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Stealth Hawk TV Antenna (See Post #304)

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#1 · (Edited by Moderator)
Awsome. It was just a shot in the dark. This thing works!:eek:



This one out performs anything that I've ever tried.

I get all my regular OTA digital and analog channels. No rotor required.

analog: 5,6,9,11,13,19,25,28,31,41,47 [11 channels that's all I ever could get Cdn]

digital: 2.x,4.1,5.1,7.1,9.1,11.1,12.x,15.1,17.1,23.1,24.1,26.x,29.1,36.1,44.1,49.1,51.x,54.x,66.x [30 digital channels]

The front side is facing Toronto [30deg] 52miles, the back face Erie [210deg] 57 miles, Buffalo [86deg] 40 miles to east the side, Hamilton [340deg] 22miles on the other side.

It must be mounted at the tip of the mast and it can't seem to be used with any reflectors or any deflectors. It can not be stacked or ganged. Don't know why? But it outperforms anything I've ever tried.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=9c6be0724b5f66

I'm getting all the way through the tvfool list down to -10NM:D

I'm hoping someone else can build one of these to see if it works in other reception areas.

___________________________

This antenna either has an extremely wide beam width, or it has multiple lobes to be able to cover all these broadcast sources with one single aim.

___________________________

What's in a name? "Stealth Hawk Antenna":

Stealth: At 35ft up on the tip of the mast it is barely even noticable.
Hawk: It looks like a faint siloette of a hawk sitting up on top of the mast.
Antenna: It's a fully functional, stable UHF/VHF Bi-directional antenna.

There are so many builds and trials posted in this thread. Development and improvements are ongoing thanks to all of the contributors of these forums. I have selected some favorites that I would recommend: http://www.digitalhome.ca/forum/showpost.php?p=1149902&postcount=304
 
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#376 ·
Give me abit to model both above and below . NEC shows clearly the importance of spacing for a combo , and real world testing seems to back it up.
Eg. Spaced too close , the lower UHF ant. ( Mantis ) pattern would bend upwards. Spaced too far it push the end of the UHF pattern down > if I remember correctly. When I did my combo with the GH elements , spaced correctly , each anttena pulled a slight bit more gain from each other . I believe the VHF gained .4 dbi and UHF gained another .9 . So the correct spacing is important to this type of setup. Whether above or below makes a difference on the Mantis design , we`ll soon find out.
 
#377 ·
I modeled it out with the E.D.100 above and below . The best spacing above was 32.5" ( feedpoint to center of top ant. ) . Below was 28 " . Above added a good 1dbi stronger , below was alittle less.
The bottom of the UHF band was pretty much un-effected . The bad news is that either position messed up the 4 lobed pattern on the higher UHF .
This type of set-up doesn`t seem to be a good thing for the multi-lobed antennas unlike being done with a GH .
So all-in-all , put it far away from the Mantis. I couldn`t even guess at what a safe distance would be.
 
#378 ·
Today I received my CM 7777 in the mail. I mounted the Eden about 2 and a half feet below ota_canuck's stealth hawk post #289 (I had to hook it up at this distance). I hooked the stealth hawk up to the uhf post and the Eden up to the vhf post. I gained two channels over the stealth hawk alone with my winegard amp (88 channels, do you believe that?).
 
#382 ·
Built my Stealth Hawk last Saturday afternoon. Running it to a cheap two year old Sharp LCD TV gave me television I had only dreamed about. I watched the Miss America pagent in full HD with wonderful clarity and color. Amazing picture from such a simple antenna which was so easy to build.

I used the 3/4" x 1/16" aluminum flat stock that ota_cunuck recommended. I used a Radio Shack balun which provided great, full reception even from my local ABC affiliate who broadcasts on ch 7 here at 34K watts (everyone else is around 1,000K watts so I figured I would have problems). This is in a western suburb on Oklahoma City.

Tuesday I split the cable to feed a new TV for the bathroom (think wife acceptance factor!!) and my ABC feed is starting to give me problems. I have a Winegaurd preamp on the way, we shall see how it goes. Mind you this antenna is placed at my peak inside the attic.

