Wednesday, 27 July 2022

(tr)uSDX Review Part.1


The (tr)uSDX is something of a marvel! Okay, so it's no KX3, but neither is it £1500. It's a supremely affordable QRP transceiver which can be purchased pre-built or (if you're into diy), can be ordered as a simple, easy to build kit. Because I'm tight-fisted ๐Ÿ˜‚ I bought mine second-hand from YouTube's  TechMinds.

Everything about the (tr)uSDX looks cheap - it's encased in a 3D printed enclosure with all the associated crude detailing and tacky colours. The VFO encoder knob is also 3D printed. The case is held together with bulky screws and it has those stick-on rubber feet that you can buy from the £Shop.

The sound from the built-in speaker is pretty shocking and the audio is generally poor. The receiver isn't particularly sensitive and when sat next to my beautiful little BELKA DX receiver, you feel like maybe you've made a mistake purchasing the (tr)uSDX.

But that's where the negativity ends! The (tr)uSDX is a fabulous little transceiver which is not much bigger than a pack of cigarettes and weighs next to nothing. It has a small but clear OLED screen which provides an amazing amount of information. The screen is not easy to read in direct sunlight, so be prepared to shade it with your hand.

This is a 5-Band radio (mine is configured for 80-60-40-30-20) providing up to 6W output and CW/LSB/USB/AM/FM modes. There's a convenient built-in microphone and PTT-switch (which can even double up as an emergency CW key), making the radio pretty self-contained. Needless to say, you'd be better using an external mic and speaker, but at least they're there as a backup for those occasional days when you reach your SOTA Summit and realise you've left the mic at home! The radio has a socket for a CW Key (straight or paddles).

The receiver's noise floor is fairly high, but again, you have to remember the price point of this radio and accept the fact that it's not your DX base station - it's your "stick it in your pocket" radio, your "pop it in the glovebox" radio. And when you're sat on the beach or on top of a hillside with a bit of wire, you'll be pulling in plenty of signals strong and loud enough to be able to have some fantastic QSO's in any mode you like!

A couple of minutes Audio of my (tr)uSDX

As soon as my (tr)uSDX dropped through the letterbox, I quickly connected it to a 9V supply and an EFHW and tuned around 40M. On 7.144 I found PA0PIW and although he was in a mini-pileup, I thought I'd shout into the built-in mic and see if he could hear me. He almost instantly read back my callsign and gave me a good signal report! That was very pleasing and I look forward to taking this little beauty up to my local Sota point to see just how far I can get. My second attempt got me a 55 from F4HEC in France (he’s the one featured in the recording above).

Navigating around the (tr)uSDX's operating system is fairly straight-forward. The primary function of the rotary encoder is (as you'd expect) to control the frequency of the VFO, but if you push it down and turn, it controls the volume. Single pushes of the knob alters the tuning rate and a double-push changes bands. Single-clicking the Enter Key changes modes, while double-clicking changes filter width and a long push brings up the RIT function. Nice!

The rest of the radio's functions lay in the Menu and it's all surprisingly intuitive - no doubt thanks to the software skills of DL2MAN's partner - PE1NNZ who's done a fabulous job. When you first get hold of your (tr)uSDX you can put it into 'Practise Mode' so that the PA is shut down while you learn your way around the radio. Speaking of PA, there is a connector on the side of the radio to allow you to connect to an External Amplifier.

 DL2MAN's website is a great place to learn more about the (tr)uSDX and its heritage; there's lot's of great tutorial videos there too. Manuel seems like a real nice character and his videos make for easy watching. His command of the English language is pretty good too. There's also a very useful FORUM.

The (tr)uSDX can be run on a wide range of voltages using the small DC connector port and can even be powered from a 5V USB power pack. At 5V the TX power is limited to 500mW but even than is a great feature for those wishing to play at the lower end of QRP levels. This USB port can also be used for CAT Control and Programming.

As I mentioned earlier, the OLED screen provides lots of info and can be tailored to suit your personal preferences. You have the frequency, the VFO indicator, S-Meter, Filter Width, Rx/Tx indicator, Mode, Tuning-Step and even your CallSign.  Things like the S-Meter can be altered to show reflected power, forward power, swr, watts, efficiency and more, but the latter can only be done in CW mode. 

Another great feature of the (tr)uSDX is the built-in CW Decoder! Again, just think about the price of this tiny transceiver and ask yourself would you really expect a CW Decoder to be included?? I wouldn't! 

And it works really well too. I usually set the CW Speed to 20wpm and it pretty much decodes everything I can hear as long as the signal is strong. Occasionally I have to drop the speed down when I know the speed is particularly slow, but otherwise, it does a great job.  The radio can also SEND an automated CW Message from memory which can be a great assistance when calling CQ.

