# Video: Oscilloscope Balanced Antenna System Tuner Performance Test

Discussion in 'Amateur Radio News' started by KA0KA, Sep 1, 2018.

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1. ### WA1ZMSHam MemberQRZ Page

I'm afraid our friend Tyler still doesn't quite get it. The CURRENTS as measured by a thermo-ammeter in each wire of the feedline need to be equal. Period. Think for a moment...what is the meter showing then? It's showing the MAGNITUDE OF THE CURRENT VECTORS. No more, no less. The feedline could careless what the phase along its length is at any point.

This is simple high-school vector math here. Each current and voltage has both a magnitude and a phase. If you want to stop feedline radiation, then the magnitudes of the current vectors needs to be the same.

I fear this is a case where Tyler only has an o'scope and so can only think of things from a voltage and time perspective. "Has a hammer, every problem is a nail."

The hams and engineers of the 1920's figured all of this anteena and feedline stuff out without o'scopes. They used paper and a pencil and math. We owe it to them to be able to do the same. Start there. Do the math.

New thought:
Tyler, when you made your experiments did you always use the same antenna? If you did, then it's possible that your antenna is always very ballanced. So you can't help but to see things from the perspective of an already good system. V & I will appear to be closely in-phase. That's beacuse the load looks very resistive; i.e. a low value of jX. But the rest of us aren't always so lucky. The jX is different on each half of the antenna. Go try it. Hang a dipole in an odd way and you'll see things change alot. It's no different than you trying to show folks about SWR issues when you're experiment is only with one good dummy load. It's misleading and fails to show what can really happen.

Last edited: Sep 8, 2018
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2. ### VK2OPHam MemberQRZ Page

Tyler,
I think the music is an excellent innovation and added a dynamic to what is an excellent production. Stay true to your own style and you will never go wrong. Wondering what is the 10kW balanced ATU on the right hand side of the operating position. I am a dedicated doublet fan, and always interested in balanced ATUs for 600 Ohm feedline.
Peter
VK2OP

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3. ### KA0KAHam MemberQRZ Page

Thanks for your comment, yes after not watching it for a week I did go to my youtube channel to review the really great comments there as well, lots of subscribers too for one week old. I felt the video was great and very well edited for a novice. You cant make everyone happy all the time...

That is a custom tuner, I made the design for the panels and the meters you see there were part of the design. It has two Gates rollers and a Jennings vac cap. The coax is 'bypassed' it is only a balanced tuner. I have a second part video showing you how to choose the length of ladder line with a given ant you would like that one. I will upload soon. This is the URL of the Ty-Fi KA0KA channel.

Last edited: Sep 10, 2018
4. ### W0LVJGuest

Good presentation. I love the antenna tuner. That's a monster. My tuner isn't that massive, but it does a good job feeding my Delta Loop.

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5. ### KA0KAHam MemberQRZ Page

Yes it is actually too big, it is 80lBS and too big... I use it for low freq band only when I have to achieve a LOW-Z balanced load on 160M because my 280 foot loop is a half wave on that band. Oddly, the system works fantastic, typically last year my reports were 25 over S9 past 1000 miles on that band.
This year, I may employ a noise sensing ant and adjust my phase and gain in the second diversity receiver to null some QRM out, really cool stuff the 8000 can do in the right hands.

6. ### WN1MBXML SubscriberQRZ Page

"Sunny" or "sonny" boy? Or was that some more of your complex wordplay that I don't understand?

Karma is going to get you for that "CRUSTY" accusation. It may take years, but count on it. Until then, grab a towel and sop up that moisture behind your ears.

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7. ### WR2EHam MemberQRZ Page

Couldn't one construct a fairly simple pair of current probes and put one around each leg of the feedline and then into the same o'scope?

I think it would be very interesting to actually use a four channel scope (or two two channel scopes) and view both the voltage and current at the same time.

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8. ### AB1KRHam MemberQRZ Page

That's what I was wondering. Check this out (also from our great state of Colorado)