Category Archives: QRP

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

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:

  1. Chose the frequency and mode;
  2. Hold the STEP button for one second or more, then release. You’ll then see a split display indicating the TX and RX frequencies.
  3. 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, but I consider those ATUs to be some of the most flexible on the market.

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. A perfect combo.

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 faint relay click when switching from TX to RX and back again.

This isn’t a problem for me, as I rarely set my CW rigs for full break-in, but 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.

All in all, the CTX-10 will serve the CW operator much like a military set in field operations. True, I wish it had a few more adjustments, but it has all of the basics, and I’ve received several great reports regarding signal and tone.

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.

Please note: some of these 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 heartily recommending it in my initial review.

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 values a very simple, straightforward radio. Perhaps someone who began operating in a commercial, military, or aviation field, and/or who likes the “get on and get the job done” approach.  Someone more interested in making contacts than in radio operations and refinements. Those who want a sturdy, lasting, 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 to a T.

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, or Elecraft KX3. All of these excellent rigs are time-tested and very flexible.

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 strong 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
  • HF packs
  • Digital modes like FT-8 and the ability to operate them in the field from internal batteries for extended periods of time
  • The equivalent of a simple portable military/commercial set
  • A well-balanced receiver with few manual adjustments
  • Broadcast listening, as the CTX-10 is also superb 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––the construction is top-shelf, for sure. It should run for decades without need of repair.

The CTX-10 is built like a tank, and has excellent receiver characteristics 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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Initial impressions of the ALT-512 QRP transceiver

So the ALT-512 QRP SDR transceiver has landed at SWLing Post HQ. This little rig is on loan from Aerial-51 and I’ll be spending the next month or so putting it through the paces.

I can already tell that the ALT-512 has some strong points:

  • It’s incredibly portable and easy to take to the field, providing you have a battery and resonant antenna (or external ATU).
  • The color backlit display is quite readable at any angle despite being rather information-dense.
  • I really like the waterfall display. It’s large enough to be quite useful.
  • The ALT-512 can connect directly to your computer for digital modes like FT-8. No external sound card needed.
  • The menu system contains a wide array of features and options for granular tweaks and modifications.
  • The ALT-512 includes the European 4 meter band.
  • Although I prefer using headphones with small radios, the ALT-512’s small internal speaker does a fine job.
  • Rob Sherwood tested the ALT-512 (indeed, this very unit) recently and added it to his receiver test data. It performed quite well especially considering the price.

Any negatives so far?  Nothing major:

  • No internal ATU or battery options. At this price point (799 EUR), I wouldn’t expect either of these.
  • The ALT-512 is not general coverage. This is a negative for those of us who like SWLing, but a positive for ham radio use as the ALT-512 sports band-specific bandpass filters to reject out-of-band strong stations. You can tune to some stations above the 40M band and also the full mediumwave band and below (down to 100 kHz), although I wouldn’t expect stellar performance in those regions.

So far, I’m very pleased with the ALT-512’s performance.

Next, I’ll be taking it to the field and see how easily I can activate a few POTA (Parks On The Air) sites! Stay tuned!

Click here to check out the ALT-512 at Aerial-51.

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The new Icom IC-705 QRP portable, backpackable transceiver

This weekend at Tokyo’s Ham Fair 2019, Icom announced an innovative transceiver to their line-up: the Icom IC-705 QRP transceiver.

The IC-705 introduces several industry firsts for a backpack portable radio:

  • It uses the same BP-272 Li-ion Battery pack as the ID-51 and ID-31 series D-Star handy talkies. To my knowledge, this is the only HF transceiver that uses battery packs that can be swapped so easily in the field–like one would swap an HT battery pack
  • It has a general coverage receiver that spans a whopping 0.5 to 148 MHz
  • It sports a full color, touch screen with spectrum and waterfall displays
  • It includes the D-Star digital voice mode
  • A GPS receiver
  • Bluetooth connectivity
  • A MicroSD card slot for memory storage, screen captures and recordings

All of this appears to be included, not add-on options.

The only IC-705 omission, in my opinion, is an internal ATU (antenna tuner). Something I would have expected, but not a deal-breaker for those of us who could really benefit from the amount of features this radio offers.

Side and back panel view noting ports and connections.

There is no word yet on pricing or availability, but you can count on us to post these details once they’re available. If you would like to follow updates, bookmark the tag: IC-705

We will also review on the Icom IC-705 as soon as it’s available.

