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Last week, we packed the car and headed to coast of South Carolina.
The trip was a bit impromptu but through the creative use of hotel points, we scored a two bedroom ocean front unit with a fantastic little balcony.
The vacation gave me an excuse to test the new passive loop antenna my buddy Vlado (N3CZ) helped me build recently.
The loop design came from AirSpy’s engineer and president, Youssef Touil.
This passive mag loop takes advantage of the new AirSpy HF+ Discovery‘s exceptionally high dynamic range. Youssef had reported impressive results, so I had to build one.
Vlado had a length of Wireman Flexi 4XL that was ideal for this project. The only tricky part was penetrating the shielding and dielectric core at the bottom of the loop, then tapping into both sides of the center conductor for the balun connections. Being Vlado, he used several lengths of heat shrink tubing to make a nice, clean and snag-free design.
The results were truly exceptional. I spent most of my time on mediumwave from the hotel balcony because I was determined to catch a transatlantic signal.
Check out the spectrum display from my Microsoft Surface Go tablet:
Our ocean front hotel was inundated with noise, but I still managed to null out most of it and maximize reception using the passive loop. I simply suspended the loop on the balcony rocking chair–not ideal, but effective and low-profile.
Want to take a test drive?
If you’d like to experience this portable SDR setup, why not tune through one of the spectrum recordings I made?
The recording was made on November 17, 2019 starting around 01:55 UTC–I chose it at random and have yet to listen to it myself. You’ll need to open this file in AirSpy’s application SDR# or a third party SDR app that can read AirSpy .wav files.
Stay tuned…
I’m writing an in-depth report of the HF+ Discovery, my experiments with this setup and AirSpy’s soon-to-be-released passive loop antenna for the January 2020 issue The Spectrum Monitor magazine. Spoiler alert: I am truly impressed with the wee little AirSpy HF+ Discovery. It’s a powerhouse!
The FCC approved today the adoption of a rulemaking allowing AM stations to transition to all-digital operation.
Hubbard Radio’s “The Gamut” 820 WWFD Frederick MD has been operating in all digital mode since July 16, 2018 in collaboration with HD Radio owner Xperi. The new rulemaking will allow AM stations to go all-digital and establish operating parameters for doing so.
The FCC today also is opening a comment period on the removal of the programming duplication rule adopted in 1992. The rule limits AM or FM stations from airing more than 25% of total hours in an average broadcast week of duplicative programming. The rule applies to commercial stations in the same service (AM or FM) with substantial contour overlap that are commonlyowned or subject to a time brokerage agreement.[…]
For over two weeks now, I’ve had an early production model of the RSPdx here in the shack operating on a beta version of the SDRuno application.
In the spirit of full disclosure, SDRplay is a long-time supporter of the SWLing Post and I have alpha- and beta-tested a number of their products in the past. This early production RSPdx was sent to me at no cost for a frank evaluation, and that’s exactly what I’ll offer here. To be clear, while I am using beta software, this is not a beta SDR, but one from a first limited production run.
And thus far, I must say, I’m impressed with the RSPdx.
Upgrades
The RSPdx has been introduced as a replacement for the RSP2 and the RSP2pro receivers. It has been updated and upgraded, with a completely new front-end design.
Here are the highlighted improvements and changes:
Performance below 30 MHz has been enhanced when compared to the RSP2/RSP2pro.
Performance below 2 MHz has been substantially upgraded. Through the use of the new HDR mode, both dynamic range and selectivity have been considerably improved.
There is now a BNC antenna connector on antenna C position instead of a HiZ port. Both A and B antenna ports are SMA like other RSP models.
Let’s face it: those of us interested in low-cost SDRs are spoiled for choice these days. The market is chock-full of sub-$200 SDRs, especially if you include all of the various RTL-SDR-based SDRs and knock-off brands/models one can find on eBay.
Personally, I invest in companies that support radio enthusiasts for the long haul…those that do their own designs, innovations, and production. SDRplay is one of those companies.
SDRplay’s market niche has been providing customers with affordable, high-performance wideband receivers that cover an impressive 1 kHz to 2 GHz.
Wideband coverage can come at a cost. Unless you pay big money for a commercial-grade wideband receiver, you’re going to find there’s a performance compromise somewhere across the spectrum. On the RSP2 series, those compromises would have been most apparent on frequencies below 30 MHz.
That’s not to say HF, MW, and LW performance was poor on the RSP2 series–indeed, it was quite impressive and well-balanced; it just didn’t stack up to the likes of the similarly-priced AirSpy HF+ and HF+ Discovery, in my humble opinion. Both little Airspy SDRs have wooed DXers with their impressive dynamic range and overall ability to work weak signals in the HF portion of the spectrum.
