Category Archives: Reviews

A review of the SDRplay RSPdx wideband SDR receiver

SDRplay recently announced the latest product in their line of affordable 14 bit wideband SDRs: the SDRplay RSPdx.

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.

I compared the SDRplay RSPdx with the WinRadio Excalibur and Airspy HF+ Discovery. Here’s how I set up my comparisons:

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:

740 AM – RSPdx vs. Excalibur:

860 AM – RSPdx vs. Excalibur:

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.

40M LSB – RSPdx vs. HF+ Discovery:

80M USB – RSPdx vs. Excalibur:

31M Broadcast – RSPdx vs. 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.

Click here to check out the RSPdx at SDRplay.

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It’s not a travel radio if it doesn’t have an alarm clock

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The CC Skywave SSB is set to wake me at 3:30 to catch a 5:30 flight.

I have a pretty accurate body clock. Regardless of when I doze off, I always wake up at the same time.

When I’m at home on my regular schedule, I trust my “internal chronometer” so much, I haven’t set an alarm in years.

When I travel, it’s a completely different story…

It’s a rare occurrence when a flight, train, or even road trip allow me to wake up at my normal time, so I rely on an alarm clock.

In fact, I’ll let you in on a little secret: I’m a nervous Nellie when I’m forced to break my sleep cycle to catch an early flight. My fear of missing a flight may even border on paranoia–I’ll wake up multiple times during the night in a panic unless I feel completely at ease that there’s an alarm system in place to wake me no matter what.

I recently told a friend about this fear and he asked, “Why not just set the alarm on your phone?!”

Simple answer: I don’t trust smart phones and tablets. They’re too complicated with so many nighttime settings, alarm/alert volume levels, short battery life, etc. etc.

Case in point…

Earlier this year, I had to catch an early flight and needed to wake up at 4:00 AM, so I scheduled my iPhone and iPad to alarm at 4:00. (When at home, I try to have my iPhone/iPad wake me first, because the alarm is very gradual and doesn’t disturb my wife.) Of course, I also set my travel radio’s alarm clock for 4:10, as a fail safe.

Knowing I had a total of three(!!!) alarm clocks set, I slept like a baby.

At 4:10 AM, my travel radio alarm started beeping. The iPhone and iPad were completely silent.

Turns out, the iPad decided to do an operating system update during the night. For some reason, after rebooting, it simply forgot about the alarm. (Thanks, iPad!) And the iPhone? I’m still not sure how/why, but the mute switch on the side of the phone was engaged and if it vibrated to wake me, I never heard it rumbling on the night stand.

Thank goodness the travel radio had my back, else I would have missed that flight.

Travel radios: Never leave home without one!

I like to be a self-sufficient traveler even though I only travel with one bag and pack very lightly. I never rely on my destination to have a functioning alarm clock (with battery backup, of course) or effective wake up call service. Regardless of how minimally I pack, I always take a travel radio.

In February, for example, I travelled to Philadelphia for the Winter SWL Fest. Even though my trip was nearly a week long, to keep from paying a carry-on fee with Frontier airlines, I packed everything in a bag that met their strict “personal carry-on” bag size.

Regular readers know I’m a bit of a pack geek, so my bag of choice was the Tom Bihn Stowaway. Here’s the bag fully packed out at my feet in the airport:

Here’s a photo of everything I packed in the Stowaway for that trip:

This particular trip really pushed the limits on my minimalist travel philosophy. Honestly? It was a fun challenge! I had to hone my pack contents down to only the essentials (don’t make fun of me for believing three flashlights were essential–the previous year, our hotel was without power for several days).

Still, I made room for one of the smallest travel radios in my arsenal: the County Comm Marathon ETFR:

I chose the ETFR because it has a custom case that could attach to my belt or pack strap if interior space became too tight. The ETFR radio hasn’t been in production for a decade, but it’s an effective radio companion and the alarm works without fail.

Choosing a travel radio

Most modern digital portables are based on DSP chips that have clock and alarm functions, so you might already own an effective travel radio.

