I have been advised to ship this back to manufacturer for repair, is there any idea on how much the repair would cost??

Can anyone advise from an official point of view?

Can this be repaired in anyway?

In answer to my own question about type of coax, that would be RG213. As for replacing the coax myself, I wish I hadn't bothered as the center of the RG213 is now broke inside of the gamma match :( Not sure if I had done irreversible damage.

Thank you for the reply Adrian.

Is the coax stub easy to change? I removed the outer nut but the inner fixing was stuck solid and with it being what looks like brass I didn't want to ruin the fixing. What coax is used?

To perform a hard reset of the controller, either switch off the power supply for a few seconds, or pull out the power plug to the controller. When you turn the controller off from the front panel it does not really shut off, but simply enters a standby state.

The loop is not really directional in the same way as a beam antenna. In fact, to get the most out of a loop you should turn it to achieve maximum sign-to-noise ratio by utilising the very steep and deep null off the side of the loop. This can be used to reject interference.

As for the connection of the RF feed to the actual gamma match of the loop, when you measure the resistance it should be essentially a short-circuit. If sweeping across the band you do not find a deep resonance and a SWR close to 1:1 then the feeder is not connected to the gamma match. Time to get more intrusive and really examine the wiring to the gamma match bar.

73, Adrian, 5B4AIY

Its been a while since my original post. I have finally got myself an analyser and a dummy load.

I have checked both my feedlines and patch leads on the analyser to the dummy load and all seems fine.

I then checked the ATU2 connected to the feedline and dummy load and entered manual mode, input frequency of 14.000MHz and it showed a swr of 1:1

Finally I connected the feedline to the loop, the other end to the anaylzer and set it to sweep from 7MHz to 20MHz, I used the ATU2 in manual mode to open and close the loop. The SWR remained at 10 across the bands and did not move.

I decided to check the coaxial cable that connects to the actual loop. I removed the heat shrink where the coaxial cable connects to the loop and noticed that there seemed to be water inside. I haven't unbolted or removed the coax as I am unsure if I am able to do this without any damage or if its user serviceable. Could this be the issue? What other parts are there that I can check that effects tuning?

I recommend that anyone having problems with their ATU and antenna add ferrite cores to ALL the cables (except the antenna cables) leading into the rotor control box (if you have one) and the ATU to suppress RFI. Once I did this I stopped having problems with tuning, motor failures, and automatic antenna detection.

Very nice antenna base setup

Good stuff, glad you got it to work its a great antenna. I have one question for you, do you notice much difference using the rotator, I have never tried it with one.

Regards,

Richard.

UPDATE! Thank You everyone, especially Adrian. This evening I was rotating my antenna on the rotor to check the cabling and while it was 90 degrees from the position where it failed, everything started working again! Obviously I have a wiring issue. It's nighttime here so I'll have to wait till the morning.

Once I find and fix the problem I will report back.

What lead me to try this is that tuned my antenna analyzer to 7.185 and tried to manually tune using diag mode. The SWR did not change and remained at 19-20. It lead me to believe that I must have had a catastrophic failure of some type. So after moving the antenna around with the rotor, I thought I'd try again to confirm. And BAM! It works again!!! I am so so happy!

Thank You!

I have also had these issues with the ATU, it is defiantly not failsafe and in my case always the fault of the box. So to start with disconnect the PSU for at least 5 min then try a hard reset of the box. In my case I have two boxes so when one locks up then I put the other on and open the loop manually then close it, then put he original box back on then it works. There is an issue which needs to be addressed in a firmware update.

Ciro-Mazzoni Loop Antenna Debug Mode

To enter the debug mode, press and hold the / key for 3 seconds.

Enter a suitable frequency and press the ENTER key.

To tune the antenna at high speed, press the 9 key to open, and the 3 key to close.

To tune the antenna at a low speed, press the 8 key to open and the 2 key to close.

To fine tune the antenna, briefly press the 7 key to increase the frequency, and the 1 key to lower the frequency whilst observing the measured SWR. You should also be able to hear the cross-feed synthesiser signal in a connected transceiver at the frequency you entered, and in most cases the signal level is about S9+60dB.