Neither of the AirSpy HF+ models are wideband receivers, but still offer a generous range: 9 kHz to 31 MHz and from 60 to 260 MHz––about 11.5% of the frequency coverage of RSP models. (Note that the Airspy R2 and Mini do cover 24 – 1700 MHz.) For shortwave radio listeners that also want to venture into the UHF and SHF regions, a wideband SDR is still required.
It’s obvious SDRplay’s goal is to make the wideband RSPdx into a choice receiver for HF and, especially, for MW/LW DXers. But have they succeeded? Let’s dive in…
Performance
As I say in most of my SDR reviews: doing comparisons with receivers that have so many features and adjustments is never easy. In other words, we want an apples-to-apples comparison, but it can be difficult to achieve, especially with new products.
The RSPdx, Excalibur, and HF+ Discovery all used the same antenna in my tests––a large, horizontal delta loop antenna, via my ELAD ASA15 amplified antenna splitter. I’ve used this antenna splitter for years and can vouch for its equitable, lab-grade distribution of signal.
The RSPdx is not in full production at time of posting, thus application options are limited. Typically, I’d load comparison SDRs in SDR Console or HDSDR and test them with identical settings as well. At present, the RSPdx is only compatible with a beta version of SDRplay’s own application, SDRuno (which will come out of beta rior to the first major production run). The benefit of using SDRuno is that you unlock the full potential of the RSPdx, plus signal and noise numbers are incredibly accurate.
For each SDR in this comparison, I used their native/OEM application to give them the best possible performance.
I also matched filter settings and made an effort to match AGC and volume settings as closely as I could.
Additionally, I resisted the temptation of comparing my RSP2 with the new RSPdx because I didn’t want to run two simultaneous instances of SDRuno on the same computer––especially considering one was in beta.
Is this comparison perfect? Probably not, but I did the best with the time I had available. I do intend to make further comparisons in the future.
Longwave performance
Via the RSPdx’s new “HDR” mode, both dynamic range and selectivity have been considerably improved with frequencies below 2 MHz. While I’ll fully admit that I’m not much of a longwave DXer, my very first listening session with the RSPdx started in this region of the spectrum.
In fact, the first evening I put the RSPdx on the air and confirmed that I was, indeed, in HDR mode, I noticed a small carrier via the spectrum display on 171 kHz. I clicked on it and quickly discovered it was Medi 1. The signal was faint, but I could clearly ID at least one song. This truly impressed me because I believe this was the first time I had logged Medi 1 on longwave from the shack.
I didn’t connect the Excalibur at that point to see if it could also receive the faint Medi 1 signal, but I imagine it could have. I’m pretty sure this would have been outside the reach of the RSP2, however.
I tried to explore more of the longwave band, but due to local RFI (I suspect an appliance in my home), most of the LW band was inundated with noise. With that said, I did grab three of my benchmark non-directional beacons.
Obviously, the RSPdx is a capable LW receiver. I would like to spend more time on this band once I’ve tracked down the source of my local RFI.
Mediumwave/AM performance
In the past two weeks, I’ve spent many hours with the RSPdx on mediumwave.
We’re heading into the winter months in the northern hemisphere, and that’s normally when my listening habits head south on the bands.
In short: I find the RSPdx to be quite sensitive and selective on the mediumwave bands while the HDR mode is engaged. A major improvement over its predecessor.
I primarily compared the RSPdx with my WinRadio Excalibur on mediumwave since I consider the Excalibur to be a benchmark MW receiver. And, as you’ll hear in the screencasts below, the RSPdx truly gives the Excalibur a run for its money:
Note that my horizontal delta loop antenna is omni-directional, hence the tug-of-war you hear between stations in the clips above.
In truth, I could have done more to stabilize the signal on both of these fine SDRs, but I wanted to keep the comparison as fair as possible.
You might have noticed that both were running AM sync mode. It seems the sync lock on the RSPdx may have also improved––though I would need to do a direct comparison with the RSP2 to know for sure––but in terms of stability, I still found that the WinRadio Excalibur was superior. Mind you, the Excalibur is a $900 – $1,000 receiver and has the strongest synchronous detector of any radio I’ve ever owned.
Shortwave/HF
SDRplay notes on the preliminary specifications sheet that the RSPdx has been “enhanced” when compared with the RSP2 series.
And, after having spent two weeks with the RSPdx on the shortwave bands, I would say this is a bit of an understatement. For although I haven’t compared the RSPdx directly with the RSP2 yet, I do feel HF performance is substantially better than its predecessor. Indeed, in my comparisons, I often found it gave the Excalibur some serious competition. Overall, the Excalibur had an edge on the RSPdx, but the gap has closed substantially. That’s saying something.