Video from Amateur Logic/Ham College

Ray Novak (N9JA) with Icom America did a live video interview with Amateur Logic/Ham College TV yesterday. The video includes a full announcement in English from the Icom Booth:

Click here to view on YouTube.

IC-705 Pre-Release brochure

Many thanks to Ray Novak for snapping a few photos of the pre-release brochure:

Update: click here to download the full IC-705 brochure. Hat tip to Dave Zantow!

A surprise from one of the “Big Three”

The “Big Three” transceiver manufactures–Icom, Yaesu and Kenwood–have not shown a lot of interest in backpackable QRP radios over the past two decades.

By “backpackable” I mean QRP transceivers specifically designed for portable use in the field–radios that typically have built-in battery options, internal ATUs, and designed to be lightweight shack-in-a-box units.

Yaesu introduced the FT-817 almost twenty years ago and it lives on today (with modest upgrades) as the FT-818. Kenwood has no portable/backpackable HF QRP radio at this point.

I bet the IC-705 is being introduced today because Icom sees a strong market among field-portable operators who enjoy travel and outdoor radio activities like SOTA (Summits On The Air) and POTA (Parks On The Air).  In addition, many ham radio operators live in neighborhoods that are either plagued with radio interference (RFI) or don’t allow antennas to be installed outdoors. Portable radios liberate ham radio ops from their shacks and allow them to set up a station far away from noise or home owner’s associations.

Looking forward…

Again, I’ll be in touch with Icom about the IC-705 and will share updates here when they’re available. I’m looking forward to evaluation this rig when it hits the market!


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The lab599 Discovery TX-500 ruggedized portable QRP transceiver

Many thanks to SWLing Post contributor, Vlad, who shares some images and a video of a new QRP transceiver in development: the Discovery TX-500 by a company called lab599.

Specifications have not been published yet, but we have confirmed a few details from the manufacturer:

  • 10 watts PEP
  • HF plus 6 meters
  • Weight 570 grams (1.25 pounds)
  • Voltage 9 – 14 VDC
  • 105 milliamps at 13.8 VDC and with backlit display on
  • CAT control via USB and using Kenwood codes
  • I/Q outputs
  • Weatherized
  • Expected availability autumn 2019
  • Target retail price is $700 US
  • Product website is forthcoming

All of the following images came from the Discovery TX-500 gallery on Instagram:

Here are a few videos:

View this post on Instagram

Discovery TX-500, Lab599

A post shared by Laboratory599 (@discovery_tx_500) on

Click here to view on Instagram.

Click here to view on Instagram.

Click here to view on Instagram.

For someone, like me, who loves playing radio in the field (Parks On The Air and Summits On The Air) this looks like an ideal rig. It’s one of the only ham radio transceivers I’ve seen that is weatherized to some degree (how much, we don’t know yet).

I don’t see a speaker on the TX-500, so I’m guessing it might require a mic/speaker combo or an external speaker of some sort? I also don’t see a built-in ATU, but at $700, I certainly wouldn’t expect one.

With a power consumption of 110 milliamps at 13.8 VDC, this little transceiver should run for ages on a modest battery pack.

This is certainly a fascinating prototype QRP transceiver. If the Discovery TX-500 transceiver can be produced and marketed at $700 with all of the features mentioned so far, it should certainly fly off the shelves. They can certainly take my money!

Of course, I will plan to grab one of these for review. I’m also eager to see how this little SDR transceiver might perform on the broadcast bands.

We will post post TX-500 updates and details as they become available. Bookmark the tag Discovery TX-500 and stay tuned!


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Hamvention Highlights: The QRP Labs QSX 10 watt, general coverage, low-cost HF transceiver kit

Hans (G0UPL) of QRP Labs holding a QSX transceiver prototype at the 2019 Hamvention

Each year at the Dayton Hamvention I enjoy checking out the latest radio products and services. This year (2019) I found an exceptional number of innovations and will share these in Hamvention Highlights posts. If you would like to check out 2019 Hamvention Highlights as I publish them, bookmark this tag: 2019 Hamvention Highlights

The QRP Labs QSX Transceiver

Hans (G0UPL) of QRP Labs was, without a doubt, one of the most popular guys at the 2019 Hamvention — especially within the QRP community. In fact, at the Four Days In May (FDIM) vendors’ night his table was so busy I didn’t bother trying to force my way through the crowd to speak with him.