 Note that I fitted an SMA to BNC adapter but it leaves a gap, so I inserted a brass ‘Cup Washer’. Perfect fit! I also use a compact (but very clear) plug-in speaker from Amazon. Highly recommended!

Although I've got a SotaBeams EFHW and LINKED DIPOLE, I've sent off for a QRP GUYS 'No Tune' End-Fed-Half-Wave antenna which covers 80-10M. This will be the perfect companion for the (tr)uSDX. It comes in Kit-Form and should only take a few minutes to put together. All you then need to do is connect the appropriate length of wire to suit the band you wish to operate on. No counterpoise is required. Conveniently, all the wire-lengths are printed on the antenna former.

It should be a simple task to cut the wires and trim them to attain the best SWR using my NanoVNA. I'm guessing that most of the time this antenna will be used in a Sloper configuration by throwing one end up into a tree, thereby allowing me to leave my telescopic mast at home.


As I write this mini-review of the (tr)uSDX, I am reminded of the infinitely more expensive PreppComm MMX which I purchased a few months ago. The MMX is a small CW-ONLY 3-Band, Decoder/Encoder which has not only cost me a small fortune, but has caused me months of disappointment and anxiety. And even now when all the troubles are supposedly behind me, I am left wary and cautious about using it.

The (tr)uSDX on the other hand, has proved to be a product that just worked from the get-go. Not only does it do what it's supposed to do, it does it with ease and reliability. It has some amazing built-in tools to diagnose problems, has a built-in SWR Bridge and even a PA efficiency indicator to help you tweak the toroids, if you're so inclined.

The levels of support for such a cheap product are amazing and I'm very pleased to have it in my arsenal. I reckon I'm going to get more fun and enjoyment from this budget rig than some of my other much more expensive radios! We'll see ๐Ÿ˜Š

* Super Cheap!
* Easy Kit build or Pre-Built.
* Super Light & Compact!
* Informative OLED Screen.
* Intuitive Operation.
* Robust Design.
* Built-In Diagnostic Tools.
* Built-In CW Decoder!
* Five Bands!
* Great Performer!

* Tacky 3D Printed Enclosure.
* Fairly High Noise Floor.
* Small Screen.
* Horrible Speaker.
* No Bandscope, Waterfall, ATU, GPS ๐Ÿ˜‚

More Soon :
Booked a couple of days off work to do field test. Will report back.

Before I forget, DL2MAN has a great video on preparing the (tr)uSDX for Data HERE.

Monday, 18 July 2022



Please note that this is a review of Eric Anderson's PreppComm MMX and it is written by a lowly UK M7 Licence Holder. There's no oscilliscopes involved and no fancy technical talk. It's just an honest account of what happened when I decided to purchase a QRP CW Decoder/Encoder from a small company in Idaho, USA. This is a "Warts And All" review which may not go down well with PreppComm, but it is what it is and facts are facts. I can assure you though, where credit is due, credit is given. There's no malicious intent here.

The review is written in a kind of Diary Format, where I enter new information as the purchase-order progresses and the story unfolds. Hopefully, as the "diary entries" continue, things will improve and continue to do so, but let me make it clear - my purchase did not get off to a great start.


It has long bothered me that I can’t work CW. I find it very appealing and recognise its ability to potentially reach much further than SSB. Even in poor band conditions, CW Operators seem to be able to have QSO’s.  But what can I do?? I’m too old and too damned busy to learn a new language.

I bought a Morse Tutor and Key and I tried my heart out for a week or so, but soon realised that it was going to take me many months to reach the point where I could call myself proficient - and that means many months of not doing something else with my leisure time.

Well the answer is to use a CW Decoder and Encoder. But traditionally, they’ve all been pretty rubbish at decoding. Many modern transceivers include a morse decoder and some even allow the transmission of short pre-written CW messages stored in memory and accessed by a bank of 4 or maybe even 8 buttons. That's fine for very basic messages like "CQ TEST M7MCQ" for use on the Reverse Beacon Network, but it's not really much use in a QSO with a human being.

A few companies manufactured Morse Code Readers/Keyers such as MFJ with their 464 model, but reviews of this and other similar devices are not very complimentary at all, so I figured all was lost ๐Ÿ˜ข

And then the April 2022 RSGB  RADCOM magazine dropped through my door, with the answer to all my prayers - or so it seems. On the front cover was a PreppComm DMX-40 and inside was a detailed review of it. I didn't realise it at the time, but this this product-review was not an original piece written by RADCOM staff in the UK, but was just a copy of an 8-month old online review from an American blogger "The Tech Examiner" ๐Ÿ˜ฆ Does it matter that it wasn't written by a UK reviewer? Well you can decide later when you have read all this review.