Thanks to all on this forum!! If I can convince Foxnews (wife watches in the morning before work) to start a trail OTA broadcast here in Oklahoma City, I would dump cable in two seconds.......guess I need to get on that campaign!

Bob E.
 
#383 ·
Actually FOX News is being broadcast OTA in select markets on a subscription basis using the Mobile TV standard. For the OP, no OK City station is offering Mobile TV subchannels. For this board, two stations in Detroit have Mobile TV streams: WDIV offers an echo of its main channel and WXYV offers RTV in the clear.
 
#384 ·
Safetybob,

Sounds like you're using an ordinary splitter to feed two the TV's. The SH is a low gain antenna and the splitter will divide that low gain in half. You will need a dist amp/booster before the splitter to overcome the splitter loss. The preamp idea will help too, but a preamp may cause overloading if you are too near any local broadcast towers.
 
#385 ·
Stealth Hawk with reflectors?

Hey folks,

This might belong in area 51 but it could also belong here.
While it defeats the purpose of a SH to put reflectors on it I wanted to give it a try because of the ease a SH can be built. With my limited tools a couple screws and some wood I have managed to make a pretty decent standard SH that I use on my own home. I also built one for my sis who just moved to the state of Missouri 50 miles south west of St. Louis. The closest transmitter is 45 miles away with the rest are farther, she now has 13 channels on an antenna that averages only 6 db gain.

While looking over nikiml's website I combined his Stealth Hawk that he optimized for 14-69 with the 4 reflector design that he used for his Bi-Quad design and it produces a neat radiation pattern that seems to climb the antenna as the frequency increases.

I'm still improving my 4nec2 skills so I don't have the knowledge to produce one of those nifty graphs with the gain on the left and the swr on the right. If some one would like model this Frankenstein against the 2 originals I think it would be neat to compare side by side.

Code:
CM Frakenstein
CM A mash up of 2 of antennas by nikiml 
CE
GW	10	12	0	-0.0392	-0.012	0	-0.2375	-0.043	3.175e-3
GW	11	1	0	-0.0332	0	0	-0.0392	-0.012	3.175e-3
GW	12	13	0	-0.0332	0	0	-0.151	0.1836	3.175e-3
GW	13	8	0	-0.151	0.1836	0	0	0.2344	3.175e-3
GX	10	010
GW	1	16	-0.111727	0.151796	0.224465	-0.111727	-0.1517963	0.224465	3.175e-3
GW	2	28	-0.111727	0.264552	0.0680049	-0.111727	-0.264552	0.0680049	3.175e-3
GW	3	28	-0.111727	0.264552	-0.068005	-0.111727	-0.264552	-0.068005	3.175e-3
GW	4	16	-0.111727	0.151796	-0.224465	-0.111727	-0.151796	-0.224465	3.175e-3
GW	100	5	0	-0.0332	0	0	0.0332	0	3.175e-3
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	3	0	1	0	0	0
FR	0	0	0	0	480	0
EN
I take no credit for this antenna I was just fiddling around and found something neat and wanted to share.

Procyan
 
#386 ·
I'm still improving my 4nec2 skills so I don't have the knowledge to produce one of those nifty graphs with the gain on the left and the swr on the right.
Thats done with other plotting programs, like MS Office or Open Office or GNUplot etc. Just plot the Raw Gain and SWR from the 4nec2 frequency sweeps as two pictures, thats easy.:) Use a program like SWBcap20 to screen capture the graphs.

As far as the pattern goes, you may be better off flipping the antenna upside down.
 
#389 ·
In 4nec2, Charts and Geometry-Editor drawings can be saved using: SHOW/PRINT/SAVE-AS
NOTE: If you simply do SHOW/SAVE-AS, it will save the 4nec2 *.txt file instead!!!!!

Just like PRINT-SCREEN, this results in a VERY LARGE *.bmp file, which must be changed to a *.jpg
file for posting (and conserving HDD). Many image/photo editing programs can perform this function,
incl. DRAW in OpenOffice. I use the BATCH function in PaintShopPro to convert the entire folder at once.

