ELECRAFT KX3 & EMTECH ZM-2

After another miserable fortnight of Covid, I was looking forward to my week off work so that I could spend some quality time playing radio in the great outdoors. Originally, I had planned to take my dog Betty out with me, but with all the antenna wire and counterpoises I though it would be better to leave her behind and so I took her for a good walk before heading out for the day.

Today's destination was a local highpoint close to my holiday home (static caravan) called Nicky Nook in the beautiful Forest Of Bowland. It's a lovely walk, with plenty of space to setup antennas with little risk of impacting other walkers. The climb is a surprisingly steep one, made all the worse by a set of high steps that sap your strength. There’s also some gravel paths inbetween. The elevation is about 750ft above sea level and it overlooks the Bay Of Morecambe, out to the Irish Sea and beyond.

 

Normally, I walk up to the Trig Point of Nicky Nook without a second thought, but within two minutes of starting the uphill walk, I was knackered and my heart was POUNDING!! I was obviously suffering the after-effects of Covid and I had to seriously make an effort to slow my heart rate.

It seemed like I had to pause for a break every few steps and I must admit that although I wanted to ‘soldier on’, it made sense to take my time and keep stopping to catch my breath. Crazy!

I was regretting leaving Betty behind - she would have provided some useful pulling power, LOL. Every time I saw someone coming down the track, I pretended to be taking in the views instead of looking like a frail old man with some sort of lung problems.

About 2/3rds of the way up, I spotted a little oasis. A small pond off to the right of the footpath, with some small tress which offered great shade from the increasingly hot sun. Normally I’d walk all the way up to the trig-point, but today wasn’t normal and I didn’t feel like going much further, so I hopped over the fence and sat under one of the trees.

A previous visit to Nick Nook

My KX3 doesn't have a built-in ATU - I use the amazing Elecraft T1 tuner which is a match made in Elecraft Heaven! The beauty of investing in a T1 instead of spending the same amount on an internal tuner, is that you can use the T1 with any of your qrp radios. It's a fabulous tuner with a very compact form factor - light and easy to operate. The unit runs off a PP3 9V battery and this will typically last for around a year before needing replacement.

However, when I was sorting out my gear to go on a radio-outing recently, I decided to leave the T1 behind and take my  Emtech ZM-2.  The ZM-2 is a fully manual tuner, requiring no power source which means that one needn't worry about the battery state or failure of relays, etc.

It's a 2-mile hike from the caravan to the peak of the hill, so I used my trusty RuckShack which (on this occasion) holds the following gear...

• KX3 Transceiver HF/4M
• HandHeld 2M Transceiver
• SotaBeams 20/40 Linked Dipole
• Sotabeams BandSpringer Multiband
• Hawkins Vipers 2/4/6M
• Emtech ZM-2 Tuner
• 13.2V LifePO Battery
• Headphones
• Bits & Bats!

Before long, I had my BandSpringer Midi erected which provides coverage on 8 bands, but requires the use of a tuner, so out came the ZM-2. The BandSpringer is a long wire with a counterpoise and is easy to erect using the telescopic mast.

Although I normally stick to my BandHopper when out and about, I really should use this BandSpringer more often! It gives you access to all those bands which makes it far more versatile than the dipole and gives you more chance of bagging contacts.

The first band to be worked was trusty old 20M and it was surprisingly quiet!! I found a few very strong European stations who were using mega-power, but I couldn’t hear who they were talking to and I couldn’t get through to most of them either.  

VIDEO OF THE LOCATION

I started to use the KX3's memory keyer to call CQ on 14.285MHz until I got a response. It took an awful long time before I had my first QSO. I tried the other bands but only had any luck on 17M with a contact from UA3QKA in Russia. Following that, I switched to 40M and conditions weren’t much better to be honest. I managed to speak with DL8ECA/P and no one else. I moved to the QRP frequency 7.090MHz to call CQ, but unfortunately (as is often the case) there were a couple of QROOOO Italians chin-wagging, making it unusable - even a few k either side!

I'm fully aware that 14.285 and 7.090 are designated as the "Centre of QRP Activity" and not owned by QRP operators - yes - anyone can operate there. But surely it's just common decency (not to mention good practise) to avoid these frequencies when you know that people using low power look to that part of the band to stand a chance to be heard - especially when others are chucking out 1000W! 😲 It's a similar situation on FT8 frequencies, where you can frequently hear Italian accents blasting over .074MHz. Surely to god they must know how their massive signals are impacting adjacent frequencies? Or maybe that's what FT8 haters do??

Anyway, I'm digressing. Back to my lovely day spent outdoors.

