Category Archives: Portable Radio

Guest Post: Revisiting the Realistic DX-440

RadioShack ad for the Realistic DX-440

Many thanks to SWLing Post contributor, ShortwaveGuy, who shares the following guest post originally published on his blog, Shortwave.me:

Tried And True. . .Revisiting Older Receivers – Realistic DX-440

by ShortwaveGuy

Anyone who knows me, knows I am a fan of the “latest and greatest” when it comes to shortwave receivers. Like most of us involved in the hobby, I am always on the lookout for what newer technology has to offer me in order to pursue my quest of either capturing that elusive DX signal, or whatever will bring my favorites in the clearest. As a result, over the past few years, I have collected an assortment of receivers, each one serving a different purpose. My wife can not only attest to this, but can also relate to this phenomenon, as someone who has far more shoes than she will ever have time or fortune to wear! That’s how I am with my radios!

The other day, however, while listening to some of my favorite stations on what is arguably my best current portable receiver, the Tecsun PL-660, I got to thinking about some of my other receivers, in particular, my Realistic DX-440. I have had this receiver for as long as I can remember and I can remember back a long time! Around the time it came out, the radio most of us had our eyes on was the venerable Sony ICF-2010. Like a lot of people, however, I had no means of purchasing a receiver as expensive as it was at the time. I hoped that somehow, I would be able to afford one and one day, I did buy one, but that’s a story for another time, however.

In the mean time, I can remember perusing the latest Radio Shack catalog, something I did as often as they came out when I saw it. . .a radio with all kinds of wonderful buttons and knobs! The top of the page screamed out at me: “CATCH THE ACTION ON MULTIBAND PORTABLES”. It was the Realistic DX-440! Here is a picture of the ad as it appeared:

Once I saw it, I knew I must have it! While the MSRP on the Sony ICF-2010 was $449, this gem could be had for less than $200! All my previous radios had analog tuning so the prospect of getting a radio with a digital display was quite appealing to me! Try as I may to convince my parents to get me just this one Christmas gift instead of several, it didn’t happen. . . .at that time. But fast forward several years later. . .

I finally got my digital receiver in the form of the Realistic DX-380 from my parents one Christmas. I worked that thing for years, and was mostly happy with it. It didn’t have SSB, which I had begun to understand by that time. I had pulled in a lot of great stations such as HCJB, BBC, VOA, Radio Havana Cuba and many others. However, because it didn’t have SSB, there were several occasions where I would happen upon ham radio operators who were talking back and forth, utility stations or even pirate stations. I could never be for sure, though, because my unit was not equipped to decode those signals. I knew that it was time to finally remedy that.

I purchased a few other radios that would do SSB and most of them worked reasonably well. At one point, I had even managed to procure the much-celebrated ICF-2010, which I loved dearly until it died a slow and unfortunate death that those with the know-how told me was beyond repair. But always, in the back of my mind, I wondered about that near-mystical Realistic DX-440. . .dreaming about what might have been.

I contented myself with the radios I had, still enjoying this wonderful hobby that I have participated in for so many years. I was, with the exception of the now-departed 2010, generally happy with the receivers that I had. I wasn’t looking for a new radio, but one night, mostly out of boredom, I wandered on to eBay and did a search for shortwave radios. I looked at tabletops and ultralights, primarily as I really had neither and had plenty or portables. About two pages in, I saw the Realistic DX-440. It only took about 10 minutes before I decided that this one must be mine. I placed my bid and waited patiently. . .only to lose the auction. “Oh, well”, I thought. If I saw another one, I might try again. . .or maybe not.

Well, the next day, I did a search and found one. This one looked in fantastic shape and had no bids. There was a “Buy It Now” price, but I wanted to get this for as inexpensively as I possibly could. The auction ended in 5 hours. I chose not to bid, not wanting to draw attention to it. I set an alarm on my watch and came back in an hour. . .still no bids. I set another alarm. With only 3 hours left, I began to get excited. Another hour went by and another alarm had been set. 2 hours to go. Any bidders, yet? No! Could this really happen? Maybe!

