[time-nuts] frying pan antenna

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Mar 16 03:41:16 UTC 2010


Microwave absorption of ice is also low as is that of beeswax, rosin and 
pitch.
I use a conventional hotplate for melting the latter 3.

Bruce

Bruce Griffiths wrote:
> Below 600C the only significant source of microwave absorption in wood 
> is the water content:
> http://pubs.acs.org/doi/abs/10.1021/ie901336k
>
> Bitumen has very low microwave loss so if the asphalt doesnt have any 
> taconite in it its loss should be low.
> http://www.nrri.umn.edu/egg/REPORTS/TR200419/CTS0510.pdf
>
> You could always try the microwave oven test with some samples.
>
> One thing to consider is the reflection loss from the roof due to its 
> non unity dielectric constant.
>
>
> Bruce
>
> Mike Naruta AA8K wrote:
>>
>> True Bruce.  Alas, those trees to the West are matched by
>> trees to the East.  Power lines run in front of the house
>> to the South.  And the towers, guy wires, and wire antennae
>> are to the North in the back yard.  It's like looking up
>> a funnel to see the satellites.
>>
>> I have another Motorola patch under the roof that also works.
>> What is the dielectric of wood sheathing and asphalt shingles?
>> I may try the cake pans on the inside one; not much snow
>> inside the attic.  :)
>>
>>
>> Mike - AA8K
>>
>>
>> Bruce Griffiths wrote:
>>> A pity that the GPS receiver elevation mask can't generally be made 
>>> to be azimuth dependent.
>>> You could then have a higher elevation limit in the direction of 
>>> those trees.
>>>
>>> However, it is possible in principle with an M12+T, M12M T or 
>>> similar timing receiver which provides the relative timing 
>>> contribution of each SV to the solution, to back out the 
>>> contribution of a given SV and compute the corresponding timing 
>>> correction for software correction of the PPS pulse timing.
>>>
>>> Bruce
>>>
>>
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>
>
>
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