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I'm looking for an ATU-10 kit (preferably) or build. Since I didn't find a kit, I was looking where to buy an already built ATU-10.

I read some recommendations for newdiytech.com that is also an official supplier of?the?(tr)uSDX.

So I wanted to ask New DIY some questions before ordering, but could not find any email address on their website.
Also, after creating an account, I never received a email to validate my email address and the account password can't be changed. So all quite strange and IMHO not trustfully.
If I can't contact the seller, how I'm supposed to communicate when there is a problem with their product?

Thanks for any tips or opinions on that matter!

73 Stephan

My opinion only, but if you want to buy from newdiytech, I would use their Aliexpress store, which is uptech. I have found that the buyer protection on Aliexpress is pretty good, as long as you are willing to document any issues you find with your purchase.



However, I would have to say that building your own ATU-10 is the preferred option, as one can buy the parts from reliable vendors.

73 de va3rr

Hi?Russell,

Thanks a lot for your opinion!

I have found that the buyer protection on Aliexpress is pretty good...

Seems you were more lucky than me. I once had problems and only got?automatic, but misleading replies.?
Anyways, I just wrote a message to Up Tech Store, let's see if I get an answer.?

...building your own ATU-10 is the preferred option, as one can buy the parts from reliable vendors.

If there would be a kit, I would definitely go this route. But when I have to order from different vendors and paying all import and handling fees, the total price would be too expensive.?

From all portable QRP ATUs I looked at, the ATU-10 looks like the most interesting to me, since I can use it with any TRX and install it where an ATU belongs: at the antenna feed point. No button to press on the ATU. Otherwise the Icom AH-705 could be another option, with IP54 ingress protection rating and a more practical TRX cable/antenna layout. I never understood why both BNC connectors are on the same side. IMHO, this makes only sense if you want to include the antenna coax in the matching network, which may incur coax losses and moreover one needs an additional coax cable. Unfortunately, that's how the majority of QRP ATUs are mechanically designed.

73 Stephan, HB9EAJ

One option, and what I would do now that I have built one, is order all the parts for 10 and sell 9 kits. It spreads out the shipping cost and 9 other people get a chance to build. Taping SMDs onto a sheet of paper with the identification number (eg C19) makes it easy for the builder.?
--
Colin - K6JTH?

I got this one,only issue was the pic was locked,not a big issue tho,cant beat it for the price! https://es.aliexpress.com/item/1005001620051835.html?spm=a2g0o.order_list.order_list_main.5.21ef194dFFLbDp&gatewayAdapt=glo2esp

Colin, thanks for your suggestion.
I don't know anybody who would be interested in building one, but even if I would, I don't feel confident enough to solder SMD.?

Hi Paul,

I'm looking for the AT-10, exclusively for QRP SOTA activations.

Your proposed kit is for the AT-100.

I'm still waiting for an answer from Up Tech Store...

I cant remember how i unlocked it,a fella called david helped me,but i cant remember what i did exactly,sorry i cant be of more help! 73 m3vuv.

Hi Mike.
For the ATU-100 you should be able to follow the attached thread.
Re: ATU100 QRP Mod (groups.io)
This goes through the steps to re-program an ATU-100, and the configuration changes for QRP operation.
A PICkit2 or PICkit3 programmer is required.
For the ATU-10 with latching relays, the process would probably be similar (not too sure), but you would need the appropriate *.hex file.
73, Dave

Hi Stephan,

Over a year ago I was at the same point as you are now. I finally bought ready made unit, but it had problems. Sloppy assembly and soldering. Luckly Relay_Test and Manual_test programs help in locating problem source and location.

Recent v1.6 works wery well for me both with EFHW and Long Wire antennas I have.?

Unit is not water resistant at all, so you need to protect it from rain and snow.

Would I recommend it? Yes I would despite need for repairs, Repairs, in the end gave some satisfaction, almost the same as making unit from scratch ;).

