Bob takes a look at the (tr)uSDX

Many thanks to Bob (K7ZB) for sharing the following guest post:

A CW Operator’s First Look at the (tr)uSDX by Malahit

by Bob Houf  (K7ZB)  

April 22, 2024 – Gilbert, AZ

I recently bought an assembled (tr)uSDX from [affiliate link] in April, 2024, the mainboard is version 1.2 and the RF board is version 1.0.

Due to antenna limitations – a 17-foot wire antenna with a 6-foot counterpoise hanging from a second-floor condo balcony, matched through a Tokyo Hi-Power antenna coupler for an SWR well below 2:1 – I’ve been operating exclusively on the 20-meter band.

A short coax run into the dining room has given me some great on-air time over the weekend, with good band conditions for 20-meter CW.

The radio powers up when 13VDC is applied and I quickly figured out the menu structure with the minimal documentation available from DL2MAN.

I’ve learned that the filter is best set to 500Hz and it is effective for the conditions, and as the band gets hot with all the various weekend contests, I drop in a little attenuation and soon the radio begins to sound good – actually, for the money, it sounds really good.

QSK set to ON allows my keyer in Iambic B to do a good job and I don’t miss any contacts which are forthcoming across the US from Oregon out to the East coast, on down to the Virgin Islands and then, quite a surprise, my Magnificent 7 Watts is heard for a choice contact with a VK2 down under.

I pound out contest QSO’s all up and down the band, adding in a few SOTA and POTA stations and very few have trouble copying me – I certainly had no problem copying weak signals from them.

I do notice that this is not a $1,500 transceiver, especially in the receiver performance, but for the price the satisfaction derived from effortlessly working CW makes up for any limitations.

During the MST contest, as I write this, stations were piled on top of each other. I found that tightening the filter down to 50Hz wasn’t ideal – 500Hz worked better for my ears. Signals filled the band from 14.030 to nearly 14.050, ranging from very weak to extremely strong. Thankfully, the well-behaved AGC prevented any ear-splitting surprises.

I also tested SSB mode briefly and it works and sounds good, though I’m unlikely to use it much myself.

Overall, this little gem is far from a toy. With its filters, AGC, attenuator, and fine-tuning, it should bring a smile to any CW operator’s face.

7 thoughts on “Bob takes a look at the (tr)uSDX”

  1. Your report and especially the settings advice is very helpful for me on two points- I just completed a Classic truSDX build and had one of the electronics whizzes in my club just finished running diagnostics on it, did some troubleshooting and repairs on a short with the OLED and tuned all the bands for near perfect operation. Can’t wait for it to be returned to me and get it on the air. Secondly, I am going to continue working on my CW so I can be anywhere, in a park, on a trail, making activations. I had to have one of these radios when I tested the Elmer’s truSDX and my first contact was from Ontario to the Canary Islands on SSB. What a marvel of a little radio! Thrilled that it is a great CW performer.

  2. Thanks for the report Bob. Thanks Thomas for having so many guest posts. Here’s another (tr)uSDX report from another Bob.

    I too have good experiences with my (tr)uSDX, “Quirky Lil Orange.” Mine is built from a kit, the Hi-Band version. Recently, I had 2 coast to coast QSOs with Zach, K7FC, on 15m and 20m. They delighted us both by showing how well 2-3 watts works. My (tr)uSDX has the word “quirky” in its name because of the occasional audio squeals, which I have tamed through the use of an inline headphone amplifier.

    See a little more about mine, including some unique bundling, by clicking on my name on this comment.

  3. My (tr)uSDX has been unused and sitting in a box for a while so your posting has convinced me that it needs to get more air-time. I used it for the Zombie shuffle back in 2022 and worked really well.

    The following video by K6ARK really demonstrates the versatility of this little radio :

  4. Bob- it’s great to see all the positive comments here about this radio – my experiences have been positive as well, I take it along in my pack as a back-up radio most days.

    I noticed on your web page that you have a QRP Labs transceiver as well – how do the two compare?

    Happy hunting.

    Scott ka9p

    1. Thanks for the comment, Scott. The QCX+ on 20M is also a fun little rig and very easy to use. I have no issues with it in general with the exception of a lack of AGC – and why I specifically mentioned that in my (tr)uSDR report. Another difference is that this rig allows for CW practice without an antenna attached and the QCX+ does not – I made the mistake of powering up the QCX+ without an antenna and setting up the iambic keyer first then found out I could have blown the output Q’s, which I fortunately did not. Both rigs are a lot of fun and I can recommend them both, but for the moment I am taken by the (tr)uSDX and will spend more time with it. Final note – the speaker audio in the radio is poor but a decent set of headphones gives quite nice audio. 73 de K7ZB

  5. Very much appreciate the CW-specific review, Bob. Most of the chatter about this design that I’ve found online has been SSB operators, and/or people who aren’t hardcore brasspounders. As you know, we’re particular about some facets of performance that other hams don’t consider deal-breakers, and as a lifetime CW-only operator, I’ve learned that you need to hear from others like that before you consider a newly-offered rig.

    One way or the other, it sure seems like this one is opening a lot of new opportunities in amateur radio. Thanks again!

  6. I have a different version of the uSDX transceiver. Knobs/switches/display on the end with connectors on the rear, about 4″L x 3″W x 1″H.

    I loaned to a friend who just got his General and was new to HF. He really worked the rig even checking into our state wide phone net.

    I packaged mine in a bag with battery, key and end fed wire antenna.

    These little rigs are great way of someone getting into QRP, dont need to spend a lot of money to see if it is right for you.

    73, ron, n9ee

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