Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: RF Shielding Posted: Sat Mar 17, 2007 12:14 am
Joined: Tue Feb 27, 2007 6:16 am
Hello. Can anyone direct me to a manufacturer of RF shields
that will supply free samples?
Lastly, can anyone direct me to where I can find some literature on RF
shielding? Im particularly interested in learning whats the best practice, i.e can I shield my reference
oscillator and PLL together or will one intefer with the other.... how I can avoid the need to provide shielding?
Post subject: Posted: Fri Mar 23, 2007 6:59 pm
Joined: Mon Jun 27, 2005 2:02 pm
You can find many manufacturers by
running a Google Search.
Here is an example to one:
You can't avoid
shielding if you design Oscillators and other frequency sources. Usually the reference oscillator and the PLL
should be placed as close as possible to each other. If you have forward and reverse links on the same PCB then
you should shield each of them to avoid coupling between the two which can produce feedback and lead to
The purpose of shielding is to prevent radiation from propogating and to prevent coupling
between adjacent frequencies.
Post subject: Posted: Mon Mar 26, 2007 5:38 am
Joined: Fri Feb 17, 2006 12:07 pm
Location: London UK
Engineering Director of a well-known company for which I once worked (as a very young green-horn) often maintained
that "the cheapest development equipment is a hacksaw", by which he meant "cut the lid off someone else's box and
learn from what you see inside". Whilst I would not dream of advocating plagiarism, or still less, copyright
infringement, you could learn more about screening by looking into existing products that use PLL-VCO circuits
than by reading up the theory.
Screening theory is notoriously difficult from which to formulate strict rules.
Even simple analytical situations of say a cylinder of metal enclosing an oscillator requires several types of
Bessel Functions to derive the leakage field outside the can. Oisch, my brain hurts already, thinking of the pages
full of math.