[time-nuts] Choke Ring Pictures

[Brian Kirby]

And the Andrew , Motorola and Pansonic have patches....

Brooke Clarke wrote:
> Hi Brian:
>
> The Lucent bullet antenna has a quad helix antenna structure, photos at:
> http://www.prc68.com/I/DAGR.shtml#Ant and scroll down,
> or maybe faster go to:
> http://www.prc68.com/I/DAGR.shtml#DC
> and scroll up.
>
> Have Fun,
>
> Brooke Clarke
> http://www.PRC68.com
>
>
> Brian Kirby wrote:
>> Dr. Clark passed on a tip that I used.  Put the funnel in a microwave 
>> oven and run it and see if the funnel warms up.  If it warms up, you 
>> do not use it.  I do not know what type of plastic the funnel was 
>> made out of; it was white, semi-transparent.
>>
>> There were also comments about surveying and timing antennas.  If you 
>> investigate about every national timing laboratory uses choke ring 
>> antennas.  Some enclose the antenna unit and they temperature control 
>> it.  They do this for timing stability reasons.
>>
>> The commercial timing antenna is bullet shaped and is operated 
>> without a ground plane.  They are patch antennas.  When there is not 
>> ground plane, the antenna picks up best from the overhead and less 
>> towards the horizon.  These antennas usually have a lot more gain 
>> (30-50 db vs most normal antennas in the 15-25 db range).
>> Also in surveying, we cut off the horizon at 15 degrees in software.  
>> A free Army Corp of Engineering manual on GPS Surveying is at 
>> http://140.194.76.129/publications/eng-manuals/em1110-1-1003/toc.htm
>> The main difference in surveying and timing is in surveying they use 
>> the carrier phase method, were in timing most use a solution derived 
>> from the processing of the coarse acquisition code, in were the 
>> receiver is in a fixed over-determined position .  Some timing labs 
>> are using carrier phase method, when they need more resolution.
>>
>> Brian - KD4FM
>>
>>
>>
>> Bob Camp wrote:
>>> Hi
>>>
>>> Any idea what the funnel was made out of? Some plastics aren't real 
>>> great at
>>> microwaves...
>>>
>>> Bob
>>>
>>> -
>>
>>
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>
>
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