With that said, I always prioritize radio features that benefit a traveler, of course; here are some that I look for:

Small size: Naturally, it’s sensible to look for a travel radio that’s small for its receiver class for ease in packing.
Overall sturdy chassis: Any travel radio should have a sturdy body case that can withstand the rigors of travel.
Built-in Alarm/Sleep Timer functions: We’ve already exhausted this topic, right?.
Powered by AA batteries: While the newer lithium ion battery packs are fairly efficient, I still prefer the AA battery standard, which allows me to obtain batteries as needed in most settings; a fresh set of alkaline (or freshly-charged) batteries will power most portables for hours on end.
Standard USB charging cable: If I can charge batteries internally, a USB charging cable can simply plug into my smart phone’s USB power adapter or the USB port on my laptop; no extra “wall wart” equals less weight and less annoyance.
ETM: Many new digital portables have an ETM function which allow auto-scanning of a radio band (AM/FM/SW), saving what it finds in temporary memory locations–a great way to get a quick overview of stations. (As this function typically takes several minutes to complete on shortwave, I usually set it before unpacking or taking a shower. When I return to my radio, it’s ready to browse.)
Single-Side Band: While I rarely listen to SSB broadcasts when traveling, I still like to pack an SSB-capable receiver–especially for longer trips.
RDS: Though an RDS (Radio Data System) is FM-only, it’s a great feature for identifying station call signs and genre (i.e., public radio, rock, pop, country, jazz, classical, etc.)
External antenna jack: I like to carry a reel-type or clip-on wire external antenna if I plan to spend serious time SWLing. Having a built-in external jack means that the connection is easy, no need to bother with wire and an alligator clip to the telescoping whip.
Tuning wheel/knob: Since I spend a lot of time band-scanning while travelling, I prefer a tactile wheel or knob for tuning my travel radio.
Key lock: Most radios have a key lock to prevent accidentally turning a radio on in transit–but with a travel radio, it’s especially important to have a key lock that can’t be accidentally disengaged.
LED flashlight: Very few radios have this, but it’s handy to have when travelling. Note that the County Comm ETFR (above) does!
Temperature display: Many DSP-based radios have a built-in thermometer and temperature display; I like this when I travel anytime, but especially when I’m camping.

While I don’t have a portable that meets 100% of the above travel radio wish-list, I do have several that score very highly.

Since this is a favorite topic, I’ve written a number of articles with reviews of travel radios. In my CC Skywave SSB review last year, I list a number of current favorites.

I should also mention that one great deal at time of posting is the Eton Executive Traveler.

It’s a brilliant little radio for $34.99 shipped (note this affiliate link supports the SWLing Post).

One of our readers has been following the price of this little radio for months–it’s being sold at an all-time low at present.

What’s in your travel pack?

What’s your favorite travel radio? What features are important to you? Anyone else paranoid about missing early flights?

Please comment!

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Final review of the CommRadio CTX-10 QRP general coverage transceiver

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Earlier this year I published what I called an “initial” review of the CommRadio CTX-10 QRP transceiver, promising an eventual final review. The reason for this is that I sensed there were important CTX-10 updates on the horizon, and I wanted to re-evaluate the rig once the upgrades had been implemented through firmware.

This final review builds upon the initial review––think of it as the second installment, or “Part 2″––so if you’re considering the purchase of a CTX-10 and haven’t read the previous post about it, please do read the initial review first.

Upgrades

As anticipated, via simple at-home firmware updates, since my initial review the CTX-10 has now been upgraded and tweaked a number of times. [Click here to view all of the documented firmware updates and notes at CommRadio.]

I’ve been very pleased with the attention CommRadio has paid to their customer feedback on some of the most important requests.

Instead of reiterating what I wrote in the initial review, I’ll jump straight into the upgrades.

Operating split

At time of posting my initial review, the CTX-10 didn’t have A/B VFOs. This was my primary gripe about the CTX-10, because without A/B VFOs, there was no way to operate split, which meant that you could not work DX stations that use split to manage large pileups. This is actually a really important feature for a QRP radio because during split operation, a pileup is pulled apart across a few kHz of bandwidth, thus giving a 10-watt signal a better chance of being heard through a collection of legal-limit signals.

