ATU-100 Latest news

Equipment Antennas
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What’s the latest state of play / thinking on the many N7DDC auto ATU kits/units on sale?

I’ve got plenty of radios with an auto ATU inbuilt and my KX2 unit gets a lot of use. But I don’t have any stand alone not-QRP ATUs. Something that will be happy with 50-100W 1.8-30MHz signal.

I was thinking I could pickup a manual unit for not much money for the few special uses I have but then I saw plenty of ATU-100-OA units on Aliexpress for pennies that make a manual unit for the same price seem expensive. Prices around £31 for the ATU-100 with free shipping 7 day delivery and free 90 day return. I guess there’s just VAT to pay so £38 all in.

Has the design/software matured? Any CN vendors to avoid?

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Hi Andy,

I found the one with a green button to commence the tune cycle to be very good and simple to use. You might recall I built one of these but at the current prices for assembled units I don’t feel inclined to do that again although the kit of bits are a bargain.

If you buy one with an internal battery, always a good idea, imo, make sure you use the right charging voltage. A socket taking a round barrel plug may not be for 12 V.

73
Ron
VK3AFW

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Hi Andy,
I have an early ATU-100 (no internal battery) but only used it with my 20W Xiegu X-108G - so I can’t say how it works with 100-watt radios. It seemed OK and the price has come down even more since I bought mine about 3.5 years ago.

73 Ed.

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Hi Andy,
ummmmmmmmm!!
Look at this video
73

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Ah, the build quality is a bit pish. And he wanted to tweak the software. That’s what I expected. :wink: I’ll check the battery insulation though.

I’ve just ordered one with allegedly v3,2 software for £37.86 delivered. It’s going to be used in a 50-100W situation so needing 5-10W to tune is no problem which suggests the stock software may be OK.

Thanks for the link to the video Jose. First time I have used auto-translate subtitles, worked well enough for me to understand a few of the translations that seemed strange.

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Here is a tuner worth consideration, the AT-100M Pro
Antuner - Official Website AT-100M Automatic Antenna Tuner (Universal) Portable and ultra-small volume antenna tuner, power resistance 120W, supports any antenna, etc.。

I have the earlier version and have only just recently found an antenna that it wouldn’t match on all bands, but in its defence my LDG Z-100 Plus tuner could only match fewer bands on the same antenna.

Here is a link to the video of the earlier version…the one I have.

I took this tuner to a ham coffee morning and passed it round at let one ham borrow it for a couple of weeks The upshot is there are nearly a dozen of them in our branch now. QRP operators especially like them as they will tune with only 2 to 3 watts. They are very much favoured by our GROTA - Green Radios on the Air - fraternity. Some of these old war time radios are only putting out 2 watts.

These are not mass made tuners made by different Chinese companies. It is the brainchild of one ham developer, BI3QWQ and only he makes them. He also does all the technical support and is very responsive I believe.

Anyway, just sharing a product that I have had great success with.

Cheers
Phil ZL3CC

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That is SO much better than my AT-100 tuner I have!
Perhaps you can add the URL for orders Phil?

73 Ed.

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The blue link above in my post. On the very first page there is a “Buy Online” button on the top right. That takes you through to his official shop on Aliexpress. Delivery for me was 2 weeks to my door in NZ.

Cheers
Phil ZL3CC

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I have one of the old models of the ATU-100, I built it in 2020.

I was always reluctant to do the QRP mod by removing windings from the tandem match (SWR bridge), since I would like to keep it working also for 100W.
Last week I saw this video by MW0SAW :

It’s a bit fuzzy because he mixes up the ATU-100 (EXT), ATU-100 Pro and a ATU-QRP 40 (all in the same video !), but basically I took the advice to only change cell 05 to value “01” (tuning from 1W), without changing any hardware.
I did not set the “auto” bit (cell 02) to “01”, because I have a button to put the tuner in AUTO or MAN mode.
This week, I took the tuner to the field for a POTA activation, with my IC-705.
It worked (almost) perfectly with my regular antenna, a random endfed (9.15m wire, sloping from 1m to abt 5m above ground, 9:1 UNUN and a 4m CP).
Tuning results before (1) and after (2) tuning with 5W,

image
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values shown above were from the ATU-100 display, but corresponded with the IC-705 SWR meter.
With only 1W it worked on all bands except for 20m , where I needed to set the rig at 2W to get the tuner working.

I also had one instance where the tuner would kick in in the middle of a QSO (SWR change by the wind ?), the solution is to put the tuner in MAN mode after tuning, and before making any QSO’s.

