I don’t try to make my truSDX the operational equiv of my KX2. Instead, I leverage its strengths (size, lower power requirements, etc) to build a smaller, lighter kit.
My truSDX kit is a full pound lighter than my KX2 kit:
truSDX: TX, battery (same type for KX2), earbud for RX-audio (I use the internal mic for TX), and homebrew 40/20 EFHW antenna with micro-transformer. Weight: .8lbs
KX2: TX w/ATU, internal battery, Sony earbuds for TX/RX, BNC adapter, 57’ wire, 17’ wire. Weight: 1.8lbs.
Both weighed on my digital archery scale (made for measuring draw weight, but works great for weighing static loads).
Volume-wise, the truSDX kit is a bit larger than a baseball. The KX2 kit packs up snugly in a Lowepro CS40 case. The truSDX kit fits in my bike’s handlebar bag, the KX2 kit does not.
I use a home brew, resonant, 4 band trapped EFHW, following the plans on the QRZ page of K1JD. So carrying a radio with an antenna tuner or a separate antenna tuner is redundant. I used the (tr)usdx on an activation in NM about a week ago with good results. With the help of K1JD, I changed out the display to one with white digits, which worked fine outdoors. I only do CW, so SSB issues do not effect me. Volume is very good at 11, with earbuds, clear signals and 23 QSO’s in about 20 minutes. I used my KX2 on the next activation, about 1.5 hours later and made 23 QSO’s. I understand the variability in propagation, but by comparison, this is acceptable to me. The (tr)usdx RX is sensitive enough to compete, in the real world, with other radios of its genre and puts out a solid 5+ watts @12V. I’m not a real techie, I only focus on results and they were fine. The weight factor difference compared to a KX2 is significant, given I use resonant antennas. Regularly hiking up to 8 - 10k feet ASL, weight matters.
I have MTRs and they are more refined, but they lack an SWR meter, which gives me some comfort in the field. The new MTR 4B V2 has an SWR meter, but the radio is a bit more bulky than the typical MTR. The QCX is good, but I have to carry 2 of them to cover 3 bands. The (tr)usdx ticks off a lot boxes that suit me.
If anyone doesn’t want theirs, you can sent it to me:-)
My feelings after three weeks of playing with this little radio are positive. It has a good and not so good side as Richard said. On a good side I would add CAT control - I can control this radio from my CQRLOG logger just as I do control my home KX3 radio.
I did some chasing last three weeks and I was suprised what one can do with just 0.5W (when powered from home computer USB port) or with 4 W (powered from lion battery). Today I chased five activators in the middle of their pileup with no problem.
I am using Samsung phone earbuds, so no problem with acoustic feedback. Receiver quality is not so bad compared to KX3, it is quite OK for casual chasing.
I am not sure about SSB voice quality. Listening locally on my KX3 it sounds awful. I made just one SSB chase till now, my output power was 0.5 W (powered from USB computer port) and you know what - without asking him to comment on my voice quality, the activator said my sound quality was good (!).
I did not finish yet my new multiband resonant EFHW antenna, so my first activation with (tr)uSDX is delayed. But based on my home experience I am quite confident that it will be a successful activation.
Today I tried the (tr)usdx in activation, on I/LO-226. I also had the 817 and of the 53 qso total, I made 27 with the orange rig, used in ssb as a walkie-talkie, 15 in 30 cw and 12 in 40 SSB. About 4 watts in 30, 3.5 watts in 40. In my opinion it is a big YES for activations with long gradients and distances. In RX it is not comparable to the 817, but its work does. A problem may be the poor readability of the display in bright sunlight, but if I want to do 40 S2S and 100 qso I bring the 817, if I have to do 15 km and 1000 meters of elevation gain I bring the little orange box.