When I got down to the final hour of the auction, I didn’t bother to set an alarm. Like a watched pot that never boils, I stared at the web page, refreshing it every couple of minutes. With every refresh, it began to seem as if this might come to a happy conclusion. 10 minutes left. . .no bids. 5 minutes left. . .still no bids. I waited until 30 seconds before the end of the auction and placed the minimum bid.

Tick. Tock. Tick. Tock. Tick. Tock.

Auction over.

I HAD WON!

A dream over 20+ years in the making had finally happened! I quickly paid for the radio and then purchased the appropriate “wall-wart” adapter to make sure I had it ready for when the radio arrived. It said it would be 7-10 days for delivery, but it was at my house in 3!

I opened the box and carefully wrapped in old newspaper, was the radio that I had been pining for since my early teens. I quickly checked it out to make sure it was in good condition and was pleased to find it was. My heart sank a little bit when I opened the battery compartment to find 2 AA cells left in for the last 5 years that were supposed to power the clock and the memory functions. Fortunately, they had not exploded and I quickly removed them and replaced the unit with a fresh round of batteries. The only flaw I was able to find was that it seemed that the previous owner had lost the screw on tip of the internal whip antenna and had placed a plastic cap on the end in its place. It didn’t look out of place and was very secure, so I shrugged it off. Now for the moment of truth: I powered the radio on and it worked! I checked all the bands and was able to receive quite well on all of them except LW (which is to be expected, given my geographic location and the lack of stations on the longwave band, in general). All the knobs were there and in place and there were no dirty switches or tuning pots to deal with. I had snagged myself a honey of a bargain!

Now it was time to use this thing for what I bought it for: to listen to shortwave radio! I usually use a 100 foot longwire antenna when I listen to shortwave, and this time would be no exception. However, I was anxious to pair the DX-440 with the Realistic 20-280 amplified antenna that I had picked up years ago at an auction. I had used it with other radios, but never in conjunction with a longwire antenna. I was ready to change that. I wanted to use the preselector function of the amplified antenna as well as the actual amplifier in order to maximize my ability to pull in distant stations. When the radio was first manufactured, there were a lot more stations on the air to listen to and less of a need to do much more than throw 20 feet of wire up in a tree. Obviously, with many of the powerhouse shortwave stations having gone the way of the internet, I knew that my plan to couple the longwire with the amplified antenna had the potential to pay big dividends. I took a look at the back of the radio, where the external antenna jack was and I was surprised to find not the 1/8? jack I was accustomed to, but in its place was an RCA phono plug. The amplified antenna had an RCA plug on its side, as well, but it wasn’t to connect to a radio, it was for connecting to an antenna. The amplified antenna had the 1/8? plug and accompanying cable that was used to connect to the external antenna jack of nearly every modern portable radio. To be honest, I wasn’t completely sure how I was going to go about handling this issue. I thought about using alligator clips, but wasn’t sure how to integrate this into my coupling scheme. I pondered over this for all of about 3 minutes and than quickly got into my car and headed to my local Radio Shack. I told them I was looking for a 1/8-inch phone plug-to-phono jack and they were quick to accommodate me. They gave me the adapter you see pictured here (Catalog #: 2740871). It would handle either stereo or mono input of a 1/8-inch plug and as a bonus, it says “MOM” on the end, if you are willing to use the input hole as the letter “O”.

I got it home and quickly got it hooked up. As I expected, the “MOM” adapter was a perfect fit. I made sure I had fresh batteries in the amplified antenna, though it would accept an AC adapter if I wanted. I chose to run it on battery, so as to reduce any possible introduction of noise to the signal. And then, I powered on both the amplified antenna and the DX-440. . .the moment of truth had arrived! I tuned to WWV on 15 mHz, which I use as a baseline for most test I conduct on my radios during the time of day I was listening. I must tell you, I was NOT disappointed in what I heard. It was a rather cloudy day weather-wise and I was concerned about a middling solar flux. I needn’t have been worried at all. The signal was robust and clear as the familiar sound came booming in from Fort Collins, Colorado! Not only was the signal strong, but using the separate bass and treble controls and the wide selection on filters, it was actually rather pleasant listening, not fatiguing at all. I pulled up my trusty shortwave schedules app on my phone and began searching for things to listen to.
I heard domestic broadcasters like WRMI and WBCQ with no issues and managed to catch BBC to West Africa, as well! I listened to quite a bit that night and into the morning hours, checking out not only broadcast shortwave, but utilizing the BFO to listen to ham bands, particularly my favorite, the Freewheelers Net on 3.916 mHz, LSB. The BFO was easy to operate and the addition of the Realistic amplified antenna helped to bring in signals with great gusto. As with any amplified antenna that is not a loop, this one amplified not only the signal, but the noise as well. That said, the propagation deities were kind to me and I enjoyed a long night of listening.

