Category Archives: Reviews

Matt’s mediumwave audio comparison of the C.Crane Radio 2E and the Potomac Instruments FIM-41

Many thanks to SWLing Post contributor, Matt Blaze, who writes:

I did another head-to-head receiver comparison, this time of two MW BCB AM portables: The C.Crane Radio 2/e vs. the Potomac Instruments FIM-41 field intensity meter.

The latter is not intended as a receiver, but rather a test instrument, but it turns out to be the among most sensitive MW receivers I’ve ever used. So I thought it would be interesting to compare its performance with that of a well-regarded modern portable.

Audio Comparison:

Our two contenders with comparable portable radios: the GE Super Radio, Panasonic RF-2200, and Sony ICF-EX5MK2.

Another brilliant audio comparison, Matt! Thank you so much for taking the time to put this together! I actually believe audio comparisons, as you’ve set them up, are a fantastic way of sharing A/B comparisons.

Click here to check out all of Matt’s receiver audio comparisons.

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Icom IC-705 blind audio tests: Let’s take a look at your choices!

Before I had even taken delivery of the new Icom IC-705 transceiver, a number of SWLing Post readers asked me to do a series of blind audio comparison tests like I’ve done in the past (click here for an example).

Last week, I published a series of five audio tests/surveys and asked for your vote and comments. The survey response far exceeded anything I would have anticipated.

We received a total of 931 survey entries/votes which only highlights how much you enjoy this sort of receiver test.

In this challenge, I didn’t even give you the luxury of knowing the other radios I used in each comparison, so let’s take a look…

The competition

Since the Icom IC-705 is essentially a tabletop SDR, I compared it with a couple dedicated PC-connected SDRs.

WinRadio Excalibur SDR

The WinRadio Excalibur

I consider the WinRadio Excalibur to be a benchmark sub $1000 HF, mediumwave, and longwave SDR.

It is still my staple receiver for making off-air audio and spectrum recordings, and is always hooked up to an antenna and ready to record.

In the tests where I employed the WinRadio Excalibur, I used its proprietary SDR application to directly make recordings. I used none of its advanced filters, AGC control, or synchronous detection.

Click here to read my original 2012 review of the WinRadio Excalibur.

Airspy HF+ SDR

The Airspy HF+ SDR

I also consider the Airspy HF+ SDR to be one of the finest sub-$200 HF SDRs on the market.

The HF+ is a choice SDR for DXing. Mine has not been modified in any way to increase its performance or sensitivity.

In the test where I employed the HF+ I used Airspy’s own SDR application, SDR#, to directly make recordings. I used none of its advanced filters, AGC control, noise reduction, or synchronous detection.

Belka-DSP portable receiver

The Belka-DSP

I recently acquired a Belka-DSP portable after reading 13dka’s superb review.

I thought it might be fun to include it in a comparison although, in truth, it’s hardly fair to compare a $160 receiver with a $1300 SDR transceiver.

The Belka, to me, is like a Lowe HF-150 in a tiny, pocket package.

Elecraft KX3 QRP transceiver

The Elecraft KX3

The KX3 is one of the best transceivers I’ve ever owned. Mine has the CW roofing filter installed (only recently) and is, without a doubt, a benchmark performer.

Click here to read my full review.

If you check out Rob Sherwood’s receiver test data table which is sorted by third-order dynamic range narrow spaced, you’ll see that the KX3 is one of the top performers on the list even when compared with radios many times its price. Due to my recording limitations (see below) the KX3 was the only other transceiver used in this comparison.

Herein lies a HUGE caveat:

The WinRadio application

As I’ve stated in SDR reviews in the past, it is incredibly difficult comparing anything with PC-connected SDRs because they can be configured on such a granular level.

When making a blind audio test with a stand-alone SDR radio like the IC-705–which has less configurability–you’re forced to take one of at least two paths:

  • Tweak the PC-connected SDR until you believe you’ve found the best possible reception audio scenario and use that configuration as a point of comparison, or
  • Attempt to keep the configuration as basic as possible, setting filters widths, AGC to be comparable and turning off all other optional enhancements (like synchronous detection, noise reduction, and advanced audio filtering to name a few).

