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Author Topic: Adding 6 meters to a tri-band yagi????  (Read 2139 times)
KC0THF
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« on: August 30, 2006, 07:21:18 PM »

Is it possible to add 6 meters to a 10/15/20 tri-band yagi? Would it be as easy as adding another set of traps?
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WB2WIK
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« Reply #1 on: August 30, 2006, 07:33:48 PM »

No, because the element spacing is too far apart for six meters.  And if you didn't mind sacrificing gain because of that, you'd have to add three sets of traps, for the director, reflector and driven element.

This is complex and costly enough that simply adding a separate six meter beam is usually easier and more effective.

WB2WIK/6
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N3OX
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« Reply #2 on: August 30, 2006, 08:24:22 PM »

Yep, even the SteppIR totally adjustable design adds on extra 6m elements for best performance.

There are lots of easily homebrewed 6m beam designs out there though, and it doesn't add too much to the tower loading to stick a 3 or 4 element yagi above your tribander.

73,
Dan
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
K9RQ
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« Reply #3 on: August 30, 2006, 08:31:43 PM »

I will mention that my Hy-Gain TH2MK3 two element tribander works quite well with a low swr and some gain on six meters.  I've been using it on six for over two years now.  No modifications, just a standard TH2.
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K0ZN
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« Reply #4 on: August 30, 2006, 10:35:56 PM »


WB2WIK hit the nail on the head.... it is much better to stack a 6 M antenna on top of it.

You "could" fabricate 1/4 wave decoupling stubs for the driven element that would allow it to work/function on 6 M, probably with minimal impact on the HF operation...but you would end up with just a basic 6 M dipole in terms of function; it would not be a "beam". This would allow the use of the existing transmission line, however. A separate 6 M antenna would require its own line (or a remote switch at the antenna).

73, -- K0ZN
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WD8PTB
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« Reply #5 on: August 31, 2006, 05:38:53 AM »

The elements of Tri Band Yagis interact so adding or changing anything would likely screw up everything.
  When 6 opens it doesen't take much for an antenna. I worked over 30 states an a 5BTV using the auto tunner in my radio. I have an 80/40/20 inverted V that will also work 6m with the auto tuner. Eventualy I put up a beam for 6 but don't hesitate to try what you already have. Don WD8PTB
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N3OX
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« Reply #6 on: August 31, 2006, 05:57:03 AM »

I'd add that if you *do* add some sort of stubs to make the driven element resonant on 6m, you'll have less loss in your coax than if you need to use a tuner in the shack to load the antenna system.

Dan
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
WA9SVD
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« Reply #7 on: August 31, 2006, 06:48:15 AM »

Possible?  ANYTHING is possible.  But it's not advisable or feasable.  Modifications (such as accomodating 6 M) to an existing multi-band Yagi design will also require readjustment of the HF antenna components; there may not even be sufficuent adjustment possible, and could prove mechanically less stable or durable because of adjustments for which it was not designed.   But you could spend days or even weeks getting the adjustments properly set, if ever.  Time better spent on the air.  
    If you already HAVE a tri-bander, it's a much better idea to add a 3-4 element 6Meter Yagi then to try adding or modifying the tri-bander.  And it WILL work better than anything you could "ADD" onto the tribander.  And it won't affect the performance of the tri-bander.
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WA1RNE
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« Reply #8 on: August 31, 2006, 11:21:22 AM »

 Why bother when you can simply add a 6 meter monoband yagi over the tribander and obtain superior performance.


 Chris

 
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KA5ROW
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« Reply #9 on: September 01, 2006, 02:30:59 AM »

I see your are a Tech and if you stay a Tech you can put a 10M and 6M beam on the same boom.
I had a 5el 6 meter and a 5el 10 meter antenna. I mounted the 6 meter right on the 10 meter boom  It worked fine And saved enough tower space to mount my 22 el cushcraft beam above it.
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VA7VO
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« Reply #10 on: May 21, 2013, 04:57:35 PM »

6 meter driven element open sleeve coupling to a ta-33, 6 meter reflector to tribander DE 37 13/64. 6 meter DE to tribander DE 10". 6 meter DR to tribander DE 57" 13/64.
Works well and no interaction.
Used this concept over 30 years ago.

Glenn, VA7VO
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W9GB
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Posts: 2616




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« Reply #11 on: May 21, 2013, 07:01:19 PM »

Quote from: KC0THF
Is it possible to add 6 meters to a 10/15/20 tri-band yagi?
Would it be as easy as adding another set of traps?
Scott -

IF your tower and rotator can handle the additional wind-load,
the common (popular) practice is to place a 3-element 6-meter yagi above your tri-band (20-15-10) antenna.

Joel R. Hallas, W1ZR wrote an article to do exactly what you desire in September 2012 QST magazine.
Here is that article (PDF), courtesy of DX Engineering (who sell parts you need for DIY Build)
http://static.dxengineering.com/pdf/Hallas.pdf

W1ZR's design uses parasitic coupling to a single element.
This concept was first described by Gary Breed, K9AY and published in The ARRL Antenna Compendium, Volume 5.  Gary called it a coupled resonator antenna.
I have known Gary since mid-1970s, when he was teaching Electrical Engineering at Bradley University and doing broadcast radio/TV consulting for D.L. Markley & Associates.

The W1ZR Tri-Band yagi antenna was a Wilson Electronics SY33.
That antenna looks like the popular Mosley TA-33, but with wider element spacing.
« Last Edit: May 21, 2013, 07:20:01 PM by W9GB » Logged
VA3GUY
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Posts: 177




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« Reply #12 on: May 21, 2013, 08:19:44 PM »

YES!  I have done it, successfully.

I read the Hallas article last year (http://static.dxengineering.com/pdf/Hallas.pdf) and tried it on my Cushcraft A3S.  It worked perfectly with a 1.5 SWR from 50-54MHz.  I did have to play around with the spacing of the 6 meter parasitic elements but once I got it, I had a 5 band tribander.  I had the A-743 40 meter add-on kit, so my tribander was good for 6, 10, 15, 20 and 40 meters.

Go for it!

73,

- Guy
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K0OD
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« Reply #13 on: May 22, 2013, 06:29:50 AM »

Here's another vote for just trying the tribander, as is, on six, thru a tuner. Probably won't see any front to back directivity. 

I remember a guy who made 300 Qs on 6-meters in the June VHF contest a few years ago. As I recall he used something like a stock TH6 but it was at about 70 feet. Conditions were fabulous that weekend. Keep your power down.
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