After giving up on HF, I was keen to see if I could catch anyone on 70MHz, so I erected the 4M Hawkins Viper and gave it a go. Now bear in mind that the KX3 only puts out about 3W on 4M, but I figured that my location might provide some much needed 'gain'.

I started with some AM shouts on 70.260 and got no response, so I moved up to 70.450 FM. Sadly, no one was around, so before giving up I tried some SSB down at 70.200 - nothing.

Ah well, the day wasn’t wasted - I was sat in a glorious spot with the sun shining, fabulous views and beautiful bird song. This day was also the day (26yrs ago), that my wonderful son Michael died, so it was nice to sit in this peaceful spot and remember how lucky we are to just enjoy these simple pleasures and to remember to make the most of every beautiful day we have.

73 my friends!

Tom, M7MCQ.

EMTECH ZM-2 QRP ATU

Hello and welcome to my latest post. I have a few QRP ATU's ranging from the mighty (costly) Elecraft T1 to a (cheap) Kanga TransMatch kit which I built myself. All of them perform well and so I didn't really need another, but the fact is, I always wanted an EMTECH ZM-2 and for months I've had saved searches on Ebay, Facebook and many other sales platforms in the hope of finding one.

The ZM-2 is a Z-Match type tuning unit and is known by virtually every ham on the planet - whether they've seen one in person or in a magazine or on the internet. It's an American based company and the product is available in kit form or prebuilt. You can also opt for BNC or SO-239 connectors.

The only issue with buying a new ZM-2 (if you live in the UK) is the shipping costs - they're astronomical at the time of writing.  That's the same for anything that you buy from the US unfortunately, so what starts out at £75 might end up costing you £125 😲 Makes you wonder how China can do it all for pennies! Someone's taking the pi$$. If you do order one, email them immediately after and ask them to give you some options - I'm sure they will!

If you ever see a used one for sale in the UK, grab it with both hands!!

So, onto the device. It weighs about 8oz and is about 130mm wide, 67mm deep, 40mm high. The outer case is made from a tough plastic and there are two large rotary dials for tuning around. You can connect an antenna using the BNC/UHF connectors or the binding posts. If you were using a ladder-line, it would plug directly into the red and black posts. If you were using say an EFHW, then you'd plug that directly into the red post. All very simple.

To improve the unit's ability to tune virtually anything, you can add further capacitance by using the toggle switch, providing an extra 250pF or 500pF (or leave it with zero additional capacitance).

The tuner will work from 80M thru to 10M and it will handle a maximum of 15W. That's fine by me, but I can already hear the 20W radio owners crying 😂 I must admit that I'm more than curious to know what you would need to do to improve the ZM-2's power handling. Could you replace the 2W resistors with 5W and use thicker gauge wire to wind the toroid?  I strongly suspect that the actual tuning capacitors are the limiting factor.  I dunno - maybe you do? Anyway, I would rarely use it at its 15W limit on SSB - if I was using DATA modes I'd definitely drop to 5W or less.

If you've never used a manual tuner before, don't worry - it's all very simple and easy to do. And the best thing about manual tuners is that you never have to remember to charge them or put fresh batteries in them - they don't need power other than the RF power of your transmitter.

The ZM-2 has a built-in SWR Bridge, controlled by a toggle-switch marked TUNE/OPERATE.

Broadly speaking, to operate the ZM-2 and get a good match, you simply follow these steps....

 

• Flick the ZM-2 to OPERATE mode.
   
• Set the two large dials to the centre position and adjust the left dial until you get the most noise from the radio (highest reading on your S-meter).
   
• Then adjust the right dial to see if you can increase the noise further.
   
• When you've achieved that, flick the ZM-2 to TUNE mode. 
   
• Key up your radio with a constant carrier and the red LED will light up.
   
• Rotate the dials again to fine-tune and you will see the LED go brighter or dimmer. You need to find that perfect sweet-spot where the LED extinguishes (or near enough).
   
• Un-key the radio, flick back to OPERATE mode and check your SWR reading. If the LED went out during the tuning, you should have a 1:1 reading (or near enough).

 

During any tuning process, your qrp radio may see some pretty bad reflected power levels which can (and often does) damage your finals. With the ZM-2 in TUNE mode, your radio will only ever see a 1:1 match, so you needn't worry about that. However, it's still worth going to the trouble of reducing the radio's power output during the tuning process because (depending on how long you take to extinguish the LED) you will be heating up the resistors inside the ZM-2.

Depending on the antenna and the band you're working, finding the sweet-spot where the LED extinguishes may be quite tricky. If you're using a vertical with a loaded coil, the null may be extremely small. This isn't unique to the ZM-2, it's the same with my AlexLoop. You soon get good at finding it though 😊.

