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   Home   Help Search  
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Author Topic: ATAS 100 mobile antenna - Help !!!  (Read 2528 times)

Posts: 17

« on: June 09, 2002, 02:59:53 PM »

I was in Orlando, Florida on vacation in January 2002, and bought, among other equipment, a Yaesu FT 100D and a matching Yaesu ATAS-100 antenna from AES.
I set it up in my rental Chevy Blazer, and used it for a week while I was on vacation in Florida - it worked great. I then got back to South Africa, and installed it into my Toyota SUV. The antenna is mounted right at the top of the vehicle whith a Diamond K400 mount. I had seen other users report problems with getting a decent ground for this antenna, so I earthed the antenna to the extreme. I have thick earthing straps for the mount and the radio.
This setup worked great for the first 3 months - in fact I was so happy with this antenna, I was ready to sing its praises wherever and whenever I could.
Then about 3 weeks back the antenna developed a fault... It seems like there is a short within the antenna - to explain fully, if I screw the antenna securely into the mount, the FT-100D dies on receive, a station that was 59+ is unhearable......and if I lossen the antenna off the mount so its not making good contact with the earth, my FT-100D comes alive.
Because there is no Yaesu backup in this country, I decided to strip the antenna to see if I could see an rf short inside the antenna.
Well....I think you need a degree in electronics to fault-find this baby. It has a circuit board inside the antenna with surface mount components,2 IC's, and a transistor etc. I tried to track the path of the rf..but it seems the rf goes via the shield of the coax up the tubing, onto the coil and up the whip - there is no continuity, as checked with a meter, on the centre pin of the antenna at the base up through to the whip.
I'm confused and frustrated with this antenna. Like I said, when it works, it works great. But now I'm 9000 miles from Yaesu help, don't have a scematic diagram, so I dont know if I should purchase annother, and hope for the best, or to go back to using my Outbacker.
Ps. The mount and coax to the rig are perfect - if I put the outbacker onto the same mount, I have no problems with the outbacker.
Can anyone help.
John ZS5J in Richards Bay, South Africa

Posts: 10248


« Reply #1 on: June 10, 2002, 10:00:01 AM »

My brother Evan, KØHYG (sk) had the exact setup you have, and his failed as well. From reading the various web site reports, you're not alone. What the actual problem is (was), I can't say, but in my brother's case the dealer replaced the antenna no charge.

My only suggestion is to ship it to someone here in the states who can do the leg work for you.

Good Luck

Alan Applegate, KØBG


Posts: 24


« Reply #2 on: August 11, 2003, 10:59:14 PM »

I have seen break downs of the ATAS-100s online,(can't for the life of me remember where) you can search for them I know, or if I earth them up I will try and get the to you via e-mail.

Posts: 7

« Reply #3 on: March 21, 2004, 01:37:07 AM »

There is a loading/matching coil contained within the base unit (underneath the circuit board) which is not soldered very well. I have had to resolder mine already. The real trick is how to dis-assemble the base section. There is no info from Yaesu on this section, the repair literature only shows it as an assembly.
That being said, if you can remove the two stainless pins  in the side of that section, it simply unscrews at the top and bottom (remove the pc board before unscrewing the top part).
I don't have any magic way of getting the pins out, but they must be pulled out to dis-assemble (I tried to push them in but that failed because it is not drilled thru).
You could try removing a little of the plastic around the pin and pulling them with surface cutters, or maybe tack weld something to the head and then pulling them.

Good luck es 73,
Robert KM5RG
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