Category Archives: Longwave

The XHDATA D-808 and longwave: how to build an effective antenna

Many thanks to SWLing Post contributor, Mad Radio DXer, who writes:

I said I would share my results for attempting to receive LW signals on the XHDATA D-808, & if I can use a longwire to improve reception on this radio. This was after posting videos when I used around 50 metres of longwire connected to the D-808 for improved Medium Wave reception & to prove it works.

This first video shows that it is not possible for LW, no matter if I connect the 50 metres longwire to the 3.5mm input or the whip antenna. I also compare reception of the same station with the Degen DE1103 PLL using the 3.5mm input. The Degen DE1103 still had better reception even when I used the whip antenna extended at the very minimum when using the LW/MW external antenna trick. I know I should have used the internal ferrite antenna of the Degen compared to the D-808, but in any case I did try off camera & reception was about the same. So unfortunately the D-808 was never going to win this round.

However, there is a solution.

The answer? Build yourself a Long Wave induction antenna as shown in the second video [below]. I made one some time ago, as I grew frustrated at how poor the Tecsun radios were on this part of the band & that there were no LW induction antennas available to buy. I tried a signal on 207 kHz which is RÚV Rás 2 from Iceland. Either a radio with a very good internal antenna or a good external antenna is needed to receive this station at my QTH in southern England.

Placing the D-808 on the induction antenna resulted in a very pleasing result, which was it did get reception of Iceland on 207 kHz. So this shows that it is possible to DX on the LW bands with the D-808 with some “external help”.

For anyone interested making a LW induction antenna as shown above, here is a link to a video that has basic instructions & further results. It may be a very simple build & finish what I did, but for me the most important thing is that it works.

I hope my comments & videos will be a great help to all. Happy DXing.


Mad Radio DXer.

Excellent–your comments and videos are most welcome! There are quite a number of SWLing Post readers who are avid longwave DXers. I love the simplicity and efficacy of your longwave antenna–something anyone could build.  A clever upgrade to the affordable D-808. Thank you for sharing!

Addendum: More Notes on the HF+ SDR on Medium Wave & Long Wave

In my recent post on the AirSpy HF+ vs Elad FDM-S2, I commented on medium wave reception only.

This past weekend I swapped out the Wellbrook ALA1530S+ for another Wellbrook loop, the ALA1530LN Pro. This LN Pro model is less likely to overload receivers at my suburban Tacoma, WA location. Both AirSpy and Elad radios performed admirably with the LN Pro and it was nearly impossible to find any reception differences on medium wave.

Before the antenna swap though I experimented with inline attenuation modules (“bullets”), typically used in cable TV installations. I used the same sample rates on the SDRs as described in the previous article. After some tests with different attenuation levels, I came to the following conclusions during daytime comparisons:

FDM-S2 with ALA1530S+ loop, medium wave: needs a minimum of 6 dB attenuation to avoid overloading. Anything less causes saturation of the spectrum & waterfall, “crunching” overload noises, and minimal or no received signal.

HF+ with ALA1530S+ loop, medium wave: I had to search diligently to find any signs of false signals or overloading, but finally noticed a weak image or spur of a S-9+60 dB (-13.5 dBm) local station on 1560 that was appearing very weakly on 1270 kHz, mixing with the station on that frequency. Sometimes it was there, other times the spur or image would drop down and disappear, leaving the 1270 signal alone. If I added just 3 dB of attenuation in the antenna’s feed line, the interference from the 1560 station was gone for good. The S-9+60 dB station is a very strong signal; it’s impressive that the AirSpy HF+ deals with this and similar powerhouse signals so well.

Long wave: Below are two screen captures from my local long wave reception in the evening, made moments apart with each receiver.



As you can tell, there are a half dozen or so additional signals seen on the HF+ below 200 kHz that do not appear on the FDM-S2. These extra spikes are images or spurs from medium wave signals that were missing from the FDM-S2’s reception–bravo Elad! However, the remaining spikes on both radios below 200 kHz seemed to be noise or interference.