I chose the latter path in this comparison which essentially undermines our PC-connected SDRs. Although flawed, I chose this approach to keep the comparison as simple as possible.

While the IC-705 has way more filter and audio adjustments than legacy transceivers, it only has a tiny fraction of those available to PC-connected SDRs. Indeed, the HF+ SDR, for example, can actually be used by multiple SDR applications, all with their own DSP and feature sets.

In short: don’t be fooled into thinking this is an apples-to-apples comparison. It is, at best, a decent attempt at giving future IC-705 owners a chance to hear how it compares in real-word live signals.

Recordings

The Zoom H2N connected to my Elecraft KX2.

Another limiting factor is that I only have one stand-alone digital audio recorder: the Zoom H2N. [Although inspired by Matt’s multi-track comparison reviews, I plan to upgrade my gear soon.]

The IC-705 has built-in digital audio recording and this is what I used in each test.

The WinRadio Excalibur and Airspy HF+ also have native audio recording via their PC-based applications.

With only one stand-alone recorder, I wasn’t able to simultaneously compare the IC-705 with more than one other stand-alone receiver/transceiver at a time.

As I mentioned in each test, the audio levels were not consistent and required the listener to adjust their volume control. Since the IC-705, Excalibur, and HF+ all have native recording features, the audio levels were set by their software. I didn’t post-process them.

Blind Audio Survey Results

With all of those caveats and disclaimers out of the way, let’s take a look at the survey results.

Blind audio test #1: 40 meters SSB

In this first test we listened to the IC-705, WinRadio Excalibur, and Belka-DSP tuned to a weak 40 meter station in lower sideband (LSB) mode. Specifically, this was ham radio operator W3JPH activating Shikellamy State Park in Pennsylvania for the Parks On The Air program. I chose this test because it included a weak station calling CQ and both weak and strong stations replying. There are also adjacent signals which (in some recordings) bleed over into the audio.

Radio A: The Belka-DSP

Radio B: The WinRadio Excalibur

Radio C: The Icom IC-705

Survey Results

The Icom IC-705 was the clear choice here.

Based on your comments, those who chose the IC-705 felt that the weak signal audio was more intelligible and that signals “popped out” a bit more. Many noted, however, that the audio sounded “tinny.”

A number of you felt it was a toss-up between The IC-705 and the Belka-DSP. And those who chose the WinRadio Excalibur were adamant that is was the best choice.

The WinRadio audio was popping in the recording, but it was how the application recorded it natively, so I didn’t attempt to change it.

Test #2: 40 meters CW

Icom IC-705In this second test we listened to the Icom IC-705 and the Elecraft KX3 tuned to a 40 meter CW station.

Radio A: Icom IC-705

Radio B: Elecraft KX3

Survey Results

The Elecraft KX3 was preferred by more than half of you.

Based on your comments, those who chose the KX3 felt the audio was clearer and signals had more “punch.” They felt the audio was easier on the ears as well, thus ideal for long contests.

Those who chose the IC-705, though, preferred the narrower sounding audio and felt the KX3 was too bass heavy.

Test #3: Shannon Volmet SSB

In this third test we listened to the Icom IC-705 and WinRadio Excalibur, tuned to Shannon Volmet on 8,957 kHz.

Radio A: WinRadio Excalibur

Radio B: Icom IC-705

Survey

The Icom-705 audio was preferred by a healthy margin. I believe, again, this was influenced by the audio pops heard in the WinRadio recording (based on your comments).

The IC-705 audio was very pleasant and smooth according to respondents and they felt the signal-to-noise ratio was better.

However, a number of comments noted that the female voice in the recording was actually stronger on the WinRadio Excalibur and more intelligible during moments of fading.

Test #4: Voice of Greece 9,420 kHz

In this fourth test we listen to the Icom IC-705, and the WinRadio Excalibur again, tuned to the Voice of Greece on 9,420 kHz.

Radio A: Icom IC-705

Radio B: WinRadio Excalibur

Survey

While the preference was for the IC-705’s audio (Radio A), this test was very interesting because those who chose the Excalibur had quite a strong preference for it, saying that it would be the best for DXing and had a more stable AGC response. In the end, 62.6% of 131 people felt the IC-705’s audio had slightly less background noise.

