[time-nuts] Choke Ring Pictures
Brooke Clarke
brooke at pacific.net
Mon Mar 15 21:21:41 UTC 2010
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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