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Author Topic: Tuner to use with various antenna experiments  (Read 859 times)
AA8RF
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Posts: 67




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« on: April 17, 2003, 09:51:28 PM »

I want to try a flagpole antenna, various multi-band dipoles and random wire antennae. Some in attic, some outside.

Which autotuners would be up to the job? I can live wtih one that is not outdoor sealed since some will be indoors, and the outdoor one would need a camaflage box anyway since I am in an antenna restricted sub anyway.

I am after something that will work well on the autofunction without requiring a remote control head if possible. I'd like to play with 160M on up to at least 10m.

It would be nice if it would work with any radio including the tune button on my 706, but also my Swan 400 vacuum tube rig.

Tnx in advance,
-Jim
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AA8RF
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Posts: 67




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« Reply #1 on: April 20, 2003, 08:53:20 PM »

Well I broke down and ordered the SGC SG-239. It is down to $179 on their web site and it looked like I could do something with it even if it is not my ultimate tuner for all time.

I would have tried the Icom AH-4 but it would only work with my Icom rig out of the box.

-Jim
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N3BIF
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Posts: 1190




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« Reply #2 on: April 21, 2003, 11:48:15 AM »

    My understanding is that auto tuners are limited in their abilities to an swr of around 3:1 , Manual tuners have far greater capabilities and this is what I use, HOWEVER !!!! If you are looking for heavy experimentation you may be better off with an "Antenna Analyzer". These devices apparently give you much more info so that you can make adjustments to the antenna itself and not just make the rig "like" the antenna as is the case with the tuners.
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AA8RF
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« Reply #3 on: April 21, 2003, 07:47:24 PM »

Thanks - I have a big Dentron manual antenna tuner as well at an antenna analyzer. I'm after getting the SWR right directly at the feed point for experimantation on many bands. I could an open wire feed from my manual tuner, but here I want to use coax so the only place to tune really effectively is at the other end.

The 239 is not SGCs best unit, but it will handle huge SWR ranges. It can match an impedence range of .5 to 5000 ohms for example.

-Jim
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N6AJR
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« Reply #4 on: April 26, 2003, 10:08:18 PM »

I use a dentron MT2000 A for the high power stuf and a mfj 945 e for the low power stuff, I also have a couple of dentron supertuners for stuff in the 1 kw range.  the trick to flagpoles is to use a gamma match so the base can be grounded and the top still transmit.  there is an article in the May 2003 QST on these .  they are often used on yagi's like a shorting bar with a coax center in a piece of aluminum  tubing.  I also have a mfj antenna analyzer wich I use to play with, but you can do this manually if you don't want to cough up the $200 to $300 for an auto tuner.. any how have fun and I like using the dual cross needle swr meters as they make it much easier to tune.  73  tom N6AJR
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AA8RF
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Posts: 67




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« Reply #5 on: May 11, 2003, 09:59:46 PM »

Interesting! The flagpole I was looking at has an insulated base. I had not considered a gamma match and a real grounded flagpole.

Got the $179 autotuner and it is really plug and play. Makes experimenting easy and turns almost any chunk of wire into a functional antenna without wasting all the energy on heating the coax.

-Jim
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