Will do further testing soon … on our 14 day roadtrip to FN :wink:

PS : just joking, but maybe does this tuner work like an amplifier ?
I was working QRP 5W but got an RBN spot of 75 dB ??? WOW :wink:

image
image1495×211 30 KB

73,
Luc ON7DQ

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If you have not understood any part well, tell me and I will translate it for you.
73

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Bringing this thread back to life.

I originally wanted a 100W capable ATU as I was intending a slightly exotic family holiday and wanted more than the 10W my KX2 or 705 could produce. I have an MX50 PA but no tuner. So I took the plunge and bought one from AliExpress. I bought cheap and didn’t expect Rhode&Schwartz quality and I was not disappointed with the pish quality I received :slight_smile:

Mine had an built in 3.7V LiPo cell, USB C charger and inverter to get the voltage up to 5V except it seemed to be set to 6V :frowning: Everything is just glued in place with lots of some unpleasant thick opaque white gunk. Oh and la pièce de résistance, there are no toroid cores in any of the coils which are also wound with the wrong thickness wire. Hey it was cheap for a reason.

It appeared to work but was V3.1 not V3.2 software but that’s no biggie. What I did notice when testing it with my 705 was that it seem to have a huge loss in circuit. I had the 705 on an external battery but measuring the power through the ATU I could 10W on 80-30m but 20m up the power was much less and was only 5W on 10m. I put this down to the cruddy coils and thought this needs rectifying.

Then I had a wee cancer scare which meant I couldn’t go on the planned holiday as I couldn’t get any travel insurance but I hadn’t bought tickets so no cash loss. I was blessed in that my wee cancer scare was a scare and I got the all clear. This year we’re having an extension built, no holidays this year but I decided I wanted to get one of the many projects that are on the go completed.

Jobs:

  • remove all the glued in components and clean things up
  • the inverter was powered all the time and the power switch applied the inverter output to the ATU board. This meant that the battery was discharging all the time. I have to ensure batteries for radios are charged, this was another complication to remember. So the battery and inverter have been removed, a 7805C (far to big but no 78M05s in the junk box) attached to the case. We now have 5V not 6V applied to the board.
  • wind coils with correct wire on correct cores. I have a 500g reel of 0.8mm wire and plenty of T68-2 cores. That was straight forward after winding coils on T50 and T37 cores.
  • The programming connector, 5pin 0.1in header was a Molex type socket instead. This connector is for programming and connecting the OLED display. Replaced with a 5pin straight header, the display connector still fits and isn’t going to fall off.
  • The RF connectors were a pair of SO239s which I hate with considerable vengeance. The back panel has been replaced with a piece cut and Dremel’d into shape and now sports 2x BNC sockets. They are wire to the board with some pieces of RG-316. BNC can handle upto 1250W into 50Ohm, they’ll cope with 50-100W into worse loads easily.

That completed the turning cheap Chinese pish into something acceptable. However, testing with the 705 still showed only 5W on 10m. This was when I discovered only 5W on 10m with the ATU removed from the circuit. I was sure I’d measured my 705 when I bought it so I dug further. I was used to the FT-817 where the power is 5W as long as you have more than 10.5V applied. I’ve seen my KX2 only produce 7/8W on 12/10m when using a LiPo as the voltage falls. 10W on the other bands and as the voltage starts to drop the power out drops linearly. So what was up with my 705?

It turns out nothing! I was using a 3S LiPo to power it and it was giving about 12.0V on load, using FM and the mic to key the rig and get a constant signal. And with 12V or so my 705 gives 5W. More on the lower bands but it’s either 5W or 10W and nothing in between. I did some internet searches and this is normal. Yes the damn thing switches to 5W when the voltage is a lower than 12+V. B@st@rd! I swapped to a LiFePo and 10W on 10m could be produced. OK, the LiPos are secondary use now and I’d normally have a LiFePo with me anyway.

At this point I’d been reading about the software, it’s all open source and you can find it and the docs for the ATU on github. Sadly the software is written in C and PIC processor C compilers cost money, lots of money, like $400US minimum. That is a bit rich for intellectual stimulation. I wanted to play with the software but that can wait.

But I would like to update the software installed as the images are free to download and there are 30+ configuration options in the EEPROM. But to program it / configure it you need a PIC ICSP (in circuit serial programmer). I have one but it is 20+ years old and the software is 16bit and wont run on Win10 64bit. Before breaking the welds on my wallet, I checked with my local club and a member had a PICkit2 programmer which I could borrow.

Of course life is never simple. The PICkit2 is obsolete and the software it came with no longer works on Win10 64 either. :scream: :sob: But digging showed there is software PPICKitPlus for £25-30 which didn’t seem bad. But there is also a free version PICkitminus and the PICkitPlus guys have no love for the others. Now to install PICkitminus you need to install .NET 3.5 runtime and that installs .NET 2.0 runtime. You can do this from inside Windows control panel and it worked fine. There are Linux versions which should just work. Then I tried to install the PICkitminus app and that worked and it found the PICkit2 I have borrowed. I have a PIC16F887 demo board and the the programmer attached and read the device on the demo board. Result… we’re in business.