On June 10, 2019, CommRadio released a firmware package that added A/B VFOs and the ability to operate split to the CTX-10.

Even though there are only a limited number of buttons on the front panel, it’s incredibly simple to enter into split mode:

Chose the frequency and mode;
Hold the STEP button for one second or more, then release. You’ll then see a split display indicating the TX and RX frequencies.
Use the left arrow key [<] to toggle between them.

I do like the clear TX and RX lines, which leave no doubt in the user’s mind what the frequency used for transmitting and receiving is. On some radios, this can be a bit confusing.

Split operation is simple and effective, thus I consider this issue fully resolved.

ATU flexibility

In my initial review, I noted that the CTX-10 ATU needed near-resonant antennas for the ATU to make a strong 1:1 match. Indeed, a number of times I actually used a near-resonant antenna in the field––the EFT Trail-Friendly, for example––and the ATU couldn’t get below a 3:1 match. For what it’s worth, CommRadio states that the CTX-10 can easily handle 3:1.

Making a Parks On The Air activation at Tar Hollow in Ohio.

CommRadio has made modifications to the ATU function, improving the performance of the antenna-tuner algorithm, which had a significant impact on 80 and 60 meters. I’ve also had better luck with a number of field antennas I’ve tried on 40 and 20 meters. Is it as good as the Elecraft KX-series ATUs? No.

Having a built-in ATU on the CTX-10 is certainly a valuable feature in the field. When I need to match a challenging antenna with the CTX-10, I bring my Emtech ZM-2 manual tuner along for the ride.

SSB operation?

There still is no way to adjust the microphone gain control nor microphone compression on the CTX-10. Much like a military or commercial radio, the CTX-10 is optimized for just one style of mic: in its case, the modular MFJ-290MY or Yaesu MH-31A8J handheld mic.

The CTX-10 microphone input has a limiting pre-amplifier with built-in compressor and ambient noise gate–in short, the CTX-10 handles all microphone settings automatically.

Through firmware updates, a number of positive adjustments have been made to the microphone settings:

the microphone-decay timer has been tweaked so that audio clipping is less of a concern
audio clarity and gain have been improved
audio power has been improved resulting in .5 to .75 watts of additional peak power
microphone audio leveling has been improved
VOX attack and decay timing has been improved

These are all welcome adjustments.

I would note here, though, that if you plan to use a mic other than the MFJ-290MY or Yaesu MH-31A8J handheld mics, you will have a limited means of adjusting the mic parameters unless you have an external mic EQ. A number of readers, for example, have asked about using their Heil boom headset with the AD-1-YM cable adapter on the CTX-10. Boom headsets are a wonderful tool for field operation because they free your hands to log contacts. As for using boom headsets on the CTX-10, since I don’t have the appropriate adapter, I can’t speak to this. But since you can’t control mic gain, it might take time to learn how to position the boom mic and adjust your voice level for optimum performance.

CW operation

As mentioned in our initial review, the CTX-10 does not support QSK/full break-in operation. Rather, the CTX-10 uses a traditional relay for switching between transmit and receive. During CW operations, you’ll hear a relay click when switching from TX to RX and back again.

The CW hang time delay on the CTX-10 is not currently adjustable. For high-speed CW ops that prefer a faster relay recovery, I suspect this could be an annoyance.

There have been recent CTX-10 firmware upgrades that have helped solve issues found with CW keyer timing in early units. I found the timing issues were mainly present while sending high-speed CW (25 WPM+). My buddy Vlado (N3CZ) put the CTX-10 through some high speed tests, and was pleased with the results overall.

I will reiterate here that the CTX-10 lacks other controls many CW operators appreciate. Currently, the CTX-10 lacks a sidetone control; as a result, you cannot change the sidetone volume/tone, nor can you turn it off. I continue to hope that CommRadio will fix this quirk via a future firmware upgrade.

The CTX-10’s built-in CW keyer does not currently support iambic keying. Meaning, when both levers of a dual paddle are closed simultaneously (squeezed), it will not send a series of alternating dots and dashes. I imagine this could be addressed in a future firmware update.