The DMX-40 Morse Decoder & Encoder Transceiver (designed and built in Idaho, USA by Eric Anderson) is a portable single band (40M) QRP device which allows users to decode morse signals and it also allows you to transmit morse code by simply typing your message on the supplied keyboard with up to  3W output.

Now, similar claims have been made in the past and some manufacturers have got closer than others in achieving this holy grail, but according to the reviewer in RadCom, the PreppComm actually works - every time!!

That is great news and it will be of considerable interest to many people out there who want to join in the fun of CW and benefit from its long reach. The DMX-40 has a CW receiver which matches some of those on much more expensive radios. Thanks to its high-noise immunity decoder, it has superb sensitivity and selectivity and decodes text even when the band is very noisy and busy with people transmitting very close to one another.

One of the most appealing features of this transceiver is that it's compact and portable and will be a fantastic aid in SOTA & POTA operations. Unfortunately, you have to use the supplied keyboard - you can't just use any old USB keyboard, but thankfully, the supplied unit is light and will fit into your go-bag with ease. I managed to find an alternative on Amazon called the SR Mini Keyboard as a backup. 

What I liked about Eric Anderson's approach to this project is his focus on making it fun and easy! The unit not only works out the speed of the incoming CW, but also detects your typing (sending) speed. If you're typing speed fluctuates wildly, then it will use the receive-speed to send your message (it has a keyboard buffer).

There's also options to program macros to save you typing out repetitive information such as Name, QTH, Rig, Antenna, etc. I've never worked CW in Contest Mode, but I'm guessing that these macros will be extremely handy for that.

The 3.5" colour-screen is a Touch Screen, making operation very simple and intuitive. There are 28 menu screens in total, including a built-in Help Section - that's always good to have when you're out in the field and you've forgotten how to use a particular feature.

In addition to being a self-contained CW Transceiver, you can also connect the device to your existing radio and (in theory) use it to decode/transmit CW on any of the bands that your radio has - including VHF/UHF. That would be amazing!

Finally, this device could become your active (and passive) morse tutor. You can attach a key and practice as much as you like and instantly see the results on screen. Currently, you can only use a straight key, but hopefully, there'll be a firmware update in the future which allows paddles.

PreppComm is a tiny company, but the benefit of that is that you feel like you can relate to them and it's both interesting and amusing to read through their Development Blog and learn about the trials and tribulations of getting an idea to a working product. One part of the Blog relates to installing SMD components on PCBs and boy, I think everyone in ham radio can symapthise, LOL.

MARCH 2022

I ordered my unit direct from America on 17 March 2022 and rather than ordering the single-band DMX, I opted for an upgrade in the form of the Tri-Band MMX which covers 80/40/20.  

Shipping to the UK was pretty darned expensive at $50 but there are no UK distributors yet, so there's little choice but to pay that. I'm very excited and can't wait for the unit to arrive.

Much more information is available in this >>>PDF FILE<<< from PreppCom.

More when it arrives ๐Ÿ˜‰

Tom, M7MCQ.


UPDATE 19 MAY 2022

After waiting ๐Ÿ˜ขTWO MONTHS ๐Ÿ˜ข for the MMX to arrive (PreppComm were having trouble obtaining parts), UPS eventually texted to say they could deliver it once I’d paid a pretty shocking Import Duty Fee of £95 ๐Ÿ™„ I was expecting to have to pay something but not that much. Anyway, I clicked on their link and paid the fee and got another text from them confirming the fee had been paid and the item would be delivered the next day - it was! 

Perhaps now is the time to mention another matter which has caused great annoyance and even moments of anger. Over a month after paying the Import Duties, I received a letter from UPS saying that they were charging me a late payment fee and I had no idea what they were talking about, so I had to ring them up.

Needless to say, it took an awful long time to get through to a human being and the person on the other end of the phone had a thick Indian accent which resulted in a very difficult conversation where we were both asking one another to repeat what had just been said ๐Ÿ˜ซ

I was asked to email over proof that I had paid for the original invoice and I explained that I had never received an invoice - all I got was a text to say that the item was being held at CUSTOMS until I paid the Import Fees, which I did by clicking on the LINK contained within the text. Once I'd paid I received another text thanking me for the payment and the parcel arrived the next day. I sent screenshots of all this to the UPS guy and thought that was the end of it.

Sadly, that wasn't the end, because they continued to bombard me with emails for payment. I continued to send proof of payment by sending screenshots of my Bank App showing that I'd paid. It drove me absolutely NUTS and I realised that i'd be better off just paying the £7 LPF to avoid these idiots messing up my Credit Score ๐Ÿ˜ก

In the end (after a whole load more demands), I got an email showing that everything was paid.