For the comparison videos below, I also included the excellent AirSpy HF+ Discovery.
As you can see and hear, the RSPdx is now in the league of some of the finest HF receivers in my arsenal.
But I’m curious to know what you think after listening to these comparisons. Please comment!
Notch Filters
For those of you living in areas with DAB/DAB+ broadcasters nearby, you’ll be happy to note that the RSPdx has a DAB filter to help mitigate any potential overloading.
Also, if you live near a blowtorch mediumwave station, you’ll be quite pleased with the MW notch filter. It’s so effective at filtering out the mediumwave band, my local blowtorch on 1010 kHz is barely visible on the spectrum once the notch filter is engaged. (Note: I should add that neither the DAB nor the mediumwave notch filter was engaged during any of my previous comparisons above.) Check out the screen shots below showing the mediumwave band before and after the MW notch filter is engaged:
Before:
After:
Summary
For those of you looking for a budget wideband SDR with solid performance below 30MHz, look no further.
For $199 US, you’re getting a quality UK-designed and manufactured SDR in a proper metal housing. The OEM application, SDRuno, is one of my favorite SDR applications and can fully take advantage of the RSPdx’s new HDR mode. No doubt, with a little more time, most third-party SDR applications will also support the RSPdx.
Frankly, I was expecting classy mediumwave and longwave performance as this was the most touted upgrade of the RSPdx. SDRplay certainly delivered.
In my experience, SDRplay doesn’t oversell their products. Their preliminary product sheet mentioned improved performance on HF, but their press release didn’t even mention the HF upgrades. And this is where I, in particular, noticed significant improvement. Perhaps this is because I am primarily an SWLer, thus spend a larger portion of my time in the HF region.
SDRplay products also have a mature, robust SDR application via SDRuno. Day to day, I tend to use Simon Brown’s SDR Console as my primary SDR application, since it’s compatible with so many of my SDRs and also offers some of the best recording functionality for those of us who do audio and spectrum archiving. Each time I beta test or review an SDRplay SDR, however, I’m more and more impressed with SDRuno. It’s evolved from being a rather cluttered application to one with a thoughtful, cohesive user interface that’s a joy to use––a product of true iterative agility.
Indeed, after having used SDRuno exclusively these past two weeks, I believe I would consider it as my primary SDR application…if only it had audio recording in addition to spectrum recording, and could run multiple instances with multiple SDRs. Again, given a little time, I wouldn’t be surprised if some of this functionality is eventually integrated.
Questions?
Since many SWLing Post readers already own an SDR, I’m sure some of you will have questions. Let’s address a few of those right now.
Question: “I have an RSP2/RSP2pro. Should I upgrade to the RSPdx?”
My recommendation: If you are a shortwave, mediumwave, or longwave DXer, I would indeed recommend upgrading to the RSPdx. If you primarily use your RSP2 series SDR on frequencies above 30 MHz and only occasionally venture below for casual listening, then I’d keep the RSP2.
Question: “I have an RSP1a. Should I upgrade to the RSPdx?”
My recommendation: If you’ve been enjoying your RSP1a and would like to take your listening/monitoring to the next level, then, yes, I would upgrade. Not only can you take advantage of the RSPdx’s enhanced performance, but the RSPdx affords you three antenna ports, and has a more robust front end.
Question: “I have an RSPduo. Should I buy the RSPdx?”
My recommendation: I’m a big fan of the RSPduo. Unless you’re a dedicated mediumwave/longwave DXer, or you’d just like to add another separate SDR to your radio arsenal, I wouldn’t rush out to buy the RSPdx.
And while I’m offering advice, I’d like to offer my standard two cents on the subject of performance optimization: a radio is only as good as its antenna!If you have a compromised antenna, invest in your antenna before upgrading your radio. You’ll be glad you did.
Conclusion
Happily, I can recommend the SDRplay RSPdx without hesitation. This latest iteration of the RSP series SDR is a proper step forward in terms of performance and functionality––obviously implementing years of customer feedback.
SDRplay also has a proven track record of innovation and customer support. Their documentation, video tutorials, and community are among the best in the industry. Purchase with confidence.
Many thanks to SWLing Post contributor, Mei Tao, who writes:
Yesterday, I received a new radio: the HanRongDa K-603, which was sent to me by the manufacture.They want me to test this prototype machine in order to find any bugs. If there is nothing to fix, I believe this radio will hit the market in this or next month.
K-603 is a small portable radio which also has some great functions. Its major features include:
FM, AM, and SW bands
Bluetooth 5.0 connection
TF Card Player
Recording function
Line in
LCD can display three different languages,English?Chinese and another foreign language.