This mode allows you to make a full functional check of the controller and antenna. If the motor is drawing current, then the blue LED will illuminate either continuously in the fast tune mode, or flashing in the slow tune mode, of with a brief flash each time either the 7 or 1 key is pressed and released.

Adrian, 5B4AIY

OK, let's impose some order here. As with any complex system, the approach to fault-finding is 'Divide & Conquer'. The component parts of this system are: Power Supply, Loop Controller, RF Feed Cable, Motor Feed Cable, RF Loop Section, Motor Loop Section. The power supply can be checked with a multimeter, and should be 24V. The Loop Controller is more difficult to check, but if it powers up and behaves normally, then the majority of its logic should be working. I will return to the Loop Controller later. The RF Feed cable can be checked by connecting a 50 ohm dummy load at the loop end and measuring the DC resistance with a multimeter at the controller end. Similarly, the Motor Feed cable can be checked by shorting the loop end and measuring the DC resistance at the controller end. It should be essentially a short circuit, or at most a few ohms loop resistance. The RF section of the loop can be measured by using an antenna analyser and checking the SWR. The motor resistance can be measured with a multimeter, and should be very low, a few ohms at most. Now for some functional checks. The motor can be checked by applying a DC voltage from a regulated current limited power supply. Set the output voltage to anywhere between 18V and 24V, although the motor will run quite happily on as little as 12V, set the current limit to about 400mA, and connect the motor to the power supply. You should see a motor current of about 400mA and the motor should move the antenna. Currents higher than this indicate some mechanical stiffness or binding and should be investigated. Reverse the polarity and check that the motor operates in the reverse direction. Do not be concerned about reaching the inner or outer limit, there are limit switches in the motor to break the circuit when the mechanical limit is reached. To drive out of the limit, simply reverse the polarity. If the motor and actuator are working, then the next check is the controller itself. You can easily access the motor drive voltage on the motor connector on the back of the controller. With the loop RF feed and the motor connected, enter the debug mode of the controller and use the fast tune button. You should see about 24V on the motor connector. When you use the other fast tune button, you should see the polarity reverse and again 24V. With the transceiver connected, tune it to the desired loop frequency, and enter this frequency on the keypad. You should be able to hear a S9+60dB loop tuning signal. From these tests you should be able to determine where the fault lies. In my case water had entered the actuator assembly, the sealing gasket had failed, and had damaged the motor. After drying the actuator out I could then get the motor to work, but obviously it was no longer waterproof, and had to be replaced. Hopefully these notes will be of some assistance, if not let me know, and I will try and help.

Adrian, 5B4AIY

The ATU attempts to auto-tune and red light comes on in semi-auto tune - working properly

The ATU motor does not actuate

The ATU cannot detect the antenna

The ATU blue light does not come on

I think the actuator motor or ATU or both failed.

More precise data;

Rig Expert AA-600 Antenna Wire to Antenna - SWR 6.2    4.385 mhz - TDR IR SR is FLAT util the antenna at about 78ft

ATU Motor Cables - Resistance is 4.1 ohms from ATU to antenna (about 80-ft) 12g power wires - 0.003v from ATU at rest and when attempting manual tuning (red light on, blue light off)

I just started to have the same exact problem with my MIDI that is less than a week old. I was using it and all of sudden it stopped working with the EXACT error messages you describe. And the Blue motor light will not come on. The antenna is less than 1 week old. I have been having intermittent problems with it tuning to 20m after sitting in a 40m position all day, so I started parking it at 20m (fully closed) and the problem went away for a couple of days.

I am getting resistance with an ohm meter on the antenna power wires. The last reading on the ATU is freq 3500 swr 1.6. The antenna appears to be 'stuck' about 1/3 of the way open and my antenna analyzer (RigExpert aa-600) reads 6.3 SWR at 4.387 mhz which doesn't make any sense.

HELP!

I have just tried a manual tune but to no it was no good. I will get the loop down and see if the coax from the loop is all good and report back.

Excellent, thanks for the advice. I'll give it a go when I have 5 minutes spare :)