I have since given my DX-440 a place next to my bedside and have enjoyed listening to whatever I could find to listen to most nights. While a radio like the Tecsun PL-660 offers newer technology and the addition of an excellent synchronous detector, the DX-440 holds its own against the newer technology. At the end of the day, it’s still a portable and while most portables pale in comparison to tabletop rigs, this one is rather excellent with what it has offer versus its price point. The build quality is solid and ergonomically it is a pleasure to operate. If I had any critiques at all, I would have made the BFO and the RF Gain knobs a bit bigger, but now I am truly splitting hairs. I can see why contemporaneous editions of the Passport To Worldband Radio listed this as an Editors’ Choice radio back in the day.

I wanted one from the day I saw it those many years ago, and I can say unequivocally, that it was worth the wait!

–ShortwaveGuy

Thank so much for writing about the DX-440–that radio has a special place in my heart. The ‘440 was my first digital shortwave receiver–it revolutionized my shortwave listening.

As I’ve mentioned before, I also travelled with the Radio Shack DX-440 while studying French and living in Grenoble, France. The DX-440 delivered my daily dose of the Voice of America (the only English language news I allowed myself to listen to at the time). Since the VOA broadcast often coincided with meal time at the Université Stendhal cafeteria, I left my voice-activated Micro Cassette recorder in front of the DX-440 which was, in turn, set to turn on one minute prior to the VOA broadcast. It was an amazingly reliable arrangement.

I’d better not wax too nostalgic, though, else I’ll start searching eBay for a 440 just like you did! Hang onto that DX-440–I wish I would have never given mine away!

Visit ShortwaveGuy’s blog by clicking here.

The brilliant little Tecsun PL-310ET: serious DXing on a budget – part 2

16 Replies

Hi there, here is part two of my original post containing various reception videos for the amazing Tecsun PL-310ET pocket shortwave receiver. I continue to be amazed at the sensitivity and selectivity of this rather modest and diminutive receiver, particularly at it’s price-point of around £40 in the UK and less elsewhere! Here is the second half of the reception videos, with some nice signals from Brazil, Guinea, Ethiopia, Swaziland and India. You might notice that some of these catches involve the use of a 240 metre (approx.) length of barbed wire fence! I’m not sure how beneficial the electrical properties of the fence were, probably somewhere between not great and not good lol, but some pretty decent DX was had with the PL-310ET attached to it via the external antenna socket and a crocodile clip!

The barbed wire fence extends almost to the treeline on the horizon; about 240 metres

I hope you enjoy this set of reception videos, they certainly help to demonstrate the great performance of the PL-310ET and in addition of course, it’s ability to handle large antennas quite well. Embedded videos and text links follow below. Lastly, there are now approaching 1,200 reception videos on my YouTube channel Oxford Shortwave Log and I would like to take this additional opportunity to thank everyone for their support, friendship and advice. In the meantime, I wish you all a very Merry Christmas, a Happy New Year and excellent DX!

Clint Gouveia is the author of this post and a regular contributor to the SWLing Post. Clint actively publishes videos of his shortwave radio excursions on his YouTube channel: Oxford Shortwave Log. Clint is based in Oxfordshire, England.

