[eldgreen]

Where would I find the latest instructions for building a Gray Hoverman ( or any other high gain flat screen antenna)that would be best for channels 28 to 45? Thank you.

 

[300ohm]

No vhf-hi needed ? Most GHs excel in that channel range.

JEDs single bay GH10 here : http://www.jedsoft.org/fun/antennas/dtv/gh.html

Or for a bit more gain in a double bay you could build the modified DBGH original in mesh, tips and plans here : http://www.digitalhome.ca/forum/showthread.php?t=95898

If you have strong signals on channels 42 - 45, then maybe the GH10 rev0 curved mesh build would be for you, I also have step by step plans for it.

 

[Dalek Prime]

His signals are weak on those channels.

 

[eldgreen]

Hello 300 ohm. Its good to talk with you again. How does the GH compare to the old style 4228? We discussed before about making a single channel high gain antenna for channel 45.But now the wife says she would like to get channel 28 also. At 130 miles it realistic to make a GH for my attempt to get these channels or should I just stick with making a yagi for channel 45? Thanks again for taking time with me again. I didn't realize you were the resident guru on GH antennas.

 

[300ohm]

Yeah, and he also needs channel 9.

eldgreen, dont switch threads on us, we get confused, heh.

Build nikiml GH10n3 here : http://clients.teksavvy.com/~nickm/gh_n3_uV/gh10n3_9V7_15u0.html

 

[300ohm]

At 130 miles it realistic to make a GH for my attempt to get these channels or should I just stick with making a yagi for channel 45?

Either way, the odds are slim to none for consistant reception. After Line of Sight (LOS) which is basically around 70 (outside 80) miles, there has to be some kind of a rare geologic abnormality to get uhf signals well consistantly. Tropo reception isnt consistant. And IMO, a broad side type antenna, like a GH or bowtie , is better for tropo reception than a yagi or LPDA type. Lower VHF frequency signals will bend somewhat to the curvature of the Earth, and AM radio signals, which are very low frequency, really hug the Earth for great distances.

How does the GH compare to the old style 4228?

Even the original DBGH gen1 beats the pants off it for the range your talking about, heh. Building the original DBGH with a mesh reflector frame is even simpler and gives even more gain. But for obvious reasons, NARODs cant be used with a mesh reflector frame.

 

[eldgreen]

Man ya'll are fast. I'm sorry for changing horses in the middle of a stream. I'm still learning.But don't hesitate to get on to me. I'm going to play with my new found hobby and if I have any problems now I know to just continue on with this thread. When I talked about making a single channel antenna, I was thinking about using it with a broadband antenna and using an
a-b switch at the tv.Again ya'll are great.

 

[300ohm]

Man ya'll are fast. I'm sorry for changing horses in the middle of a stream.

In the words of Monty Pyhtons Flying Circus, you dont want to change threads, unless its "Now, its time for something completely different", heh.

“Nudge, nudge, wink, wink. Know what I mean?”

Yeah, choosing an antenna from all the plans here can be confusing. Basically, most of the time you have to weigh gain vs beamwidth or even weird lobes. And IMO, theres plenty of room to come up designs that have very odd lobe patterns, but useful to a select few. Of course they should be separated in something like Area 51.

 

[eldgreen]

I've noticed that simply moving the balun around can have a noticable effect on the signal (on the 4228). Would I get a better more stable result by building one out of coax? If so please tell me where I can find simple clear instructions on how to build one.

 

[300ohm]

A coax balun is a cost effective method to eliminate feeder radiation, but is limited to a narrow set of operating frequencies.

* One easy way to make a balun is a (λ/2) length of coaxial cable. The inner core of the cable is linked at each end to one of the balanced connections for a feeder or dipole. One of these terminals should be connected to the inner core of the coaxial feeder. All three braids should be connected together. This then forms a 4:1 balun which works correctly at only a narrow band of frequencies.

http://en.wikipedia.org/wiki/Dipole_antenna

 

[eldgreen]

Its me again. What difference does it make whether the director elements on a yagi are insulated or not? And would it work to space the elements an inch off of the boom?

 

[Dalek Prime]

Its me again. What difference does it make whether the director elements on a yagi are insulated or not? And would it work to space the elements an inch off of the boom?

If they are not insulated, they cease to act as directors, and the entire structure becomes an untuned, unpredictable hunk of metal. And to space them off the boom? Why? You still have to line them up with the active element, and to hold them in place with an insulator. Really, just keep it simple.

 

[mclapp]

They still act as directors just have to do a correction for the element length because the mounting point makes the element look fat in that spot.

