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Author Topic: 6/10 meter yagi  (Read 2743 times)
ONLYON6METERS
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Posts: 32




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« on: June 17, 2007, 07:07:00 AM »

is there/was there ever a commercially made yagi that would work on BOTH the 6 & 10 meter bands?  can one be homebrewed?  

obviously 28.400 & 50.150 are not even close harmonically like 144/432, and i suppose a decent tuner would be able to resolve a mismatch, but i am looking for TRUE gain, on the order of at least 3+ dbd, with at least some noticeable side & rear rejection.  i know i could go horizontal on 1 band & vertical on the other, but i want both to be horizontally polarized.  in my little part of the suburbs, i have room for only 1 antenna, and it needs to  be as obscure as possible, so quad/quad shape PROBABLY won't cut it. OR-WOULD 6 & 10 meter quad loops work on the same spreaders/same boom......?

i am open to other suggestions, but remember space & looks are at a premium, only 1 roof mounted tripod or pushup pole-type alongside a rear gable is possible, boom would have to be no more then 16', 12' would be better.  i know what gain can be made on such a short length, so, please don't tell me 3 dbd isn't worth the trouble....it's all i got/all i can get-i'll take it.

i'd even consider some type of hybrid-say a 6m quad & 10m yagi horizontally polarized on same boom.  

lastly, how close can i truly put say a 3 element 10m yagi & 4 element 6m yagi on the same mast & still have an effective increase in performance without diminishing peformance of E skip or F layer-propagated DX?  feedpoint of lowest antenna would be approx 25' above ground/22' above roof level.  local communication is not a concern, i have a vertical & a g5rv jr well buried on my heavily treed suburban plot-& i don't really want to talk to them guys anyway ;-).
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N3OX
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« Reply #1 on: June 17, 2007, 11:03:03 PM »

But you'll have to change your login name :-)

It is certainly possible to build a dual band 10m/6m beam... I don't know of one but I bet it would be a pretty good seller given the new licensing structure...

I don't know of a design already.  If I wanted to build one I'd hack around in EZNEC for a while and see what I could come up with.  

If you're not a modeler you might try just taking a 10m 2 element yagi or maybe something like a Moxon and trying to add a 6m beam to it experimentally... just build both antennas, put them on the same boom and see what happens.  

If you think you can deal with the looks, a quad would probably work pretty well, and they have the advantage of being somewhat easier to adjust than yagis... I really hate it when I've cut too much aluminum rod off my yagi ;-)  The three-dimensionality of a quad does call some attention to it.

Anyway, it's certainly POSSIBLE but I've never seen a design.

It's actually good that 6m and 10m aren't harmonically related... it'll make the elements on the other band a little more "transparent" if they're far from resonance... I think it might actually be possible to casually interlace a 10m yagi and a 6m yagi of your choice and have it actually work with some modest tweaking...

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

Monkey/silicon cyborg, beeping at rocks since 1995.
KB1GMX
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Posts: 813




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« Reply #2 on: June 18, 2007, 07:35:20 AM »

>is there/was there ever a commercially made yagi that would work on BOTH the 6 & 10 meter bands? can one be homebrewed?<


Not known if there is a commercial 10/6m around.

Can you build one, most certainly yes.

A three element beam is around 7db of gain and a 2 element will be around 5db. A moxon is slightly higher gain than a 2 element beam but less than a 3 element yagi but it's shorter than both!  So there are all sorts possible antennas worth persuing.

I'd suggest not messing with a quad as they are larger
and more three dimensional than the standard yagi or moxon.

Two possibilities and mounting.

1) seperate 10m 3 element with a 8-12ft boom and a 6m 3 element (typically 6foot boom) mounted on a small roof tower (say 8ft) with 6ft of vertical seperation between the two will do nicely and it's simple.

2) Again a roof tower and mast and build a 10m/6m
 on a single boom.  the spacing and all are resonable to do  both on a 8-10ft boom.

So you have a few basic examples.  The first you can use commercial antennas easily.  The second you make
it but it's a reasonable project.

Allison
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KB1GMX
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Posts: 813




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« Reply #3 on: June 18, 2007, 07:43:56 AM »

Since you had a few question I will answer sperately.

>lastly, how close can i truly put say a 3 element 10m yagi & 4 element 6m yagi on the same mast & still have an effective increase in performance without diminishing peformance of E skip or F layer-propagated DX? feedpoint of lowest antenna would be approx 25' above ground/22' above roof level. local communication is not a concern, i have a vertical & a g5rv jr well buried on my heavily treed suburban plot-& i don't really want to talk to them guys anyway ;-).<

The seperation rule is no less than a quarter wave for the higher frequency antenna [6M] or half the boom length. most of the 4 element 6M beams have booms under 12ft so 6 feet minimum works fine.

