[TowerTalk] Wired Anemometer for Tower?

Fri May 2 00:26:59 EDT 2014

On 4/30/2014 7:40 PM, Bill Parry wrote:
> I think that anemometers are an interesting topic but it appears this one
> has been beat to death and I'm not sure why this is even a topic for TT. Is
> it because it is attached to a ham radio tower?  If so maybe we need to
> discuss the "ins and outs" of the flag I hang on my tower on 4th of July.
> (Incidentally I have an anemometer on my tower too.)
>
> I haven't gotten any raunchy pictures yet from TT but this will be my test.

Lotsa reasons, Just weather, wind for your area, storm chasers, just cuz 
we can, calculate the stress on the tower for the antennas you have.  'd 
like to know how much reserve I have. Wind took down tree to the East of 
me...just curious (and happy) I didn't lose anything)

Claim you're rich! It might help...maybe?

Good Luck...and you ain't missed much

73

Roger (K8RI)

> Bill W5VX
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of GARY
> HUBER
> Sent: Wednesday, April 30, 2014 5:17 PM
> To: k1ttt at arrl.net; TT TowerTalk
> Subject: Re: [TowerTalk] Wired Anemometer for Tower?
>
> The fans at
> http://en.wikipedia.org/wiki/File:Twin_Groves_Wind_Farm_DSC03252.JPG --- 85
> foot blades on 270 foot tower.
>
> -----Original Message-----
> From: GARY HUBER
> Sent: Wednesday, April 30, 2014 12:54 PM
> To: k1ttt at arrl.net ; TT TowerTalk
> Subject: Re: [TowerTalk] Wired Anemometer for Tower?
>
> I really have a problem with the big fans, several hundred locally, that
> blow almost constantly around EN50nj. (tongue firmly in cheek)
>
> 73 & DX,
> Gary - AB9M
> -----Original Message-----
> From: David Robbins
> Sent: Wednesday, April 30, 2014 7:11 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Wired Anemometer for Tower?
>
> and accuracy compared to what, and over what period??  wind speed is HIGHLY
> variable over small distances and elevation change.  There are
> specifications for measuring wind that require so much open area, a specific
> height above terrain(much lower than you would think), distance from
> buildings, etc... basically measuring wind speed on a tower is only
> interesting for you and your antennas, no one else would have any use for
> it.  take a look at my station's quality control charts...
> http://weather.gladstonefamily.net/qchart/AR841?date=20140428  you will see
> that normally things like temperature and barometric pressure track the
> expected values pretty well... but my wind speed, when I just looked at
> yesterday's values, were off by a factor of about 10 (my reading is higher!)
> from the expected values.  this is because my anemometer is 50' up and not
> far enough from the house, and my house is almost 1000' above the nearest
> airports or nws offices.  and yet when measuring gusts usi ng skywarn tree
> motion estimates or a handheld pith ball pressure gauge it usually reads low
> by a factor of 2 (a gust estimated at 50-60mph only reads 25-30mph on the
> anemometer).  part of that is the response time, but most is probably the
> averaging over 3 to 5 seconds that I think the davis uses.  I tried at one
> time to look up the specs for reading gusts, it gets very confusing even on
> the noaa web site, there are at least 3 different specs (that I found) for
> different instruments that use 3, 5, or 8 second gust averaging.  If you
> really want an eye opener about wind and height above ground come up my 180'
> tower some day, it can be dead calm on the ground, and even at the 50'
> elevation of the anemometer, but still have a nice 5-10mph breeze at the
> top... nice for me, but tough for the ground crew fighting black flies,
> mosquitoes, and deer flies.
>
>
> Apr 30, 2014 07:40:14 AM, K8RI-on-TowerTalk at tm.net wrote:
>
> On 4/29/2014 9:59 PM, Jim Lux wrote:
>> On 4/29/14, 5:08 PM, Al Kozakiewicz wrote:
>>> I'm not going to belabor the point. Wind speed is derived by
>>> measuring the change in rotational position divided by time. The
>>> shorter the sampling interval (time), the lower the measurement
>>> accuracy. There is no reason for this to controversial.
>>>
> Just count the pulses, and divide by time. Plastic anometers have very
> little rotational mass.
>
> With out getting fancy you can easily get better than 1 mph accuracy.
>
> To me, more than every three seconds is wasted energy/effort/money/time as
> is all the effort expended to measure errors that are meaningless unless you
> want lab accuracy for a study. Then calibration becomes a major portion of
> the effort. Then you need standards traceable to the NBS and someone
> certified to do it. Been there and done that, but not with anemometers.
>
> 73
>
> Roger (K8RI)
>
>
>
>
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