Hi,
I recently purchased an ATU-100 clone from China. I did some continuity checks using the multimeter before plugging into the HF Rig. These are my observations. There is something wrong yeah?

• RF IN and OUT Center conductors - SHORTED (Beeps in continuity mode)
• RF IN/OUT Center & Outer conductors - SHORTED (Beeps in continuity mode

I see that the L1-L7 coils are in series with the two center conductors of the SO239 ports. But still, I am confused..

There are no physical shorted solder blobs etc I could find. Have you had similar observations?

Please find the pics below.
73 de 4S6TMP.

Wolf

On my N7DDC original ATU-10? PCB I measure: With 5W in from my IC-705 and a dummy load on the output side:-

@5W input???? Vf = 1.94v? Vr = 0.005v

So something seems to be wrong with your PCB in the SWR bridge area.? As Onno says, to clarify my previous post, reverse the input and output coax connections and measure again.

In my case I get??? "Vr"? = 0.02 ??? and "Vf" = 1.92v?? (using the same pads as above for Vf and Vr.)? ie the voltages should be close to the same in reverse configuration.

You could also measure the resistance with power OFF.?? With Neg lead of the DVM to ground and positive lead to Vf and Vr I get 47k ohms.? If you look at the Schematic, you will see that Vf and Vr both have a 47k resistor to ground from those points.
If you reverse the DVM leads the resistance will fall as the diodes will become forward biased.
eg in my PCB, reversing the leads gives a resistance of 33.5k ohms.

This should help to isolate the problem with your PCB.

You should? also measure the resistance of your dummy load to verify it is 50 ohms.



Glenn

Hi my name is David and just wondered if anybody had some good quality photo's of the top and bottom
PCB, as waiting for my board to arrive and just want to see where all the parts go with there values because
I will use better quality capacitors for the tuning, mica caps.

I redesigned the PCB motherboard and schematic diagram, and rewritten the program.
it is very mini.and support input??power 0.1w-100w.

more info

Hello to everyone, my name is David and my call sign is G4RVH and live in West Cumbria. As I am waiting for my ATU 100 PCB to arrive could anyone help me with a possible link to a high definition photo's of the top and bottom PCB board please.
Regards David? G4RVH

Edit:? I was trying to use the wrong file.? I downloaded the zip files and everything worked fine.? ?The firmware is upgraded and modified for QRP.? ? An initial test shows the tuner does work, although not quite 100% of the time.? Will have to do some more checking when I get a chance.


Hi All,? I am new to this group, but not to the ATU-100.? ? A little over a year ago I built one of the ATU-100 (extended) tuners, but recently purchased a second one to modify for QRP use.? ?As several others have reported, the tuner came read protected, so when attempting to read the microcontroller all I get are zeroes.? ? I have been to GitHub and have seen all the files, but I don't know for sure which one to use for firmware version 3.2.? I have watched the videos on doing the QRP mod, and have read many messages, but have not seen anyone supply the file name I need to download.? ?I am assuming the file ends with a .hex extension.? ?On GitHub, I downloaded? ?atu_100_fw_EXT_32.hex, but when I tried to import it in the PICit3, it reported an error importing the hex file.? ?Is this the correct file to us, and if not, which file should I be looking for?? ?Also, I believe I read that you can just write the new firmware over the old, without having to erase first - is that correct?? ?I am new to this type of firmware upgrade (have done a little on a uBitx, but that's a little different) so any help would be appreciated.

Thanks,
Jim? (w8ykg)

Uups ... forgotten:
4) With reference to Glenns tip I measured voltages forward / reflected:
a) Power 5 W -> ~ 1.3 / 1.0 -> SWR 7.7 corresponding to displayed SWR
b) Power 2 W -> ~ 0.9 / 0.7 -> SWR 8.0 dito

<You should then be able to reverse the RF power in connection ...>
Not understood und thus not done ...

