Welcome to the LOOP Antenna Community!                                                                  Join and enjoy it!

We've been thinking of a community where we can all exchange ideas, opinions, or simply have a friendly chat about LOOP Antenna.

We rely on all members to help keep these discussion forums a safe place for people to share and view information.

So, please treat other community members the way you would like to be treated: be courteous and respectful, stay on topic, share your knowledge.

We will remove any post that includes personal attacks, swearing or offensive language, non-constructive criticism or falsehoods. Such a poor behavior will result in losing the community posting privileges.                                                                                                                                                                                         Thank you for your time and your help!

neilwatling
18 giu 2018

No antenna detected

38 commenti

I have been using my Baby loop for the past few months with no issues but last night I was trying to tune and it would not do so, it kept coming up "tuning resonance fail." This led me to believe the coax was the issue.

 

So today I removed all connectors and re-soldered them along with any patch leads. I tried two separate feed lines, both Messi & Paoloni Ultraflex 7 and still the same result.

 

I also updated the firmware on my controller and then tried to auto detect the antenna, it continues to do a frequency scan and the comes up "Autoset Fail: No Antenna".

 

The control cable to the antenna is fine as I can open and close the antenna and also both sets of feedline I have tried are in good condition and no shorts.

 

Any assistance would be appreciated.]

adrian04
18 giu 2018

Ok, so you have verified that both your feed line and the antenna actuator control cable are good. If you have have an antenna analyser you could also measure the SWR which would also verify that the antenna is indeed connected. I would also suggest connecting a 50 ohm dummy loadat the antenna end of the feed cable and using an ohm-meter at the other end to measure the resistance. Then connect the feed cable to the antenna and verify that you see essentially a short circuit with an ohm-meter which would verify that the RF cable is actually connected to the gamma match thus proving that the RF link cable is OK. The next step would be to see if the internal controller's synthesiser is operating. If you have a transceiver connected then it is usually possible to hear the synthesiser as a very strong signal, often S9+60dB, when the controller is tuning. Set the transceiver to a suitable frequency, for example, 7,100kHz, and then command the loop to tune to this frequency. You should be able to hear a very strong carrier. If not, then this suggests that the synthesiser has failed. Sadly, the only option is to return it to Ciro-Mazzoni for repair. The 'No Antenna' and tuning resonance fail error messages indicate that the microprocessor is not detecting any forward or reflected voltage from the internal SWR bridge. If you can detect a strong tuning signal, then this would suggest a SWR bridge or microprocessor A-D converter fault, also fatal.

Adrian, 5B4AIY

neilwatling
19 giu 2018Ultima modifica: 19 giu 2018

Thanks for the reply Adrian, I have recently sold my Analyzer as I never used it although I feel it may have been too basic for the tests involved. I will need to purchase a new one and a dummy load. Would a Rig Expert AA-35 Zoom or a METROVNA 180 perform the tests I require, if not what could you recommend for someone on a budget?

adrian04
19 giu 2018

Hi, Neil. Either of these analysers would be quite suitable. The Metrovna has a few more features, covers a greater frequency range, but is more expensive. I use a RigExpert AA-230 Pro. If all you want is to verify that the antenna is resonant, then you can use your transceiver. Simply tune to a frequency in one of the amateur bands, and starting from the loop fully closed, use the manual slow tune and SLOWLY tune the antenna. As it becomes resonant at the same frequency as your transceiver there will be a sharp increase in the noise level in the receiver. Now set the power of your transceiver to its lowest setting and transmit a CW/FM carrier and observe the SWR using either the transceiver's meter or an external SWR Bridge. By varying either the transmit frequency or using the slow tune buttons on the keypad find the lowest SWR. This will prove that, a) the feedline is OK, and b) that the loop is OK. In which case the fault must be in the controller. Let me know what you find.

neilwatling
19 giu 2018

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

neilwatling
19 giu 2018

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.

k6fvc
14 set 2018

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!

k6fvc
14 set 2018

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)

k6fvc
14 set 2018

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.

 

adrian04
14 set 2018

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

k6fvc
14 set 2018Ultima modifica: 14 set 2018

I'm going to bypass the wiring from my antenna to my shack with shorter runs in the proximity of the antenna, but based on the results of my antenna analyzer and the Debug Mode Testing, I am pretty sure all the wiring is OK.

