[time-nuts] Difference in GPS antennas
Bruce Griffiths
bruce.griffiths at xtra.co.nz
Sat Aug 15 03:13:26 UTC 2009
Hal Murray wrote:
>> My Panasonic VIC100 antenna had a few screws to hold the bottom to the
>> plastic cone top. The bottom had an o-ring seal that stuck a little
>> but was still pretty easy to slide the bottom from the top half.
>> Inside was a patch antenna on top of a pcb.
>>
>
> Thanks. I tried again and it came apart easily. There is an O-ring but no
> glue. (I wonder why I didn't get it the first try.)
>
> The antenna isn't a patch. (Or I don't recognize it as such.)
>
> It's a cylinder, 2 inches tall, 3/4 inch in dia, sticking up over a 2 inch
> square PCB that's screwed into an aluminum base place.
>
> It's made of flexible PCB material wrapped around to make a cylinder. The
> outside bottom 3/4 inch is a plane. There is an obvious solder joint line
> closing the plane. The inside top has 4 fingers spiraling around at 45
> degrees. The lower inside part (opposite the plane) has some wiggles in some
> traces, but I haven't figured out the equivalent circuit.
>
>
>
Thats a quadrifilar helix antenna.
bruce
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