Another consideration when using a sidemount with a large
antenna vs. a TIC ring is the large moment arm create by an offset
wind load. WIth a TIC ring and Rohn 45, the boom is offset from
thetower's center by about 10-12 inches. In the case of a side
mount, it can be several feet. This can create large twisting
moments around the tower. Perhaps one of our helpful PEs can
comment further. I'm at the limit of what I remember from my
25 year old college engineering.
Barry
On 15 Mar 01, WD4K wrote:
> Ok, now "I" am curious. When you said that you sold a couple of sidemounts
> to a guy who was going to mount C49XR's, I asked privately what kind of
> tower. You replied 90' of Rohn 45. Now-The C49XR has 40" of clearance
> between the elements and your last post says that your mount requires 56.5
> for Rohn 45. Looks like the C49 will not rotate using that sidemount. Am I
> missing something here? The reason I asked is I now have two C31's and am
> nearing a C49 purchase and am legitimately looking for info.
> NOTE! PS. For Jay and all, I use Jays products and have the highest regard
> for him and his products and am in the process of buying more!!-this is just
> a question of sidemount applications and design among friends---nothing
> more. Tommy
>
> -----Original Message-----
> From: JayTerleski [mailto:jterleski@home.com]
> Sent: Thursday, March 15, 2001 11:55 AM
> To: TOWERTALK@contesting.com
> Cc: WD4K@bellsouth.net; K7LXC@aol.com; w2up@mindspring.com
> Subject: Re: [TowerTalk] TicRing vs. Side Mount
>
>
> Tom and TTers,
>
> The Array Solutions Side mount reviewed in QST is one of those that can
> turn a large beam.
> I know it will turn a C31XR "Stretch", and other large tri-banders. But
> we need to have 44 inches of clearance for 25G and 56.5 for 45G towers.
> That is why I suggest the stretch version. One thing that is important
> to us was including wide saddles with the U-bolts to make sure the load
> was not going to crush a tower leg by an over-zealous tightening of the
> U-bolts.
>
> It will not have any problems turning the weight of a C31XR, indeed it
> includes a Delrin bearing block to make this a smooth operation.
>
> The issue is the breaking force of the rotor to handle the load in the
> wind. I would not use a small rotor.
>
> We do warrant our products to work, and I will give a full refund if the
> side mount doesn't turn your beam safely.
>
> Jay, WX0B
>
>
>
>
>
>
> WD4K wrote:
> >
> > Well, after going through this and solving the problems I can tell you
> this.
> > The weight, design (open area), and rotatability (balance, windload etc)
> of
> > the antenna itself have more to do with the decision than cost. I looked
> at
> > commercially advertised mounts and decided to build my own. I found no
> > sidemount that would turn a C31XR. Some were OK for monobanders, 2M, 6M
> etc
> > but I also saw design flaws in some that make it downright dangerous. I
> had
> > folks tell me that theirs would work, but when asked point blank if they
> had
> > done it or seen it work, the answers were either "no" or vague. They will
> > tell you why it SHOULD work--not that it does.
> > I would suggest the following as food for thought from my experience::
> > If your antenna has less than 40" open area, weighs more than 75 lbs, you
> > cannot build your own, and if the maker of the sidemount cannot absolutely
> > GUARANTEE that it will work (backed with free return shipping etc.) --go
> > with the TIC. If I did not have the ability to do my own- I would use the
> > TIC. My lower C31 has been up for a year, through 60+MPH winds,numerous
> > contests, rotates 300 degrees, all with no problems so it can be done.
> > You will also notice that most ads for sidemounts show monobanders--not
> > tribanders. That should tell you something. There is a BIG difference
> > between a 30# monobander and a 100# (+ -) tribander. Sidemounts with big
> > tribanders are a different animal. As LXC says, there are places for
> > both--BUT--Do your homework FIRST. Been there-done that:) Tommy WD4K
> >
> > -----Original Message-----
> > From: owner-towertalk@contesting.com
> > [mailto:owner-towertalk@contesting.com]On Behalf Of K7LXC@aol.com
> > Sent: Wednesday, March 14, 2001 7:36 AM
> > To: rmidgett@bellsouth.net; w2up@mindspring.com;
> > TOWERTALK@contesting.com
> > Subject: Re: [TowerTalk] TicRing vs. Side Mount
> >
> > In a message dated 3/13/01 8:00:02 PM Pacific Standard Time,
> > rmidgett@bellsouth.net writes:
> >
> > > That depends (doesn't most things?) on the rotor investment. For
> instance,
> > > a Ham IV can be had at a hamfest for <$300 with controller, or from
> Rotor
> > > Doctor for $375.00. IDC Technology offers the Sidewinder for Rohn 25G
> at
> > > $250.00, an investment of $550 - $575, which is much less than a new
> TIC
> > &
> > > its bag of headaches. If 360 degree rotation isn't absolutely required,
> > the
> > > side mount wins my vote.
> >
> > I agree. By the time you factor in the time involved to install either
> > of
> > them (the sidemount is simple, the TIC takes more time and screwing
> around)
> > and the apparent greater reliability of the Ham IV, I'd go for the
> sidemount
> > anyday. Providing of course that the antenna is capable of turning around
> > the
> > tower, which is the problem which makes people purchase the TIC in the
> first
> > place. They both have their place.
> >
> > Cheers, Steve K7LXC
> > Tower Tech
> >
> > --
> > FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > Submissions: towertalk@contesting.com
> > Administrative requests: towertalk-REQUEST@contesting.com
> > Problems: owner-towertalk@contesting.com
> >
> > --
> > FAQ on WWW: http://www.contesting.com/FAQ/towertalk
> > Submissions: towertalk@contesting.com
> > Administrative requests: towertalk-REQUEST@contesting.com
> > Problems: owner-towertalk@contesting.com
>
> --
> Jay Terleski
> WX0B - Array Solutions
> Phased Arrays - Horizontal and Vertical
> RF Switches, Antennas, Towers
> www.arraysolutions.com
>
--
Barry Kutner, W2UP Internet: w2up@mindspring.com
Newtown, PA FRC alternate: barry@w2up.wells.com
--
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
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