Troy reviews the Audiomax SRW-710S

37 Replies

Many thanks to SWLing Post contributor, Troy Riedel, for the following guest post:

A Mini-Review of the Audiomax SRW-710S

by Troy Riedel

Why would someone want a sub-$20 shortwave radio? Wait … I guess I should be answering questions & not asking them, right? But I’ll give you my answer to “why I want a sub-$20 shortwave radio”: I have many nice radios, but I wanted one that I consider “disposable”. I define “disposable” as something I won’t be upset if I lose, get it splattered with paint, or leave it outside only to get rained on. Taking the family of four to the movies nowadays costs upwards of $100 (the three ladies I live with can really throw-down pop & popcorn!) so a sub-$20 radio, even a “disposable one”, is a true bargain.

I have seen the SRW-710S badged under three different names: Audiomax, VITE and TIVDIO. There very well may be other badging. I paid $18.52 for my Audiomax badged device direct from a vendor in China. I’ve subsequently seen it as low as $13 on eBay and as much as $37 on Amazon. So much for a sub-$20 radio, huh?

The SRW-710S comes with only a USB charging cable in the box to recharge the Li-ion BL-5C battery (no earbuds, no case or pouch – just a very simple set of basic instructions). The 710S features a small LCD screen that offers menus in three languages: English, Spanish & Chinese.

The screen greets you with “welcome” (lowercase) when turning it on & “Bye Bye!” when you power-off. There is a Sleep Timer function that I have yet to use. All of the ports are on the right side of the unit (nothing on the left). It has a TF Flashcard Slot – no card provided – for recording off the radio & for playing pre-loaded mp3 & wma files from the flashcard.

It has 100 memories, a Line-In port, a built-in mic, and a headphone port. There is no ANT-In port. This radio has AM, FM & SW (no LW) with the appropriate international tuning steps. Lastly, there is no folding stand on the back (one is provided and is attached to the wrist strap – it is inserted into a small slot just above the battery cover).

One Chinese web site listed the SRW-710S as having an “AKC6951 DSP chip”. Until now, I had never heard of this DSP chip and I frankly know nothing about it. Maybe some more informed readers can comment?

Operation is easy (except for one quirk that I will detail later). There are two rows of numbers for direct input of a frequency. Simply input the frequency … and then wait (there is an approximate 3-5 second delay from input to the radio actually tuning to the frequency … I am still getting used to this pregnant pause). You also have an option of tuning directly to a meter-band.

Of course, there is no SSB for this low price.

The one speaker is a bit “tinny” but adequate (stereo via user-supplied earbuds). And considering the price point, the RF shielding isn’t too bad. I can actually use the shortwave band of this radio in my kitchen and breakfast nook (I cannot say that for my more expensive receivers).

The biggest limiting factor in reception is the size of the telescopic antenna (15.5”). However, for its size I am quite impressed (it’s exponentially better than the old Grundig G2000A Porsche that has a 21.25” antenna – but that radio is notorious as needing a reel antenna). Just via the telescopic whip, I can actually tune the major broadcasters to NA (e.g., Radio Romania), I can adequately tune to the VOA 15.580 MHz signal to Africa during the North American East Coast AFTN, and the time signals are easily audible (of course, frequency appropriate for the time of day).

I do not plan to open the radio’s chassis, but AM reception seems to be limited due to the obvious small size of the ferrite antenna (the radio itself is essentially palm-sized, approximately 4.75” x 3” & less than 1” thick). My postal scale indicates it weighs 5.5 – 6 ounces including the battery. The radio must be propped to support it when attaching the telescoping whip to a Slinky Antenna (even the weight of the Slinky’s alligator clip causes balance problems)
One quirk I have found: there is a “Lock” key. However, it only seems to lock the radio power “on” (locks are used to lock the power “off” during transport so the power remains off and the battery doesn’t drain). The “Lock” feature is not discussed in the instructions and at present I have not figured-out if this switch works in the traditional way. I find this to be quite amusing because it’s either an odd quirk or I’m just not smart enough to intuitively figure it out.

I am quite satisfied with my new “disposable” $18.52 Shortwave Radio (I have no information whether the quality I have considered is consistent through a production run or between badging). For those who wish to listen to a local AM or FM station – or listen to one of the “major” shortwave broadcasters with a booming signal into your part of the world – you can’t beat it for this price point. I can see myself using this radio while I complete outdoor household repairs or while cleaning-up the garage. Too bad it’s so close to Christmas, this would make a great stocking stuffer to introduce someone, young or old, to the world of shortwave.