So the two on a 6-8ft roof tower with 8-10ft of mast will work just fine.  Also that combo should do ok
to good for local work.

Allison
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WB6BYU
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Posts: 13475




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« Reply #4 on: June 19, 2007, 01:25:16 PM »

Actually there IS at least one commercial beam that covers 6m and 10m,
it just happens to cover 15 and 20m as well.  Think it is called a "Hybrid
Mini-Quad".

You certainly can build any number of such antennas - the 6m quad
on the boom of a 10m yagi sounds interesting.  One approach you might
want to try is a Hex Beam.  Here is EI7BA's description and photos of
building one for 17m in 3 hours:

http://ireland.iol.ie/~bravo/ahexbeam.htm
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ONLYON6METERS
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Posts: 32




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« Reply #5 on: June 23, 2007, 11:42:11 AM »

GOOD starting point!  THANKS!  gonna check the website, as well as into hybrid, then experiment with a 3 element maco & 3 element mfj & see where this gets me!
more suggestions/info always welcome!
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WB6YIK
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Posts: 10




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« Reply #6 on: June 27, 2007, 03:26:42 PM »

Also, the SteppIR 3-element Yagi covers 20-6 and everything in between.
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AB2KT
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Posts: 62




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« Reply #7 on: June 27, 2007, 09:51:52 PM »

Since the frequency ratio between 10 meters and 6 meters is less than an octave, you might think about a log periodic. The KMA 2856 covers 28-56 MHz with 12 elements on a 15' boom. Looks like a large TV antenna.

73
Frank
AB2KT
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KA5ROW
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« Reply #8 on: October 08, 2007, 04:20:54 AM »

I Had a Hy-gain 5 element beam and a 5 el  6 meter beam of unknown manufacture, sense I was limited on tower space I put the 6 meter elements on the 10 meter antenna boom and I worked great no interaction
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ONLYON6METERS
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Posts: 32




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« Reply #9 on: January 06, 2008, 05:26:19 PM »

this may be a bit old, but since i started it, i'd like to continue!
i tried interlacing, and, as 'ROW says, i acquired a maco 4 element, & along with the mfj 3 element i had, built them individually & then tried to put them on the same boom.  due to 'landscaping', i had to end the project prematurely, but hope to continue this spring.  my results were not what i had hoped for.  testing was done at about 8'-9' off the ground, no metal within 60' or 70', and a wooden stockade fence 25' one way & a large maple tree 25' the other way.  i could get the SWR on individual antennas to 1.1:1 on 28.400 & <1.3:1 on 50.200.  the 4 elements on 10 meters could be spaced practically anywhere across 16' of boom, SWR would change minimally, and gain & rejection always seemed to be 'significant/noticeable'.  the mfj needed modification to the elements for a 'bracket' to mount on the maco 2" boom as it is made to assemble 'through-boom'.  this too worked well, and even the addition of 4th & 5th elements was impressive. in fact, a 4th element added & SWR came down to 1.1:1, as noted on a 259 analyzer & sx100 wattmeter. i tried numerous ways of 'interlacing' the 6 & 10 meter elements on the single boom-3 el/4 el, 4 el/3 el, 3 el/5 el, 3 el/3 el, including keeping the 6 meter reflector between the 10 meter driven element/director. i would see good SWR, but #'s on the 259 seemed out of whack, or, i would see good SWR on 1 band, but not the other.  most all attempts showed significantly less gain & rejection vs the single antenna on the boom.  out of frustration, i installed the reflectors on opposite ends, so the antennas were sort of looking at each other, and may have had better results that way.  well, maybe not, but, it DID work....any suggestions?  anything i may have overlooked?  or not tried?  i have found out that force 12 inc makes an interlaced 6 & 10 meter yagi called the 'TANGO 3/4'.  it is a 3 element 10 meter & 4 element 6 meter beam on the same boom....exactly what i'm after.  tom from force 12 tells me 'the antenna works as advertised' with gain being just shy of 6 dbd on both.  again, something i can work with.  i've emailed him again, as of yet with no reply, but, obvioulsly not convinced spending another $450 when i already have nearly $300 of aluminum laying around is a smart move based on 'the antenna works as advertised'.  i do see that here on eham, force 12 reviews are among the best, so, maybe they have the answer!  
that said, does ANYBODY have any experience with the force 12 tango 3/4?  or the assembly instructions?  i'd love to see what i'm doing wrong!
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