Test #5: Radio Exterior de España 9,690 kHz

In this fifth test we listened to the Icom IC-705, and AirSpy HF+, tuned to Radio Exterior de España on 9,690 kHz. I picked REE, in this case, because it is a blowtorch station and I could take advantage of the IC-705’s maximum AM filter width of 10 kHz.

Radio A: Icom IC-705

Radio B: Airspy HF+

Survey

The IC-705 was preferred by 79% of you in this test.

Again, very interesting comments, though. Those who preferred the IC-705 felt the audio simply sounded better and had “punch.” Those who preferred B felt it was more sensitive and could hear more nuances in the broadcaster voices.

So what’s the point of these blind audio tests?

Notice I never called any radio a “winner.”

The test here is flawed in that audio levels and EQ aren’t the same, the settings aren’t identical, and even the filters have slightly different shapes and characteristics.

In other words, these aren’t lab conditions.

I felt the most accurate comparison, in terms of performance, was the 40M CW test with the KX3 because both employed similar narrow filters and both, being QRP transceivers, are truly designed to perform well here.

I essentially crippled the WinRadio Excalibur and Airspy HF+ by turning off all all but the most basic filter and AGC settings. If I tweaked both of those SDRs for optimal performance and signal intelligibility, I’m positive they would have been the preferred choices (indeed, I might just do another blind audio test to prove my point here).

With that said, I think we can agree that the IC-705 has brilliant audio characteristics.

I’ve noticed this in the field as well. I’m incredibly pleased with the IC-705’s performance and versatility. I’ll be very interested to see how it soon rates among the other transceivers in Rob Sherwood’s test data.

The IC-705 can actually be tailored much further by adjusting filter shapes/skirts, employing twin passband tuning and even using its noise reduction feature.

If anything, my hope is that these blind audio tests give those who are considering the Icom IC-705 a good idea of how its audio and receiver performs in real-word listening conditions.


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Matt compares the Tecsun PL-990 and Sangean ATS-909X sharing an external antenna

Many thanks to SWLing Post contributor, Matt Blaze, who shares the following comparison of the new Tecsun PL-990x and the original Sangean ATS-909X communications receivers.

Like Matt’s recent comparison of the Tecsun PL-990x to the Icom IC-R9500, this review is in audio form and brilliantly narrated by Matt. I highly recommend listening with headphones or, at least, an audio device with separate left/right channels as his comparison takes advantage of this.

Enjoy:

Yet another superb presentation, Matt! Thank you so much for taking the time to make these audio comparison tests.

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Matt compares the Tecsun PL-990 to the Icom IC-R9500 on an external antenna and the results are surprising

Many thanks to SWLing Post contributor, Matt Blaze, who shares the following comparison of the new Tecsun PL-990x and the benchmark Icom IC-R9500 communications receiver.

Matt’s excellent comparison  is in audio form. I highly recommend listening with headphones or, at least, an audio device with separate left/right channels as his comparison takes advantage of this.

I love not only how he set up this comparison with both radios sharing an identical antenna, but his evaluation also explores how well the PL-990 handles a proper external antenna via its external antenna jack.

Click below to listen to Matt’s piece, or right click here to download the audio:

Thanks for sharing this, Matt. You’ve inspired me to do similar narrated audio comparisons!

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Shortwave listening in the field with the Icom IC-705 transceiver

Yesterday, I took the new Icom IC-705 to the field for another Parks On the Air (POTA) activation. My goal at this particular activation was to make a couple of posts for QRPer.com: first, to test the new mAT-705 ATU on loan from Vibroplex, and secondly, make a short video about full break-in CW operation.

I also wanted to do a little shortwave listening after completing the activation. I had no idea what propagation would be like, but thought I’d tune around below the 20 meter band where the antenna was currently resonant.

I deployed the CHA Emcomm III Portable random wire antenna which, I must say, is a superb shortwave listening antenna for the field.

Since you can’t see the antenna in the first photo below, I marked up the second one. The blue line represents the 73′ radiator, and the green line the counterpoise:
Here’s the short video I made around the 22 meter band:

I had planned to make a few audio recordings via the built-in digital recorder but I left my MicroSD card at home. No worries, though, as I plan to make some recordings for readers to compare in the coming days if time allows.