Each receiver had roughly equal performance in the bulk of the long wave spectrum, when I did A-B comparisons on the same beacon signals. I’m not a LW or NDB DXer however, so I can’t claim any expertise on these frequencies. In short, though, both radios seem neck-and-neck from about 200 to 500 kHz.

The DXer of LW frequencies may want to look elsewhere for a better performing radio than either the FDM-S2 or HF+. SWLing Post reader Tudor Vedeanu has commented that the SDRPlay RSP1A  and the Eton E1 work very well at long wave.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

WI2XLQ: Brian Justin’s annual longwave broadcast Dec 24-26

Canadian Reginald Aubrey Fessenden in his lab believed circa 1906 (Source: Radio Canada International)

Now an annual Christmas tradition, Brian Justin (WA1ZMS) will put his longwave experimental station WI2XLQ on the air to commemorate the 110th anniversary of Reginald Fessenden’s first audio transmission.

WI2XLQ will be on the air from 17:00 UTC Dec 24th on 486 kHz and run for 48 hours until 16:59 UTC on Dec 26th.

Listener reports may be sent to Brian Justin, WA1ZMS, at his address.

If you would like more information about Brian Justin and WI2XLQ, check out our interview with him in 2013. Indeed, I successfully heard the 2013 WG2XFG broadcast and posted this audio clip on the Shortwave Radio Audio Archive.

Additionally, SWLing Post reader, George Stein has a very personal connection with radio pioneer, Reginald Fessenden: click here to read his story.

Don shares spectrum recordings from northern Peru

Many thanks to SWLing Post contributor, Don Moore, who writes:

I’ve been traveling through northern Peru and I’ve made some SDR recordings along the way – medium wave, long wave, and some shortwave meter bands. I hope to eventually get through them all!

I have also uploaded some recordings to a shared Google drive so that other DXers can hear what the bands sound like in northeastern Peru, on the edge of the Amazon jungle. Maybe some of the blog readers would be interested in this. You will need the below link to see the SDR files and an explanatory document. I plan to add a few more once I get another hotel with a good Internet connection again.

Click here to download.

Fantastic, Don!  Thank you for sharing your spectrum recordings!

Post readers: If you don’t already have HDSDR installed on your PC, you’ll need to grab it here. HDSDR is free and can playback these spectrum recordings. Once installed, simply press the “play” button on the HDSDR console and point HDSDR to the downloaded spectrum file. You’ll be tuning through Peruvian spectrum in no time!

Also, check out Don Moore’s excellent blog: 

A review of the SDRplay RSP1A software defined radio


Today, SDRplay, the UK-based manufacturer of affordable software defined receivers, announced a new addition to their product line: the SDRplay RSP-1A.

The RSP1A joins the SDRplay product line of the RSP2 ($169.95 US), and RSP2 Pro ($199.95 US). The new RSP1A will retail for $99.00 US.

But what of this SDR’s performance?  In a nutshell: as of today, I’d contend that the RSP1A will simply be the best SDR value on the market. End of story. There is nothing I know in the $99 price bracket that can beat it.

How do I know this?  I can make this statement with confidence because I have been involved with real-world testing and evaluation of the RSP1A Alpha, Beta, and production models since May. I took the RSP1A with me to Canada this past summer for field recordings with my laptop, and I’ve also evaluated the RSP at my home. Like a number of other reviewers, I’ve been intimately involved with putting the RSP1A through its paces. And let’s just say I like what I’ve seen.

I actually do quite a bit of Alpha and Beta testing for manufacturers. While it’s time-consuming volunteer work and requires meticulous attention to minor details, it gives me an opportunity to have meaningful positive impact on an upcoming product. Manufacturers that actively involve enthusiasts in their testing phase tend to produce better-quality products on the first run. Better products, of course, mean a better radio market with options for those only now discovering the mystery––and fun––of radio as well as DXing.