73 de wolf, dk1et

Hello together,

thanks very much for all contributions so far. Below my findings until now:
1) I reworked a suspicious soldering point and a possible shortcut, but this didn't fix the problem.
2) I tried to use Relay_Test and Manual_Test but failed because I don't understand the cryptic behaviour of the tests, how to use them and what they show as result. I asked David for a short description (/g/ATU100/topic/85305214). If someone has some explanation I would be grateful.
3) Following on from Scotts approach I'll try to get my money back via 'Buyer Protection' of PayPal. But it looks complicated ... dunno if it will work. I'm not very motivated to invest too much time in this ...

73 de wolf, dk1et
jo30ms

Hi David,

my ATU-10 doesn't work as it should, have a look at /g/ATU100/topic/89736113

Due to a hint in the thread I would like to test it more closely with Relay_Test / Manual_Test. I loaded the hex but I don't understand how to use the tests. Would be really great if you could provide a short description ...

73 de wolf
nr Bonn, Germany

hi,i designed atu-100.
www.atu-100.com

Ron
They probably vary a bit but mine needs a bit over 1W to tune.

Glenn

Will a stock ATU-10 work with QRPp rigs (1 Watt or less)? ?If so, what is the minimum Tx power that will allow an ATU-10 to tune?
Or is a modification required for use with transmitters that output less than 5 Watts Tx?

Thanks and 73,
Ron
n6ywu

tks, marius - just the info i was looking for!

73, bill

Chen from Hisonauto was a member of this group last year, dunno if he still is or if he left.

Vince - K8ZW.

--
Michigan VHF Corporation -- nobucks dot net
K8ZW -

Hi folks,

Brand new here and I am considering the purchase of an ATU-100 for my mobile.? I normally use a Kenwood TS-440 in the mobile and I am considering this tuner to go along with it since the 440 I have doesn't have the one built in.? However, after researching the ATU-100 yesterday, I am confused as to which one to purchase!? I see ones on eBay, for example, and it's hard (at least for me) to figure out whether I am getting the kit with or without the case.? The Chinese venders don't seem very clear about it.? I guess the baseline question here is: are there any good* kit versions available with case for $50 US or less? ?

I * good because that was something else I came across yesterday during my research.? I read about insufficient toroids and caps used in these units and would appreciate knowing whether or not this is correct.? The 440's maximum output is 100 watts on SSB, so the hope was to be able to run one of these units if a good, corrected one could be recommended.? I am on limited income, so I have to get this right the first time. ?

Thanks in advance,
Jon?

The Aliexpress seller tried desperately to get me to return the bad tuner at my expense before he would send me a new one. I refused (I told him I would send it back but he was going to have to pay for it), and when we reached a stalemate, I simply told him that I was going to dispute the charge with my credit card company and he can deal with them. That's when he decided to send me a new one. I now have two: one good and one bad. Your results may vary.

73
Scott
AK5SD

Once you have the picki3 it’s easy. You can adjust the horizontal and vertical too to get rid of the trash at the edges if there is any.?

m0nnq

I also use an mcHF. My ATU is a 100 with reduced turns on the transformer and adjusted config.?

I haven’t experienced the problem you describe but I can see how it would happen. ‘Proper’ transceivers with built in ATUs, such as my ftdx1200, are usually limited to 3:1 on the internal tuner. If you want to use a more marginal antenna you need to use a manual tuner.?

With a low power txcvr like the mcHF you’d be better avoiding such compromise antennas anyway.?

I don’t recall, but you may be able to configure the fallback power on the mcHF to be 1w.?

m0nnq

开云体育

Hi William,

I use ATU-10 with an mcHF; this transceiver also has 20W (and more) in 40m.

I noticed that at powers over 18 ... 20W the display shows "Overload" and the voltage on the ADC pin is over 4096mV. In order to be able to use the tuner with powers over 20W, I made the tandem at a ratio of 1: 6 and recompiled the firmware with the new value.?In this way the FWD voltage on the ADC pin does not exceed 4V, the maximum power applied (by tunning) would be somewhere around 30W, but it is at the limit supported (I think) by toroids.

Of course the deal will be made with a maximum of 15W as set by David.