[time-nuts] Troubleshooting an HP 58503A
jimlux at earthlink.net
Sun Oct 14 19:07:27 EDT 2018
On 10/14/18 3:03 PM, Matthew D'Asaro wrote:
> All -
> Thanks again for all the suggestions and advice I have gotten on
> this project. It ran all night without loosing lock, so I am calling it
> fixed. There is just one more order of business before I can use it, and
> that is some way of "mounting" the GPS antenna on the roof in a
> non-destructive manner, both to avoid damaging the (flat membrane) roof
> and so that I can move it if necessary. See the attached photo of what I
> have come up with. All the parts (minus the cable and antenna) came from
> Home Depot.
> The concrete block is a generic 1 sqft paver stone which cost all
> of $1.18. This is to provide a heavy base and avoid tipping. Attached to
> that is an upside-down PVC toilet flange from the plumbing section. It
> is attached with 6x stainless steel machine screws and wing-nuts that
> pass all the way through the paver and are counter-sunk on the bottom so
> that the heads won't damage the roof. Nylon spacers separate the toilet
> flange and paver block by about 1/4 inch so that water can drain if
> needed and to provide a space for the coax feed line to come out.
> Pressed into the top of the paver is a 3" to 2" reducing adapter and
> pressed into that is a 2" to 1-1/4" reducing adapter. The mast itself is
> just a 2-foot section of 1-1/4" PVC pipe. The 58532A antenna is
> apparently designed to mount over a 1-1/4" mast since its inner diameter
> is 43mm and the outside of a 1-1/4" pipe is 42mm.
Standard "non-penetrating" roof mounts use this technique - they have a
frame which you ballast, by bricks, pavers, or sacks of gravel.
After that it's more a matter of figuring out how to do the mechanical
structure - sandbags and plumbing fittings are a fine way to cobble
something to together.
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