Update: Searching for the SRW-710S

Note that the lowest prices omit the model number in eBay search results.

Click this link to search eBay for the SRW-710S on eBay.

Scroll through search results to find a matching receiver.

Thank you, Troy, for mini-review of the SRW-710S! Like you, I have very low expectations from shortwave portables at this price point. Still…for the glove compartment of your vehicle, for outdoor listening, for small gifts? These fit the bill! I’m most impressed you could receive the number of stations you did from inside your home.

Medium wave SDR spectrum with over 20 transatlantic signals: a quick tour

5 Replies

Tour of a medium wave spectrum with over 20 transatlantic signals

Hi there, I thought some of the readers of SWLing Post might be interested in a review of a MW spectrum with multiple transatlantic signals – all with audio. This is one of the recordings I took with the 200 metre Beverage antenna and although I haven’t properly counted, I believe it generated about 50 catches that were either personal firsts or best-ever receptions. You will note that this video is nearly 20 minutes long, whilst the recording is only just over 5 minutes, thus to capture the signals listed below and demonstrate audio to you, it was necessary to effectively ‘rewind’ a few times. I haven’t annotated the video, however, the stations I’ve paused on to demonstrate audio are listed below. There are actually more catches in this spectrum, but hopefully the video will give you a good idea of propagation on the morning of 10/10/16 and the effectiveness of the Beverage/Elad FDM DUO combination. Also note, I didn’t have time to fully optimise the demodulation settings, so for example, I haven’t used AM SYNC in this demonstration. Individual videos of all catches, with optimised settings appear on my YouTube channel Oxford Shortwave Log. I hope you enjoy it! Recorded in Oxford UK on 10/10/16 at 02:00 hrs UTC. Thanks for watching and I wish you all great DX!

590 kHz VOCM Saint John’s
600 kHz CBNA Saint Anthony
620 kHz CKCM Grand Falls-Windsor
660 kHz WFAN New York
710 kHz WOR New York
730 kHz CKAK Montreal
750 kHz CBC Radio 1 Bonavista Bay
790 kHz WAXY (presumed)
800 kHz VOWR
970 kHz WBGG
1010 kHz CFRB Toronto
1030 kHz WBZ Boston
1130 kHz WBBR New York
1190 kHz WLIB New York
1280 WADO New York
1390 WEGP Presque Isle
1400 kHz CBC Radio 1 Gander
1440 kHz WRED Westbrook
1510 kHz WMEX Boston
1520 kHz WWKB Buffalo
1570 kHz XERF La Poderosa, Mexico
1580 kHz HJQT Verdad Radio 1580 kHz, Bogotá, Colombia
1610 kHz Caribbean Beacon, Anguilla
1660 kHz WGIT Puerto Rico

Guest Post: “Car Shack” Radio Listening

3 Replies

Many thanks to SWLing Post contributor, TomL, for the following guest post:

“Car Shack” radio listening

by TomL

My car is an unusual place to listen to shortwave radio but has interesting possibilities. Due to the obscene noise at my home QTH, I decided that I must try something away from this unfortunate situation. So I took my homemade 14-inch loop antenna and outfitted the appropriate ancillary equipment with DC power packs. My trusty Sony ICF-2010 is the radio “vehicle” to “drive” this experiment (LOL). And, seriously, this is a way to show the public that it is not that hard to have a portable radio listening setup. Believe me, if I can do this, anyone can!
The basic ingredients are pictured here with some variations (see text):

Homemade 14-inch Loop antenna + EF-SWL balun mounted backwards
Wellbrook amplifier powered by DC power pack of 10 eneloop AA batteries
KIWA Broadcast band (mediumwave) inline filter
Palstar preselector (active antenna) plugged into car cigarette lighter
Sony 2010 connected to a second DC power pack
Sony ICD PX333 digital recorder
Sennheiser earbuds
7 inch Samsung tablet and 4G MiFi device to do internet schedule lookups

Illustration SEQ “Illustration” 1: Car Shack in operation.

