is the largest of the four and the size of these radios can be determined by the eye but by the ear as well.
The PL-330 has digital VOLUME control and the volume level is indicated on the display. In contradiction, the three other radios have analog volume control. All radios have a 3.5 mm socket for a stereo headset. A nice feature of the PL-330 is that the FM stereo decoder only works with a plugged-in headset. Else FM remains in mono. I think that’s a very clever feature because why would the stereo decoder degrade the mono-sound through the speaker in case of poor FM stereo reception?
Personal audio quality ranking from best to worst:
The PL-330 is supplied with a BL-5C battery of 1000 mAh. The battery can be charged in the radio through though a micro USB port. The display permanently shows battery status, regardless whether the radio is on or off. USB makes it very easy to charge from any external USB charger or an external USB battery. Here a quick comparison of the powering of the four radios:
| Radio | Battery | Charging Port |
| Tecsun-PL-330 | 1 x BL-5C | Micro USB |
| CountyComm GP5 | 3 x AA NiMH | Mini USB |
| XHDATA D-808 | 1 x 18650 | Micro USB |
| Eton Satellit | 4 x AA NiMH | Bus |
I don’t have runtime figures. I just charge when indicated on the radio’s display and carry a spare USB battery to charge the radio in case.
All four radios have an extensible whip antenna (what else would you expect). Also, all four radios have a 3.5 mm socket for an external antenna. The only radio with an antenna attenuator switch is the Satellit.
All four radios have backlit. But a feature that none of the other radios has is the ability with the PL-330 to toggle the backlit between “always on” or “automatic off”. Just hold and press the 5 button to toggle between the two modes. For comparison, the Satellit has the nicest illuminated display of all four, while the D-808 is way too bright.
The PL-330 supports the following radio bands:
To enable or disable the LW-band you must long press the 2 button when the radio is powered off. When the radio is powered on and LW has been enabled you can select between LW and MW by short press of the MW/LW button.
The American or Rest of World MW-band plan can be toggled by long press the 3 button when powered off. When the radio is powered on you can select between MW by short press of the MW/LW button.
To select the regional FM-band plan you should long press the 0 button when the radio is powered off. When the radio is powered on the FM-band can be selected by short press FM/ST. button.
When the radio is powered on the SW-band can be selected by short press < or > button.
In LW, MW and SW bands de-modulation can be AM, SSB and AM synchronous (SYNC). A short press of the SSB button toggles between AM and SSB. A long press of the SSB button toggles between AM/SSB and AM synchronous mode.
A nice feature within the SW band is that you can quickly skip to pre-determined broadcast or HAM bands. In AM and SSB mode you can skip to the desired band by pressing < or > button. The following bands can be selected and indicated in the display:
There is one (digital) TUNING dial for all tuning operation in any radio band. It only tunes up and down the bands and has no other function. (That makes tuning with the PL-330 so easy compared to the other three radios with multifunction dials.) Depending on the selected band and de-modulation the tuning steps can be altered by the STEP button.
In the LW and MW bands for AM demodulation the step size can be toggled between 1 kHz and 10/9 kHz by short press of the STEP button.
In SW for AM demodulation the step size can be toggled between 1 kHz and 5 kHz by short press of the STEP button.
In the SW band for SSB and synchronous mode the step size can be toggled between 10 Hz, 1 kHz and 5 kHz by short press of the STEP button. My other three portable radios, but only plus or minus 1 kHz of the actual frequency in steps of 10Hz. The PL-330 has continuous fine tuning in SSB; you can tune the entire SW band up and down in steps of 10 Hz. However, I noticed that the step size can change from 10 Hz to 50 Hz in case you turn the TUNING dial fast.
In the FM band the step size can be toggled between 100 kHz and 10 kHz by short press of the STEP button.
For AM and SSB you can change the bandwidth by pressing the AM BW button, turn the VOLUME dial to the desired bandwidth and press the AM BW button again.
I decided to purchase the PL-330 because of my good and bad experience with the GP5-SSB (PL-365). The PL-365 is super portable and I think ETM is great for occasional shortwave listening. However, without direct frequency entry the GP5-SSAB is a nightmare to operate just now and then. Now the PL-330 has an enhanced version of ETM: ETM+. No other radio has such a feature and I think ETM+ is fantastic.
