ATU-100 Latest news

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,

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:

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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