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1-10 of 14 messages
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Compact HF auto-tuner
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by W6WO on July 5, 2009
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I would be interested in any examples /experience/ideas/opinions/links etc regarding compact auto-tuners at the 300 Watt level.
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RE: Compact HF auto-tuner
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by AD5X on July 7, 2009
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I think that all the compact auto-tuners out there are rated at 200 watts max. MFJ has some 300 watt auto-tuners, but they are much larger. I use a MFJ-925 auto-tuner for portable operation. It is small and works great. I have a review of this auto-tuner in the "Product Review" section at www.ad5x.com.
Phil - AD5X
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RE: Compact HF auto-tuner
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by KG4RUL on July 7, 2009
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Look at the LDG line of tuners. Admittedly they are limited to 200 watts but they are compact and don't require external power.
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RE: Compact HF auto-tuner
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by W6WO on July 9, 2009
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Thanks for the comments OM There are some very compact commercial auto tuners
for KW amps so a home brew project at 300-500 Watts should be quite feasible
73 Ron
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RE: Compact HF auto-tuner
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by W6WO on July 10, 2009
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I am only interested in building one which is the reason I created this thread. Guess this wasn't crystal clear in my original post.
Have not found any recent descriptions of homebrew solid state HF amps at the 300-500W class.
What have I missed ?
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RE: Compact HF auto-tuner
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by N3OX on July 10, 2009
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"Have not found any recent descriptions of homebrew solid state HF amps at the 300-500W class.
What have I missed ? "
I'm guessing, among other things, it's because it's somewhat easy to let the smoke out if you're tinkering around with solid state power devices rather than tubes. I haven't done any amp building, but I've pondered it and it seems like maybe you have to wrap your FET's in a pretty soft blanket of extra circuitry (including, perhaps, a microcontroller to monitor a lot of stuff and run the autotuner). And if you're looking at hundreds of dollars worth of fairly fragile solid state devices, experimentation is out the window, and it becomes more of an extensive design exercise than an "ordinary" homebrew project.
It's a chicken and egg problem. There's nothing to copy and tweak to your junkbox or even draw inspiration from because few people are building.
That said, looks like IXYS has come out with (or is coming out with) some "linear" MOSFET devices with some hefty power output ratings.
IXZ2210N50L, apparently available from Newark for $73 (.. or.. maybe $90 with handling) will do 550W out it seems in CW operation and is good to 175MHz I guess.
I'm a little tempted to buy one...
Though my current plan is probably to start dabbling in Class E using cheap power FETs on 160m. Given that my more immediate plan includes getting my Ph.D. done with, the 160m amp may be a while coming...
73
Dan
PS, IXYS needs to use easier to read part numbers...
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RE: Compact HF auto-tuner
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by W6WO on July 11, 2009
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Hi Dan
Thanks for your entertaining and helpful response.
I have a confession to make; you responded to my comment about Class E amps inadvertently mentioned in this thread about tuners.
A compact tuner, Class E amp and switching PS in a single package is the grand project that I have in my mind (or is it dreams?)
Please note the thread in the Amplifier Forum on Class E amps for 10 MHz and above.
My only excuse is the low level of sunspots and having experienced 5 cycles of them I can categorically state they are inversely related to senior-moments. Hi Hi
Hey GL with the studies
73 Ron W6WO
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RE: Compact HF auto-tuner
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by TANAKASAN on July 12, 2009
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The best homebrew tuner I have ever come across is the Picatune designed by Peter Rhodes, G3XJP. Some pictures can be seen at http://www.carnut.info/star-parts/builders-pics/picatune/picatune_builders.htm but I am not sure if it can handle 300 watts. There is also a Yahoo group for antenna tuner builders which can be found at http://groups.yahoo.com/group/Smartuners
Hope this helps.
Tanakasan
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RE: Compact HF auto-tuner
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by W6WO on July 12, 2009
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Thanks for the link and suggestion. I looked at the image of that tuner and wiil see if I can locate the full article. The W8ZR EZtuner is also of some interest.
73 Ron
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