Powered by the BL-5C Li battery
MW channnel space can be switched between 9KHz adn 10KHz.
Tuning methods: Scan, ATS, and direct key entry
The designer told me that this K-603’s fm coverage is from 87MHz to 108MHz, but they will extend it to 64MHz in the next version. That’s really good news.
In a few days, I will test it carefully. If necessary, I will make side-by-side comparisons with my own Tecsun, Sangean, Radiwow, and Degen radios. Then i will present some text and video reviews.
I would like to share some pictures of this new radio with you and other BCLers
Best wishes to you!
Photos
Thank you, Mei Tao! We look forward to your review of the HanRongDa K-603. Yes, please let us know how it compares to your other receivers. We also look forward to any update regarding price and availability. Thanks for sharing those photos!
Yesterday afternoon, the family and I spent some time at my happy place: Mount Mitchell State Park. This might be our last visit there until spring of 2020 since the Blue Ridge Parkway is often closed during the winter.
Yesterday was unseasonably warm at 48F (9C)–a shot of warm weather before an Arctic front moves in tonight dropping temps to about 10F (-12C) and, likely, dropping 1-3″ of snow as well.
The afternoon at Mount Mitchell gave me a little time to play radio, of course, and put my recently acquired Sony ICF-7600A on the air.
How did I acquire the Sony ICF-7600A? Via the generosity of SWLing Post reader, Ed Earps.
Ed reached out to me after I made the following comment in a recent post:
“The ICF-7600A is a cool analog portable and one I’ve thought about acquiring at some point.”
Ed contacted me immediately:
“Thomas, if you would still like to acquire a ICF-7600A, I have one I would give you. This would be in appreciation of all the work you do in writing the SWLing Post blog.”
A few days later, the ICF-7600A with original box and accessories arrived. Wow!
Thank you so much, Ed! Over the years, members of the SWLing Post community have been so kind and so generous, it makes a guy feel humbled and appreciated. Thank you!
The ICF-7600A fits perfectly in my Red Oxx Hound pack.
I’m loving the ICF-7600A.
There’s something so authentic about tuning a good analog portable. It’s hard for me to describe, but I can certainly say it always takes me back to my radio roots.
The ICF-7600A has a low noise floor and seems to be incredibly sensitive. I easily snagged several stations on 31 meters, but ended up enjoying music via All India Radio while brewing a little coffee with my alcohol stove (handmade by my buddy, Greg–thanks, Greg!).
Hey, when you’re a coffee snob, you brew where you are!
But I digress…
I’m especially impressed with the ICF-7600A’s mediumwave performance. I logged a number of benchmark daytime and greyline stations yesterday. I haven’t opened the ‘7600A, but I imagine it has a decent ferrite bar inside based on its overall performance on the AM broadcast band and its nulling capabilities.
Next time, I’ll bring the AN200 mag loop and couple it with the ‘7600A. I’m pretty sure that’ll make for a winning combo.
All-in-all, I couldn’t have asked for a better day: the weather was wonderful, the coffee freshly-brewed, and the gifted ICF-7600A was the perfect radio companion as our family soaked in the scenery after a hike to the summit.
However, placing the Ferrite Antenna near the center of the loop does enhance its performance and the Lazy Susan was something I had been using long ago to quickly re-orient the radio azmuth to accommodate the signal source. But, like my mentor, minor improvements like this can really enhance performance of smaller portables on medium wave. He used cardboard and I used scrap wood from the work shop. Either way, not much money was involved in this minor enhancement.
These inexpensive additions to the listening post really make the PL380 and the AN200 combo provide hours of enjoyment from medium wave DXing. Now,if only I can find the gent’s name who came up with this little gizmo, I’d love to thank him!!
73’s!
Thanks for sharing your setup, Jack! I can assure you that Rich Stahl (WR3V) will be happy you “stole” his idea. That’s what it’s all about–helping each other! I love the little table/stand you built for the portable and how it perfectly accommodates the loop. Great job!
The signal was lost in August when the main transmitter’s rusty mast on Rarotonga was dismantled.
Radio Cook Islands’ general manager Jeanne Matenga said Blue Sky, which manages the network, reactivated a smaller transmitter near the airport late last week.
She said the government seemed to be worried about the absence of a radio signal to some parts of the country as the cyclone season neared.
“People in Aitutaki can hear it and I got a text message from someone in Mitiaro saying they could hear it there as well.
“If it reaches Mitiaro, it will get Atiu and Mauke because those islands are very close to each other. Possibly Palmerston might be able to get a signal too because it’s closer to Aitutaki, and the Northern Groups still have their FM.”
