Category Archives: New Products

Reader Survey: Comparing the Tecsun PL-680 and PL-660 synchronous detection

PL-680-Sync-Detector

[Update: Please note that this survey has been closed, but the audio samples–labeled Radio A and Radio B–will remain to allow others the opportunity to make an evaluation prior to reading the PL-680 review.]

[Update 2: The PL-680 review and readers’ survey results have now been posted! Check it out here.]

The results from the PL-680/PL-660 reader survey have been pouring in! As of this posting, over 160 readers have participated by listening to and evaluating the AM shortwave audio samples. Thank you!

This morning, I spent time comparing the Tecsun PL-660 and PL-680 with synchronous detection in mind. Time permitting, I hope to publish at least a medium wave audio survey, too, before I post the PL-680 review later this week.   I doubt I will post an SSB reception survey since my digital recorder injects a bit of noise into those recordings.

If you’re not familiar with these readers surveys, please read our previous post, as it contains all of the vital info and disclaimers.

To participate in this survey, start by simply listening, then fill out the form that follows with your choice of “Best Radio” for each broadcast. Please note that I include two recordings per broadcast, but ask that you choose the best radio overall for each broadcast.

For example: if you feel that Radio A is better in the first recording of Radio Australia, but Radio B is slightly better in the second recording (again, of Radio Australia), you still need to chose which radio is best overall in the Radio Australia recordings set.

You’ll note that signal stability varies between the two recordings; this is simply the nature of shortwave radio. Also note that each recording was made within one minute of the other in each set.


 Audio Samples

Radio Australia 9,580 kHz

ABC-Radio-AustraliaBelow I’ve provided two recordings of Radio Australia on 9,580 kHz. In both recordings, I have the PL-660 and PL-680 in normal AM mode for the first half of the recording–you will hear a het (hetrodyne–which sounds like a high-pitch tone) in the upper sideband. About halfway through the recording, I switch each radio into lower sideband sync, which effectively removes the het sound.

I have provided two recordings for each radio since QSB (fading) was fast and deep. Indeed, you’ll note in the second set of recordings that the radios had more difficulty maintaining the sync lock.

First Recording: Radio A

First Recording: Radio B

Second Recording: Radio A

Second Recording: Radio B

Radio Riyadh 17,615 kHz

Saudi-Arabia - Radio-RiyhadRadio Riyadh could certainly be considered weak-signal listening this morning, though their opening on 16 meters was quite good for the time of day.

In the recordings below, I start in AM mode, then switch the radio to USB sync after 15 seconds, and to LSB sync after 30 seconds.

In the first set of recordings both radio’s filters are set wide; in the second set, narrow.

First Recording: Radio A – (wide band filter)

First Recording: Radio B – (wide band filter)

Second Recording: Radio A – (narrow band filter)

Second Recording: Radio B – (narrow band filter)

 


Submit your response

Click here to use our response form to vote on your favorites, or simply use the form embedded below:

I’ll leave all PL-660/PL-680 comparison surveys open for evaluation until I publish the Tecsun PL-680 review.

Reader Survey: Comparing the Tecsun PL-660 and PL-680 on AM shortwave

Tecsun-PL-680

[Update: Please note that this survey has been closed, but the audio samples–labeled Radio A and Radio B–will remain to allow others the opportunity to make an evaluation prior to reading the PL-680 review.]

[Update 2: The PL-680 review and readers’ survey results have now been posted! Check it out here.]

I’ve been spending a little time with my new Tecsun PL-680 today, and it’s been most interesting. Of course, I’ve already begun to form a few opinions about the radio and am taking notes. Yet I never believe a shortwave radio can be judged in one sitting; there are simply too many variables to account for, such as minute changes in propagation, fading, local radio interference, all of which can have a temporary effect on performance. It’s better to judge a radio after having used it over the course of at least a week or so, in diverse reception conditions.

Still, as I tuned the PL-680, I was already wondering how it compared with its predecessor, the PL-660–? And since I’ve received at least ten emails from readers curious about the same thing, I thought I might start a series of blind audio tests in order to let our readers decide for themselves.

So…ready for some fun?

TecsunPL680andPL660

Below, I’ve embedded eight recordings comparing the PL-660 and PL-680 on shortwave. All of these are recordings of broadcast stations, no SSB yet (I simply didn’t have the time today).

