[HCARC] Antenna Mast

[Kerry Sandstrom]

Gary,

I just looked at the article on masts in the new QST.  Two issues 
mentioned were the bending moment and ice on the antenna.  I don't think 
ice is much of a problem here in the central Texas Hill Country.  The 
two factors that determine bending moment are the antenna wind loading 
and the distance between where the antenna is mounted and the top tower 
bearing.  If the antenna is mounted within a foot of the top tower 
bearing there won't be very much bending moment.  I hope some of the 
others on the reflector will let you know what they have done.  At this 
point, you have several options to choose from.  I certainly would mount 
the antenna as close to the bearing as possible and not have to worry 
about bending moment.  If your tower is typical, you probably only need  
6 foot mast.  Close to a kilobuck for a mast seems outrageous to me!  
I'm glad you asked the question.

Have fun

Kerry

On 8/16/2014 4:35 PM, Gary J - N5BAA wrote:
> It's why I ask the questions - that and an article in the latest QST 
> about masts.  Paying in excess of $500.00 for a 22 foot piece of metal 
> tubing just sort of struck me as down right STUPID.  I guess there are 
> people who can afford that kind of money - I had trouble even thinking 
> of the $129.00 shipping to get it here from DX Engineering.  The mast 
> would have cost me as much as the whole tower did.  Didn't even think 
> about Texas sales tax too.
>
> Gary J
> N5BAA
>
> -----Original Message----- From: Kerry Sandstrom
> Sent: Saturday, August 16, 2014 1:44 PM
> To: Gary J - N5BAA ; HCARC Reflector
> Subject: Re: [HCARC] Antenna Mast
>
> Gary,
>
> I used a 10 foot section from an old 40' TV mast for several years with
> no problem.  It was the next to the bottom section so it was fairly
> large diameter.  About 6 feet was above the tower bearing.  I had a 4
> element 15 m Yagi just above the bearing, a 4 element 10 m Yagi about 3
> feet above the 15 m Yagi and a 5 element 6 m Yagi at the top.  I had it
> up for several years in San Antonio, TX with no problems.
>
> Forty years ago hams seemed to be more willing to take a chance than
> they are now.  Also, Yagis back then were considerably smaller than the
> current crop.  Now  everything seems to be a status symbol:  You have to
> have the "right" rig, "right" tower the "right" antenna, the "right"
> mast,  etc.  I believe this is all foolishness.  Things which are about
> the same size will perform about the same.
>
> For your particular situation,  The Cushcraft A4S is a small light
> antenna.  If you mount the antenna a foot above the bearing on the top
> of the tower, almost any mast should work fine.  If you want to have the
> antenna 15 feet above the top of the tower, then you probably need an
> exotic and expensive mast.  Ask your self how much that extra 15 feet is
> worth?  If its worth $550 plus shipping and taxes plus the difficulty of
> getting it and the tribander installed - Go for it.  If it were me, I'd
> mount it right above the tower bearing and save my money.
>
> Kerry
>
>
> On 8/16/2014 1:05 PM, Gary J - N5BAA wrote:
>> What do people use for antenna masts on crank up towers, etc.  My 
>> crank up tower will only have one antenna probably a Cushcraft A4S 
>> beam with possibly the 40 meter modification added.  It will go to a 
>> Yaesu 800DX rotator. Another fixed tower may have a 20-10 meter Hex 
>> Beam on it with a Hy-Gain Rotator with possibly a DIY 6 meter beam 
>> below it.
>>
>> All I see are Chrome-Moly masts from DX engineering in 22 foot 
>> lengths that are in excess of $550.00 delivered.  There has got to be 
>> a better source than that.
>>
>> Gary J
>> N5BAA
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