Issue with ATAS-120A

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BiggSean

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Oct 25, 2013
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Hello all:

I recently installed an ATAS-120A and an 857D into my FJ Cruiser. I ensured that I had a good ground at the antenna mount by testing for continuity, and the antenna worked well for about 24 hours. It tuned on all bands, and I was able to make some contacts.

I was outside in my driveway using it last night, when it suddenly stopped tuning. The "ATAS" icon disappeared, and despite pressing the tune button, I could not get it to reappear again.

I did a full reset on the radio, configured the ATAS to control "HF and 50" and tried again. Still no dice. When I press and hold the "tune" button, "init" appears on the screen for a split second and then disappears. I again confirmed that I had continuity with regards to the ground, and checked my coax connection at the radio and at the mount. The coax on the radio was slightly loose, so i tightened that back up and again reset the radio and configured the radio to utilize the ATAS to tune "HF and 50".Additionally, I ran a temporary grounding strap from the battery all the way to the antenna mount to ensure that it had an even better ground. Still the same issues as listed above.

I ran out of time at around 11pm, and was not able to do any further troubleshooting.

Is there a setup in the configuration process that I'm missing aside from setting the ATAS to tune "HF and 50"?

When I get home tonight, i'm going to use a multimeter to check for shorts in the coax connection.

Should I be seeing voltage in the coax lead?

My biggest source of confusion is why the "ATAS" icon no longer appears. I just get a firm "Beep" whenever I try to initiate it or turn it on.
 

AK9R

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I don't know how the ATAS antennas work, but I can make some assumptions.

If there is no control cable between the radio and the antenna, then the voltage to turn the motor that's inside the antenna has to travel over the coax. I'm going to assume that a DC voltage is injected into the RF output from the radio and that voltage is tapped off the coax where it enters the antenna. I'll further assume that a positive voltage drives the antenna one direction and a negative voltage drives the antenna the other direction.

So, if you don't have continuity on both the center conductor and the shield between the radio and antenna, you won't have a DC circuit to turn the antenna's motor.

Beyond that, there may be a setting in the radio that isn't correct or something in the radio or the antenna has failed.
 
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