Many thanks to Joe (N0LSD) who shares the following guest post:
Getting Started with HF Digital Modes – Without Breaking the Bank
by Joe (N0LSD)
Amateur radio can be an expensive hobby: the reasons are myriad, made more difficult for newcomers because they tend to not have the experience to know what their requirements might be. Brick-and-mortar stores where one might bounce ideas off knowledgeable staff, browse the aisles, and walk away with a suitable set-up are pretty few and far between. Similarly, asking on various internet forums will often be met with, “It depends…” –followed by a wall of text filled with jargon and terminology that can be…intimidating.
For newcomers that maybe don’t have the time to invest in learning CW right off the hop, and perhaps get a bit of mic fright, digital modes such as FT8, JS8, and the like tend to be a great fit. While “shack-in-a-box” solutions by the big-name manufacturers offer convenience, this convenience comes at a price that can be cost-prohibitive.
What follows is a QRP digital modes kit that I’ve experimented with over the last year. No single piece of this kit cost more than US$150, and the entire kit can be had for under US$600. What’s more, nearly everything can be purchased from Amazon.
We’ll start with the most expensive part of this kit: the radio, which is the Tr(u)SDX. It can be had on Amazon for US$138, and covers 20m, 30m, 40m, 60m, and 80m bands. It is a quirky little radio with a sub-par speaker and a tiny little microphone.
The Tr(u)SDX is just about as bare-bones as one can get with an HF transceiver, and is decidedly a compromise. However, unlike other ultra-compact transceivers, this one will do CW, it will do voice, and it will do *any* digital mode. It can run on USB power at 1 watt output (micro-USB port on the side of the case); but it can also run on 12v (nominal) power via a 5.5mm x 2.1mm barrel connector on the top of the unit.
I’m powering this radio with a US$43 battery bank (Romoss Sense8P+), and a USB-C to 5.5 x 2.1mm cable (US$8.99) –both available on Amazon. This battery bank will keep the Tr(u)SDX going for hours –long enough to do multiple POTA activations. And, because there’s no special adapters, the battery bank can be re-charged in the same manner as a cell phone –or even off a small solar panel.
The sound card interface is the Digirig (US$57) with a US$19.97 cable that is TRRS 3.5mm on one end, and breaks out separate Mic and Speaker 3.5mm TRS. Now, I will say that a recent firmware revision on the Tr(u)SDX has been demonstrated by the developers of the radio to allow for audio through the micro-USB connector of the radio – so the use of a sound card interface *may* be redundant. However, in viewing the demonstration video for this, it seems rather dependent upon finding the right micro-USB to USB-A cable; with no clear indication on where one can obtain a cable that meets the specification. Now, add a USB-C to USB-A or a USB-C to USB-C cable to interface with the computing device, and we’re in business!
So far we have a radio, power, and a way to get sound in and out of the radio. Now, let’s talk about antennas. Of course, one can homebrew an antenna for the cost of parts and time in construction and testing. For the kit I’m using, I went with the N9SAB OCF Dipole –specifically because I do a lot of 80m QRP work. Also available from N9SAB is a 6m-80m random-wire end-fed for US$89.99 from his eBay store.
If using a non-resonant antenna, an antenna tuner will be needed: I went with the ATX-100 (US$126 from Amazon). The reason I went with this is because it recharges with USB-C, which is consistent with everything else in this kit.
For coax, I personally use Times Microwave LMR-240 –a 50-foot length terminated in BNC is US$65 on Amazon. For something less bulky, perhaps RG-316 from ABR Industries (abrind.com) might fit the bill The ABR-240 coax at 50-feet in length is US$58. For a jumper from the tuner to the radio, I use a 3ft RG316 cable from Amazon – which cost me US$13.99.
All that’s left is a device to run software…this can be a Raspberry Pi, or one’s laptop, certainly –however, these are bulky and require special power…and are a pain to re-charge easily. Another solution is something one might already have: an Android smartphone. There are apps (some free, some paid) for RTTY, PSK31/63, WSPR, SSTV – these have been out for some time. Additionally, one can do many of the modes contained in FLDigi, using the AndFLMsg app (not available on the Play Store –one has to download the .apk file from a 3rd party). However, what I’ve been using –especially on POTA activations – is FT8CN. This allows for full-function FT8 using just an Android phone –which can also be charged via USB-C.
[Note: eBay, Amazon and ABR links below are affiliate/partner and support QRPer.com at no cost to you]
| Tr(u)SDX | $138.00 | Amazon |
| N9SAB Random Wire End-Fed | $89.95 | N9SAB eBay Store |
| ATU-100 Antenna Tuner | $126.00 | Amazon |
| RG316 Coax Jumper (3ft) | $13.99 | Amazon |
| USB-C to 5.5×2.1mm cable | $8.99 | Amazon |
| ABR-240 50 ft Coax | $58.00 | abrind.com |
| Romoss Sense8P+ Battery Bank | $42.99 | Amazon |
| DigiRig MobileSoundcard Interface | $49.97 | digirig.net/store |
| uSDX Cable for DigiRig Mobile | $19.97 | digirig.net/store |
| Total | $547.86 |
This kit is –for sure– a compromise: one isn’t going to bust pile-ups or win contests with it However, for a “starter kit” that can easily be carried in a small backpack that can not only be used for HF digital modes, but also can do SSB voice and CW, it will at least get an operator on the air and enjoying the bands –without breaking the bank.
“and the entire kit can be had for under US$6600″… Well that’s comforting. Who’s your (tr)uSDX guy? Here, you need to call my true SDX guy You’re getting ripped off, lol.