I also routinely save all of the Gain/SWR/Impedance/et.al. files under the PLOT menu.
[I let them go to the default c:\4nec2\plot folder and copy to individual antenna folders later.]
Hint: When opening the first (Raw Gain) *.txt file, do a COPY on the displayed file name and
PASTE it into the SAVE-AS name field & add "Hi-VHF Raw Gain" or "UHF Raw Gain". Skip this
step for all subsequent *.txt files and simply copy/edit the previous name. After you've done
this a few times, it goes more like greased lightning and less like molasses....

I then "Get External Data From Text" [DATA/TEXT in Excel2007] for Raw Gain, SWR, Rin & Xin
*.txt files, filling in individual columns in an Excel spreadsheet to calculate/plot Net Gain,
as well as the other performance curves (F/B & F/R). This also facilitates making comparison plots.

PS: I still don't know how to use different scales on both the Left AND the RIGHT in Excel......
 
#392 · (Edited)
I have done the wire version of SH #289 but will like to try it with the flat alum. A friend of mine is a mech engineer and loved the idea when i showed this forum info to him. He quickly threw together in autocad and I was just wondering for this as well what the dimensions are for the angles. Do they match still to the original one?

He wants to make sure it is exact and perfect to what you have done before.:)



 
#394 ·
The little antenna that could

I'm impressed.

After reading this forum and taking into consideration the advice to try this antenna before anything else, I decided to try to build this antenna, following the dimensions of post #289, 2 weeks ago (my first antenna build!). Am I glad I did! Much better than my little "amplified" indoor Philips antenna. Now that I finally put it in my attic (25-30 feet high), I get every channel on my TVFool report wih a positive NM rating, except for the ever evanescent WVNY (that's ABC 22 on RF 13 for those who wonder), no pre-amp or amp needed, and about 60 ft of RG6 to my Motorola DSR-550 Voom tuner box. I guess I must be in a good location. What's odd though, TVFool gives me lower NM results for US channels when I increase the antenna height. Very counter intuitive and goes against my experience of the last 2 weeks.

Now I'm going to wait until Sept 1st before I try to tweak my setup further, but I still wonder if there is anyway to make this antenna have more gain on VHF-high? I see that the gain and the aiming chart found in post #286 for VHF-high look exactly like that of a dipole, so it's pretty basic.

Thanks to all the knowledgeable people on this forum!
 
#395 ·
What's odd though, TVFool gives me lower NM results for US channels when I increase the antenna height. Very counter intuitive and goes against my experience of the last 2 weeks.
Yeah, that happens in some cases. Keep in mind TVFool cant take into account all the little local differences that may exist at ones house. It only tries to give a general overview of the signal strength that should be there.
Some of the local things TVFool cant account for are trees, shrubs, metal fences, the type of siding you and your neighbor have, metal sheds, electrical lines, cars and trucks parked nearby, and any large pieces of metal nearby.
 
#396 ·
booster amp or preamp?

Boukman,

Can you post a link to your tvfool report?

The Stealth Hawk antennas as they stand alone are low gain, but multidirectional. Maybe that is all you really need for your location. You could try using an inexpensive booster/amplifier [aka: distribution or a drop amp] to improve the VHF&UHF signal strengths somewhat. If you have a lengthy run of cable between your antenna and TV, then it may be wiser to consider a preamp.
 
#398 ·
After seeing your TV fool, I would think a preamp would cause serious tuner overload with so many broadcasters being so close to your location. Given that you have about 50ft of cable downlead, a distrubution amp or one of those UHF/VHF boosters should help your tuner with some of the weaker signals though.
 
#399 ·
Thanks ota_canuck, but I've tried a distribution amp and it doesn't help. WVNY is known to be notoriously difficult to receive, and it is believed to be because of too much interference from CFCF-12. As a matter of fact, if I tune to channel 13 on my analog tv, I can see a lot of diagonal banding and I can hear quite clearly the sound from CFCF-12.

That's why I'm waiting until Sept. 1st when CFCF-12 will start broadcasting a digital signal, because its power should be slightly lower, and also because it is believed that digital broadcasting creates less interference. I will also buy myself a new hdtv by then, so I should get a newer generation tuner that will be much better than what I have now.

However, I still wonder if this antenna could be made to be more directional / have more gain in one direction for VHF-high. How do log-periodic antennas do it? Is there any way to apply that to the Stealth Hawk?
 
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