Life's too short for this crap

So, let's get back to the MMX!  I connected a 5W Dummy Load and plugged it into a 13.2V LifePO battery and went through the initial setup stage where you input your CallSign, name, etc. Once finished, I switched it off and back on again. NOTHING!

Well actually, the MMX showed a message saying  “CPU’s NOT INITIALIZED”. Nothing else worked and the keyboard didn’t work at all ๐Ÿ˜ญ๐Ÿ˜ก๐Ÿ˜ญ

I contacted Eric Anderson and he confirmed the unit was faulty and asked me to return the faulty MMX for a repair/replacement. Then he realised that I wasn’t in America and offered to send me a replacement PCB if I could install it. I said yes.

So I'm now waiting for the new PCB to arrive. Disappointing, but these things happen I guess.


UPDATE : JUNE 1st 2022

The replacement PCB from PreppComm has arrived, so I can start to do the swap-out. I must admit that I was initially surprised to find that the part PreppComm sent over was actually from what appears to be an earlier device called an RTS COMMANDER. 

I'm guessing that the RTS COMMANDER is an earlier product which was being developed for Radio Texting and was abandoned when they realised it could be put to better use as a morse code decoder/encoder.
At this point I had no idea whether or not this item had been sent in error or if it was the right part. Well I needn't have worried because the PCB/PANEL sent to me was absolutely fine! I think ALL the DMX/MMX are fitted with this RTS Commander board behind the front panel.

Carrying out the repair was very simply indeed - no soldering required - just a case of swapping out one board for another, taking care, of course, to avoid any static charge damage. It literally just took a few minutes. 


I connected it to a 13.2V LifePO battery and had a play with the rig. Everything was working well. I tested the transmission side of things with the Dummy Load still fitted and a QRP RF/WATT Meter to monitor output power.

I need to connect it to a resonant antenna at some point and start the learning process. Thankfully, there's the long bank holiday weekend coming up (Queen's Jubilee), so I'll get into it then. Excited!!

Will report back soon...

UPDATE : 3 June

Well, this morning at our holiday home, I connected the MMX to a dummy load again and put a QRP WATT/SWR meter inline along with a volt/ammeter.

I started off in EXTERNAL Mode to get more familiar with everything and then switched to FREQ Mode to test the TX side of things. Pressing CALL and RESTART, the radio began transmitting the standard CQ call and the Watt Meter showed  3-4W out, so I was pleased that everything was working fine. In fact, I was a little surprised to see it occasionally swing over to 5W, but that's probably the meter being slightly optimistic ๐Ÿ˜ƒ. The MMX was working perfectly and I had a little grin on my face, knowing how much fun this radio was going to be ๐Ÿ˜

I decided to move everything to another room so I could work more comfortably - and that’s when things started to go wrong. Although the radio APPEARED to be functioning perfectly well, it wasn’t actually putting out any RF!! ๐Ÿ˜ฎ๐Ÿ˜ซ Nothing had changed between moving locations - it must have faulted right at the end of the testing in the other room.

I couldn’t understand why. If I hadn’t had the meter attached, I wouldn’t have actually known there was something wrong because the radio itself gave no indication of a problem. My RF meter showed there was no output from the antenna port to the Dummy Load.

I stripped the radio down to look for anything obvious, but there was nothing to see. I checked over all the boards with a jewelers magnifier for ANY indication of damage, overheating, shorts, etc. Nothing!!

After waiting so long for this radio to arrive (I ordered on 17th March and we're now in June) and then to have the CPU failure followed by this TX failure is deeply, deeply disappointing ๐Ÿ™„๐Ÿ˜ญ๐Ÿ™„.

I’ve posted a request for help on the Forum. Hopefully, someone will be along soon to help. A while later, Eric Anderson explained that he was at a HamFest up to his eyeballs in work and would get back to me in a day or two.

UPDATE : 7 June (AM)

I wrote an email to Eric directly and explained in detail what had happened. I tried to keep it brief and to the point, but was keen to provide all the relevant information to avoid email ping-pong.

Eric replied the next day asking questions which clearly showed he hadn't read my email fully. He was also implying that the MMX failure was down to HIGH SWR due to an error on my part - possibly over-voltage - this is despite the fact that I had clearly stated I'd used a Dummy Load and a 13.2V battery.