Additionally, without re-wiring your paddle, you can’t change which side of your paddle sends ‘dits’ and which sends ‘dahs.’ A minor con, for sure–still, most modern QRP transceivers allow you this flexibility.

Revisiting the basic feature set

Let’s be clear: as I stated at length in my initial review, the CommRadio CTX-10 was designed around simple operation, like one might expect from a military or commercial channelized radio. I know ham radio operators and preparedness enthusiasts who prefer this approach to gear design, and they will appreciate this CTX-10 design philosophy.

Still, the CTX-10 lacks many of the features and adjustments you’d typically find on a QRP transceiver in its price class. Instead, the CTX-10 was designed to handle many of these adjustments automatically.

The CTX-10 still has no separate RF gain control. The CTX-10’s RF gain is directly tied to the three AGC settings (slow, medium, and fast). While I believe it does a fine job of adjusting RF gain, I do ride an RF gain control a lot during noisy summer conditions, and miss this feature.

The CTX-10 still has no passband (PBT) control, notch filter, or noise blanker––all features I’d normally expect in a QRP radio at this price level.

There are no CW (os SSB) memory keyers. I wouldn’t expect these, as I believe only the Elecraft KX2 and KX3 sport this feature in this price class of QRP radios.

Also, the ARRL lab reports of the CTX-10 are found in the July 2019 issue of QST (Bob Allison, WB1GCM) noted:

Though adequately sensitive, its third-order IMD and blocking gain compression dynamic ranges, as measured in our laboratory, are more suited to casual operation with antennas of modest gain.

Even with the AGC disabled, one or more strong, adjacent signals will result in the reduction of speaker volume, and I was unable to measure the reciprocal mixing dynamic range (RMDR).

The dynamic range was reported as 58 dB, which is a very low number. Blocking was 65 dB.

Update, 25 Nov 2020: Rob Sherwood recently tested and added the CTX-10 to his receiver test data table.

Out of his comprehensive table which includes vintage radios, the CTX-10 scored the lowest of all of them sorted by third-order dynamic range narrow spaced. It is literally at the bottom of his list: at time of posting, number 146 out of 146 tested radios. Rob concluded that an out-of-passband signal that is approximately S9 will start blocking the radio. Click here for his full notes (PDF).

The CTX-10 doesn’t really have the tool set or receiver performance to cope well with contests or DX conditions.

Please note: as with most firmware-based radios, some missing features could potentially be added in future firmware upgrades. If one of these items is keeping you from purchasing the CTX-10, please contact CommRadio and inquire.

Is the CTX-10 for you?

The CTX-10 on air at the W4DXCC conference

With the most recent upgrades, CommRadio has solved the major issues that kept me from recommending it in my initial review. I still feel there are more capable portable transceivers for the $1,000 US price.

The addition of split operation was especially key for me, as I do operate split. The more nuanced adjustments to the CW keyer, an extra feature to prevent the radio from accidentally turning on while in transit, and the adjustments to the mic algorithm, all make this radio more pleasant to operate at home or (especially) in the field.

As I mentioned in the initial review, the CTX-10 owner is one who operates casually and values a very simple, straightforward radio. Those who want a sturdy, no-frills, set-it-and-forget-it rig. If that’s you, take a closer look at the CTX-10: it may just suit your needs if you’re not planning on using it on Field Day or during RF-dense contest environments.

If, however, you’re looking for a full-featured QRP radio with many of the features and nuanced adjustments you’d expect in the shack, check out the Yaesu FT-818, Elecraft KX2, Elecraft KX3, lab599 TX-500, or the Icom IC-705. All of these rigs are excellent.

The two major advantages of the CTX-10 over competitors are:

the ability to charge the internal batteries from almost any voltage source, and
a higher TX duty cycle (without needing to add external heat sinks).