If you have any questions about the IC-705, feel free to ask in comments.

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The HobbyPCB IQ32 transceiver fills a special niche in the ham radio world

The following review was first published in the September 2020 issue of The Spectrum Monitor magazine:


The HobbyPCB IQ32 transceiver fills a special niche in the ham radio world

This summer, I’ve been exploring the world of general coverage QRP transceivers. I’ve been taking my LnR Precision LD-11, Elecraft KX3 and KX2 into the field; and I’ve just finished a comprehensive review of the Xiegu G90. I also have a TX-500 and IC-705 arriving in the near future [update].

Yes, I’ll admit, I’m a devotee of the “all-in-one” nature of the latest model portable QRP transceivers.

Most of the QRP transceivers now on the market are products of large, popular ham radio manufacturers. Usually, a company will come up with a product concept, follow through with their market research, then design, develop, and produce the radio. In fairness, that’s an over-simplification of the process, but let’s just call it a “top down” design approach––meaning, the product idea is generated within the company, and is often based upon customer feedback.

Not all ham radio products come about this way, though. Some have more “grassroots” or collaborative origin.

The HobbyPCB IQ32

(Image Source: HobbyPCB)

I first noticed the HobbyPCB IQ32 transceiver at the Dayton Hamvention a few years ago. I checked it out carefully at their booth, and recall a crowd gathering around their table. Noting this, I decided, at a later time, I would also find an opportunity to check out the radio in more detail.

A couple of months ago, I was working on my list of General Coverage QRP Transceivers and asked for help filling in details of any radios I’d forgotten. A reader commented and reminded me that the IQ32 was, indeed, general coverage.

At this point, I reached out to HobbyPCB and asked for a loaner unit to explore for a few weeks. The company very kindly sent one my way some weeks ago, and I’ve been testing it on the air ever since.

Form factor

When I received the IQ32 package, I was surprised by how lightweight this transceiver is:  a mere 1.5 lbs (700 grams) packs it all in one compact package.

The chassis is made of aluminum and incredibly sturdy. It even includes side panel extensions to protect the front faceplate and knobs.

The IQ32 sports a 3.2″ color LCD touch-screen display large enough to contain all of the functions, a spectrum display, and even an area for text––both transmitted and received in PSK31 and CW. The display is reminiscent of the uBITX V6 I recently reviewed. It is recommended that the operator uses a blunt plastic stylus (or retracted ballpoint pen) for navigating the color screen, since several of the  menu settings, memories, and the like require some fairly precise tapping. The graphic user interface (GUI) feels a bit like what I’d expect to find on a piece of test equipment: a bit old school, but nonetheless quite functional.

The main encoder and selector knobs are lightweight and made of some sort of plastic or nylon. They work quite well––but if I owned an IQ32, I believe one of the first things I’d do is replace those with a lightweight aluminum equivalent.

As I mentioned earlier, the weight of the IQ32 is very reasonable at 1.5 lbs. I don’t think I’d even notice it packed in a backpack.

The IQ32, like the recently released Lab599 TCX-500, lacks an internal speaker. However, my unit came with a speaker microphone, which works fine.

The right side panel of the IQ32 has a toggle power switch, power amplifier connection, power port (5mm X 2.1mm, positive tip), PS2 keyboard connector, USB Type A, and a BNC antenna port. The left side has a 3.5mm I/Q Output, 3.5mm headphone jack, 3.5mm speaker/mic port,  and a 3.5mm CW key input.

The IQ32 also has two legs that can be adjusted so that the radio will prop up at a comfortable angle for operation. The legs can be a bit finicky to adjust and keep in place, so I preferred using an angled radio support I use for my Elecraft KX3.

A collaboration

The IQ32 also feels like a project joint effort, bringing to mind the old chocolate-peanut butter cup commercial of a bygone era: “My chocolate got mixed with your peanut butter!” And or, “My peanut butter got mixed with your chocolate!”

Curious about this seeming blend of radio ideas, I reached out to Jim Veach (WA2EUJ) at HobbyPCB for more information; he gave me a little history behind the IQ32.

Jim writes:

The IQ32 is the fusion of two products: the HobbyPCB RS-HFIQ, and the STM32-SDR. 