What I particularly like about the ZM-2 is the fact that you can easily connect a small vertical antenna to the RF connector (like an Elecraft AX1) and use it as a stand for the antenna, with it all sat on your picnic bench close-by.

 

What I don't like too much is the oversize (30mm) dials which look fantastic but actually hinder operation more than they help. It might just be me, but I think I'm going to try a couple of 20/25mm dials to give a bit more finger space in-between them. I'm also not convinced on the longevity of the white paper fascia. You need to treat it with some clear-coat varnish to protect it. A plastic, screen-printed fascia would have been far better (not to mention a little more professional).

The build manual for the ZM-2 can be found HERE and from it you'll be able to determine whether or not you fancy building it from a kit (or not). It's very straightforward but requires some manual dexterity.

One useful modification I made to my ZM-2 was to attach a camera tripod bracket - for two reasons. First reason was to add a little ballast so that I could attach small telescopic whips (such as the AX1) to it on a picnic bench without the whole thing tipping over. Second was so that I could have even greater stability by attaching it to a table-top tripod. 

For anyone worrying about the insertion loss of this tuner, well don't worry - there is none. The Emtech ZM-2 is a lovely bit of kit and it's great to use out in the field. If you can get your hands on one without suffering the extortionate shipping charges, then I'd highly recommend buying one.

Needless to say, for half the price you can buy the Kanga equivalent, and it works quite well - but it's just not an Emtech ZM-2 😂 And let’s not forget that a manual tuner like this can be a very valuable asset to SWL’s. 

Comments welcome below.

73, Tom, M7MCQ.

 

 

SOME VIDEO REVIEWS....

 

KX2/KX3 ULTRA-LIGHT MIC

The microphone which is designed for the KX3 (the MH3) is a great mic, but considering this is a compact QRP radio, the supplied mic is ridiculously big! It's like putting a size-12 boot on a baby!

Thankfully, there's alternatives out there and this one from Dave Pegler is probably the smallest one you'll find and at 27g, the lightest too!  If you want one of these, I suggest you contact Dave (M0JKS) directly and he’ll sort one out for you straight away.

They cost a measly £20 and not only is it great value, but it also includes a handy little carry case (pouch). The TRRS to TRRS lead can be detached, which I really like. 

I also like the fact that the tiny mic has two extra buttons for changing the radio's frequency, That's handy! Finally, it comes with a stick-on belt-clip which I personally won't be bothering with because it makes this little gem a bit bigger.

I ordered the mic and it was delivered very quickly and well packed. Inside was a note explaining how the microphone's performance can be tweaked to suit an individual's voice by altering the radio's setting - and Dave provides a link to a PDF file is included to show you exactly how to do this.

After plugging the mic into my KX3, I spun the dial and found EG7SDC on 15M. I only had some Duracell AA batteries inside the radio, so I tried making contact  on SSB down at 4W through an EFHW. I was rewarded with a 59 and compliment on the audio. This was very encouraging considering that I had just plugged it in and played without any setup other than to turn MIC BIAS on.

After making a few more contacts on other bands, I decided to read the PDF that Dave had written and made some adjustments to the Compression and Mic Gain levels. This made the mic produce a more ‘punchy’ sound which is great for DX, but can be switched back when you want to transmit something easier on the ear.

I’m extremely pleased with this tiny mic. IMHO Elecraft should have produced something like this themselves instead of offering the MH3 (which I never liked). I look forward to using this mic much more in the future and it would be handy if Dave gave it a proper designation so people could find it easier, such as DP27G or DPKX3 or whatever.

Anyway, no matter what it’s called, it’s a little cracker and I highly recommend it!

73, Tom, M7MCQ

VK3IL CW Pressure Paddle

I love the idea of this minimalist CW paddle - it’s so tiny you can always find room for it no matter how small your field bag is! And it’s super cheap too. So I ordered the kit and it has sat on the shelf for months!! Why??? Here’s why…..

CW Paddle from VK3IL

Yes, those SMD components are incredibly tiny 😳 😳😳  Boy, I knew before I ordered the kit that they were small, but it was only when I came to pick them up that I realised I just how awkward SMD work is for a novice. Even with a pair of tiny tweezers I struggled to pick them up and keep hold of them! They kept pinging out of the tweezer’s grip and very nearly got lost on more than one occasion.

Somehow, I managed to get them soldered onto the pads and although it’s not pretty 😂, it worked!

I plugged the paddle into a transceiver set to 20wpm and was delighted to discover that I didn’t miss a beat on my usual CQ CQ TEST DE M7MCQ string.