I believe the CTX-10 will have appeal for radio enthusiasts who value these characteristics:

All-in-one-box portability with no extra wired accessory components
Best-in-class internal battery life
Best-in-class intelligent battery charging
Digital modes like FT-8 and the ability to operate them in the field from internal batteries for extended periods of time
Very few manual adjustments
Broadcast listening, as the CTX-10 is also a broadcast receiver
Best-in-class hardware

The CTX-10’s overall construction and components are, as I’ve said, near mil-spec. While the CTX-10 isn’t weatherized or waterproof––no more than any of its current competitors (save the TX-500)––the construction is top-shelf, for sure. It should run for decades without need of repair.

Although I can’t recommend to the CTX-10 for serious radio operators, it is built like a tank, and has a simple feature set for field operation. It’s also designed and manufactured right here in the USA. All the better.

Click here to check out the CTX-10 at CommRadio.

Click here to check price and availability at Universal Radio.

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A review of the Red Oxx Hound EDC Pack

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Long-time SWLing Post readers know that I geek out about a number of things: radio, of course, but also travel and packs. No doubt my love of backpacks and carry bags stems from my love of travel…and the need to have a radio or two along. In the past, I’ve reviewed a number of backpacks, travel pouches and cases. What follows is a new pack review.

Introducing the Red Oxx Hound

Last month, Montana-based company Red Oxx sent me their latest small carry bag for evaluation and review. This small crossbody bag, affectionately known as The Hound, is made to stay by your side and carry your important gear––just as you’d expect of man’s (or woman’s) best friend.

Red Oxx is not a new name here on the SWLing Post. In the past, I’ve reviewed the Red Oxx Lil’ Roy and helped Red Oxx evaluate and review their first-generation Micro Manager pack. I also travel frequently with my Red Oxx Mini Boss, one of my favorite one-bag travel packs. I have several other Red Oxx brand accessories and travel cubes. All of which hold up very well, indeed.

Hazel thinking, “Seriously? Another pack?…Okay, I like the name, but are there any treats in there?”

In the spirit of full disclosure, this pre-production pack was sent to me at no cost for comment, evaluation, and eventual review, assuming no design changes are made before production.

So what is the Hound? I would describe it as a small padded EDC pack with a carry strap, designed to be a stand-alone, to function as a travel pouch––and/or to moonlight as a packing cube, since it easily fits inside another travel pack.

In terms of size, the Hound is somewhere between the Red Oxx Lil’ Roy and Micro Manager. It’s roughly 9” tall, 7” wide, and 3” deep, by my measurements. It’s not quite big enough to hold my Microsoft Surface Go tablet, but it holds my eReader and my wife’s iPad Mini with room to spare.

On the front exterior panel, you’ll find a zippered pocket. While this pocket isn’t pleated, the pack is forgiving and flexible, so it’ll easily hold a thick paperback book as long as the main compartment isn’t packed out densely.

On the inside of the Hound, you’ll find one main compartment with one open pocket opposite the side panel of the external pocket.

The floor and two 7”x 9” side panels are padded and do a great job protecting contents. I like the new super-thin Hyper-Cel padding Red Oxx uses for the Hound because it gives the bag’s contents padded protection without making it too rigid, thick, or unforgiving, if you want to cram a little something extra in.

I posted a small teaser a few weeks ago when I took one of my favorite radios (the Panasonic RF-B65) and a copy of the WRTH to a local park for some relaxed radio listening. Both the Panasonic and WRTH fit inside with just a little room to spare for small accessories like earbuds, spare batteries, a wire antenna, and a snack. The radio fits perfectly in the interior open pocket and is essentially protected on all sides, save the top, which is no problem if you’re carrying it with the strap.

Like all Red Oxx packs, the Hound’s exterior sports 1000-weight Cordura nylon material that’s available in twelve solid color combos (plus 4 extra “Red Eye” colors for a limited time) . This is a proven, incredibly durable material that will surely outlast this bag hauler’s handling.

The Hound also features the Red Oxx standard #10 YKK Vislon zipper on the main compartment, and a #5 zipper on the front pocket. These beefy zipper pulls also have attached “monkey fist” knots made from nylon cording that permit easy zipper operation. The Hound is designed for and ships with a shoulder strap made of durable webbing. Two D-rings on opposite sides of the main zipper insure balance on the shoulder.

Taking the Hound for a walk

The Hound makes for a great bag to protect your portable tech, but also accommodates other items in your everyday carry (EDC).

