Norm Replying to your post is difficult. There may be others on this forum who can reply more effectively than I can but let me pass on some thoughts. First of all the Rohn guyed tower specification
Yes Jim and I wish I could get my aerodynamics students to see it beyond that level of simplicity. Indeed the coefficient of drag will increase rapidly when there is boundary layer separation, which
Jim The non-linear character of the numbers you have chosen are characteristics of the so-called "drag bucket." Note in the description of the calculator that the author has used a parabolic algorith
I guess I see it partly the same and partly differently Jim. Risk analysis incorporates more than just the person building the tower, which is why the manufacturers specify the limits of their design
Those things are great for field day ops Gene. You can hang a couple of slabs of ribs in the field and have a great barbeque . The "ether" in the atmosphere helps to tenderize the meat and sets the s
Hi Guys Can you explain the "right triangle." My understanding is that the three are in an equilateral triangle (60 degrees between each antenna). Bill W7VP __________________________________________
Another source for phased vertical information is in a Telex-HyGain Engineering report entitled "Phased Multi-Band Verticals for Additional Gain and Low Angle Radiation." The report is undated but co
Don: What you are describing sounds like simply two 2-antenna systems placed 90 degrees to each other where on of the antennas is common to both. I conclude that from your statement that there are 4
Which design are you referring to Tor? Bill W7VP -- Original Message -- From: <rt_clay@bellsouth.net> To: <towertalk@contesting.com> Sent: Wednesday, April 05, 2006 11:30 AM Subject: Re: [TowerTalk]
Tor N4OGW Stated "Also note that the phasing for the cardioid array shown in that report is incorrect. You can't just add a "delay" line of 1/4 wavelength to get 90 degree phasing." and "Two vertical
For only 200# Try this. Bolt a muffler clamp a few inches from the rotator. Then hook one end of a loading strap (the kind with the ratchets) to a tower rung a couple feet above the clamp and wrap th
Jim Nice explanation Feedpoint matching is a big problem for most of us amateur designers. I have had a big 20 meter yagi for more than 30 years. It came as a Bill Orr type design with 4 elements equ
Gary I have not tried to measure it and so far I have only anecdotal experience. It will take time to see the true difference. Nevertheless the difference in a mid level signal is very noticeable aur
Roger It is true that the tower acts as a torsion bar in the high rotor configuration. The extent that the tower deflects and acts as a damper (what is the source of the damping?) will depend on the
My RC5-3 just quit indicating but the preset knob still turns the beam to the correct position. Any thoughts? Bill W7VP _______________________________________________ _______________________________
The formula is sigma (stress in lb/sq.in) = m ( moment) times c (distance from centroid) divided by I (area moment of intertia). The moment is 10500 in-lbs. The distance from the centroid is 1 inch a
Gene I am not sure what you mean by a "moment force." There is both a moment and a force involved. The force is the combination of all the arrays with the wind load calculated. It is applied at the t
You are very right JC, although they are probably more damned if they don't. As a manufacturer they are subject to court developed law called "manufacturer's strict liability." Under that law they ar
Right on Jim! Note that the disclaimer of warranties is not valid against a tort claim. It is intended to avoid liability under contract theory for violation of the promises made relating to the prod
I guess that is because I am an engineer too, Jim :-) 73 Bill W7VP -- Original Message -- From: "Jim Lux" <jimlux@earthlink.net> To: "Bill" <w7vp@comcast.net>; <wc1m@msn.com>; "'JC Smith'" <jc-smith@