He offered some solutions which included me paying for a new motherboard or me replacing SMD components on my motherboard ๐Ÿ˜ฎ๐Ÿ˜ฎ๐Ÿ˜ฎ  

Obviously, I'm not interested in any of those options and told Eric so. I paid 500 bucks for this product plus another 100 for Import Fees. I'm hoping that when Eric is back home and no longer under the pressure of exhibiting at a HamFest, he can focus better on my situation and respond more favourably and sensibly.  It's been two and a half months since ordering and I'm still in a position where I've been unable to actually use the MMX!๐Ÿ˜ฒ

Like I explained to him, I'm not after a refund/return. I am desperate to have a working MMX (I even bought a spare Keyboard so I had one for home and one for the caravan). I actually like to be involved with smaller companies and don't mind a few teething problems as a product develops - as long as the support goes both ways! I've bought 4 Elecraft products in the past and their support has been exemplary over the years. 

Let's see what happens...

UPDATE : 7 June (PM)

Eric has been in touch and asked me to check the tiny SMD fuses on the three Band Boards. They are all blown. I'm guessing that makes things easy in terms of what action is required. I'm waiting for him to email back with a solution. I'm feeling hopeful! 
.UPDATE : 8 June

No Email from Eric yet...

UPDATE : 9 June

No Email from Eric yet...

UPDATE : 10 June

Eric emailed to say he’s going to send a replacement PCB motherboard and band boards. Just hope it doesn’t take forever. 

UPDATE : 14 June (morning)

Not received any notification of shipment yet. No idea when Preppcomm are going to be posting the warranty replacement parts. Guess I'll just have to sit here and wait patiently. In the meantime, I've ordered a set of Quick-Blow fuses to insert between the battery and the radio. If there's any more issues, the external fuse will blow before the SMD fuse does. Hopefully!  £12

UPDATE : 14 June (afternoon)

Eric Anderson posted on the Preppcomm forum....

To be honest, I wasn't overly happy with the bit about there must be "something wrong at my end" if the replacement parts also fail.  If you replace the complete unit (PCBS and 3 band boards) then yes, you can perhaps point your finger at me, but if you're leaving one PCB unchanged, then it's back to you Eric.

Then there's the bit about it being a BAD MOVE to change bands when you're not getting anything out of one of the bands. In the absence of any guidance in this regard, I think it's perfectly reasonable behaviour to try another band. 

BEAR IN MIND that the MMX gave every indication that it was working!! There are no warning lights. The radio seemed to be operating normally and sent out it's CQ Call on screen. It was only because I had an RF Meter attached that I knew there was no power being transmitted.

The note in Eric's post about fitting a 'strong battery' to the radio being a hazard is a bit ridiculous IMHO.  99.9% of buyers would attach the radio to a battery or to a regular shack PSU. And most shack PSU's are capable of producing 25-30Amps!!

If you should only use a Current-Limiting power supply, then that should be made abundantly clear in the Operating Guide and probably on the product page of their website too. Perhaps PreppComm should alter the price of their transceivers to include this specialist Current-Limiting PowerBank and associated USB lead if it's that critical.

Or at the very least, include a fused power lead with a 0.5A QB fuse.

Another great addition for future production runs might be to include some diagnostic functions and details of how and where to take measurements for fault-finding. QRP LABS do all of this for their products (eg QDX) which cost as must as 8 times less!

It may appear to readers that I've fallen out with PreppComm and want my money back, but I don't  After two and a half months since ordering, I just want a product that works reliably - one that hasn't got a glass jaw! Not much to ask after spending $600 ๐Ÿ˜ฎ

HOPEFULLY, HOPEFULLY, HOPEFULLY the parts will arrive soon and everything will work perfectly well and I can delete all this negative text. I hate writing stuff like this - I want to be talking about how great my MMX is and how I've got some fabulous QRP morse contacts.

UPDATE : 15 June (AM)

I saw this morning that Eric had posted a couple of messages on the PreppComm Forum in response to my post and other members' comments. He admitted that his earlier post about batteries, powerbanks, etc was unhelpful and he removed it, so all credit to him for that.

But he seemed quite agitated and asked for credit for his response to warranty claims, in light of the fact that there was only a 5% failure rate (2% on one PCB and 3% on the other PCB).

I decided to write to Eric directly...

EMAIL SENT 15 June 2022 11:39am

Hi Eric 
I've just seen your posts on the Forum.

I had no intention of causing any issues on there and certainly did not want to upset you or generate any ill-feelings. I simply started a thread about the issue I was having at the time and people responded. As usual, with the internet, things can be taken the wrong way and before you know it, people end up getting shirty and offended. To avoid any further unintentional upset, I have deactivated my account.

You are obviously a straight-talker and that's great. So am I.

5% failure rate is good for a new product, I agree. It’s a small figure and you must be pretty happy with that. 

Being one of the 5% doesn’t generate the same levels of joy. First I have the CPU failure and now the PA failure. You probably don't mean to, but some of your messages leave me feeling like I'm the one at fault and you're just having to accept it.  Just as you ask for some credit, please give me some too. I'm no brain surgeon, but neither am I a fool. 