In fact, if you’re a bit of an EDC minimalist (ahem…not quite me) you likely don’t want a full backpack or shoulder bag to carry your gear. Something the size of the Hound would make for an ideal lightweight carry companion.

Red Oxx went through a couple iterations of this bag before adopting its current dimensions; the result is an incredibly useful and accommodating pack.

The Hound packed in the top of my GR1

One function I find the Hound ideally suited for is as an in-flight kit bag. Being a one-bag traveler when I fly, I only carry one main travel pack that can fit under the seat in front of me. Having this flexibility means that I don’t have to worry about being first during a boarding call to grab that limited overhead bin space, because I know I’ll always have space for my bag.

Thing is, when my bag is stowed under the seat in front of me or especially in an overhead bin, the last thing I want to do is reach for it during a flight to grab a book, protein bar, water bottle, and the like. That’s why I always pre-pack a removable bag for the flight. When I get on the aircraft, first thing I do is open my backpack, pull out my in-flight bag, stow the pack, and keep the in-flight bag at my seat.

On a recent cross-country trip I packed out my GoRuck GR1 backpack and left room at the top to stow the Hound. The Hound made for an ideal in-flight pack. It carried my reading glasses, a book, a Kleen Kanteen water bottle, granola bars, pencil, pen, paper, earphones, adapters, my iPhone, a small battery pack, and an assortment of cables. And there was room to spare.

The Hound taking its inaugural flight on an Airbus A321!

Another benefit of carrying a bag-within-a-bag? Say you buy your kiddos or spouse some gifts, or someone gives you a cool item that you plan to carry back home––let’s say, a shortwave radio. By having a separate pack, you can always carry the Hound outside your pack freeing up capacity for the new item(s) in your pack. Since the Hound is designed to be carried over the shoulder, your hands are still free.

You could even use the strap to tie the Hound to your main bag. Since the Hound is so small, you won’t get charged extra, even by unforgiving low-cost carriers.

If you’re into radio gear, then the Hound should easily accommodate most full-featured portable radios (like the Grundig G3, G5, Satellite, Sony ICF-SW7600GR, Tecsun PL-660, etc.) It’s also large enough to hold any HT (handy talkie) on the market, although you might remove long antennas unless you close the zippers around it. No worries, no antenna will poke through this bullet-proof fabric.

And of course, women readers: the Hound would also make a great casual crossbody purse that would be as comfortable on a hike as touring a European city. In fact, after I received the Hound, my wife nearly walked off with it. I could tell, she was already mentally sorting out how all her gear would fit inside. Likely the only thing keeping her from declaring this one hers is the fact that this bag is khaki––if it were her favorite shade of Red Oxx red, I’d likely have already been forced to surrender it!

Is the Hound for you?

If this simple, super-sturdy bag is the size and configuration you’ve been looking for to haul your radios and other EDC (or, let’s face it, dog owners: biscuits and baggies) around with you, then I can recommend it without reservation.

While I truly enjoy doing product evaluations, beta testing and reviews, my time is very limited. I’m picky about what I choose to invest my time in. When Red Oxx contacts me about gear evaluations, I make time. Why? Because their products have never disappointed me.

Red Oxx build and materials quality is second to none. All their gear is designed and manufactured in Billings, Montana––yep, in the good ol’ US of A–– and will last a lifetime. Or potentially longer.

Plus: in the unlikely event your Red Oxx gear is damaged due to rough treatment (or even neglect), Red Oxx will fix it. For free…and for life! Their “No Matter What” warranty requires no receipt and no explanations. No doubt, this is one of the reasons why used Red Oxx gear appears on sites like eBay with prices near what you’d pay for it, brand new. These bags not only hold your gear, but they also hold their value: a bit of a rarity in today’s disposable world.

This top-notch workmanship comes at what most of us would consider a premium, when compared with mass-produced gear you’ll find on Amazon or a big-box store. But for me, I still find incredible investment value in Red Oxx gear. On top of that, I feel like I’m supporting a company that takes pride in their their simple-but smart innovations, their good work, and their hard-working employees who do it.