Since the RSP1A is essentially iterative agility on behalf of SDRplay, the RSP1A was surprisingly solid even in its early release. And try as I might, there were very few issues I ever needed to report back to the engineering team. SDRplay took each item of feedback seriously, logged it, and followed-up. Over the course of the evaluation period, SDRplay improved their dedicated SDR application SDRuno, as well.

In essence, the RSP1A hardware now in production and shipping has been thoroughly tested and is ripe-and-ready for your radio adventures.

I have not compared the RSP and RSP1A side by side; running two instances of SDRuno on the same PC has been problematic. To my ear, when I’ve tested one after the other, the RSP1A serves up slightly better sensitivity, perhaps due to a slightly lower noise floor. Also the RSP1A frequency stability is much improved over the RSP1.

Specifically, the following upgrades have been made per SDRplay:

  • ADC resolution increased to 14-bit native for sample rates below 6 MHz, increasing to 16 bits with decimation
  • Enhanced RF pre-selection (greater filter selectivity plus 4 additional sub-bands compared to the original RSP1) for reduced levels of spurious responses
  • Improved LNA architecture with variable gain––the RSP1 had just a single gain step
  • Improved intermodulation performance
  • Performance extended to cover 1kHz to 2 GHz with a single antenna port.
  • Bias-T facility
  • Improved frequency stability incorporating a 0.5ppm TCXO (software trimmable to 0.01ppm)
  • Selectable broadcast AM/FM/DAB notch filters
  • RF shielding within the robust plastic casing


Suffice to say, this budget SDR delivers, and users will be wooed by its stellar performance.

I’ve spent 95% of my evaluation time on the HF and mediumwave bands and I’ve been impressed with the receiver’s sensitivity, selectivity, and AGC control. The audio fidelity is also highly customizable since it’s pumping audio directly through your PC’s system.

I haven’t spent any time above the aviation bands (higher than 140 MHz); I have, however, tested the RSP1A thoroughly on the FM broadcast bands and found it a solid FM performer. Note, too, that SDRuno’s built-in RDS decoder window provides quite a lot of data.

I’m also pleased that I haven’t noticed any front-end overloading––this, despite the fact that during travel, I’ve used it in the vicinity of some powerful broadcasters.

Comparing to benchmarks

I’ve compared the RSP1A to the Elad FDM-S2 ($500), WinRadio Excalibur ($900) and Microtelecom Perseus ($900).

The WinRadio G31DDC “Excalibur”

But let’s be clear, here: this is not an “apples-to-apples” comparison since the RSP1A is a fraction of the cost of the others, and is also a wideband receiver (1 kHz to 2 GHz). The only other SDR I own that has VHF coverage is the FDM-S2, which tops out at 160 MHz.

Pricier HF-focused SDRs have distinct hardware advantages––especially in terms of filtering––that give them an edge over budget wideband SDRs. Still, in my comparisons, the RSP1A holds its own quite well.

Compared to the WinRadio Excalibur, for example, this SDR came fairly close in terms of sensitivity.  The WinRadio’s synchronous detector––which I consider to be the best in the business––was indeed more stable than that of the RSP1A. The RSP1A sync lock could falter a bit during a weak signal’s QSB dip compared with the Excalibur.

But again, HF SDRs in the league of the FDM-S2, Excalibur, and Perseus have the luxury of designing receiver architecture around a much smaller portion of the spectrum. If you are a hard-core DXer looking for uncompromised performance on the HF/MW bands, then you should invest in one of these benchmark SDRs. I have, and I’d never give one of them up.

With that said, even though I have these amazing benchmark SDRs at my disposal, I still purchased the original RSP1 (then at $159 US) years ago. Why?  For one thing, it’s more portable than the Excalibur or Perseus as it requires no external power supply (like the excellent FDM-S2, the RSP derives its power from the USB data cable). Additionally, I do like to play with frequencies above 50 MHz from time to time. The RSP offers up an all-in-one RF toolbox at a very affordable price. I don’t hesitate to throw the RSP in my pack and take it anywhere I’m travelling. If it gets damaged or lost, I’m only out $99––not $1,000.

