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My Stealth Hawk

The Stealth Hawk is a newly developed antenna for using in the OTA TV world.  It is supposed to be a pretty good antenna in the VHF-HI frequency range.  I decided to build and test this antenna mainly for the digital post-transition in 2011, where there will be a few digital channels relocating to the VHF range from their current temporary UHF setups.  The channels in question are CFTO will move to its analog RF9 from its current RF40, CHCH will move to its analog RF11 from RF18, and CKCO will hopefully transition to a digital feed on RF13, which will be an alternate to CFTO should it not be reliable post-transition.

The main design of the Stealth Hawk can be found here:

It was primarily developed and tweaked by Digital Home user 'otacanuk'.

View my Gray-Hoverman post for my TVfool report.

My design is shown in the pics below:






It is made out of 10AWG copper wire, which I bought a meter length of 10AWGx2 from Home Depot.  The cost was around $6/m.  The box is a 3/4" conduit box for external use, but I ended up putting too many holes in it for allowing to use outdoors.  The balun was a standard 300:75 ohm type from Home Depot at about $4.50 each.  I've used these on most of my antenna designs, and they have all worked great.

I'm not really keeping a running log on this antenna, but a couple weeks back, I had the first opportunity to try this out at a friends parents house while demonstrating my M4.  Pointed towards the CN Tower transmitters, it picked up most of the Canadian channels below UHF51, meaning digital City, Global, Sun (from TO), and OMNI1 it didn't get.  The other thing it did pretty good at was picking up the VHF stations as well.

Pointed towards Buffalo, I was only able to get CW23, in addition to CBC, CHCH, SunTV, and CTS.  But I was only able to get those with the M4 as well.  So overall, I was pretty pleased with the build and proceeded to throw it up in the attic.  I temporarily set it up and rested it on the joist that afternoon and ran out of time to really change it around and try different locations.  Below is the picture:

I connected it to the VHF input on my CM-7777 pre-amp
Even in that horrendous mounting location, I was able to pickup VHF11 and VHF13 pretty decently.  But I couldn't get VHF9, which was one of the important stations.  The next day, I went back up and attempted to mount it higher up, but the attic was getting too hot to stay for any length of time.  I wasn't happy with how it was mounted, but I was still able to get a very snowy VHF9, along with snowy VHF5 and 6, and a really clear image on VHF11 and VHF13.

Last weekend (May 22), the day was cool and overcast, which made going up in the attic a little more bare-able.  I played around with different locations in the attic to clear up VHF9, and when I found a spot, I mounted the antenna there in a more permanent fashion.  Now VHF9 is almost clear (only a little bit of snow can be seen in the analog image).  VHF11 is still clear.  VHF13 is almost clear (same quality as VHF9).  VHF5 and 6 are snowy but still watchable...though it doesn't really matter, since VHF5 is analog CBC, which a get a clear digital HD image on UHF20.  VHF6 is a Global analog affiliate, but I get Global analog on UHF40, which is very clear.  I don't get its digital counterpart on UHF65, but after 2011, it should be moving to the analog location on UHF40.

So I'm hoping this is all that will be required come the 2011 transition, but we will have to wait and see.

I also found out that there could be a new station broadcasting on RF7 from Buffalo.  This signal started popping up around the beginning of May, but this past weekend, people in Kitchener were able to get it.  I hadn't done a scan since Saturday afternoon, so I will have to do one and see if I can get this channel as well.  If I do, then this Stealth Hawk will have proved itself in gold, as the TVfool report indicates that RF7 is just under 75 miles from my house.

Well, last night and this morning (May 26th/2010) I did a couple of scans and the hawk was able to find RF7.  Problem is, that right now the signal is not strong enough and the 1250 Capture card can't get a lock on the signal.  The Hauppauge signal meter is reporting a max of 11dB SNR (the software requires around 16dB for a channel lock).  Provided that RF7 is not transmitting at full power yet, they may be my first digital channel in the VHF range.  Which would be a good test for both the Stealth Hawk, and the rest of my setup.  This would also indicate that the Hawk is a more than capable antenna, because of the distance to RF7 transmitting location.


Never thought I'd keep on adding entries to this page.  Most recently though, I was able to receive WNGS, which just started broadcasting on out of Buffalo on a low power transmitter at RF7.  This was my first VHF digital station, and the Hawk picked it up at 75 miles away.  I'm hoping that this will be good news to come for the transition, and it's always nice to get a new channel from time to time.  Below are the screen captures of WNGS with MediaPortal:
 



Unfortunately further testing has been halted until I get the HTPC fixed...see that thread for details of what happened. 


*27/09/10*

Well, I was going to have a good'ol shootout this weekend between this antenna and the Scatter Forager.  When I went up in the attic, I discovered that during the course of the summer, this antenna fell apart.  I figure it was a combination of events between the heat in the attic, the mount, and the actual design of the antenna all contributed, but the end where the balun cable comes out was facing downwards.  This rotation caused the element on the opposite end to flip up and hit the plywood of the roof.  I guess the force of the impact popped the element from the screws fastening it down (see diagram).



So the antenna was only working off of one element, and when I discovered it, the antenna was vertical.  Surprisingly I was still receiving some VHF channels.  This was a TV capture prior to going up in the attic and discovering the fault:


*15/10/10*

Built up a second generation Stealth Hawk to compete against the Scatter Forager.  This Hawk is based on this design:

This was modeled and tested by OTA_Canuck over at the digitalhome.ca website.  The intent is to see if this antenna can compete against its original, and against the Scatter Forager in the VHF-Hi frequency range.  So far, from the living room test location, it hasn't tested on par with the Scatter Forager.  But understanding that this antenna can be a rather finicky at location, direction, and its surroundings, it doesn't surprise me.  The true test will be in its performance in the attic.

So I'm hoping to have a shoot out between this antenna, the Scatter Forager and a 2-bay VHF-Hi bowtie antenna to see what will be the final antenna for VHF use.

*20/10/10*

So far in using this antenna for the past few days, I haven't been as impressed with it as I was with the original design, or when comparing the channels received, quality wise, to the Scatter Forager antenna.  It has picked up the same stuff as the Scatter Forager.  WNGS and RF12 out of Erie both remain elusive.  The difference is that I get absolutely no signal from either one of those stations, unlike the Scatter Forager where I get signal, but far from being a lock.  Even CTV analog and CKCO (RF9 and RF13) both appear to have more "snow" than when using the Scatter Forager.

I will continue to use this antenna until the weekend, when I may go back to the Scatter Forager, or I may have together a 2-bay bowtie geared for VHF-Hi use ready to mount and try out.

I don't want to say this is a bad antenna...I just think it is not really suited for my requirements, and location of install (attic use).  I think as indicated in the digitalhome.ca forums...this antenna indeed needs open space to benefit fully from it.

*26/10/10*

Here are the pics of my second gen Stealth Hawk in accordance to the drawing above:



Disclaimer:

I am not an electrical/electronics engineer, nor am I claiming to be a professional at designing electronic circuits, I am, though, an Electronics Technologist, and have a firm understanding of all the circuits that I have built.  If you choose to try some of the projects that I have done, I take no responsibility to your lose of personal health or property.  All projects are performed at your own risk.