Bear in mind that I ordered in March and we’re now mid June. I’ve still not had the opportunity to have a qso! You said a week ago (7th June) that you would send replacement parts. It's now the 15th and I've still not had any further communication.

What am I to do? Just wait indefinitely after investing $600 in your product? If you said "Hey Tom, your parts will leave on the nn June" then that's fine, but to be kept hanging is not.

I fully appreciate Eric, that you are working your socks off and the HamFest made everything ten times harder for you. Honestly, even though I'm now in moaning-mode, I still have no regrets about purchasing the MMX. I'm still super excited about your product and will be singing its praises once I get a working model.

I look forward to getting a dispatch notification.

And I offer you my best wishes.


UPDATE : 17 June
(3 months after initial order)

I just received an email from PreppComm's courier to say there's a shipment on the way to me.

UPDATE : 21 June

While I'm waiting for the new parts to arrive from America, I'm just thinking about how I'll go about testing the repaired MMX. I need to make sure that I cover all bases and prove to PreppComm that I've done everything right, in case it goes wrong again. I'll be making a video of the process....

* Verify Dummy Load with MultiMeter (SotaBeams Dummy Load). * Show Power Supply being used. * Show QB 0.630mA inline-fuse. * Show Initial Switch-On and Setup. * Show first 40M TX on Dummy Load with SWR Meter inline.  * Show 40M antenna including description and analyser performance. * Show 40M TX tests on resonant antenna. * Repeat tests on 20M & 80M. * Report successful results to Eric. * Live happily ever after! ๐Ÿ˜

UPDATE :  1 July! 

Well, I'm very sad to say that we're into another month and the parts have still not arrived ๐Ÿ˜ญ๐Ÿ˜ญ๐Ÿ˜ญ๐Ÿ˜ญ๐Ÿ˜ญ This of course, is beyond the control of PreppComm, but it's nevertheless extremely disappointing for me. I tried to find out from USPS why the parcel has not arrived yet, but they told me that the delivery service that Preppcomm had chosen, does not provide detailed tracking data and it will basically arrive when it arrives! ๐Ÿ˜ข

UPDATE :  4 July! 

Okay. I'm getting tired now.  A new week and the parcel has still not arrived and the Tracking Number provided by PreppComm just shows that the parcel hit London 11 days ago and is in perpetual transit!

I am unable to get more information from USPS so I decided to email Eric Anderson again to see if he can find out from his end what the ridiculous delay is. I'm doing my very best to stay calm and accepting of the situation, but it's not easy.

REPLY FROM ERIC : Later this afternoon Eric emailed back saying that he only has the same tracking access as me, so he couldn't really help. He suggested that I contact him if the parts haven't arrived by the 15th ๐Ÿ˜จ and he'll ship out some more.

UPDATE :  17 July! 

PARTS ARRIVE ONE MONTH AFTER POSTING!  Wouldn't you know it?? Just as the parts eventually arrive, I end up getting Covid!  Very poorly and locked in bed for days with no energy, chesty cough, aches, pains, etc, etc. ๐Ÿ˜ฐ๐Ÿ˜ฐ๐Ÿ˜ฐ๐Ÿ˜ฐ๐Ÿ˜ฐ

Ah well, such is life. I waited for a period where my energy levels allowed me to carry out the repair work and made some videos to save typing ๐Ÿ˜€

If video doesn't show, Click Here

If video doesn't show, Click Here

If video doesn't show, Click Here

So as you can see, the MMX appears to be functioning correctly so far. I have now got to Calibrate the VFO following the "instructions in the Avanced Reference Manual". Well to be honest, the instructions are kind of sparse - it simply tells you to calibrate the VFO against WWV (which is I believe some sort of 10MHz transmission over in America).

Needless to say, that transmission is very weak over here in the UK so it's not very useful. And there are no guidelines on how to Zero-Beat anyway!  I have decided it would be better to employ the services of a local expert - Chris Moulding of Cross Country Wireless

So my next entry will be when I get the MMX back from Chris - but before I drop it off with him, I need to lose this damned Covid-19.

Back soon....

UPDATE :  20th July! 

I met up with my kind friend Chris Moulding of Cross Country Wireless and he confirmed that the VFO was already calibrated!  I kinda suspected this to be honest, because although the Warranty Parts arrived with a TRANSCEIVER PCB REPLACEMENT NOTICE card telling me that I would have to calibrate the PCB, but then I found another card in the box, showing a Factory Calibration record carried out back in April!

This second card showed a calibration value of 90 which was what my radio is showing. The serial number on the card was obviously from someone else's radio.  I'm guessing this was a PCB that had failed at some point and then been repaired and re-issued as a warranty replacement part to someone else (me). That would explain the appearance of that chip that I mentioned in the first Video.   Anyway, the radio is working, so I should be grateful for small mercies I suppose.