Very pleased with this little kit. Recommended for SOTA!

73, Tom, M7MCQ.

QRP-LABS QMX *PLUS* PART-2

The first build of the QMX+  (HERE)  ended up being a fail due to a short inside the CPU. Needless to say I didn’t make this diagnosis - it was a guy called Ian (G4GIR) who very kindly offered to examine the kit for me and he in turn received technical guidance from Jeff (W1NC) - I thank them both for their extremely helpful assistance.

As a result of Ian and Jeff’s help, I was able to convince Hans that the fault was not of my own making and so he sent over a replacement PCB and other components (but not the toroids). This meant that I had to reuse the old toroids, but rather than trying to desolder them all and then struggle to get them to fit with extremely short ‘legs’ (which would be nigh on impossible - it was tough enough originally), I decided to rewind them. Thankfully, I had two bobbins of the correct thickness enamelled wire.

The first problem though, was removing the hot-glue that I’d applied to the toroids on the original pcb! 🙄

Before I installed a single component onto the new pcb, I hooked it up to a PC with a USC-C lead and fed the pcb's Vdd with 3.3V (current-limited at 200mA) to make sure that the board showed up as an external drive - it did! 

I wish I'd done this on my original kit because it would have showed that there was something wrong with the pcb because I wouldn't have wasted all that time and experienced all that frustration. It should be the first instruction in the build-manual.

Once I started the new build, it went together pretty quickly, although I will say again, it was a bitch to solder! I’ve never come across a pcb that’s given me as much trouble. It seems like the ground plane is huge and the solder pads are tiny.

Throughout the build I checked for a short between Vdd and Gnd. There were no issues this time and before I knew it, I was ready for the first power-up (again with a current-limited power supply set at 7V/200mA). The QMX showed up as a flash drive again on my PC so I dragged the firmware across to it and rebooted the radio. Bingo!….

With everything seeming to be working fine, I raised the voltage to 12V and tuned around for signals. I’m pleased to say that it seemed to be working okay, so then I tried some transmissions through my EFHW and searched the RBN to see how far I’d reached.

Once I could see that I was getting out well, I put the case together and tuned around the bands to test the CW Decoder - it was working really well!

So for now, I’m very happy! I’ve not done any proper testing of each band because I’ve had enough for now 😂 😂 I’ll do more tests next weekend and update this page.

When you make a warranty claim against a small company like this, you feel kinda bad about it and some people try to make you feel even worse, but when the claim is totally valid, I feel no guilt whatsoever and expect a very positive reaction from the supplier.

In the case of this build, the claim was appropriate and it was handled superbly by Hans Summers, without any delay or hesitation and I absolutely appreciate that. So much so that I went onto his donation page and made a voluntary contribution as a thank-you for making it easy.

 

UPDATE - TEST RESULTS<<<

Okay, so after successfully building my QMX+ 😵 I connected it to a PC and ran the terminal-emulator PUTTY to run some tests. I haven't evaluated the outcome - for now it's just a case of running the tests and grabbing screenshots. They may be of use to other kit-builders.

AUDIO TESTS

 

DIAGNOSTICS TESTS

RF TESTS

ADC I/Q TEST (all bands similar)

 

The main area for concern is in the AUDIO TESTS where the separation between the two traces is not particularly good - especially on 20, 30 and 40M. Well, that's how I'm reading it anyway! Your comments are very welcome and so too are your recommendations for how to improve the readings.

The DIAGNOSTICS readouts don't ring any alarm bells with me and I'm quite pleased with the power-output on most bands. As for the rest of the figures, I'm not really sure what I'm looking for. Again, any helpful comments would be greatly appreciated.

The RF TESTS indicate (to me) that 20, 40 and 80M need some work. How to improve those readings - I have no idea.

I'm guessing that the first approach should maybe be to REFLOW all the solder joints on the toroids, followed by a redistribution of the windings and see what changes. Other than that, I'm at the mercy of you, the readers 😊🙏

UPDATE <<<<<

28 AUG 2024

For the tests above, I had used a cheap Dummy Load that I'd bought from a rally, and tonight I decided to try the tests again with a good quality Dummy Load. There was quite a big difference in the readings!  So before you run your tests, make sure you are using a good DL with sound connections.

Having seen the new readouts, I feel quite happy with the results 😍

The only thing remaining to do with this kit is to install the GPS unit, which I’ll do shortly.

PLEASE LEAVE A COMMENT BELOW!

(Either anonymously or with your callsign)

Thanks!

73, Tom, M7MCQ.

 .

.