An important finding was that anything that has a cheap IC circuit to regulate and/or convert DC power can be extremely noisy! The pictured 16000 maH lithium brick would initially be quiet but after a while it would start spewing noise all over the bands. Power cycling it sometimes helped but I decided that it is too unpredictable. Also, converter cables that convert 5V to 12V for devices needing 12V also produce overwhelming amounts of noise. Even a small 5V USB converter plugged into the cigarette lighter makes a modest amount of ubiquitous noise. I am ditching the lithium power pack and converter cables and any cigarette lighter adapters!

So, the main radio power pack will use the internal Sony battery comparment consisting of nine 2700 maH NiMH AA’s inside three D-cell battery holders that can each hold 3 AA batteries in parallel. This boosts the capacity to around 8100 maH for a modest cost (I already have NiMH chargers and the 4.5V requirement is not too high for the batteries in question). Pictured are examples of a single D-cell AA holder of which I bought 12 and the silver-top Powerex 2700 maH AA’s from fleaBay. The total voltage is slightly low (3.6V) but the Sony 2010 still works at a slightly lower performance (received signals are slightly weaker). I run the Sony on Local sensitivity and crank up the Palstar active antenna to compensate.

In a further quest for clean, portable DC power without noisy IC chips, I have been researching lithium batteries and it is quite a large amount of work to sift through all the variables. The Palstar active antenna and the Wellbrook amplifier both use external connections of 12V, 2.1mm (+ tip) plugs. NiMH is not going to cut it, too many needed and getting too heavy. Amongst the variables are things like:

Using a proper charger and not leaving it unattended or it could burn down your house
Chinese fakes being sold by the zillions that look exactly like the real thing
Initial cost being higher than current NiMH
Avoiding 1.5V step down batteries with noisy step down converter built-in
Learning the new terminology for sizes: AA = 14500 = 14mm diameter & 50mm length
Learning the differences between type of lithium: Lithium, Li-ion, LiFePo4, IMR, etc.
The difference between protected vs. non-protected batteries
How to avoid discharging the batteries too much which could render them completely useless (not just usage but also NON-usage as well)
How to physically handle Lithium batteries to avoid shock and temperature extremes
Learning how to compare maH’s of lithium to NiMH batteries
Finding out that most top rated 14500 Li-ion batteries are too long to fit into AA battery holders without risking damage to the protection PCB mounted at the bottom of the battery
and the list goes on and on…..

Here are some of the web pages I read to try to understand this technology:

So, to cut to the chase, I have decided to order this one from XTARDirect because:

I can order from a USA distributor who orders from the factory in Shenzen China
The price is very reasonable for “protected” lithium ion batteries
They actually should fit into typical AA battery holders without damaging it

Illustration SEQ “Illustration” 2 XTAR 14500 800 maH Li-ion

They are not the highest rated in terms of capacity, load drain, amp surge ability, etc., but they seem to have enough positive statements from users that indicate it gets the job done. Since I don’t have the lithiums yet, I am using some temporary 10-cell AA holders with good old Eneloops – good enough for now. And I am buying this discontinued charger at a discount to recharge lithiums:

Illustration SEQ “Illustration” 3: Nitecore i4 original version

I will make two power packs made from these items pictured. The wire is fragile so I super glue the insulation directly to the DC power plug housing (avoiding getting any glue onto the bare wire inserted at the back). I will use three sets of lithiums (9 batteries) plus one set of Eneloop Pro’s (3 batteries) per power pack in the aforementioned parallel AA holders.

Illustration SEQ “Illustration” 4: 4X D-Cell battery holder.

Illustration SEQ “Illustration” 5: “9V” Snap connector.

Illustration SEQ “Illustration” 6: 2.1mm x 5.5mm DC power plug.

Other items of note: The umbrella stand is optional since I found I like to move the antenna around and even tilt it to get slightly better directional signal. More importantly, I found that if I cut the Sony 2010 sensitivity from DX to Local, and then crank the Palstar preselector’s amplifier, I get a cleaner sound with less background noise. Also, the KIWA mediumwave filter is essential due to overloading.