To participate, just listen, then fill out the form that follows with your choice of “Best Radio” for each broadcast. But do note the following:

  1. I’ve attempted to set the audio levels equally on both radios. Iused the broadcast in the first recording to set the audio levels; they remain at this level for the remainder of the recordings. Nonetheless, you’ll note that one of the radios seems to have lower audio on a couple of the higher-band recordings; this is not due to any change in the incoming volume nor adjustments to the audio levels.
  2. As seen in the photo above, I used a Zoom H2N digital recorder to make these recordings on the tailgate of my truck.  Any time you hook a digital recorder up to a radio on the medium wave or shortwave bands, you most likely will inject a little noise. When I listened to each radio without the recorder in-line, I determined that the Zoom injected very little audible noise.
  3. The assignment of “Radio A” and “Radio B” was chosen by a coin toss–so pretty much at random!
  4. I included two recordings of WWV on 25 MHz. This is because the reception conditions from WWV change in a a matter of minutes, which would provide recording variation. I thought it would be best to include two such recordings.
  5. Both radios have the gain set to “DX” and bandwidth set to wide. None of these recordings employ synchronous detection. The telescopic antenna was fully extended on both units. Additionally, both radios had the tone control set to “bass.”
  6. No less relevant: it was 32F/OC with strong wind gusts and blowing snow in my face when I made these recordings. But I knew our readers would understand (and likely appreciate) this dedication to the absorbing art of  SWLing…just as I appreciate your participation in judging this head-to-head radio showdown!

Audio Samples

9,395 kHz – Radio Prague via Global 24 (strong signal example)

Radio A

Radio B

25,000 kHz – WWV Fort Collins, CO

Radio A – 1st recording

Radio B – 1st recording

Radio A – 2nd recording

Radio B – 2nd recording

17,620 kHz – Radio France International (weak signal example)

Radio A

Radio B


Submit your response

Click here to use our response form to vote on your favorites, or simply use the form embedded below:

Unboxing the Tecsun PL-680

Tecsun-PL-680-6When I got home, after a very long day, I found that FedEx delivered the Tecsun PL-680 I ordered from Anon-Co.  I haven’t even had a moment to listen to the PL-680 yet, but I hope to make time tomorrow.

Tecsun-PL-680-7

I’m happy to see that the PL-680 has hassle-free, well-designed packaging: a simple cardboard insert inside the box, yet everything was held in place firmly (no rattling).

Tecsun-PL-680-2

The PL-680 comes packaged in its padded case.

Tecsun-PL-680-3

Once it’s removed from the box, you can see the accompanying accessories: four standard Tecsun AA rechargeable batteries, one external wire antenna, one set of earphones and one AC adapter/charger.

Tecsun-PL-680-4

 

The PL-680 was enclosed in a poly bag inside the padded case–it also ships with a protective plastic film over the display.

Tecsun-PL-680-5

Wow! The PL-680 certainly looks like a spitting image of the PL-600. I believe this is a good thing as I always preferred the look of the PL-600 over that of the PL-660.

More to come tomorrow! Follow the tag PL-680 for all posts about this new Tecsun radio.

The Tecsun PL-680 now shipping

pl680-frontantenna-big

SWLing Post reader, Steve, writes:

Anna [at Anon-Co] has the PL-680 in stock according to a email I received from her this morning. Readers who are interested in ordering the radio should be aware of the Chinese New Year and the potential for delays.

Thanks, Steve. I received a similar email from Anna. They have listed the PL-680 on their website and, I’m sure, will post on eBay soon. The price is $95 US plus shipping; a reasonable price, if the PL-680 is an improvement over the PL-660.

I have already ordered a PL-680 from Anon-Co and it is on the way. I paid extra for FedEx shipping, so it should arrive before week end. I’ll post updates as I test this radio.

As Steve mentions in his note, Anon-Co will observe the Chinese New Year and will be unavailable from February 13th to the 26th.

I *should* have at least a preliminary review posted before the 26th so those of you who are tempted by the PL-680 will at least have some insight prior to purchase.

Shortwave Radio Recordings: Detecting Radio Guyana/Voice of Guyana

GuyanaMap-SAMYesterday I learned that Voice of Guyana (a.k.a. Radio Guyana) is back on the shortwaves after being off-air for many years. Evidently, the station repaired some of its transmitters and antennas with the assistance of station supporter and technician Jamie Labadia. At this point the station is only capable of a 1,000 watt AM signal.

To be clear, 1 kW AM is not an easy catch for most of us in North America unless propagation is in our favor.

Last night while testing a new military-grade SDR (the Enablia TitanSDR) that I’m reviewing, I decided that Voice of Guyana might make for a good weak-signal test.

And so, last night at 21:00 EST (02:00 UTC) I tuned the TitanSDR to 3,290 kHz; I could see a faint carrier on frequency, but the audio was lost in the noise. I could detect talking and music, but I couldn’t base an ID from it. I set the TitanSDR to record a wideband chunk of spectrum throughout the night.  This morning, I played the spectrum recording and found that the signal was at its best around 0945 UTC.

TitanSDR-RadioGuyana-3290kHz

Above you can see Radio Guyana’s AM signal on the TitanSDR narrowband spectrum display (click to enlarge). While still quite weak, I could make out station IDs and music quite easily. It was wonderful to hear Voice of Guyana on the air again!

