Nails versus dielectric fasteners has been debated for years now and I don't
think anyone has come up with a definitive rule. I know of two facilities that
use nails for their shelters without ill effects (there are probably more);
other folks prefer all-dielectric material. Whether you can get away with
metal fasteners probably depends on how many you have, and how long they are
compared with the shortest wavelength you need to measure. In other words,
what do they really DO to the RF field you need to keep undisturbed? THAT is
the thing to watch out for.
My opinion, natch, and not my employers'.
Cortland
______________________________ Reply Separator _________________________________
Subject: Re: O.A.T.S. enclosure
Author: Gabriel Roy/HNS <gabriel_...@notesgw.hns.com> at internet
List-Post: emc-pstc@listserv.ieee.org
Date: 10/3/96 14:42
All the ones I have seen have used plastic bolts instead of metal nails, also
the antenna mast was always located outdoors, outside the building (except for
the ICL site which is underground in the UK).
Gabriel Roy
Hughes Network Systems
MD
To: JTOLBERT @ genicom.com @ SMTPGW; emc-pstc @ ieee.org @ SMTPGW
cc:
From: wfranklin @ bb-elec.com ("Bill Franklin JR") @ SMTPGW
List-Post: emc-pstc@listserv.ieee.org
Date: 10/03/96 01:26:27 PM
Subject: Re: O.A.T.S. enclosure
SMTP Headers: Headers
Hello,
We built a 3 Meter site a few years back - maybe some of our
experiences will help. We built it using all wood framing with nails
no bigger than 16 penny (about 2" to 2 1/4"). We have two windows
with plastic frames (to let in some light), a ridge vent that is made of
cardboard (for ventilation), and a ridge pole that is made of plywood.
The outer surface is plastic house siding. We used asphalt roof shingles.
The thing looks like a ski slope with the peak at the maximum
for the adjustable antenna. We had no problem staying within the
4 dB limits. We have passed every year so moisture must not be too
much of a problem.
We have a different problem in that the water table is very high here
and we couldn't put a basement under our site, so we built up. Our
ground plane is eight feet off the ground. It works fine for a 3
Meter site but there is no way to move outside and use it as a 10
Meter site. That also makes the building very very tall.
Bill Franklin wfrank...@bb-elec.com
>
> Winter is coming and Hurricane Fran took my fabric-type Air Support
> structure with him leaving my 10 meter "all-weather" Open Air Test Site as a
> "fair-weather" site. :>(
>
> How about passing on your experiences regarding problems with any particular
> types of PERMANENT building schemes to enclose RFI test sites. What (other
> than the obvious conductive types) materials will erode my site attenuation?
> Will I have to be concerned about things such as moisture content of the
> framing?
>
> What types of designs yield a robust structure, yet allow for the 6 meter
> high antenna clearance so the antenna can be moved from the 1m position to
> the 10m position without dropping the mast?
>
> Thanks
>
> Joe
> Joe Tolbert
> GENICOM Corp.
> Waynesboro, VA
> jtolb...@genicom.com
>
>
