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Discussion Starter #261
Post #258
My next step is to add 5.5" tips onto the lower legs with those tips sticking straight out horizontal each side. [ _/ \_ ]
I have put the 'Hawk' back into the 'Stealth Hawk'. I added 5.5 inches onto the bottom legs of the 'nikiml UHF 14-69 model' . They are slightly tipped upwards at about 15°. The tips of these wing extentions are at about even height with the level of the feed point.
Results awsome: --> a significant boost to VHF which is the original intent of the SH designs. It doesn't seem to have affected the UHF, except I now have a significant gain on all Buffalo signals and the WICU 12RF WSEE 16RF & CBC 20RF signals. I still have trouble with the WQLN 50RF signal, but I believe that is a local multipath issue. The lowest analog I can now receive is CBC channel 5RF and the highest channel is 57RF [I also see something very snowy on analog 69RF, but I have no idea of what channel that could be for this area]. The 'nikiml UHF 14-69 model' is now a VHF/UHF channels 7-69 capable.
[I believe the beamwidth may be slightly wider with these added wings]

Code:
The diamond top is gapless:

diamond top legs -                   159mm |  6.27in | 6 1/4in
diamond bottom legs -                218mm |  8.59in | 8 9/16in
feed gap - (@ balun)                  66mm |  2.61in | 2 5/8in
bottom 1st leg -                     201mm |  7.90in | 7 7/8in
bottom leg wing -                    140mm |   5.5in | 5 1/2in
diamond height(feed gap up) -        234mm |  9.23in | 9 1/4in
diamond width -                      302mm | 11.89in | 11 7/8in
bottom leg spread -                  475mm | 18.70in | 18 3/4in
bottom legs height(feed gap down) -   43mm |  1.69in | 1 11/16in

Total #10galv. wire length is 58" to make this element
Thanks to nikiml's evaluations and optimizations, this may be the boost that the Stealth Hawk has been waiting for.
 

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[a grounding block grounds the braided shield of the cable, but a separate grounding rod should be put into the earth outside the house, do not use the house's electrical ground]
Hi Ota_canuck,

Could you explain more why the electrical ground must not be used? On the picture shown in the message from your link, I see the antenna is on one side of the house and the electrical ground is on the other side. Then it would seem normal to me that you don't want to bring the lightning inside your house...

But in a general case, what is the problem to use the same ground for electrical and for an antenna?

For example, here my electrical ground wire goes from the pannels in the house to the outside through the concrete then down in the ground for 20 feet and then it is connected to the metal pipe of the well. If I'd connect my to-be-installed-in-a-few-month-when-CBC-and-SRC-Move-to-mont-Royal antenna to this big (#0 or #2) ground wire outside the house, it would have a pretty direct path to ground...

Am I missing something?

jf
 

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Discussion Starter #265
I can think of three reasons to have a separate grounding rod for your antenna:

1) Potential for spurts of household electrical interferences to your tuner.

2) Should lightning strike, you don't want to bring the lightning into your house.

3) Most important reason,.... Why tempt fate? :p
___________________________________________
viator1966,

If your considering to rebuild your Stealth Hawk, then take a look at post#261 & post #263 before you decide which design you want to build. With the one you've already built,.. it's just a matter of swapping the existing wire element for the newer design element. I've done it about a thousand times since this thread started. ;)
 

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Discussion Starter #267
No,... 12" [11 7/8" to be precise] see post #261 for exact fractional dimensions.

I posted the general dimensional figures [rounded off] in the sketch for simplification and because in most cases, and for many reasons, such tight tolerances can not be achieved anyways.

The precision of the dimesions shown in the fractional dimensions list are subject to many variables such as bend radius, wire type, wire diameter, the tools you have at hand, your skills, etc. These precise 2decimal dimensions likely won't help much unless you are machining the element's shape from a solid piece of stock in a high tech machine shop.
 

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Thanks ota canuck! I think I may, especially since I've got 8 feet of #4 awaiting the next version. LOL! I do want to get this one up this coming weekend and see how it performs at the proper atitude of 30 feet. I need to see if my "baby" will walk...LOL!
 