Again, RSP1A’s bang-for-buck simply blows my mind.

Side note: I do wish someone would develop an accessory outboard filter box that could be implemented with budget wideband SDRs, thus providing, in a sense, a hardware “upgrade.” Something like the Elad SPF-08 preselector box designed for the FDM-S2

Any cons?

This review has been overwhelmingly positive because, frankly, the RSP1A is challenging to find fault with. Of course, if it carried a price tag of $600-900, I’d be much more critical of its performance as compared with my benchmark receivers in that same price class. I’d fully expect a robust preselector system, a bullet-proof front end, and performance that could match or surpass the benchmarks.

But for just $99? You simply can’t get that kind of hardware for that cost.  So SDRplay engineering cleverly pulls every bit of performance out of their receiver by focusing on their SDRuno application, which is optimized for this receiver.  And for that reason, it’s in a class by itself.

Admittedly, when SDRplay first introduced their application, SDRuno, I wasn’t the biggest fan. I found it rather quirky and a little cumbersome to use. SDRuno has come a long way, though; SDRplay has continuously improved it, and today, I prefer it to HDSDR and SDR console. SDRuno is much less cumbersome to use than it used to be, and the default window arrangement is pleasing (though I’d still like SDRuno windows to lock and act as one window as I flip through programs on my Win 10 PC). I even prefer SDRuno to Elad’s application in terms of ease of use.

If more AF/IQ recording features are added (virtual receivers, for example) it could even become my application of choice.

The great thing about the SDRplay RSP series, however, is that they’re supported by so many third-party SDR apps. If you don’t like the one you’re using, there are numerous others to chose from. SDRplay takes an affirmative stance that their hardware should be usable on as many platforms with as many applications as possible. Kudos to them.

Here’s a question I know I’ll be asked…

“I just purchased the RSP1. Should I upgrade?”

Good question! As you might guess, my answer is fairly simple and depends on your particular needs:

If you’re happy with the RSP1 and see no real benefit in the RSP1A upgrades above, don’t bother upgrading. Seriously…enjoy what you have! The RSP1 is still a sharp, capable, versatile little SDR and fully supported by SDRplay and its community. I’ve worked some incredible DX with mine over the past few years, and love it.

If you like the sound of the RSP1A and would appreciate the upgrades listed above, then go for it! After all, it’s only $99! Consider this: the price is less than that of my recently reviewed Digitech AR-1780 portable and less than the venerable Tecsun PL-660. Even with a modest external antenna, it will perform circles around these rigs.

If you need an excuse to justify the upgrade to the RSP1A, consider doing what I’m planning to do: give your RSP1 to a friend or someone interested in the hobby. Or, donate it to your radio club as a raffle prize. Then too, of course, you can snag a decent price for it by selling it on eBay or


While a little busy, I do enjoy the combined spectrum display option on SDRuno.

If you can’t tell, I’m most impressed with this latest offering from SDRplay. I can recommend it with confidence because you simply can’t beat the performance and features for the price.

If you’re considering the RSP1A as your first SDR, you’ll be happy to know SDRplay’s Mike Ladd has also amassed a healthy number of SDRuno instructional videos on YouTube as well. If you start with the first video, by the end of the series you’ll be adept at using SDRuno. Couldn’t be easier.

Think of it this way: The RSP1A is the sporty-but-affordable compact car of the SDR world. It delivers performance well above its comparatively modest price and is fun to operate. In terms of DX, it gets you from point A to point B very comfortably––and quite affordably!

With just $99, there’s no reason you can’t join the world of SDR––the RSP1A is a very accessible, very intuitive SDR start your exploration of the radio spectrum.

Click here to view the RSP1A at SDRplay’s website.