Narrowband Gray Hoverman question

[ReiMomo]

Hi, I'm about to make a Narrow Band Gray Hoverman but I have 2 questions
Is the gap measurement taken from the center or across it?
Also is my scaling ok? I took the measurement in mm and multiplied by 575 then divided it by the desired frequency (650 MHz).

[nikiml]

gaps are measured across.
your scaling is good...
the only catch is that the perfect scaling should be applied to the wire diameter as well...

[ReiMomo]

Well, I already bought some gas pipe tubing.

http://i588.photobucket.com/albums/s...0/DSC01075.jpg

I'm just trying to get channel 44, but there is a mountain eastern side where I need to point my antenna, here is my tv fool http://www.tvfool.com/?option=com_wr...9900781473e3ae
Tv Fool shows the channel at -39.5 (nm)db if I enter an antenna height of 70 ft.
But I won't be able to put an antenna more that 25 ft.

[GroundUrMast]

Who knows, you may get some occasional DX windows that let you see such a signal intermittently... But looking at the terrain in your area, the hill/mountain looks like it's quite close to you. I seriously doubt you'll ever see much at 25'. I admire your desire... but chasing a signal that's 39.5 dB below the theoretical margin of receivabilty due to obstructing terrain is not going be solved by even a deep space array.

If you're referring to WTJX, the solution will require much higher mounting if you expect to receive reliably with an antenna of manageable dimensions.

Or, can you consider using home theater PC technology and make an agreement to locate a remote PC at a site with a view to the east? http://forum.tvfool.com/showthread.php?t=820
http://forum.tvfool.com/showthread.php?t=1286

[ReiMomo]

Yes, it's WTJX, I forgot to put the call letters.

To my surprise I was able to to get that channel yesterday with my old Antennacraft D9000 , after 3 year with no sign of life! I remember rotating slowly the antenna and waiting for a signal but nothing happened.
I have some pixelation and sometimes is untunable.
At 210 ft. TvFool shows LOS and 30.6 (nm)db so probably I'm having a strong enought knife edge effect to work with.
I guess with a coax balun I will gain .9 dB and with the Hoverman probably 4 dB more!
My D9000 is even pointing down a little and the matching transformer is like 12 yr.

Here are some pictures:
WTJX log. http://i588.photobucket.com/albums/s...0/DSC01081.jpg
My Antennacraft D9000 http://i588.photobucket.com/albums/s...0/DSC01083.jpg
The mountain to the east http://i588.photobucket.com/albums/s...01085-Copy.jpg
That mountain looks higher on real life.

[300ohm]

My D9000 is even pointing down a little and the matching transformer is like 12 yr.

To get the refraction off the mountain, aim for the top of it by tilting up.
Looks like a 25 - 30 degree tilt up is needed.

[ReiMomo]

Well, I finished the Gray Hoverman but for some reason it can't get the channel
then I put up my old CM 4221 (for the first time in years) and a few more channels appeared! Then I thought I could test another antenna and edit my TVFool picture with MsPaint and write what I can get with each antenna, just for fun.
So here it is:
What I get with different antennas.
The Antennas Used:
Narrow Band Gray Hoverman
Channel Master CM4221
Silicon Scientific SNA-950TG

WMEI Log Picture
The same cable and matching transformer were used except for the Silicon Scientific which comes with its own cable and amplified.

The CM4221 was the most stable for WTJX!

Now the question is, was something wrong made with the Hoverman?
How does excatly that antenna works?
What makes it narrow band?
Are the elements too fat?
What happens if I put split reflectors?

GroundUrMast, I don't have any other place to go, unfortunately

[nikiml]

Originally Posted by ReiMomo

Now the question is, was something wrong made with the Hoverman?
Are the elements too fat?

How fat are they?

What happens if I put split reflectors?

Does this mean that they are not split at the moment?
Have not checked it but not splitting them would produce quite different antenna...

[ReiMomo]

They are 6 mm.
Yes they are split.

[ReiMomo]

Something that I never understood is the distance between the reflectors and the active elements of the GH. A while ago I was looking for GH pictures and niticed the reflector looks too close compared with mine, some plans say 100 mm but mine is around 245 mm

[nikiml]

but your model calls for 118mm, no?
are you using JED's model?

[ReiMomo]

Oh yeah I was using JED's model! 118 mm scale to 104.38 mm for 650 MHz, how the hell I ended up with 245?
Now it gets interesting

[ReiMomo]

OMG, I finished rebuilding the GH with the correct dimentions, look where that sucker got some watchable picture Here.
I even got WAPA (CH.27) indoor!
I don't know how to manage the height tilting on a fence pole mast yet but if I can tune WIRS (CH.41) then I can say I did not lost my time building this antenna.

[300ohm]

I don't know how to manage the height tilting on a fence pole mast yet

That's not too hard, theres a few ways to do it.
The easiest IMO is to ubolt the top of the GH to the mast, and make a spacer from plastic decking material for the bottom of the GH to connect to the mast.

[ReiMomo]

Man, it get WIRS with the signal meter around 50!
but the record is for WCCV (Ch. 46) that channel is at the bottom of the list,
I can tune it 24/7! it's funny how they are called The Miracle Network
That means I will be able to tune WTJX without problems when I got it later on my main mast around 24 ft.

It worth to construct this antenna, in the future I might do 2 GH8 and stack them.

Here is my updated TVFool click on WCCV to see its path.

WIRS log picture here
WCCV log picture here

That's not too hard, theres a few ways to do it. ...

Ok I was putting the GH through the tip of the mast, it looked unsafe, now I'm gonna use bolts!