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Author Topic: Emergency manual tuning of the AT-130  (Read 2036 times)
KI6VNP
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Posts: 2




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« on: January 13, 2012, 09:33:01 AM »

My IC-718 has stopped switching it's AT-130 tuner while sailing in a remote part of the world.  I have no resources for replacing this most important tool. I need to research the possibility of manually tuning the AT-130.
The use of a serviceable spare transceiver has confirmed my tuner and circuits are Okay.  I hope to manually switch the tuner to be able to use my Transceiver or, at least isolate the problem.
If the tuner cannot be manually tuned I understand a simple dipole antenna can be used for emergency communications.
I am open to any Ideas, as this unit is the source for my weather and tracking capabilities.
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NA0AA
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Posts: 1042




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« Reply #1 on: January 13, 2012, 02:33:13 PM »

SOUNDS like the fault is with your radio, not with your tuner - I pulled the O+M manual from the web.  Looks to me like the unit requires you to ground the [Star] terminal - or drop it to under 1 volt with no more than 100 ma.  I THINK a 70 ohm resistor will do that for you.

You need to drop your output power to 10 watts or so, then ground [Star], and if you can, put an LED across Key - when the light comes back on [8 volts 100ma max] you are tuned.

That should work.

Good luck.
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KI6VNP
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« Reply #2 on: January 14, 2012, 09:51:42 AM »

Thank you for your input.  I would like to confirm I understand you fully.  The switched 70 Ohm resistor between the STAR terminal and ground is easy (this activates the tuning process), I need clarification on the LED, is this to be placed between the KEY terminal on the tuner and ground? No resistor required?  I will need to reduce the TX power to 10 W before switching the STAR terminal. After manual tuning has occured I can boost power again and Transmit?
I could not have hoped this so simple.  Thank you, My family will be so happy to know they will continue to receive my daily position reports.
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KC9SGV
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Posts: 31




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« Reply #3 on: February 03, 2012, 10:43:04 AM »

A $50 MANUAL RF Tuner from Ebay, would be much safer and much less hassle on a trans-oceanic sailing trip or other venture.

Like a tiller as opposed to a wheel....
Like a hanked on jib as opposed to a roller furling jib.
Like a full keel to a bolted on fin keel.
Like a mechanical self steering vane to an electrical/hydraulic one.
Oh, and pack a Morse key as well, for when your computer, Pactor 3 and microphone gets wet...

Just saying... Smiley

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