GL 73 Marek

Hi Marek,

Nice to read you here and not only over the air waves :)

I was waiting for some time, because I hoped that over time, a kit would be available. As you state, I'll probably also will have to re-work the solder joints. I really don't understand why Chinese low-budget manufacturers don't learn from previous failures...?

I know that this ATU isn't water proof, so I will use and experiment only when the weather is fine. It will not substitute my home brew and light 7-band EFHW that is robust and super quick to setup.

I mainly?like this ATU because it can be used in auto mode with any TRX at the feed point of the antenna. Otherwise, and also from the mechanical design, the Icom AH-705 would be a much better fit, albeit on the heavy side for our hobby.?

As va3rr proposed, I ordered it in Aliexpress and wait for the delivery. Once I could try it out, I'll give some feedback.

73 Stephan

Stephan - is the EFHW still your 'go-to' antenna for SOTA activations? I built the same unun (Owen Duffy) you used in your EFHW paper and put out a 'stealth' inverted L and I'm having so much fun with it. Thank you for documenting everything so well.

I am thinking of trying KN5L's 2xFT114-43 balun now that he has provided a pictorial, because I would like to go QRO from time to time with my K2. QRO being 15 watts - lol



Apologies for veering off topic

vy 73 de va3rr

I have build 49:1 using KN5L method on FT140-43, 2xFT114-43 and FT82A-43 all 28:4 turns. Each one has efficiency over 90%. I rewound all my EFHW QRP transformers and use KN5L method as standard.?

Hi Stephan,

I bought ATU-10 to play with EFLW antennas. I find LW useful in small spaces like on holidays or short weekend breaks, putting up 20mtr of wire its sometimes tricky in location where you visit. I like that it has own battery so I can connect it directly to 9:1 unun and run coax to my TRX,

I hope your unit works OK and it will not require any repairs.

73 Marek?

Hi?Russell and Marek,

Yes, I still use my 7-band EFHW 99%, because it's so simple, light and efficient and doesn't need an ATU ;-)

For the ones that are not familiar, this is the corresponding document:

The KN5L winding style looks very interesting indeed, but there are so many interesting things in life, hi. If I remember correctly, it had a very flat SWR curve also on 10m and above, so if it would be still usable for 6m, this could be interesting indeed. Marek, what are your experiences on 10m and up??

73 Stephan

Hi Stefan,

I never tried #43 core on 6m band, so its difficult to say. I measured efficiency of different winding styles end even KN5L method shows rapid drop of efficiency above 30MHz. So even if SWR curve might look good efficiency could be very low. You could be heating #43 core rather then radiating. However #52 core has higher frequency range but this is at the cost of poorer performance at low bands (low permeability core). I done 49:1 transformer using FT140-52 and it was working ok from 10MHz upwards, however I didn't check 6m band.?

I will dig out this core and try to test in a week or so.

73 Marek

Thanks Marek, for your information! The KN5L method looks really interesting, maybe I'll try it with a core I have at hand.

Some days ago, I received the ATU-10 from the Aliexpress Uptech Store. I checked it on the bench and all seems fine (I didn't even had to open it).?

Today I experimented with the ATU-10 on a summit, but to summarize, I wasn't convinced, mainly because of the small tuning range. But also how to quickly mount it on the telescopic pole and other small annoyances that I'm not used to.

I have to think about a different setup.

73 Stephan

Hi Stephan,

I strongly recommend KN5L method, if you are still looking for 6m band make primary connections as short as possible.

I tested my repaired ATU-10 with Long Wire antenna in the garden and it worked with SWR below 1.5:1 on all bands from 80 to 10. I am using 9:1 on FT140-43 3x7 turns and 12.5mtr (41feet) wire. The big test will be this Sunday when I plant to use it for SOTA activation on local hill. You never know we might have S2S.

I will post results next week.

73 Marek

People, how did you find your 90-98% efficiency of 1:49 transformer ?
I would like to find it too.