I just saw @K6ARK’s video on using this radio for an ultra-portable FT8 station. I have to admit I’ve not been interested in FT8 previously because I don’t want to drag a laptop or tablet up a mountain, but I already have the cellphone, so why not give it a try? I’ve ordered the parts to build the audio adapter. It could be a good arrow to have in the quiver, so to speak.
I was reading that. Were RoWaves making modifications (improvements) to the design that were out with the terms of the license? They have a 36 page document on their website describing issues and solutions and also state several times that they were running up a loss selling these kits and finished radios.
Huh,from what i know they never were “approved” seller?
Think it was because of the lacking efficiency,i dont know what they were doing,but my Chinese assembled device waa getting 80+% eff out of the box,once i set rshunt to 18 it went to 90%,then again who know how accurate the device’s reading is.
We hereby officially announce, that RoWaves will no longer be supported by us, RoWaves will also be disqualified from Approval procedure. A detailed counter-statement to their accusations in their "technical Document " will soon be released, as our side of the story has never been heard in public. We were still hoping to solve this, but recent actions have made any future cooperation impossible. 73 Manuel; DL2MAN
I saw the same video by K6ARK and it got me thinking. I have in the last couple of days got a Tr uSDX from an approved supplier with the view of getting it working for digital modes.
I was going to make up the K6ARK adapter as I have in the past used an Android phone with PSKDroid for PSK31 with good sucess and the new FT8 software looked promising, I doug out the old phone with the PSK software and loaded FT8 on it.
Then I got to thinking that I may not need to make an adapter. So a quick root again in the desk draw turned up a USB sound card adapter and a USB to Mini USB adapter. Quick re solder of an audio cable and had it up and running. No need for an audio adapted, just plugged the USB sound card into the USB adapter and into the USB port on the phone. VOX to switch works just fine.
So now have PSK, FT8, JT and WSPR. Need to play a bit with the settings for PSK as it was over driving and distoring but did manage a qso into St Petersberg so not to bad plus a few Euro FT8 completes.
Only down side is you cant power the phone during use but should get many hours use.
Cris
M0KKA
Hi Cris
Just wondering where you got your VFO knob from looking for something a bit lower profile as I am a bit concerned in case it gets damaged in the rucksack?
Had mine out for its debut today on GI/MM-017, found it difficult reading the display in the sunlight but used the log book to shade it a bit. Managed to activate the summit and qualify using the 40/30/20m CW bands still need to source a mic for SSB.
I found the knob on ebay. It’s actually a bit too large but better than the one that came with it. Would love a more professional case but can’t see anything yet advertised.
I have a Chinese copy of a Icom mic that I have converted. It has a speaker in it but have not wired it up just the mic so far. May do that later but works well.
I noted above that I was not that impressed with the tr(u)sdx - although I successfully used it on two CW only activation, I found that receive performance was too fickle.
I have just today taken delivery of an SW-3B and am finding it to be a big improvement. Of course, it doesn’t tx on SSB, but the receive on CW (and SSB!) seems far superior to the tr(u)sdx. Indeed, it has made the investment of 6 months to learn CW really very worthwhile indeed.
the tr(us)sdx is still a lot of fun, and I have managed some good SSB contacts on it in fine conditions. I very much hope the developers choose to open source the hardware so as to encourage further development.
I circled around the idea of getting the (tr) uSDX for some time and talked myself out of it many times after reading reviews and watching youtude reviews. I have many qrp rigs like QCX, QCX Mini, SW 3B plus more. However what I really wanted was a very small rig for data plus option of cw and voice if needed. Most of my other trancivers work much better for voice or cw but so far the (tr) uSDX looks like it will do just fine for data. Also got a QDX arriving tomorrow but of course no voice or cw and limited connectivity to pc / Raspberry pi. (tr) uSDX can interface with phone for ultimate portability. Hmm may be able to connect the QDX with a phone via the usb port… something to investigate!
I think bottom line is the (tr) uSDX is not a high performning but very versatile tranciever. Worth having in the stable at the price point.
I would never pay £££ for a TRX for the field.