The Hound was announced by Red Oxx yesterday, and they’ll be taking pre-orders until September 23, 2019. The price is $95 US, including shipping.

Click here to check out the Hound at Red Oxx.

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AirSpy HF+ Discovery: First Impressions on Medium Wave vs. Elad FDM-DUOr

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The highly anticipated AirSpy HF+ Discovery SDR has been in the hands of early adopters for about two weeks–and I’ve seen nothing but positive comments!

After a long run (2007-2013) with a Microtelecom Perseus, my SDR of choice became the Elad FDM-S2, and more recently an Elad FDM-DUOr “hybrid” SDR receiver. The two Elads have the same core processing components and identical performance when the DUOr is connected via SDR software.

This week I’ve compared the HF+ Discovery ($169) against the FDM-DUOr ($899) using Studio 1 software and identical modes & settings. The following video features the radios’ performance on a crowded daytime medium wave band from suburban Seattle-Tacoma USA.

Click here to view on YouTube.

Notes:

Software used is two “instances” of Studio 1, version 1.06e
Antenna is an east-west oriented Wellbrook ALA1530LNP Imperium loop
Mode, filter bandwidth, AGC, etc. are the same for each radio
768 kHz sampling bandwidth used for both receivers

Stations tuned are:

1320 KXRO Aberdeen WA, 74 miles @ 5 kW (in-line with antenna)
1110 Oak Harbor WA, 78 miles @ 500 watts (in antenna’s null)
1040 CKST Vancouver BC, 147 miles @ 50 kW (in antenna’s null)
1430 KBRC Mt. Vernon WA, 85 miles @ 5 kW (in antenna’s null)
750 KXTG Portland OR, 118 miles @ 50 kW (in antenna’s null)

I purposely sought out signals difficult to hear in the presence of powerhouse stations. Only 1320 kXRO (in-line with my antenna) and 750 KXTG are what you might consider average or fair quality signals. Headphones are recommended for most of these, particularly 1040 kHz.

You’ll note that the pass band has been “pulled” over the edge of the carrier frequency by a few hundred Hertz. This is an excellent trick that can often reduce noise and/or improve intelligibility. It’s a feature unique to Perseus, Studio 1, and SDRuno software; it works in sideband modes and in selectable sideband Sync AM (SAM) mode.

After listening to the signal comparisons, what are your thoughts on the HF+ Discovery? Please leave your comments below.

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

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A review of the Sangean PR-D17 portable AM/FM radio for the visually impaired

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Many thanks to SWLing Post contributor and producer, Peter Atkinson, who shares the following review of the new Sangean PR-D17 AM/FM radio:

Sangean PR-D17 review

by Peter Atkinson

I’ve been visually impaired all my life and a radio enthusiast for over 40 years. I was intrigued when I learned that Sangean was offering a radio for the visually impaired. I purchased one, and wanted to share my thoughts about the Sangean PR-D17 from the perspective of a visually impaired listener.

For those readers who are mainly interested in the performance of this radio, please stay tuned, while I talk a moment about the features geared to the visually impaired.

First of all: the manual, [see photo above] while it is comprehensive (as most from Sangean are), it is odd that it’s printed in the smallest type I’ve seen from this manufacturer.

The yellow controls on a black radio are easily seen. I like that the preset buttons on the bottom row of the front panel, are in Braille. The raised symbols, however, on the upper row, may be too complicated to be easily discerned by touch alone. The yellow-on-black motif, is reminiscent of my Sangean HDR-16.

When the 6 C batteries are first inserted, or AC power is connected, the radio announces that it has entered the setup menu. The voice prompt menus (whose volume can be adjusted independently of the radios’ main volume but cannot be disabled) make setting up this radio somewhat straightforward. The setup might have been easier, if the clock setting function was available as part of the menu system. The voice prompts are surprisingly comprehensive. The voice not only speaks the frequency, time & menu options, but will also tell you when something is connected to (or disconnected from) the AC input, headphone or AUX-IN jacks.

When the radio is turned on, it announces that the radio is on, the battery level & the frequency to which it is tuned.

