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Discussion Starter #3
Hi,

Sorry, fixed that. I *thought* it said above sea level so I figured out how far above sea level I am and entered that! I corrected the original link, it should be correct now.

Thanks for the help,

Alan
 

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Welcome Alan!

Changing antenna height had a very small effect on NM, the measure of signal strength used in the forums from tvfool. Based on your strong local signals, you don't need a super high gain antenna. There are high vhf and uhf channels at your location. I suggest something simple like a M-2 or a bi-quad. They are both UHF antennas but your VHF channels are very strong and will come in just fine on either antenna. You can read more about the bi-quad here: http://www.digitalhome.ca/forum/showthread.php?t=124542 There is a thread that discusses the 2 and 4 bay antennas, see: http://www.digitalhome.ca/forum/showthread.php?t=100137 There is a kit available for the M-2 here: http://m4antenna.eastmasonvilleweather.com/index.html There is modeling data for the M-2 and bi- quad antennas here: http://imageevent.com/holl_ands/multibay/uhf2bays/uhfm2;jsessionid=yp4lt393z2.penguin_s and here: http://imageevent.com/holl_ands/multidiamond/biquadkhayenorefl;jsessionid=yp4lt393z2.penguin_s

There are many other alternatives that could be chosen. Good luck! :)
 

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Discussion Starter #5
Hi,

I'm going to try a double bi-quad. I've got some 12 gauge copper to use, but it has an insulation, does that matter?

Thanks,

Alan
 

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Hmm. You have all your primary stations in one direction and very close and VERY strong. There are also a number of independent and low-power stations from a wide assortment of directions. You need an antenna of modest gain and sensitivity over a wide azimuth. I'd recommend the stealth hawk documented here.
 

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Alan, you will need to strip the insulation from the 12 guage wire. The stealth hawk is also a good possibility for your location and very easy to build.
 

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Or for extra fun, something like that:

Code:
CM
CM GH0n
CE

SY radius=0.003175
SY narod_spacing=0.012

SY feed=0.04333271' 0.01, 0.1

SY b=0.1510519' 0.075, 0.25
SY a1=0.1705078' 0.07, 0.22
SY _G3=0.07801628' 0.006, 0.1
SY a2=a1+feed-_G3'this is to avoid self intersection since _G3 is to be > radius+2.5mm
SY a3=0.1128216' 0.07, 0.22

SY n_h=0.08554887' -0.01, 0.14
SY n_top_dy=-0.01999999' -0.02, 0.02
SY n_b_taper=0.03997426' -0.001, 0.08
SY n_top=_G3+a3+n_top_dy- n_b_taper/2'hat head size

SY narod_top = a1+a2+a3+narod_spacing+n_h

SY ay1=feed+a1
SY ay2=feed+a1-a2
SY ay3=feed+a1-a2+a3
SY ay4=feed+a1-a2+a3+b
SY az2=a1+a2
SY az3=a1+a2+a3
SY n_b_z=az3+narod_spacing
SY n_b_y1=n_top+n_b_taper
SY n_b_y2=n_b_y1+b
SY angle=30
SY cangle=cos(angle)
SY sangle=sin(angle)

GW 1 13 feed*sangle feed*cangle 0 ay1*sangle ay1*cangle a1 radius
GW 2 10 ay1*sangle ay1*cangle a1 ay2*sangle ay2*cangle az2 radius
GW 3 9 ay2*sangle ay2*cangle az2 ay3*sangle ay3*cangle az3 radius
GW 4 8 ay3*sangle ay3*cangle az3 ay4*sangle ay4*cangle az3 radius
GW 11 5 n_top*sangle n_top*cangle n_b_z+n_h n_b_y1*sangle n_b_y1*cangle n_b_z radius
GW 12 8 n_b_y1*sangle n_b_y1*cangle n_b_z n_b_y2*sangle n_b_y2*cangle n_b_z radius
GW 13 16 0 0  n_b_z+n_h n_top*sangle n_top*cangle n_b_z+n_h radius
GX	20	010
GX	40	001
GW 100 7 feed*sangle -feed*cangle 0 feed*sangle feed*cangle 0 radius*.8675
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX 0 100 4 0 1
FR	0	0	0	0	800	0
EN
It is not optimized and can probably be improved a lot on the SWR end but may fit exactly to your situation...
 

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So what is that antenna nikiml? I'm not familiar with reading the NEC code and I suspect there are other readers in the same boat.... My guess at your plan is a gen one GH with 3 narods???
 

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Discussion Starter #11
Hi nikiml,

You have some pretty impressive looking designs on your site. Are there more threads about taking a design like the one you posted and building it? I would really like to build one if I had a little more direction on the build process.

Thanks,

Alan
 

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Hi nikiml,

You have some pretty impressive looking designs on your site.
Thanks. But as others said you don't need high gain antenna, but rather "wide" pattern antenna.
Are there more threads about taking a design like the one you posted and building it? I would really like to build one if I had a little more direction on the build process.
unclesam is posting some excellent notes about his progres on the GH10n3 here http://www.digitalhome.ca/forum/showthread.php?t=102202&page=24 but again you don't need that antenna.

300Ohm has instructions on how to use 4nec2 here: http://www.digitalhome.ca/forum/showthread.php?t=107457

The antenna model I posted was somewhat random. I decided to try to widen that pattern on one side by placing the active elements at an angle, and kind of worked. But the angle I chose is random and none of the parameters is select by optimization. They are in fact those of the flat reflectorless model I posted here.
 

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Discussion Starter #13
Hi nikiml,

There have been a lot of good suggestions, what do you recommend given my position and available channels?

Thanks,

Alan
 

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Hi nikiml,
There have been a lot of good suggestions, what do you recommend given my position and available channels?
Whatever 300Ohm recommends;)

But hey, I like my model...

Seriously now - the stealth hawk is the easiest to build so why not start from it.
If you are not satisfied you can try the model I posted. Or an improved version of it.
 

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Discussion Starter #15
Hi,

That stealth hawk looks pretty easy to build and like it would go well in an attic.

I have a distribution point in about the center of my house with a splitter/amplifier. Should the antenna be as close as possible to that point?

How important is distance off the ground? I have a tall attic and could mount it on a pole pretty easily...

Thanks,

Alan
 

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Are the channels to the west of you any good ? If so, youll need two antennas (one reflectorless N-S, and a GH for the west) with two coax downleads into an A-B switch at the TV.

With the strong vhf-hi channels 8, 10, 11 I think you can skip the NARODs and still pick them up.
 

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Discussion Starter #19
Hi,

I'm going to try the SH in post #289 next. For an attic install, what is the best metal to use? What is the difference between copper and aluminum? I have a house dist amplifier and could locate the antenna near that point so it only has 9 or 10 feet of cable...

Thanks,

Alan
 

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For an attic install, what is the best metal to use? What is the difference between copper and aluminum?
Copper conducts better, but the differences are very tiny. Use either, what ever you have handy and cheapest.
With copper, use brass or copper hardware.
With aluminum use aluminum or zinc plated/galvanized hardware.

What is a N-S?
Yeah, North - South. I probably shouldnt have abbreviated, heh.
 
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