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Author Topic: Handy Yagi  (Read 6498 times)
KR4VT
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Posts: 52




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« on: March 20, 2012, 09:40:16 AM »

I noticed the dual band Handy Yagi from the May '08 QST article has both antennas built on the polarization while others I've seen in looking around the web show the two antennas 90 degrees apart. Is this critical to the antenna performance? I understand the satellite phase is shifting quite a bit but wondered if there was something else in play.

Is there a dual band handheld antenna with circular polarization out there I should build instead?
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K6LCS
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Posts: 1552


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« Reply #1 on: March 20, 2012, 10:05:29 AM »

Some swear that polarization for the FM birds is an issue. During scores and scores of demonstrations in front of audiences, I have not ever experienced a dramatic change in received nor transmitted audio working the FM birds by twisting my Arrow 90 degrees during passes. I can only "sense" this phenomenon occasionally during the loss of signal - when a pass is ending.

Does this mean that the Arrow's gain is simply "masking" the phenomenon? I am not sure.

There are a couple plans for building 2M/440 handheld antennas on the ANTENNAS page on my site at ...

http://www.work-sat.com

Clint K6LCS
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Clint Bradford, K6LCS
http://www.work-sat.com
KR4VT
Member

Posts: 52




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« Reply #2 on: March 20, 2012, 10:30:47 AM »

I started checking your site a couple days ago and thank you for a great work there.  Best sat site I've found.

My thought mirrors your comment, I can twist my wrist and align any polarization. My concern was why arrow had the two antennas 90 degrees apart versus the handy yagi which has them  interlaced on the same plane.

Obviously the handy yagi cannot have foldable 2 meter elements if they are 90 degrees apart.......is it just mechanical convenience or is there a performance issue involved?
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WB6BYU
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Posts: 13339




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« Reply #3 on: March 20, 2012, 01:25:31 PM »

There is less interaction between the elements when they are at right angles to each other.
One common problem with dual-band 2m/440 antennas is that the third harmonic resonances
of the 2m elements can mess up the 440 pattern unless the 440 antenna is entirely in front
of the 2m elements.  It's easier (but not impossible) to get good performance on both bands
when the elements are perpendicular, which is why you often see that approach.
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KR4VT
Member

Posts: 52




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« Reply #4 on: March 21, 2012, 07:32:33 PM »

Well, I finally started thinking.......the Handy Yagi has both antennas on the same polarization because the DE is the radio.....only one antenna. To have cross-polarization would change the design.

Thanks for the replies. I really appreciate the work-sat site, a great way to get started.

73s
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N5XTR
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Posts: 108




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« Reply #5 on: March 25, 2012, 01:29:49 AM »

I built that Handi-yagi, results were very poor.  Tried different HT antennas and it worked best broadside than pointing. 
I could have sworn it was supposed to be in the April issue of QST, cuz it was a joke.
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KR4VT
Member

Posts: 52




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« Reply #6 on: March 25, 2012, 04:32:55 PM »

Interesting observation..........does anyone have a success story with The Handy Yagi?
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N6JSX
Member

Posts: 217




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« Reply #7 on: March 29, 2012, 02:57:55 PM »

There can be an issue with coax feed lengths with yagi/quagi/quad/J antennas. A solution is to this issue is to use a Bazooka balun (miss titled as a Bazooka is NOT a transforming balun but an RF choke to block RF from the coax shield braid).

My 'how-to' Bazooka Balun PDF article can be found at:  http://groups.yahoo.com/group/HAM-SATs/files/Antenna%20-%20Misc/

Check out: http://groups.yahoo.com/group/HAM-SATs/
for a plethora of information/files/articles
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