Not quite, I made a lead to attach the programmer to the ATU and… zilch. I checked the docs and yes the device, PIC16F1938 was supported. So much faffing with options and :trumpet: TA DA :trumpet: the ATU image was read and so were the config options. I have made a note of the config options and checked them against the manual. I loaded the download image and the config options are different as the default is a two line LCD not 4 line OLED.

So as of now I have an ATU which isn’t filled with glue, has decent connectors, a power supply that integrates with my SOTA batteries, the correct coils. I’ll try it with the installed software to get a base line on its performance before re-imaging it. It cost me £38 from AliExpress plus 2x used chassis mount BNC sockets and 6x T68-2 cores from the junk-box plus my time to rebuild it and some head-scratching getting a programming system to work.

Anyone buying one of these I would recommend they buy and build the kit. But you’ll need to make a case. The kits come with the SMD processor soldered in and programmed.

I have an ATU-10 due in a few days. That’s because I’d like a QRP ATU for use with the 705. I bought it from Amazon instead of via AliExpress where it would cost less because if the quality is pish I can get my money back with ease from Amazon unlike jumping through hoops etc. with AliExpress. Now I got a thank you for un-retiring at Christmas, a very healthy Amazon voucher some of which has been spent on the ATU-10.

You realise just how cool the inbuilt KX2 ATU really is only when you switch to rigs without an ATU. And yes, don’t say it, I could go back to antennas that don’t need an ATU. I could.

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Doesn’t MPLAB support it? It’s a free download.

I chose AVR for my projects as all the tools were readily available so you may be right about PIC - it was a while ago. Since then Microchip has bought Atmel.

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That sad tale is like recalling some of my projects, but in my case I know far less about what I’d be doing. Eventually you recall that you set out to drain the swamp.

My ATU-100 remains as a parts kit. I realised from some reading that due to the relays being non-latching, the ATU would continue to draw current despite not needing to change anything. That’s not what I wanted. Spoiled by the LDG and Elecraft tuners.

Well done persisting and presumably, getting a working ATU out of it all.

73 Andrew VK1DA/VK2DA

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Andy, I notice that one of the 50w amplifiers offered in various places comes with a pair of so239s OR a pair of BNC connectors, for the same price.

I will try to remember your description of how much you like SO239s. Good choice of words.

Cheers

Andrew VK1DA/VK2DA

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I just made up some cables, 2x BNC male to PL-259 male. That’s 705 to PA in. PA out to ATU in. ATU out is BNC so all my normal SOTA HF antennas can connect. Or I can skip the PA and BNC<>PL-259 cables.

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The latest version supports PICkit5. When I was searching I never actually checked Microchip’s website and you can download all the tools they have released so there is a download that supports PICkit3. I don’t have a PICkit3 nor does anyone in my club. But PICkit2 yes, hence using it and the PICkitminus programme.

There’s a C complier to download as well but I’m sure unless you pay to unlock it, the free version has code size limits that means you cannot compile the full ATU source.

I did lots of PIC16 code in years gone by, 1998-2000. My SOTA beacon I wrote in 2007 uses a 12C509. That was when I was running WIn7 Pro 32bit so there was support for 16bit code execution and the old programmer code would run. But I’ve not touched them since. There’s an OS 16bit VM you can download for 64 bit Windows to allow you to run 16bit apps. But that seems to be going backwards. And… I’m not upgrading to Win11 when Win10 support ends, I’ll switch to Debian full time on a new PC and will run this Win10 image as a VM with heavy isolation from the net. Then my old desktop here is going to the Sunnyland Retirement Home for ageing i7 gen 3 processors This means getting something that runs on Win and Linux was another requirement.

I’ve been playing with the Pi Pico (RP2040 cpu) which is pennies and goes like the clappers, has all the free software tools support you need. The SDK has functions that work too! I have a “thing” built that controls the KX2 under development with loads of frequency memories, CW memories etc. I’ll probably add Bluetooth so I can push spots from the phone to tune the radio for easier S2S chasing. The basics works but I need to get a case sorted and until that is done then development is stalled. But development is so easy as I use all the same development tools as I do at work supporting our ARM customers. Less thinking needed :slight_smile:

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ISTR worst case is 450mA.

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My latest homebrew rig uses one. One core controls the screen, morse keyer etc and the other core does DSP. I probably won’t be using AVR for future rigs.

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Same as a ft817 on rx. But lower than I read elsewhere.