Building The Stealth Hawk TV Antenna (See Post #304)

[ota_canuck]

There are several models in this thread. Which one are you refering? SH289?

See: http://www.digitalhome.ca/forum/show...&postcount=304

Model SH289 needs 60" for the round wire model or 60"-62" for the flat alunimum model.
[the flat aluminum model uses up 1" per side for the flat at the feed/mounting area.]

I used 1/16" x 3/4" x 60" [or 62"] flat aluminum for the SH289 designs.

Dimensions per side:using 60" total material length
6" top length
8" middle length
feed point [use 1" for flat area if using flat aluminum]
15" bottom length

Second option: using 62" total material length
6.5" top length
8.5" middle length
[use 1" for flat area if using flat aluminum]
15"bottom length

[ota_canuck]

If you want to view a upgraded Super Stealth Hawk III for a widebeam antenna,.. check out the most recent sketches and build instructions. The SH289 is good and simple to build,.. but if you're willing to build something a little more complex, then check out the SSH III:

http://www.digitalhome.ca/forum/show...&postcount=283

[ota_canuck]

I did a few test trials to make the SH element feed point mount simpler;

The fiberglass insulator that I used with the Super Stealth Hawk designs can also be used as the feed point mount for the #289 Stealth Hawk antenna. The feed point gap will then be 2 3/8", but it performs just fine.

[erorr]

Niagara Falls 4221 type 9x9 diy antenna indoors about 15 feet high. I just tried a crudely made sh289 and I get all my usual channels plus one extra which is rf23. I'm really surprised at the performance of this simple antenna, have to wait and see if this an anomoly or if the signals keep coming.

[brookcreek]

Hello ota_canuck,

I am in Cobourg and posted a couple of years ago about going OTA. I am new at TV stuff.

We downsized this spring, got rid of the shaw satellite, and now live on the south east corner on the 4th floor close to the lake. I ran RG6 from the south facing balcony during our renovation and am ready to build The Antenna. Hopefully, I will only have to do it one time.

TVFool shows that I "should" get a bunch of channels. http://www.tvfool.com/?option=com_wr...13490aade36718

Your post of 2010-4-16 for the JMS digital 7-51 caught my attention. Where do you buy 3/4" flat aluminum wire by the foot.

Any advice would be greatly appreciated.

Thank you.

Paul

[ota_canuck]

erorr,
I'm not sure where you are or what your terrain is like, but in most cases the SH should provide satifactory coverage of local reception. Getting any antenna outdoors and higher would work much better than your present antenna mounting situation provides.



brookcreek,
I found my 6ft lengths of flat aluminium at Canadian Tire. They have 1/16" and 1/8" thicknesses, so the 1/16th material is much easier to work with. See posts #289 for the basic SH dimensions,.. but refer to the pic in post #500 to see how to arrange the bends when using flat aluminium.

Your tvfool shows mostly station reception in yellow range, yet with high NM values. If you have a line of sight to TO from your apartment, then Toronto may be possible. With those distances you may require something more directional, but starting with a simple SH antenna would be an inexpensive first venture. Given your distance from the sources, I'd say a preamp will be a must have for your antenna setup no matter what antenna you are using. I'm assuming that your antenna will be mounted outside on the south balcony facing SSW? Please keep us posted on your results with the Stealth Hawk Antenna.

[antennanovice]

ota_canuck

Thanks for the link.

I saw a much earlier design in the original thread apparently.

I would be surprised if this group didn't do massive tweaking on a design.

The sharp bends at the feed points create an impedance mismatch that naturally separate the uhf top from vhf bottom elements. the angle of the bottom elements make them a nice reflector to spread the uhf pattern horizontally. The top section probably acts as both a loop and GH type due to the type of bend on the top hat. again a sharp bend to selectively separate current flow at higher frequencies. The top hat also caps some of the vertical lobe.

simple, yet elegant.

what is the optimum diameter and material? large diam Al? or is Cu recomended? if using foil / stiffener backing / encapsulant, what size adjustment is done to account for the modified phase velocity?

I might want to try one of those with foil and double face tape on thin cardboard or stiff plastic sheet for indoor use. cheap material means I can get it wrong a few times without going broke.

I like the plastic / very dry construction paper sandwich that the mohu used per ADTech's post. construction paper would pick up too much moisture without the lamination, but is less conductive at some higher frequencies than plastic. Given their parent companies other product lines, I am sure they re-scaled their design for the difference in phase velocity. they probably also had access to EMI and radiation test facilities instead of just depending on modeling alone.

[DarkNovaNick]

I'm trying to figure out if a Stealth Hawk build would work for me. Here is my TV Fool plot. I am interested in real channels 7, 9, 16, and 31. Do I have enough signal for a Stealth Hawk to work? If so, which version would be best. Thanks for the assistance.

[ota_canuck]

Since you have no line of sight [LOS] stations available, it appears that you may be located in a valley or surrounded by hills. I think the Stealth Hawk antenna would work as well as any antenna would in your location. It's a cheap build project and it may be able to pick up those 1edge and 2edge stations.

I recommend building the #289 model that can be found in post #289.

[morehp]

it would be a more difficult build
but for max gain in a "stealth hawk" style antenna why no go for gold and build a SUPER Stealth Hawk.

[DarkNovaNick]

If I build a stealth hawk, is there a rule-of-thumb about nearby metal?

Basically two possibilities -- can one mount the stealth hawk on a metal mast or should it be non-conductive like PVC?

Also, I would like to mount a cellular antenna on the same mast, this is the model. It is a vertical antenna 18" long. Is there a rule of thumb about how far away this antenna should be from the stealth hawk? Thanks.

[ota_canuck]

A metal/galv mast would be best for wind stability/sway resisence. The SH antenna works best if it is mounted at the tip of the mast. The tip of your 18" cellular antenna should be mounted at least 25" below the feed point of the SH antenna. That cellular antenna using it's standoff bracket should still give you360° coverage even if it is mounted parallel to the mast.

[DarkNovaNick]

Originally Posted by ota_canuck

A metal/galv mast would be best for wind stability/sway resisence. The SH antenna works best if it is mounted at the tip of the mast. The tip of your 18" cellular antenna should be mounted at least 25" below the feed point of the SH antenna. That cellular antenna using it's standoff bracket should still give you360° coverage even if it is mounted parallel to the mast.

Thank you for your quick answer!

[ota_canuck]

DarkNovaNick,

Your tvfool looks pretty sparse for reception, but with a preamp you should get some of those 1edge & 2edge channels that are 1+ NM value.

[DarkNovaNick]

Originally Posted by ota_canuck

DarkNovaNick,

Your tvfool looks pretty sparse for reception, but with a preamp you should get some of those 1edge & 2edge channels that are 1+ NM value.

Thanks -- all I care about are the ones at +18.6 NM and above, and I've assumed I would probably need to get a CM 7777 or something. I got the materials to build the #289 and am hoping to put it together tomorrow.