Many thanks to Barry (KU3X) for sharing the following guest post originally posted on his website:
ATU-10 from Banggood.com
by Barry (KU3X)
There are times I find myself in need of an ATU. One example is when I use my half wave end fed 40. I can not always erect this antenna in the clear. I did purchase the LDG Z100 Plus 705 with interfacing cable. The unit does as advertised but I am not impressed with its performance. My biggest complaint is, when interfaced and the IC-705 tells the LDG to tune and it does not know the antenna is matched and resonant, the LDG adds capacitance and inductance which actually raises the SWR. It’s too dumb to go into bypass. I resolved this by not using the interface cable. Now I only tell the LDG to tune where needed. Most of the time I turn the LDG off by toggling between bypass and tune using the button of the front of the unit.
Size matters to me and the LDG ATU is too big. Another downside is it uses SO-239 connectors instead of BNC connectors. Everything I have relating to QRP operating uses all BNC connectors, including my home brew two position antenna switch. I do want to get my hands on an Elecraft T1 ATU but Elecraft can’t get the parts from the manufactures to make them. So the hunt was on for a small ATU with internal batteries and BNC’s instead of the dreaded SO-239 connectors. Here is what I came up with.
I ordered the above pictured ATU-10 from Banggood.com. I have also seen them posted on Amazon.com. They can be found on eBay as well. I did not provide a link for ebay because some ebay adds are dated. There is a very good demo posted on YouTube. Here is an overview of the ATU-10 [PDF].
My ATU-10 arrived 11 June 2022. Here are my findings:
The package contained an Allen wrench and a USB cable for charging the battery as well as for updating the firmware. The package DID NOT include the interface cable for the Icom 705 nor did it included any paperwork…….no manual! My battery showed about half charged and firmware version 1.4 was installed. If you forget to charge the battery and go on site with a dead battery, you can supply power to the ATU-10 via the USB charging cable. You may have to give it a few minutes for the batteries to take a little charge, but from that point on just leave keep the ATU-10 connected to the USB cable.
The needed interface cable is nothing more than a stereo audio cable with 1/8″ male plugs on both ends. But, the ATU works without the interface cable, it’s just not controllable from the radio. As for the matching, I can say it works as good as or as bad as my LDG Z-100 Plus. Where ever the LDG provided a match, so did the ATU-10. On 80 meters where the LDG did not do so well, neither did the ATU-10.
I first tried the ATU-10 without the interface cable. I just sent a carrier from the radio and the tuner went into the tune mode. It’s that simple. It takes anywhere from 2 to 5 seconds to find a reasonable match.
To use the ATU-10 with the interface cable, there is the setup procedure. Hook up all of the cables, including the interface cable to the IC-705. Now turn the ATU-10 on. Once booted, turn on the IC-705. Go into the, “Function” screen and tap the, “tuner” icon. You are ready to go. You do not have to change modes to have the ATU-10 go into the tune mode. In any mode on the radio, like SSB, just key the mic and the tuner will tune. Give it a second or two and you are ready to go. Change bands and key the mic, same results. I lost communication between the radio and the ATU-10 when I went to 80 meters. I have no idea why? I just turned the radio off, then back on and everything was reset…ready to go.
When I received my ATU-10, I noticed all of the hardware was not that tight. I retightened each nut and Allen screw.
User group for the ATU-10 and the ATU-100.
- Size…the ATU-10 is small enough to carry in your shirt pocket ( 5″ x 2-3/4″ x 1″ )
- Antenna connections… BNC. All of my cables used when I set up portable use BNC connectors.
- Power source ….the ATU-10 has two internal rechargeable batteries so no external power source is needed. Since the ATU-10 uses latching relays, the only power that is needed is for the display. The display has a time out timer and the ATU will turn off after 30 minutes on non use. The ATU will last you for months on end before needing to be recharged.
- Display… the display shows SWR, power out and the state of charge for the internal batteries. It also shows what firmware is installed. The display will fall asleep after 5 minutes of non use. If power is applied, the display will wake up. The entire ATU will turn off after 30 minutes of non use.
- Bypass mode (simply turn the ATU-10 off)
- Construction…..the ATU-10 is built inside of a solid metal enclosure.
- Loss of communication….more than once communication was lost between the radio and the tuner. Easy fix by turning the radio off and then back on but this is very inconvenient.
- No manual…..not even a little sheet of paper showing the specs. Whatever you need to know can be found on this site: ATU-10 info at GitHub.
For the price, it think this is a great buy. It does exactly what I want it to do and provides a reasonable match to make the radio happy. You can use the ATU-10 with any radio at power level of 10 watts or less. It’s a perfect size for backpackers. I don’t think the interfacing between the radio and the ATU-10 is all that importable. I myself choose not to use the interface cable. Since the tuner will go into a tune mode if the SWR is too high, that’s all that is really needed.