[TowerTalk] Max antenna weight

[Jim Thomson]

Date: Sun, 1 Nov 2015 19:47:00 -0500 (EST)
From: "jcjacobsen at q.com" <jcjacobsen at q.com>
To: w8qwdave at casair.net
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Max antenna weight


Dave, 


Google and the MFJ/Hy-Gain site are your friends. Hy-Gain recommends the HDR-300, T2X, or the Ham IV for this antenna. 


>From the T2X manual: Max Effective moment is 3400. You get this from the sum of turning radius and weight, so 22' times 88 lbs equals 1936, so that's in limits. Antenna weight is 88 lbs, so that shouldn't be a problem, given the triple bearing race of the T2X. T2X rated at 20 sq ft of area....... 


In closing, I am neither an antenna Guru or an engineer, so you should only consider what is in print, the MANUFACTURES print as in the manuals.............. other wise, YMMV. OR you could spend the bucks and get a REAL engineer to run the numbers. 


Good luck with the project. 


K9WN Jake 

##  IMO, rating any rotor in max effective moment  and or  square feet...or max boom length is absurd.   What you want to know is max rotating torque in FOOT lbs...and max braking TQ, also in FOOT lbs, that’s it.
Any software will tell you asap how much rotating TQ  you will have on any given yagiS......and at any windspeed.  Knowing that, its easy to then size a given rotor for the job. Its also easy to properly torque compensate
the yagi, so it wont twist in a wind.  That alone will take a huge load off the rotor...whether you are trying to turn it in a wind, or hold it steady in a wind.   There really is no excuse these days to produce yagis that are not
tq compensated.   Either a  software designed plate is installed at the short end of the boom...just in front of the REF..... OR.... you instead mount the yagi at the dead center of the boom, then install a counterweight at the lighter end of the boom, IE;  DIR end. 

Jim   VE7RF