As luck would have it, our own table for ETOW was directly across from QRP Labs table at the the Greene County Fairgrounds so, in the end, I spent some quality time with Hans over the course of the Hamvention.

I’ll also make prediction: if the 10 band QSX transceiver delivers what it promises, it will be a serious disruptor in the ham radio transceiver world! This is a good thing. Why?

The QSX is a feature-packed, all-mode, high-performance, affordable, QRP transceiver.

The QSX will have a 24-bit Analog to Digital Converter (ADC) and a 24-bit Digital to Analog Converter (DAC). It will be a fully stand-alone unit and, since it’s an SDR and sports robust DSP, when connected to your PC, it will be recognized as a high-performance sound card. This equates to nearly native digital mode integration without the need for an external sound card interface.

The QSX Prototype Back Panel

The QSX Transceiver will be a through-hole kit with the surface-mounted components pre-installed on the circuit boards. This means the kit should be accessible to anyone with soldering skills.

Hans has even managed to include a mini spectrum display on the front backlit LCD panel.

The price? Around $150 US in total for the transceiver kit, 10 band filter module and enclosure. Unbelievable!

If Hans can pull this off — and I feel pretty confident he can — the QSX will set a new bar for QRP transceiver pricing and performance.

If you’d like more details about the QSX transceiver, check out the following resources sent to me by SWLing Post contributor, Pete Eaton:

The 10 band QSX will sport a general coverage receiver and although though the modes supported currently don’t include AM, Hans plans to add AM for at least reception purposes. This could make for a high-performance stand-alone SDR field radio for HF broadcast listening.

Of course, I also see the QSX transceiver as an accessible entry radio for new ham radio operators who are nervous about forking out $800+ for a new HF transceiver.

I will certainly grab the 10 band QSX transceiver kit when it becomes available and review it here on the SWLing Post. Stay tuned!

If you would like to follow other Hamvention Highlights, bookmark the tag: 2019 Hamvention Highlights


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FT4 digital mode now available in WSJT-X release candidate 5

Joe Taylor presenting FT4 at the Fair Lawn Amateur Radio Club

(Source: Southgate ARC)

The new amateur radio digital mode FT4 is now available for download as part of WSJT-X Release Candidate 5

You can download wsjtx-2.1.0-rc5-win64.exe (or for other O/S) from near the bottom of the page at
http://physics.princeton.edu/pulsar/k1jt/wsjtx.html

FT4 Protocol document
http://physics.princeton.edu/pulsar/k1jt/FT4_Protocol.pdf

See the WSJT Group at
https://groups.io/g/WSJTX/

For more information about FT4, check out this previous post.

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Kev-Flex Stealth Kevlar Antenna Wire: an incredibly durable wire for field radio

My good friend David Cripe (NMOS) has recently informed me about a new product he’s offering to the radio community via his eBay store: Kev-Flex Stealth Kevlar Antenna Wire. Kev-Flex looks like a superb option for field antennas of all stripes especially since it has an incredibly high tensile strength. It’s available in 75′ bundles, but Dave can also cut custom lengths. NM0S is also a trusted retailer in the ham radio world, so you can purchase with confidence.

Here’s the product description and link:

Kev-Flex is a unique antenna wire manufactured exclusively for NM0S Electronics. The lightweight center core of the wire is made from Kevlar fiber, giving the wire its incredible strength. The Kevlar core is wrapped with six tinned strands of 30 AWG copper. The effective surface of the wire creates an effective skin area capable of handling well over 100W.

The cable is protected from the elements by a coating of UV-resistant black polyethylene. With a total diameter of only 1/16″ (incl. insulation) and a weight of just 16 feet per ounce, the tensile strength 125 lbs allows lengthy unsupported horizontal runs. Kev-Flex is ideal for extremely long LW-antennas and Beverages and is great for balloon or kite-supported antennas. Its low weight and high break-load makes it most suitable for SOTA activations and other field operations.

The outer insulation makes the wire kink-resistant, and its slippery finish makes it ideal for stealth antennas that must be passed through trees or other obstacles without snagging.

This antenna wire is sold in 75 foot long bundles, which is enough for a 40M dipole or EFHW. Two 75 foot bundles would make a great 80M dipole. Custom lengths are available on request.

Specification

– Kevlar fiber core wrapped with six 30 AWG copper strands
– Weather-proof black polyethylene (PE) insulation, 1/16″ O.D.
– Weight: 16 feet per ounce
– Breaking-load: 125 lbs
– Velocity factor 0.97

Click here to view on eBay.

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