The RS-HFIQ was designed to be a 80-10M, 5W soundcard-based SDR––similar to the popular Softrock SDRs with some expansions and revisions. 

The STM32-SDR was designed to work with a soundcard-based SDR and [thus] eliminate the need for a PC and provide stand-alone operation. 

Inside the IQ32 is a mostly stock RS-HFIQ (in fact, we offered an upgrade kit so RS-HFIQ owners could go the IQ32 route) and a custom version of the STM-32 […] specifically for the IQ32.

The original development of the STM32 [began] a few years ago when PSK31 was the digital mode du jour and [the] PS2 keyboard roamed the land. The firmware team recently released the current FW, which greatly expanded the CW modes and reworked the memory structure based on user input.

And there you have it: even though this unique little rig has been around for a few years, I’m impressed that they continue to refine it and upgrade the firmware. Indeed, if the community of IQ32 users grow, they may be able to do even more.

On the air

To be clear, my intention here isn’t to conduct a comparative review of the IQ32. I simply want to convey what I’ve learned in the process of playing with the rig and trying out some of its unique features.

Immediately after unboxing the radio, I hooked it up to my main skyloop antenna, plugged in the power supply that accompanied the radio, then plugged in the handheld speaker mic.

I discovered rather quickly that the IQ32 user interface takes a different approach than any other transceiver I’ve ever tested. Instead of one main user interface window in which you navigate modes, frequencies, and perhaps alter spectrum and bandwidth settings, the IQ32 has a different screen layout for each mode. It’s as if each mode––SSB, PSK31, CW, etc.––has its own “page.”

Despite the very minimal controls, you can adjust many of the IQ32s settings, macros, and memories in a very granular way via the settings pages using a stylus for fine control of the screen. On the flip side, during operation, it can be frustrating when adjustments need to be made quickly between the AF Gain, RF Gain, CW Speed, and AGC, as they all use the same multi-function knob and switching between them requires several screen taps––not as quick a process as one might prefer.

Indeed, the IQ32 isn’t immediately as intuitive as most commercially-marketed radios.  But once you fully understand the settings and modes pages, it becomes easy to navigate. Note: I would advise any future owner of an IQ32 to read the manual in advance. I did this, and it certainly helped. I should add here that the IQ32 manual is one of the most comprehensive I’ve read––especially considering its collaborative roots.

Now, let’s talk modes.

SSB

Since the IQ32 requires a PS2 keyboard for PSK31, and optionally for CW, I tried my hand at SSB first.

After learning how to switch modes and filter settings, I hopped on the air. Instead of calling CQ, I decided instead to seek a park activator in the POTA program via the POTA spots website. Within 10 minutes, I made contact with two parks: one in Pennsylvania and one in Florida on the 40 and 20 meter bands, respectively. While both parks gave me a “5×9” report, I seriously doubt it was accurate based on their own signal strength. (Some park activators, like contesters, only give 5×9 reports.)

Still, my success in contacting these two parks told me that the mic settings were probably suitable and that the audio had enough punch on 5 watts to be heard. To confirm, I called CQ a few times and listened to my own signal at a KiwiSDR site in Maryland. The signal was about 5×5, but the audio was clear, clean, and had excellent fidelity.

Over the past few weeks I’ve worked dozens of stations across North America with the IQ32.

PSK31

One of the very unique features of the IQ32 is its ability to natively encode and decode PSK31. This was the second mode I was eager to try.

To use PSK31 on the IQ32, a PS2 keyboard (or USB keyboard with PS2 adapter) must be connected. I searched my shack in vain for a PS2 keyboard, but fortunately, my friend Vlado (N3CZ) came to the rescue and let me borrow one of his keyboards.

Again, note: IQ32 beginners should certainly plan to read the PSK31 section of the IQ32 manual prior to attempting a PSK31 QSO.  For starters, you’ll want to enter in your personal information into the tags settings so that you can use your keyboard function keys to automatically send CQs and to answer calls. The manual will also walk you through any other necessary settings.

Once I had everything set up, I started calling CQ on the 20 meter band; unfortunately I had no luck snagging a station. This had less to do with the radio and much more to do with the mode, which has, alas, fallen out of popularity since the advent of FT8. It’s a shame, really, because although PSK31 is a digital mode, it feels much more like a proper QSO than FT8, in my opinion. While I have a lot of respect for FT8, with PSK31, you can, as we hams say, “rag-chew”––a much more personal interaction.