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Just checked out a common Toledo Ohio location of TV fool. You've got quite the geographical scatter of stations around you and not very many in the green, however I believe you may have a reasonable chance at the first 15 stations showing in that list even though most are in the red zone.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=a362bfa1cd6109

You'll have to be very careful if your using a powerful preamp though because you have several DT stations broadcasting within 10miles of your local reception area. You also have a few analog stations broadcasting right on your doorstep that could cause you serious grief. I would recommend no preamp, but rather use a distribution amp or something inline and a little closer to the tuner.

Please share your results when you get the SH up and aimed to perfection.:p
 

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Update on my Stealth Hawk (Post #94 Design)

Original posts:
http://www.digitalhome.ca/forum/showpost.php?p=1136005&postcount=166
http://www.digitalhome.ca/forum/showpost.php?p=1136009&postcount=167

I mounted mine up in the attic this weekend and made a couple mods...

Modifications:
- Switched from the Radio Shack balun to a different one (available here) from Parts Express
- Widened the feedpoint gap to 3" from 2"

Overall, I'm definitely picking up more channels than before. I actually tested the antenna in the garage with the garage door open (same way I tested the original setup) and I can receive 36 channels, up from 19 before.

Dayton Locals
2 / WDTN / NBC - 99% (2 ch.)
7 / WHIO / CBS - 98% (2 ch.)
16 / WPTD / PBS - 84% (5 ch.)
22 / WKEF / ABC - 95% (1 ch.)
26 / WBDT / CW - 100% (2 ch.)
45 / WRGT / FOX - 91% (2 ch.)
50 / ???? / ??? - 98% (2 ch.) *NEW*

Cincy Locals
5 / WLWT / NBC - 86% (2 ch.)
12 / WKRC / CBS - 64% (2 ch.)
14 / WPTO / PBS - 91% (5 ch.) *NEW*
19 / WXIX / FOX - 81% (2 ch.) *NEW*
48 / WCET / PBS - 79% (3 ch.) *NEW*
64 / WSTR / MyN - 76% (1 ch.)

Other (near Oxford, OH)
43 / WKOI / IND - 69% (5 ch.) *NEW*

I played around with the antenna direction for about an hour and settled on a position that appeared to be the best for both the Dayton/Cincy tower farms, which works out to something between 190 and 200 degrees.

Questions/Points of Note:
The most interesting thing is that I lost WCPO out of Cincy compared to the prior setup and I also lost signal strength on WKRC.

I think 50.1 and 50.2 are a simulcast of WDTN from 2.1 and 2.2 - not sure why they're broadcasting on both?

My main concern now is that I cannot hold a steady signal on many of the Dayton Locals, WHIO in particular, during the day. The problem has been consistent except for right now (it's 1:30 in the morning) as I'm writing this; I don't see any drop-out on any of the channels. Could I be picking up too much of a signal because I'm so close to the transmitters? I did increase the feedpoint gap and I thought that might help, but it doesn't seem to have. Any thoughts/suggestions for this would be much appreciated!
 

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Discussion Starter #271
sdilullo, dayton results;

Here is a nearby tvfool report:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=a36299cc27a181
I cannot hold a steady signal on many of the Dayton Locals, WHIO in particular
I would say that you're suffering from severe overload from all 11 of those nearby transmitters. WHIO is basically in your backyard and they're broadcasting at an ERP of 1000kw. Do you have any amplifiers between the TV and antenna? You may have to attenuate rather than amplify.
 

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Here's my exact TV Fool...
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=9fbe731a58af6b

I don't have a single amp attached - perhaps I do need to figure out a way to attenuate. Of course, that could be at the expense of the Cincy stations.

Any ideas if sticking some sort of mesh reflector on the Dayton-facing side could block some of the signal or am I totally off-base with that thought?
 

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Yep, It is a recommended strategy for OTAers with attic-mounted antennas near airports who suffer airplane flutter. Stapling some mesh or foil in the direction of the airplanes can drastically reduce the problem. For outdoor use such a screen is generally too cumbersome to build and tune properly since it will affect the entire reception pattern in ways that might not be so good.

Since the beauty of the Stealth Hawk antenna is its relatively small size and ease of build, it would be a shame to have to put up something as finicky and potentially troublesome as a screen.
 

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I also should note that I'm only a mile away from an airport - it's to the South, though.

It's just a general aviation airport, but they do have an ILS and our house is essentially on the extended runway centerline so that beam probably does come quite close to our house. (I'm a pilot, so I'm quite familiar with this specific airport).