ETM + provides 24 ETM banks that are chosen automatically based on the hour. Every hour you can press and hold the ETM button to initiate a (new or renewed) shortwave scan. It will display “E” plus the hour in 24 hours format like E00 to E23 depending on the time. When you quick press the ETM button it recalls the memory bank according to the time. As an example, when you quick press the ETM button at 15:24h it will recall bank E15. Then you can select the memory locations stored in the bank by turning the TUNING dial.
To toggle between ETM and Tuning mode press the ETM button.
In addition to ETM memories, the PL-330 has a lot of memories but lacks alpha tags. I really have difficulties remembering what I put in those memories. I hardly use them. The only one of the four that has alpha tags is the Eton Satellit, that makes things a lot easier.
Memories can be automatically populated in a bank separate from the ETM banks by using the Automatic Tuning and Storage (ATS) function. All four radios have ATS and I think it’s only convenient for FM. It works like:
To toggle between Memory and Frequency tuning mode simply press the VM/VF button.
With the DISPLAY button you can change the upper right part of the display between:
The display always returns to signal strength after a few seconds. Except if time is chosen with a long press of the DISPLAY button. Nevertheless, the display returns to signal strength after applying any operation, including volume change. I’m not sure if this is a feature or a bug.
When using a headphone and changing volume, sometimes the sound is cut off. By changing the volume again, it comes back. Seems like a bug, not a feature.
I tried AM synchronous mode. It works like on the Satellit: poor. I would recommend to make this mode hidden or make it work well.
When connecting the radio with an USB cable to a PC, its operating system does not show any connection information. If the radio would have USB logic apart from charging, connection information would have showed up. I assume there is no way to update firmware via USB.
Without an English manual, and maybe even with a Chinese manual I couldn’t understand all functions.
When the radio is powered off:
There seems to be a combination to show the firmware version.
RDS display would be welcome. Even though the PL-330 shares the radio chip with the D-808 and the Satellit, the PL-330 does not display FM Radio Data System (RDS) on its display. Backlit buttons would be a welcome for operation in the dark. (Although you’ll quickly get used to the button layout.)
None of the four radios has DAB+ or HD radio. For DAB+ reception I use a Sony XDR-S41D and I can’t receive HD radio in Europe. DAB+ and HD radio could make the radio way more expensive and I prefer good SW performance anyway.
The possibility to upgrade firmware would be convenient. But I understand constraints of costs and the liability of bricking the radio.
The Satellit and D-808 support the Air band (108-135 MHz). That is ok for occasional listening to one single channel, but forget about channel scanning. I have my Bearcat UBC XLT125 VHF/UHF scanner for that purpose.
Like I started, I’m an occasional shortwave listener. I couldn’t really tell the difference in radio performance between the four radios. Of course, the best radio is the one you have with you. And because of its size, easy operation with a single tuning dial and features like ETM+, the PL-330 is probably the best portable shortwave receiver at the moment (for me ?). Thanks to Tecsun!
Jaap de Goede
October 2020
Many thanks, Jaap, for taking the time and care to put together this excellent overview of the Tecsun PL-330! This will serve nicely as an operation manual. Your father would be proud of you! 🙂
Readers: Please note that you can also download Jaap’s PL-330 guide as a printable PDF document by clicking here. The PDF has even better formatting as Jaap has used operation manual styled fonts to indicate button labels and functions.
I’ve gotten a number of inquiries regarding my lab599 TX-500 review. It is featured in the current (October 2020) issue of The Spectrum Monitor magazine:
As you can see from the cover, there are a number of fascinating articles in this issue (click here for a list of all topics in this issue).
You can purchase current individual TSM issues for $3, or buy an entire 2020 subscription for $24 US.
As I’ve said in the past (and despite the fact they publish my features–!) TSM is one of the best values in our radio world. Truly superb articles spanning the full spectrum of radio!
FYI: I understand that Ham Radio Outlet will have the TX-500 in stock within days.
Many thanks to SWLing Post contributor, Christoph Ratzer (OE2CRM), who is well aware that I’m a fan of LRA36, so sent me a tip Saturday (September 26, 2020) at 19:40 UTC that LRA36 was being received in Europe.
I had been working a few POTA stations that afternoon, so simply tuned the IC-756 to 15476 kHz USB–the ‘656 Pro was connected to my large horizontal delta loop antenna. I was rewarded with excellent weak-signal reception from the Argentine Antarctic research station. The signal was surprisingly clear even though the signal was still near noise level.
