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Author Topic: High power Auto tuner  (Read 278 times)
VK4KX
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« on: January 19, 2009, 12:11:53 AM »

Is there a High Power Auto tuner like the Icom AH4 tuner that can sit at the base of a vertical,and take 500 Watts from an Amp?
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G8UBJ
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« Reply #1 on: January 19, 2009, 03:11:11 AM »

I haven't found one. I eventually settled on a tuner in the shack (Palsar at-auto) and feeding with Andrews LDF-5-50 to reduce loss..
Maybe someone knows of a commercial one?
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K0BG
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« Reply #2 on: January 19, 2009, 05:42:20 AM »

Of course there is. The SGC SG235 will handle 500 PEP, and 200 carrier once it is tuned. It is weatherproof.

The LDG 1000 will do even better, but it isn't weatherproof, nor is the one from MFJ.

The fact remains, there are better ways to remotely tune a vertical, and with a little ingenuity, you can built one a lot cheaper than buying a high-power auto coupler.

Alan, KØBG
www.k0bg.com
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AD5X
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« Reply #3 on: January 19, 2009, 05:56:10 AM »

The CG-5000 will handle 800 watts and it costs less than the SGC tuner.  Some info at http://www.arraysolutions.com/Products/cg_5000.htm.  Array Solutions also has an auto-tuner disconnect that grounds the output of your autotuner when it is not used, as well as high current bias-Ts for powering the auto-tuner through your coax cable.  

Phil - AD5X
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W8JI
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« Reply #4 on: January 19, 2009, 07:20:14 AM »

I'd be very careful about this.

Tuners can not be exclusive to all other things "power rated". Anyone who says they have an XXX watt tuner can't be telling the whole story.

The base impedance of a vertical can range from a few ohms to a few thousand ohms. That means at 500 watts there can be anywhere from perhaps 10 amps current at low impedances up to 2000 volts (or more if the vertical is very short). There are even cases where the high voltage and current have to appear at the same time!!

Virtually all automatic tuners available will not handle that range of voltages, regardless of what people claim for power. Most manual tuners rated at 2 kW won't do it.

It is actually much more efficient to use a trap vertical, and the power rating can be much higher.

73 Tom
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W0FM
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« Reply #5 on: January 19, 2009, 10:46:33 AM »

Hmmm.  The GC-5000 looks like a beefed-up (spec wise) private-labeled version of the SGC-230 that I've had for years.  Do you suspect SGC makes this unit?

Terry, WØFM
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AA4PB
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« Reply #6 on: January 19, 2009, 01:41:41 PM »

Some of the new MFJ units look very similar as well. I've worked on a few commercial SEA units that had PC board that looked very much like SGC even though the cases were more rugged. I've long expected that there is a connection somewhere.
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W8JI
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« Reply #7 on: January 19, 2009, 06:30:13 PM »

I can build a kilowatt tuner with the ame exact parts as the 500 watt tuner.

All I have to do is restrict the matching range more.

The real question is what the antenna impedance is, that is what will mostly set the power limits in an L network. :-)

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