[TowerTalk] Fwd: Strange etc

[Patrick Greenlee]

A gyro compass is only as accurate as its initialization.  So what 
standard do you propose we use to initialize the gyrocompass?

Except for the really dumb mistake of saying longest when shortest was 
correct word (????) the method I mentioned works very well.  No accurate 
time keeping required.  You just mark the location of the end of the 
tower's (or fence post or stick in the ground or whatever's) shadow 
several  times during the day and connect the dots in a smooth curve.  
The apex of the curve is when the shadow points true north.  Short 
shadow in summer, hard to tell where it points?  No problem, the curve 
is symmetrical so you can just bisect the curve and there you have true 
north through the tower's center (or your stick or...) You don't need to 
record any data or note the time when you mark the location of the end 
of the shadow.

Works in any season.  No  arithmetic involved.  Free.  Takes several 
hours to get the result but you are only actively involved for a couple 
minutes every once in a while, say 1 hour intervals. Continental drift 
may introduce error within several centuries.

Patrick        NJ5G



On 1/27/2017 10:33 AM, Herbert Schoenbohm wrote:
> This  large sundial (Point Udall) is just down the road from my house 
> and is the Easternmost point of the U.S. in North America. 
> http://www.atlasobscura.com/places/point-udall
>
>
> On 1/27/2017 11:14 AM, Hans Hammarquist via TowerTalk wrote:
>>   I like that method. Will try it.
>>
>> I have one problem though, you will have the time for the solar noon 
>> at that day but you will only know it after the day is over. As the 
>> solar noon changes a little every day you don't know what it is the 
>> next day. You might be off by several part of one degree. :-) Just 
>> kidding!
>>
>> I think your method is way good enough for most if not all our 
>> purposes. If you need it better you have to get a gyro compass. That 
>> will show the true north, but how picky do you want to be?
>>
>> 73 de,
>>
>> Hans - N2JFS
>>
>>
>>
>> -----Original Message-----
>> From: Ed Karl <edk0kl at centurytel.net>
>> To: towertalk <towertalk at contesting.com>
>> Sent: Thu, Jan 26, 2017 9:40 pm
>> Subject: [TowerTalk] Strange etc
>>
>> A. The time between local sunrise and sunset is solar noon, in North
>> America is in the middle.
>>
>> Therefore any shadow point to True North.
>>
>> B. With most HF antenna having 3db points for the forward lobe having
>> the smallest angle of 30 degrees
>>
>> why are we picking nits over finding magnetic north away from buildings
>> and the deviation that day to
>>
>> compute True North to get 1 degree accuracy?
>>
>> To me on a circuit to ZS or G, it's "good enough" with the old sundial
>> method from here in Missouri.
>>
>> Or what am I missing?.
>>
>> 73!
>>
>> ed K0KL
>>
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