When tuning, the voice gives the frequency at each change. It’s especially helpful when using the seek function, knowing where the next station was found.

Click here to download audio clip of tuning voice prompt.

When storing a station into a preset, the voice says exactly what frequency has been stored & at which present position.

Click here to download audio clip of tuning voice prompt.

The same information is given when recalling a preset. One quirk of the voice prompt, is that when announcing the time, it speaks full numbers (e.g. “twelve thirty-seven’), but when giving the frequency, each digit is spoken (e.g. “one two three zero” or “nine six point one”).

Click here to download audio clip of time voice prompt.

Finally: Tuning time.

Image showing that the HDR-16 and PR-D17 are identical in size.

Comparing the Sangean HDR-16 with the PR-D17

This radio is the same cabinet as the HDR-16. Aside from the voice prompts, it operates similar to the PR-D5. Therefore, I’m comparing its performance to that model. Like the PR-D5, the AM tuning steps can be set for 9 or 10KHz, but the FM tuning steps are fixed at 100KHz (0.1MHz).

There are 5 presets per band. The display also shows RDS information for any FM station that transmits RDS. The clock can be set from the RDS signal, as well. I’ve found several stations, in my area, that are sending the wrong time.

Audio

The sound from the twin 2-1/2” speakers is very balanced. The bass is substantial, but not overpowering. The highs are good for definition, without being too brassy. There are no provisions for customization, though.

There is a 3.5mm AUX-IN jack for connecting an external sound source, such as an MP3 player or smartphone.

AM

While the AM sound is a bit muffled for my taste (the bandwidth cannot be changed) it makes for excellent selectivity. There was no hint of my nearby 50KW 620, on 610 or 630. Like many Sangean radios, the noise floor is very quiet. The long 200mm internal ferrite bar antenna does a superb job at snagging those weak stations. I was able to get a noisy, but readable signal on a 50KW station on 700, at 350 miles, during the day. That one is my benchmark for a great DX machine. The top end of the band is no slouch, either. Another benchmark station (10KW 1690 at 75 miles) came in loud and clear. The long ferrite antenna also helps to better null unwanted signals. This is a greater benefit for nighttime DXing.

FM

The PR-D17’s performance on FM is stellar. It has shown to be very sensitive, pulling in stations as well as my PR-D5 & PR-D9W. I easily hear FMs at 60 miles. The selectivity is also amazing. I can listen to stations on 95.9 & 96.3, with a 6KW station on 96.1 less than 10 blocks from my window. Even though the PR-D17 pulls in those weak stations with ease, it requires a stronger signal to receive stereo.

The RDS is quick to display station information. It starts off by showing the 8-character PS information of the RDS signal, then switches to the scrolling display of the RT segment.

Summary

Overall, I am very happy with the Sangean PR-D17. It is a superior radio, now with the added benefit of voice prompts. Hopefully, this will alleviate some of the annoyances visually impaired listeners may have with operating a digitally-tuned radio.

Thank you so much for sharing your review, Peter and thank you for being an SWLing Post producer!

It looks like the Sangean PR-D17 is an excellent choice for those radio listeners who would appreciate voice prompts, high contrast controls and tactile keys. I’m also happy to hear you rate AM selectivity as excellent. When radios only have one chosen bandwidth, I’d rather give priority to selectivity than audio fidelity for the purposes of nighttime AM DXing.

Sangean PR-D17 retailers:

Universal Radio
Amazon.com (affiliate link)

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Fenu-Radio reviews an AirSpy HF+ Discovery prototype

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Fernando Duarte of Fenu-Radio has just posted his review of the AirSpy HF+ Discovery SDR prototype. I trust Fenu’s reviews because they’re always thorough and based on actual listening sessions.

In short, he’s quite impressed with the prototype. In many instances the Discovery outperformed his benchmark Winradio G33DDC Excalibur Pro. Quite an accomplishment for a $169 SDR!

Click here to read Funu-Radio’s full review.

I will evaluate a first production run AirSpy HF+ Discovery. Since it’s incredibly lightweight and compact, I believe I’ll try to even build a small portable SDR station around it. Stay tuned.

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