Well I should start by saying I'm as nervous as a virgin on his first date. I feel like I need to wear kid-gloves and be super careful not to break this fragile product. For example, I would no longer feel able to use it without an SWR Bridge. I would also be very apprehensive about using it with my everyday field battery or a regular shack PSU, even though the radio is rated for use at higher voltages than the industry standard 13.8V.

Sadly, there are no quick-blow glass fuses built into the radio - only SMD fuses which 90% of owners would be unable to replace. There are no warnings or suggestions about restricting the current supply to 600mA to avoid damage to the PA. There appears to be no PA protection built into the circuit like you find in other radios which wind back the output in the presence of high SWR. Eric has already admitted in an open forum that some DMX/MMX are sensitive to high swr (and yet there's no protection designed into the circuit). It appears that some units are prone to CPU failure and I believe that this may be linked to switching the units off and back on too quickly.

Time will tell as I run "real life" tests this coming weekend. If, during normal operation, something goes wrong again, I'll pretty much be done with the MMX and put it down to a bad experience. But let's not get ahead of ourselves - everything may go swimmingly well and who knows - the radio may become a firm favourite - we'll see. I am also going to do some trials in external mode with my IC-705.  One of the Forum Members (Erik Hill) has been extremely helpful with this particular task and I look forward to trying it out.

* Light & Compact.
* Informative Touch-Screen.
* Steel front cover.
* Decodes well.
* Up to 3 Bands Available.
* Programmable Macros.
* External Mode.
* Honest And Open Company.
* Helpful Forum Members!

* Expensive!
* Tacky 3D Printed Enclosure/Case.
* No Speaker!
* No Tuning Dial!
* No USB Firmware Updates!! ๐Ÿ˜ฒ
* Only Supports Straight Key.
* Glass Jaw! (Easy to break)
* No built-in protection from high SWR
* Needs Current-Limiting PSU? 
* Fiddly Setup To External Transceivers
* Not intuitive
* 1300hz SideTone

I feel quite bad writing this negative review and even thought of deleting it, but then everything I’ve written is true and factual. I’m sure that many PreppComm customers will have had great experiences - especially in America where it’s much easier to handle warranty issues. 

But sadly I haven’t. From ordering the PreppComm MMX to getting a working product has cost FOUR MONTHS and $600 ๐Ÿ˜ฎ๐Ÿ˜ฎ๐Ÿ˜ฎ

Even though I feel apprehensive about the longevity of the MMX, I acknowledge that right now it’s working perfectly well and it’s quite good at decoding. There’s still much more experimenting to do and more to learn - I’m looking forward to it.

Would I recommend a PreppComm MMX to a UK Buyer?? Hand on heart, I don’t think I would. I reckon another year or so of development (and reliable component availability worldwide) will produce a better, more reliable machine.  The other potential issue for UK buyers (with no local distributor network) is that of FirmWare updates - there are none - unless you send it back to America. Here’s Eric’s view on it (although he refers to the as “upgrades”)…

REMEMBER THOUGH, this is all based on MY experiences with this product and this company. To keep this balanced, here's something that Eric Anderson posted recently (July 2022)...

As many of you know, we are committed to being honest and responsible, and to making a positive contribution to the amateur radio community. Sometimes, that is not easy. If you know the story of our startup, you know we were blocked during development by unacceptable product performance that was being shipped every day by other manufacturers at the time. We refused to ship such a product. After trying to solve the problem for a month, and on the verge of giving up, I believe God provided a solution in signal processing to me that enabled us to complete the project with excellent functionality.

As we rolled out the DMX-40, we of course ran into a number of problems that we did not experience in the initial units in the lab. This is always an issue - a few units may work fine, but try making 100 and see if they all work fine, not just in the lab, or manufacturing test area, but in the field. There will be problems. Guaranteed.

So, we worked through the issues and arrived at a pretty reliable DMX-40 by the time we arrived at 2022. In fact, as I recall, we rolled out the last major update to the software in December 2021, and the last major update to the hardware around the same time, the DMX-40+.

Since the MMX was essentially a copy of the DMX, we did not anticipate a lot of issues when we launched production. The transceiver PCB was different, with 3 band board plug-in slots, and it was larger, to provide the increased space for the slots. And, it has a new power supply to enable us to move the harmonics from the switching power supply to outside the ham bands.

Another major issue was the scarcity of parts. We bought up microprocessors at very high prices to stay in business. But it was through our PCB turn-key supplier that we did that. Who knows where they got the chips? Are they black or gray market copies, or the real thing? There are many companies making copies of chips and putting fake labels on them to make them look like they were made by the original manufacturer. However, they may not work as well. Especially for more demanding circuitry like EPROMs..