Here’s a short video (hoping YouTube won’t remove it since there’s music involved–!):
Since the LRA36 signal was in upper sideband mode, the IC-756 Pro was exceptionally well suited to the task! The more I use this transceiver, the more I love it.
Thanks again for the tip, Christoph!
Many thanks to SWLing Post contributor, Linus Ruckstuhl (HB3XSQ), who writes:
I am a longtime reader of your blog. My brothers band (branefive.com just released their first rock song “Free the Animal in You” today on September 25th 2020. I got the idea to launch the song on shortwave in addition to the streaming services to celebrate it, especially because there are no physical discs and records anymore. The first broadcast at 0900 UTC on Channel 292 on 6070kHz already got us many Reception Reports. The song with the corresponding announcement will be rebroadcast by Channel292 this weekend from 25.-27.09.2020. The schedule is in the attachment.
73 from Lucerne, Switzerland
Channel 292:
WRMI Schedule:
Saturday 09/26/2020
7:00 pm ET (2300 UTC) on 7570 kHz to North America
7:30 pm ET (2330 UTC) on 9395 kHz to North America
9:30 pm ET (0130 UTC Sunday) on 9395 kHz to North America
0300 UTC Sunday (11:00 pm ET Saturday) on 5800 kHz to Caribbean, Latin AmericaSunday 09/27/2020
5:00 pm ET (2100 UTC) on 9455 kHz to North America
7:00 pm ET (2300 UTC) on 7570 kHz to North America
7:30 pm ET (2330 UTC) on 9395 kHz to North America
7:45 pm ET (2345 UTC) on 9955 kHz to Caribbean, Latin America (and on Internet www.wrmi.net)
0300 UTC Monday (11:00 pm ET Sunday) on 5800 kHz to Caribbean, Latin America
0430 UTC Monday (10:30 pm Sunday in Costa Rica) on 5985 kHz to Central AmericaWRMI will repeat the same schedule next weekend. Due to the broadcast through Channel292 on 6070, 3955 and 9760 kHz we already received many reception reports from DXers and SWLs all over Europe as well as Malaysia and Australia. Now we hope to receive some more from the Americas and the Caribbean thanks to the broadcasts of WRMI.
Thank you for sharing this broadcast, Linus, and my apologies for missing your first email before the weekend.
Post readers: Check out the schedule and send in your reception reports! As Linus said, they’re especially looking forward to more reports from the Americas and Caribbean!
Many thanks to SWLing Post contributor and Ultralight DX enthusiast, Gary DeBock, for sharing the following guest post:
Nulling a local pest with dual FSL Loopsby Gary DeBock
After many dual FSL antenna experiments I’ve finally determined how to effectively cancel out QRM from a local pest that is off to the side (ideally 90 degrees different, but practical from 50 degrees to 90 degrees different) from a weak DX station, although I’m not quite sure of the theory behind this discovery.
This experiment was an attempt to cancel out QRM from a local pest, 950-KJR in Seattle, WA (35 miles/ 56 km to the north) and chase 950-KKSE in Parker, CO (1005 miles/ 1617 km to the southeast) during the early morning hours. The receiver was a basic (non-SSB) C.Crane Skywave, and two identical 5 inch ferrite rod FSL antennas were used. Please refer to the photo (above) to follow this description.
Step 1) Null out the pest station with the portable radio’s loopstick (away from the FSL antennas). Set the radio down in this nulled position, so that the pest station is as weak as possible, while ensuring that there is space to set up the FSL antennas to the back and side (see photo).
Step 2) Take the “Reception FSL” and use it to peak the pest station’s frequency, setting it up parallel to the portable radio as shown, at the position providing the maximum inductive coupling gain. This will temporarily boost up the pest station, which previously was nulled.
Step 3) Take the “Nulling FSL” and pretune the frequency to that of the pest station. You can do this either by adjusting the variable cap plates to match those of the “Reception FSL,” or by temporarily peaking the pest station’s signal in a position in front of the portable radio. After setting this frequency, set the “Nulling FSL” off to the side of the portable radio as shown, with the spacing identical to the spacing between the radio and the “Reception FSL.”
