Date: Sun, 14 Mar 2010 21:09:00 +0100
From: Magnus Danielson <mag...@rubidium.dyndns.org>
Subject: Re: [time-nuts] Choke Ring Pictures
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Message-ID: <4b9d425c.2050...@rubidium.dyndns.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Bob Camp wrote:
Hi
Wedding cake pans normally come in 1" increments and are either 2"
or 3" deep. Sets are 2" increments on the diameter:
http://cooksdream.com/store/wedding-round.html
http://www.hubert.com/store/products.asp?CAWELAID=126235277&A=SB%2E58369%2E10738&Dn=0&An=966+966&Au=Presentation+Id&Ntt=10738&N=966+966&src=chanadv&Ntx=mode+matchall&D=10738&Ntk=SKU
The height would be fairly easy to adjust. The diameter not so much so.
Looks like 2 and 2.5" are typical dimensions for the depth. ~1"
looks pretty typical for the width. A 2" deep / 2" diameter step
set looks like it would do a pretty good job . It won't be accurate
enough to be perfect. Without a 3D EM program it would be tough to
figure out just what the errors would do to you.
With 2.5" depth and 14", 12", 10", 8" and 6" diameter pans you are not
completely in a different world from some antennas:
http://facility.unavco.org/project_support/permanent/equipment/antennas/ant_cals.html
Evaluating the performance may be a different thing.
One thing to care about is the leakage between the pans if you just
stick them inside each other.
I'd be tempted to use EMI gaskets between the pans, except that
contact will soon be lost as the aluminum grows a nice oxide layer.
But it may not be necessary to make DC electrical contact, as the
capacitance between the metal layers may suffice to act as a short at
1.5 GHz. A thin sheet of mylar (or a heavy anodization layer)
between would help this along, by increasing the capacitance.
Joe Gwinn
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