We don't know the answer because discovering the real manufacturer is very expensive and difficult. What we do know is that we have been having trouble with the main processors. You have noted that there has been a spate of 'not initialized' problems in the field. Also note that reprogramming the same chips at the factory restores proper operation of the chips. This and other strange things users have experienced imply that there is something going wrong with the EPROM memory - like it is not sufficiently programmed, for example. And some of the switches we set seem to interfere with the processor running the program stored in EPROM (they should not do that). We are still working on this problem with the manufacturer, but in the meantime, we have completely replaced the computer and programming hardware in manufacturing, and have released version 30.0 of the LCD graphics software, and version 27.1 of the operating software. These two steps have already proved to be more robust and seem to be reducing or eliminating previous issues.

This new version and process should result in a much lower failure rate in the field. Units already in the field that are working properly should continue to do so - it is a small percentage of manufactured MMX that have exhibited this problem, but more than we find acceptable - we did not set up for multiple repairs at the same time - we ran with occasional repairs with the DMX-40, and we want to get back to that for MMX.  Thus, as responsible manufacturers, we continue working hard to reduce the number of customers that have the product fail on them. Of course we cover it all under our warranty, but we don't want even a few of our customers to go through a in-field failure experience. Once in a while with hundreds and hundreds of customers is unavoidable, and that is what we experienced with the DMX, and want to get to with the MMX.

Shipments are restarting today with the new software releases, and we will be monitoring how they do in the field. So far, in the manufacturing/test area, they are doing significantly better than with the previous software release and programming equipment.

We thank you, our customers, for your patience, as we work diligently to maintain our product reliability and repeatability, and to provide you with the exciting and amazing experience you deserve.

73, AF7YQ

Eric Anderson for PreppComm

UPDATE : 30 July 2022

Interfaced MMX with IC-705

MMX Decoding during an IOTA Contest

Connecting the MMX to another radio such as the Icom-705, is relatively simple. You don’t need to buy any fancy interface kits - it just requires a couple of regular 3.5mm stereo to stereo leads and a splitter. That’s it!!

The splitter can be a cable-splitter or one of those Y-shaped plastic splitters that you buy to allow two headphones to be plugged into an MP3 player. Personally, I prefer the cable-splitter.

You connect one of the stereo leads between the MMX KEY connector and the IC-705 KEY connector.

Then you plug the Splitter into the IC-705 Speaker connector. Into the other ends of the Splitter you connect your speaker (or headphones) and your second stereo lead (which then connects to the MMX Audio connector. Simple!

More soon…

PreppComm MMX Specifications :

* Advanced Direct Conversion SDR Receiver: with custom bandpass filter, balanced mixer, and low-noise preamp giving sensitivity ≈ 0.3 ยตV, -118 dBm or better. 

* GUI: 3.5″ color touchscreen LCD, Main Screen plus 27 function screens. 

* Included keyboard for control, text input, shortcuts 

* Weight: 11 oz with protective lid. 

* Size: 3.8″ x 5.2″ x (1.3″ w/o lid, 2.25″ w/lid). 

* Power Consumption, receive:  1.4/0.96 watt, LCD backlight ON/OFF 

* 80 meter band: 3.5 MHz - 4.0 MHz. SWL receiver range: 2.45 - 5.6 MHz 

* 40 meter band: 7.0 MHz - 7.3 MHz. SWL receiver range: 4.9 MHz - 10.22 MHz 

* 20 meter band: 14 MHz - 14.35 MHz. SWL receiver range: 9.8 MHz - 20.09 MHz 

80M Power Output @ 13.8V: approx - 2 W, 350 ma total power drain (key down) 

* 40M Power Output @ 13.8V: approx - 3 W, 500 ma total power drain (key down) 

* 20M Power Output @ 13.8V: approx - 1.5W, 350 ma total power drain (key down)

With regard to the RSGB RADCOM review (and front page splash), I'd like to say that I find it disappointing to see that they run a big feature in this UK magazine without actually investing any time or effort into reviewing the product from a UK perspective. The staff have simply run a word-by-word copy of an overseas review - it shows a lazy lack of regard for their readership.

I've now cancelled my RSGB Membership. I've been meaning to do it for a while because I don't really get much benefit from being a member and their "review" of the MMX just proved to me how impotent they are. I'd rather spend my money on a Practical Wireless subscription.


 willie commented on "PREPPCOMM MMX DMX-40"    8 Jul 2022

Just had my MMX go tango uniform after only a day or so of use - wasn't abusing it - worked fine until upon startup it stated 'CPU'S NOT INITIALIZED' - now waiting on a response from Preppcomm (emailed info and also posted on the 'Community Site')