Note: the TitanSDR was exceptional at pulling the audio out of the static. More about this SDR to come…

Here’s a 27 minute recording I made with the TitanSDR, using its eUSB mode (ECSS), beginning around 0945 UTC:

The Quadrus SDR: A New Military-Grade Software Defined Radio Receiver

Quadrus-SDRDr. Bertalan Eged of Spectrafold Technologies recently contacted me regarding a new military grade SDR they’ve produced: the Quadrus SDR. Today is the Quadrus official release.

The Quadrus SDR has phase-coherent multi-channel capabilities with up to 16 channels, which means that it can be used for direction finding, diversity reception, as well as MIMO applications.

While the Quadrus line is aimed squarely at government and scientific research markets, the $1490 US Quadrus DRU-244A-1-1-PCI, a four-channel SDR, might appeal to the discerning DXer, amateur radio operator, or radio experimenter.

Below, I’ve posted the full press release from Spectrafold Technologies along with several photos and screen shots.

Since I’m not a radio engineer, I’ve asked a representative of Spectrafold to answer any questions you may have about the Quadrus SDR line and its receiver architecture.


Military-Grade Software Defined Radio Receiver Platform
Now Commercially Available for Building Better Receivers

Quadrus-SDR-2

Phase-coherent, Multi-channel Quadrus Platform Brings New Features to Commercial Market

Spectrafold Technologies today released the Quadrus software defined radio (SDR) platform for commercial use, enabling access to advance, professional-grade platform for signal intelligence, spectrum monitoring communications systems and missions. The long-standing platform has features are still unmatched by other commercially available products, and include four cutting-edge, phase-coherent antenna inputs with 16 bit, 80 MSPS; high-sensitivity, high-dynamic range Analog-to-Digital Converters (ADCs) driven by a low phase noise; and high-stability sampling clock. The input signal chain also contains a Low-Noise pre-Amplifier (LNA) and an input leveling attenuator providing the necessary sensitivity while still maintaining the proper input drive. The architecture provides the capability of using high gain antennas, and standing against the overload by the crowded radio spectrum.

“Today there is strong international community of radio enthusiasts and listeners using SDR technology, looking for platforms that implement advanced radio signal processing algorithms,” said Dr. Bertalan Eged, chief architect of the Quadrus. “Physically and logically phase-coherent multi-channel SDR platforms provide the capability to implement various algorithms and receivers such as diversity reception, interference cancelling, beam forming and correlative receivers. These applications can help to deliver better sensitivity, more stable fading free reception, longer connectivity and collecting more information on the radio signal environment.”

The platform input bandwidth is wide enough to be used up VHF/UHF bands as Direct Digital Receiver (DDR). The samples are fed into an FPGA, where a non-blocking switch matrix is used to forward them to the input of the four on-board receiver signal processors. The on-board processing is capable of forming a 16 multi-channel receiver. The platform also features a standard PCI interface for PC integration, and comes with a Windows®32 bit kernel driver and fully open API, which can be downloaded from the website along with the operating SDR software. The SDR receiver software has remote control capability for system level integration via TCP/UDP/IP links. Further details on these capabilities are available at the Spectrafold website. The system has spectrum recording capability to binary files, some example can be downloaded for evaluation purposes.

SAGAX DRU244A-1-1-PCI  Stock photo 15-Jan-2015

The Quadrus API is available as a Windows® DLL, and developers and system integrators may download it from the SUPPORT page on the Spectrafold website. The hardware API is meant for direct hardware access, but a higher level remote control interface API is available as well, which can be used to (i) set up the receiver channel parameters and to (ii) access the IF as a UDP/IP stream. If you prefer to not use any of these methods, it is possible to fall back to a virtual audio card connection between the SDR software and external applications, like decoders and post processors.

Additional information on the performance and usage scenarios is available in the BLOG. Users interested in experimenting with the hardware can gain access to remote access to a computer with SDR hardware digitizer and installed SDR software. Interested parties should contact the team by email: [email protected]

Hardware orders may be placed through the manufacturer’s ORDER page. Standard secure payment option is provided via PayPal. International shipment by UPS is part of the service. The hardware is manufactured in batches with limited stock. Introductory pricing starts at $1490.

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About Spectrafold Technologies

Spectrafold is a dedicated community of professionals, who work tirelessly to invent and create affordable, cutting edge SDR solutions. Together we have decades of hands-on experience delivering working solutions to the toughest missions and environments. Our customers include academic, governmental, and military organizations, but radio enthusiasts as well.


Screen shots

Click to enlarge:

srm-4 srm-3 srm-2 srm-1

DXtreme Station Log — Multimedia Edition, Version 11.0

dxslme_v11I just received the following note from SWLing Post sponsor, Bob Raymond (NE1I), at DXtreme software:

DXtreme Software is proud to announce the release of: DXtreme Station Log — Multimedia Edition, Version 11.0.

For details, check out DXtreme Software’s Product Announcement in PDF format.
And many thanks to DXtreme for supporting the SWLing Post!