Step 4) Slowly and carefully tune the “Nulling FSL” until you hear the pest station’s signal take a sharp drop. This setting will be very sharp, but once you find this position you will have nulled out the pest very effectively, and if another station is on the frequency, it may suddenly become dominant, even if it is far away (like 950-KKSE in Denver).
Some MP3’s from this morning’s experiments:
950-KJR in nulled position with the portable only
950-KKSE generally dominant over the local pest KJR when the “Nulling FSL” is peaked
Fascinating, Gary! I don’t understand the dynamics of why this works, but it’s amazing that it does so effectively. I can think of two MW frequencies in particular where I could put a system like this to the test.
Thank you for sharing!
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 Ron, John (K5MO) and the Southgate ARC for the following tips:
Did a broken random number generator in Cuba help expose a Russian espionage network?
I picked up the new book Compromised last week and was intrigued to discover that it may have shed some light on a small (and rather esoteric) cryptologic and espionage mystery that I’ve been puzzling over for about 15 years. Compromised is primarily a memoir of former FBI counterintelligence agent Peter Strzok’s investigation into Russian operations in the lead up to the 2016 presidential election, but this post is not a review of the book or concerned with that aspect of it.Early in the book, as an almost throwaway bit of background color, Strzok discusses his work in Boston investigating the famous Russian “illegals” espionage network from 2000 until their arrest (and subsequent exchange with Russia) in 2010. “Illegals” are foreign agents operating abroad under false identities and without official or diplomatic cover. In this case, ten Russian illegals were living and working in the US under false Canadian and American identities. (The case inspired the recent TV series The Americans.)
Strzok was the case agent responsible for two of the suspects, Andrey Bezrukov and Elena Vavilova (posing as a Canadian couple under the aliases Donald Heathfield and Tracey Lee Ann Foley). The author recounts watching from the street on Thursday evenings as Vavilova received encrypted shortwave “numbers” transmissions in their Cambridge, MA apartment.
Given that Bezrukov and Vaviloa were indeed, as the FBI suspected, Russian spies, it’s not surprising that they were sent messages from headquarters using this method; numbers stations are part of time-honored espionage tradecraft for communicating with covert agents. But their capture may have illustrated how subtle errors can cause these systems to fail badly in practice, even when the cryptography itself is sound.[…]
From today, Thursday, Sept 24, the RSGB are allowing Full amateur radio online exams to be booked. All 3 levels of exam required to get a HAREC certificate can now be done completely online
Potentially this could mean amateurs in other countries could take the RSGB online exams, get their HAREC certificate and then apply for an amateur licence in their own country. This would be beneficial in those countries where provision of local exams is virtually non-existent.
Currently there is a 4-5 week backlog for amateur radio exams, the next available exam slots that can be booked are at the end of October.
You can book online UK amateur radio exams at
http://www.rsgb.org/exampayDetails of onlne amateur radio training courses are at
https://rsgb.org/main/clubs-training/for-students/online-training-resources-for-students/
The wartime BBC was involved in a range of top secret activities, working closely with the intelligence agencies and military.
by Professor David Hendy
As well as making programmes for the public, the wartime BBC was involved in a range of top secret activity, working with closely with the intelligence agencies and military. Here, newly-released archives lift the veil on the broadcaster’s role in this clandestine world of signals, codes, and special operations.
It’s always been known that just before the war began in September 1939, the BBC’s fledgling television service was unceremoniously shut down for the entire period of the conflict.
What’s less well-known is that, far from being mothballed, the television facilities of Alexandra Palace were carefully kept ticking-over by a small team of engineers – and that the transmitter which had supposedly been silenced for reasons of national security was soon sending out its signals again.
From May 1940, Alexandra Palace’s ‘vision’ transmitter was being tested for its ability to jam any messages passing between tanks in an invading German force. The following year, its sound transmitter was being deployed for something called ‘bending the beam’. One of the BBC’s engineers who remained on site was Tony Bridgewater:[…]
Issue 18 September 2020 of the RSGB newcomers publication RadCom Basics is now available online for members
RadCom Basics is a bi-monthly digital publication for RSGB Members that explores key aspects of amateur radio in a straightforward and accessible way.
In this issue:
• Magnetic loop antennas
• Metal bashing
• Station maintenanceRead the latest issue at
https://rsgb.org/main/publications-archives/radcom-basics/
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