 

I think it's an ATU and / or motor problem.

 

adrian04
14 set 2018

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

k6fvc
14 set 2018Ultima modifica: 14 set 2018

It did not tune, but the motor will operate - sometimes. I was able to open the antenna all the way at high speed and the blue light came on. When I tried to close the antenna, the ATU reset (power off and on). I then closed the antenna at low speed and was able to close the antenna partially at slow speed. Then I tried to manually tune and it started working, then I got an error "..Motor Failure". The SWR always remains 9.9.

 

In manual tune mode it will not tune. The motor will not move nor will the blue light come on.

 

I can see and hear the ATU 'tone' at the appropriate frequency on my receiver.

 

k6fvc
17 set 2018Ultima modifica: 17 set 2018

Hi Adrein,

 

I completed rewiring where I believed the fault was based on a ‘pinch point’ and 'strong angle' bending due to the rotor movement. This problem was ‘re-creatable’ on one occasion and has now been resolved. All is working fine now except I have had one “Motor Fail” when tuning from 20m to 40m. Is this an expected finding?

 

The system is tuning between 1.0 and 1.7 SWR. There is still an inconstant delay for 'semi-auto' tuning when changing frequencies, but I think this is expected. The system 'Auto Detects' the antenna and completes all tests very quickly now.

 

I have been ‘stressing’ the system to see if I can uncover any other issues. So I cannot say conclusively that the system is now problem free.  

 

As always, your expert feedback and advice is appreciated.

 

k6fvc
17 set 2018Ultima modifica: 17 set 2018

No sooner did I send this message after using the system for a couple of hours this evening, did it have the same failure that I described originally. I thought after I posted this update I would just do another ‘Auto Detect’ antenna (about 30 min after the 20m to 80m failure), AND IT FAILED. The motor light won’t come on and now I get the same No Resonance and No Antenna error.  I know there are no pinch points and I know the wiring is good. It was working PERFECTLY and now has suddenly failed after a couple of hours of use.

 

I am really wanting to return this antenna… In the just over a week I have had it, I have had nothing but problems. I don’t know what to do at this point. 

 

PLEASE HELP!

Visualizza altre risposte
Richard Hubbard
14 set 2018

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.

k6fvc
14 set 2018

How do you do a hard reset?

k6fvc
14 set 2018

Do you also get the Motor Failure and No Resonance errors?

k6fvc
15 set 2018Ultima modifica: 15 set 2018

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!

 

Richard Hubbard
15 set 2018

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.

k6fvc
15 set 2018

Hi Richard,

 

The antenna is not as directional as I thought it would be. It can make a small difference on weak signals if I know where they are coming from. For example, I usually have my antenna pointed East as I live in California. I check the call sign for an operator I hear and he's in South America - so I adjust the antenna and the signal increases some and I can hear the operator better. Where their is not-so-much a difference is having the antenna pointing East and another operator in Indonesia. (due west).

 

I've only had the antenna for about a week and the conditions have been poor, so I have yet to make many QSO's. But with time, I know I will. I am now thinking about getting an amplifier as I can hear many more people that can hear me.

 

73,

Fred K6FVC

k6fvc
15 set 2018

 

 

Richard Hubbard
15 set 2018

Thats a really nice setup.

dmcchavez
17 set 2018

Very nice antenna base setup

k6fvc
18 set 2018

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.

dmcchavez
18 set 2018

When you say " add ferrite cores to ALL the cables (except the antenna cables) " did you mean the antenna coax cable or the stepper motor control cable or both?

 

Thanks for the update

k6fvc
18 set 2018

I mean the DB9 cable, motor wires, motor cable (already had one in my case), but NOT the antenna wires.

neilwatling
1 dic 2018

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?

 

 

 

 

adrian04
3 dic 2018

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

neilwatling
3 dic 2018

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?

neilwatling
6 dic 2018

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.

I post più recenti

Ciro Mazzoni Radiocomunicazioni

 

via Bonincontro, 18

37139 Verona -ITALIA-

info@ciromazzoni.com

Tel: +39 0458903104 Fax: +39 0458902633

 

P.IVA 03063020238

© 2014 created by Sergio Mazzoni