Hi hi! I made that correction. 🙂
Hi Scott, great article. I am traveling soon to Alaska via a cruise. The last 5 days off the boat, I am hoping to activate a park. Maybe one in Canada as well.
Q: what do you think would be a similar set up for SSB only. Has to be light.
Looks like u have done your research. Thanks for sharing. Many new hams don’t know how to get a portable or home station up and running. 73
Are we able to put a link up on our local club’s reflector directing newcomers to this page? … with full credit to Joe & yourself of course 🙂 73’s G4TVP ..
100% Mike! Go for it!
Very interesting and well done. Several hardware and software items that I would like to look into and perhaps adapt for my own portable operating.
Great article Thomas. However, my (tr)uSDX uses a 3.5mm x 1.35mm power connector. I wonder if this was changed at some point during production.
Great Report Joe!
I’ve been geared up, ready to go with my QMX LoBander for months now. But, I have yet to really give it a shake-down afield.
I honestly feel guilty about it… QRPer, You and some others, have ‘inspired’ me to get out and play radio.
I have a busy schedule, perhaps this weekend I’ll give it a go. My QMX is paired with a 12v 3aH TalentCell, a Palm Pico, a Galaxy S20 Ultra with FT8CN software, a USB c/c cable and a EFλ/2 X-Tenna, cut for 40-10m. It’s been tested at the QTH, but needs some serious field trials.
Thanks again Joe… maybe I’ll see you on the air soon?
72 de W7UDT
I have a number of antennae by N9SAB (Tim Ortiz). He does wonderful work.
Thomas your equipment suggestions are always 100% accurate but I must take issue with the battery bank you recommend. The vast majority of these Chinese batteries over rate their capacity and are generally of very low quality. Although I do not own this model if you read the reviews for the brand you will understand they are made with cheap cells and will NOT perform as rated. Amateurs are much better off either crafting their own from known quality cells or purchasing a quality brand such as Bioenno, etc. YMMV…
Joe (N0LSD), which specific Times Microwave coax cable and connector model numbers did you use? Do you have a T-M crimper, as well? I like their products, and I’m trying to wade through their unique nomenclature. Thanks.
73
Stephen KJ5AWL
Stephen, ABR Industries can make up any TMR cable you want with almost any connector you can imagine. The best part is you can get a 10% discount by searching THIS site for the ABR Industries discount code they offer to Thomas’ readers. … and their service is fast!
I built two of the tr(u) sdx transceivers, one for the classic bands and one for the hi-bands. For NVIS work the classic bands model is recommended. Construction is not for the first time builder. Some SMT work is involved. Also a metric tap is needed for threading for case assembly.
Very good combination for FT8. For my part, I simplified it and made it as cheap as possible; (tr)USDx, 18650×3 battery in the DL2MAN box, TRRS cable, FT8CN in cell phone, with K6ARK interface (https://oshpark.com/profiles/K6ARK), EFHW antenna or inverted V dipole (very convenient because it works 10 m). It makes a total of maybe 200 dollars…, plus a fanny pack to carry everything on my waist.
In these difficult days with too good propagation I can only do POTA in FT8 since CW I could never learn because of my hard ear; and SSB QRP is left for me as autumn progresses in this hemisphere.
(sorry for the mistakes, translated by G)
Greetings
You know you can do FT-8 for a whole lot less, like $90 for a dedicated FT8 radio ie the QDX from QRP Labs, Yes that’s the kit price, but you can get it assembled for $135. Then you need an antenna which can be homebrewed from a couple ferrite cores.and speaker or magnet wire,a USB cable to hook your laptop or tablet to the radio, a 12v power source (12v 7ah sealed lead acid batteries are under $20 and last around 90 minutes with the QDX) and last but not least your laptop or tablet.
There are many ways to play on the bands, just drpends on how creative you have to get with your budget.
I just ordered the QMX assembled, and I won’t receive it for 4 months. I ordered a KX2 from Elecraft on Monday, and again, will probably not receive it until August. The link above to Amazon for the Tr(u)SDX, you can get in two days.
I’m seriously thinking about getting the Tr(u) SDX just to get on the air with *something* while I wait.
Absolutely! Go for it.
It’s an experimenters radio to be sure, but I know an avid SOTA activator who has adopted the (tr)uSDX as his main SOTA rig.
I think you may have the wrong link for the tuner. I went to the link to buy one, but the tuner shown is $96 and has no battery or USB-C port. Could you be thinking of this one?
https://www.amazon.com/ATU-100-Version-ATU-10-Automatic-Antenna/dp/B09PTC6DJ8
Thank you, Ben! That was my mistake. I’ve corrected the link! Appreciate that! -Thomas
Amazon is currently offering a 50% off coupon on that battery bank, making it $21.49 plus tax.
You could also reduce the price significantly if you like to build kits by swapping out the radio and antenna with a QDX or QMX and the antenna with a tufteln/K6ARK/KM4CFT antenna.
Also I know for a fact that the trusdx doesn’t use 5.5×2.1 (believe me, I wish it did because then it would work with most of my radios)
Good article, Joe; very thorough! That’s an interesting power bank that you found, not many have the 9 volt & 12 volt option.
The fully assembled (tr)uSDX from Amazon comes with an unterminated power cord; if you need to buy the connector in the aftermarket it is 3.5 x 1.3 mm. Get ones with a fairly long barrel, some are too short to make a good connection with the jack inside the case.
I think that the (tr)uSDX is a good little radio within its limits; some really amazing engineering (both hardware and software) to get so much out of a very economical platform!