I suppose I'll play around with a screen (I've got a little bit I can use lying around from the garden) and see if I have any positive results.
 

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Stealth Hawk, Open Loop or Close Loop.

I have been following this thread about the Stealth Hawk TV Antenna, as well as other antennas on this forum.

I live in Slidell, Louisiana which borders the State of Mississippi. I have a 4 bay 7 1/2 inches wiskers antenna that I build two days ago, it gave me a total of 29 channels, all my locals plus a few from my neighboring state of Mississippi. Boy was I happy.

Yesterday I build a Stealth Hawk as designed per instructions on thread # 94. I must done something wrong because I only got 14 channels when I scanned. Lost more than half of what I already had.

I made it with 14 gauge wire, the antenna is about 16ft high. Rotated the antenna, moved the bottom wire up and down, and still only receiving 14 channels. Is is better to build the antenna with a open loop or a close loop.

Any comments or help is greatly appreciated.
 

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Discussion Starter #276
The Stealth Hawk designs should do at least as well as a 4bay antenna, with less need for aiming. It sounds like something is not connected properly or the antenna build is incorrect. Which SH design did you build?

With the SH being near omni directional,.. if you're in a busy area it could be co-channel or multi-path problems. If you can post your tvfool report, maybe we can see what frequencies and distances you really need to aim for.
______________________________________
Open loop: will do a little bit better on UHF frequencies
Closed loop: will help the VHF, but may cost some gain loss on UHF
 

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Discussion Starter #278
Here's my exact TV Fool...
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=9fbe731a58af6b

I don't have a single amp attached - perhaps I do need to figure out a way to attenuate. Of course, that could be at the expense of the Cincy stations.

Any ideas if sticking some sort of mesh reflector on the Dayton-facing side could block some of the signal or am I totally off-base with that thought?
This one is a flame thrower and it's less than 10 miles away, maybe attenuating WITO [41RF] would help. Or you could simply add about 50ft of cable inline to see what effect attenuating will have on that station.
Effective ERP: 1000.000 kW (Adjusted according to your location)
Distance: 8.8 miles Azimuth: 349 degrees Compass: 354 degrees
 

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Just checked out a common Toledo Ohio location of TV fool. You've got quite the geographical scatter of stations around you and not very many in the green, however I believe you may have a reasonable chance at the first 15 stations showing in that list even though most are in the red zone.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=a362bfa1cd6109

You'll have to be very careful if your using a powerful preamp though because you have several DT stations broadcasting within 10miles of your local reception area. You also have a few analog stations broadcasting right on your doorstep that could cause you serious grief. I would recommend no preamp, but rather use a distribution amp or something inline and a little closer to the tuner.

Please share your results when you get the SH up and aimed to perfection.:p
ota canuck,

Here's my exact loc zip and I don't think I'll have the "overload" issue with using my Wingard AP8700 preamp. Let me know if you agree.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3da3625bd6699a8b

I will definately let you know my results after I "launch" her up at ~30 ft on my chimney. I'm ordering up a ground block and a lightening arrestor tonight, so hopefully, weather permitting, I'll have some info on it by Sunday.

As for the optimal grounding,My best Bud, who's an electrical engineer and lots of experience using arrestors in installs, says I need to put the arrestor between the line coming from the RS matching transformer to the preamp and then run the ground wire from the downline wire to grounding block AND then run #10 wire from grounding block to grounding rod. That's in conjunction with running a #10 wire from the mast ("aka" boom component) directly to the grounding rod to be the "lightening rod" bleed. He says the arrestor should not interfere with the signal passing thru to the preamp. Is this what you were trying to convey to me earlier?

Man...I really am having fun with this little project and this site. Awesome folks here!
 

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I will rebuilt it using a heavier wire.

I believe that my problem lies on using too thin of a wire to build the Stealth Hawk. I will rebuilt it using a heavier wire, and let see what results do I get. I follow the instructions from the post #94, which means that I should use a lenght of 72" of wire for the build. Where I live, which is in Slidell, Louisiana, the stations are almost 50/50% VHF, UHF and I sould be able to received at least 30+ stations, so far I am only able to receive about 25 stations some with little pixellation. I will send a copy of my Tvfools to see what Stations you think are reachable from my area.

Will try again and will build this one with an open loop, as soon as it gets built I wiil report my results.

Thank you
avenger.
 
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