The yagi calculators on the web usually have a place to do that correction.

 

[Dalek Prime]

Not if the active element isn't behind them being fed. But you're talking about horizontal spacing from the boom, and not vertical, which he didn't specify. I still don't see the value in it, though. And I certainly don't see the value in having them uninsulated. They are all active then, feeding the boom, if the boom itself is conductive.

 

[eldgreen]

Let me explain it more fully. A plastic electric fence insulator will hold a 1\4 inch element exactly (or at least the ones I have will). The distance then from the element to the mounting base will be approximately 1 inch. If I use a wire hose clamp or a zip tie to hold the insulator to the boom I would be able to adjust the location of the elements back and forth on the boom making experimenting easier. It should also be easy to mount the driven element in line with the directors it also being insulated.I intend to make the corner reflector in line with all the other elements and fix it so it can be slid back and forth on the boom for experimenting. I hope that I have clarified what I am thinking about. As you can clearly see the title of "Rookie" under my name is accurate.

 

[mclapp]

Not if the active element isn't behind them being fed

If there is no active element then whats the point???

But you're talking about horizontal spacing from the boom, and not vertical, which he didn't specify.

Assuming he's talking about a yagi for TV I would assume a horizontal running boom (horizontal to the ground)and he was asking about spacing the elements above or below the boom. The answer to that would be no difference in performance as long as the proper correction factor were applied to the length of the elements for each situation (isolated from the metal boom or attached to the boom).

I still don't see the value in it, though. And I certainly don't see the value in having them uninsulated.

It's much easier to build if you don't have to mess around insulating all the elements from the boom and it works just fine if you do the correction factor. Many, many, many, consumer TV Yagis are built that way

They are all active then, feeding the boom, if the boom itself is conductive.

The boom doesnt carry any current if the elements are attached at thier low voltage point (which is the center of a properly sized yagi director, reflector element) The TV / Radio waves only see the properly sized directors, reflector and driven elements which is where the current flow is happening. Antennas using phase lines like stacked dipoles need to be insulated at the phase line connection but could actually be attached to a metal boom or mount at thier low voltage points and work just fine as well.

It really does work honest, I wouldn't kid about a thing like that.

Eldgreen, If you use the insulators no correction needed as long as there is no metal to metal contact between the boom and the elements.

Sorry for going off topic

 

[Dalek Prime]

If there is no active element then whats the point???

The active element needn't be situated inline on a yagi?

Yes, preferably the boom itself is an insulator. But if, as you say, the directors do not carry current to the boom, than I have learned something new. ie. The boom can be metal, and the directors can sit on it. Is that correct?

I understand that there is no need to correct the lengths if they are merely above or below the boom, but if each half of the director were held in place to the sides by the clamp, further out, there's no need to adjust for each quarter length?

I'm learning the nuances myself, and there seems to be more of them on a yagi than I previously believed. More so than even a LPDA, which I'm more familiar with. Time to hit the books again for me.

My apologies to eldgreen for any trouble I've caused. Not purposeful. I'll keep my thoughts to myself until I know better.

Cheers.

 

[eldgreen]

Dalek Prime , there certainly is no reason for you to apologies to me of all people. mclapp thank you for your input. I've noticed on the computer programs that the boom diameter gets smaller according to higher frequency and boom length. Would this factor also apply with the directors spaced off of the boom as I described in the last post? In other words could I use a larger diameter boom, say 2 inch aluminum? Also if all of the other elements are insulated from the boom, should the corner reflector be too?

 

[300ohm]

There are some commercial yagis that have even the driven element connected to the boom.

http://www.digitalhome.ca/forum/showthread.php?t=107706&highlight=mystery+antenna&page=21

Also if all of the other elements are insulated from the boom, should the corner reflector be too?

On all the commercial corner reflectors I have, the corner reflector is connected to the boom.

 

[mclapp]

I think the change in size of the boom is more for mechanical reasons not as much strength is neede for smaller elements and further out on the ends.

If you add metal either by attaching a clamp or by attaching an element to the boom then it makes the element larger in that spot which means you will have to compensate for the length (make it shorter). Keep in mind that you can't attach the elements to the metal boom just anywhere it has to be at the low voltage point which in this case is in the middle.

Also to make it clear the elements don't carry current to the boom at the design frequencies but will away from the design frequencies.

I don't mean to come on and sound like a jerk or a know it all (I had to go research this stuff in books and on the net just like anyone else) just wanted to clear up the insulated boom thing.