One of my favorite stations is Radio Educacion (XEPPM) on 6185 kHz. A 1 kW station near the foot of Vulcan de Guadalupe in Mexico City, it is so weak that I almost never hear it and their wonderful selection of music representative of regional & cultural heritage. It is also 1675 miles distant according to Google Earth. Now, if I want to bother, I can go out and listen in my car at locations less noisy than home. So far, the safest places have been the parking deck at work (only two stories high) and the local grocery store parking lot. What I would really like is a very tall parking deck whose owners let me stay up on top long into the evening without harrassment (not sure I want to risk security personnel questioning me about the strange contraption and equipment – paranoia reigns these days)!

Sample of XEPPM, moderately good propagation from the work location:

Click here to download MP3.

Of course, the Brazilian station is booming next door at 6180 kHz (thank goodness for SSB-selectable Sync detectors):

Click here to download MP3.

Unexpected reception happens with this experiment. I mounted the antenna in the back, away from the engine and against the rear side window. Was traversing the local restaurant drive-through lane to get a hot dog, and turning the corner next to the long empty brick wall, the reception became dramatically stronger and clearer! Apparently, the brick wall blocked some interference as well as enhanced the signal coming from the Northeast. You can hear the effect starting at 25 seconds into the recording of RRI:

Click here to download MP3.

Also, not recorded from a previous evening at the grocery store location, 6135 kHz Radio Santa Cruz in central Bolivia, a 10 kW station playing Spanish rock music and a clear ID near the top of the hour.

More experiments to do, like

Mount the antenna as high I as dare with PVC pipe (too cold out now and I would rather not open any windows but I am itching to mount the umbrella stand and antenna on a 3 foot PVC pipe on the roof of the car, the increase in received signal strength is significant)
A bigger backpack to carry all this equipment away from the car
If Elon Musk has his way and builds the Gigafactory (and competitors follow suit), there could be many more experiments with lithium type batteries in the future
Perhaps get an SDR and cheap laptop computer to replace the Sony radio

PS: I found out that the three-AA battery holders do not make contact at the (+) tip of the XTAR lithium batteries I purchased. I just gently lifted up the contact inside the battery holder to allow it to reach the battery tip, that’s all that is needed. Whatever you do, do not put an extra piece of metal inside the battery holders! I accidentally damaged the outside skin of two of the batteries with a common piece of copper metal and the batteries immediately started to get HOT. I took them out as soon as I could and the batteries cooled down. So, don’t use any extra metal surface inside the battery holders; lithium batteries do not tolerate any kind of short circuit!

Cheers from Noizey Illinoiz,

TomL

Thank so much, Tom, for sharing your experiences and your ongoing experiments! Lately, I’ve been doing NPOTA activations with a portable loop antenna on top of my vehicle. I completely understand what you mean about getting strange looks from passers-by! We look forward to hearing about your future experiments fighting RFI.

Tecsun PL-680: Just How Sensitive is This Radio?

19 Replies

More than two months ago, in the Mount Evelyn DX Report I posted a review of the Tecsun PL-680 portable receiver, entitled Tecsun PL-680 Beats Expectations. In that article, I pointed out many of the positives and a few of the flaws surrounding the unit. At the end of the review, I promised I would do some sensitivity tests on the radio.

Well, I finally got around to completing the tests, and the results are in. Below is a YouTube video showing a practical demonstration of the receiver’s capabilities in this area of performance.

The portable Tecsun PL-680 receiver is a hot little radio! As these tests show, it appears to be very sensitive to weak signals. Here, we put the little 680 up against one the best HF transceivers on the market today – the Yaesu FTDX3000 transceiver. The receiver in the 3000 is quite brilliant! And it has all the “bells-and-whistles” to make it even better at digging out weak signals and reducing adjacent channel interference.

However, in these tests we turn off all the fancy facilities on the FTDX3000 and just run the two receivers side by side to see how the 680 compares. We use the same antenna and we plug both radios into the same external speaker, adjusting as close as we can to equal volume and tone quality. We select a variety of shortwave broadcast stations over a range of frequencies from the 60 through to the 16 meter bands. I think you’ll discover that the Tecsun is really a very good performer when it comes to sensitivity!