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.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?
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.How does the GH compare to the old style 4228?
In the words of Monty Pyhtons Flying Circus, you dont want to change threads, unless its "Now, its time for something completely different", heh.Man ya'll are fast. I'm sorry for changing horses in the middle of a stream.
http://en.wikipedia.org/wiki/Dipole_antennaA 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.
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.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 there is no active element then whats the point???Not if the active element isn't behind them being fed
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).But you're talking about horizontal spacing from the boom, and not vertical, which he didn't specify.
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 wayI still don't see the value in it, though. And I certainly don't see the value in having them uninsulated.
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.They are all active then, feeding the boom, if the boom itself is conductive.
The active element needn't be situated inline on a yagi?If there is no active element then whats the point???
On all the commercial corner reflectors I have, the corner reflector is connected to the boom.Also if all of the other elements are insulated from the boom, should the corner reflector be too?