And rag-chewing is exactly what I did. I contacted a friend, we set a sched for a PSK31 QSO, and it was, indeed, fun. The IQ32 has a screen with enough text space so that it’s easy to follow and to read. In fact, with this radio, I don’t feel like a computer is needed.

With the keyboard attached, PSK31 just works…and works quite well. I really like the way this feature has been implemented in the IQ32.

CW

Truly, the IQ32 actually has a lot to offer the CW operator. The IQ32 supports Iambic keyer modes A and B, with speeds up to 35 wpm. You can also adjust the weight of the dits and dahs. The IQ32 doesn’t support full break-in QSK, however: there is a slight delay after sending before the relay puts the radio back into receive mode. At present, this delay is not manually adjustable but is, rather, based on the selected keyer speed.

I’ve been very pleased using the IQ32 in CW mode with my Begali paddles and Vibroplex single lever paddle.

Of course, a really unique feature of this rig is that it provides the operator with the means to use the PS2 keyboard to send CW, just as you can with the PSK31. At present, there is no CW decoder, but for those who feel their fist isn’t quite up to par, you can surprise the operator on the other end by sending perfectly formed and spaced CW by simply typing it on the keyboard.  Herein lies a very unique feature and application for the IQ32.

Indeed, as a frequent Parks On The Air (POTA) field activator, I rely very heavily on memory keyers to call CQ, send a park number, as well as give my thanks and 73s to those who contact me. Using a pre-programmed message means that I then have time to log a station while it sends, and to ensure my code is cleaner when I send park numbers––especially since I don’t exactly excel at sending strings of numbers!

With the IQ32, I find I can program full CW messages to play when I simply press one of the function keys on the keyboard. This gives me much better flexibility and control than, say, the built-in memory keyer on my venerable Elecraft KX2.

With the IQ32, a CW op would actually have the choice of never even touching a key, and just sending all messages with the keyboard. While I could never see myself doing that (as I quite enjoy sending CW with a key), the flexibility of pre-programming an array of CW memory messages and having them conveniently at hand is nonetheless quite appealing.

As a CW operator, I’m quite pleased with the IQ32. My only wish would be for a slightly shorter relay hang time for use in contesting or on Field Day.

The IQ32 Niche

While I wouldn’t necessarily recommend the IQ32 as a first transceiver to a newly-minted ham, I can certainly envision a niche market for this unique rig.

For one, I think the IQ32 could satisfy those operators who desire a very clean and stable transmitter. The IQ32 sports a Class A 5-watt power amplifier with individual low-pass filters for each band that exceed FCC requirements for spectral purity. It also has a Temperature-Compensated Crystal Oscillator (TXCO) for frequency stability––truly, this is not common in a radio of this price class.

For another, the IQ32 could be used as a driver for a transverter when operating on VHF or UHF. Another of its unique and useful features is that the user can set an offset to display the transverter output frequency rather than the IQ32-driven frequency.

 

 

And, finally, let’s face it: I know of few other radios that you can take to the field, hook up a keyboard, and natively send and decode PSK-31 transmissions. My KX2 can do this to a degree, but I have to input the text as CW, and the number of characters in the display is quite limited. The IQ32 is robust enough to permit you to carry on PSK-31 rag-chews, if you wish. If this is your thing, you’ll definitely want to play with this rig.

Being able to send CW with a keyboard and pre-programmed messages also means CW operators could make their workflow much more efficient in either the shack or the field.

In conclusion, I’ll admit that the IQ32 isn’t as intuitive as other radios and that the ergonomics leave room for improvement. But it’s still a cool little radio. If, after having read this tour of the IQ32, you feel like you’re in this radio’s niche market, then definitely reach out to HobbyPCB: I’ve found their customer care and support to be absolutely benchmark.

All in all, I’ve had a lot of fun tinkering with this unique general coverage QRP transceiver; I expect others like me will, too. Many thanks to HobbyPCB and the IQ32 crew for letting me take a deep dive into this very special little rig!

Click here to check out the IQ32 at HobbyPCB.


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