-> wonder if someone could expand upon that premise...flames aside.
You'll get no flames from me....  Reasonable questions are always met
with reasonable answers given the opportunity. Rebuttal toward
technocratical condemnation is what triggers my flamethrower.
-> I am temporarily utilizing an old(metal)IBM Brand XT type chassis
-> case to hold my AT MB. It has a 230W PS, and works fine except that
-> it has limited space for two floppy or CDROM drive/floppy. The main
-> problem I have is the high RF disruption of the Television
-> screen...(15 feet away).
Ah Hah!  An obviously FCC approved case and you _still_ have RFI
problems!  (Hardly surprising since the case itself has little to do
with the radiation of the RFI, but then that's not _your_ fault.)
->      1) what is the cause of this RF? Is it the power supply?? Is it
Nope!  Although the power supply definitely DOES generate spurious
harmonics they aren't high frequency ones, (at least not up into the low
band VHF-TV spectrum where I expect you're getting the interfereance.)
->      Is it the metal case?? Is their anything that can be done?
Nor is it the "case" that's causing it.  (The true cause is the
radiation of harmonics of the system clock from the cables
interconnecting the various components, [drives, monitor, keyboard, etc]
exiting the case.)  Curing it means eliminating such sources of
radiation.
->      My plastic case didn't have as severe a problem but
->      nonethe less has some deletorious effect.
Probably, its overal ground/shield integrity was somewhat better even
though parts of it were plastic. (The _overall_ system having probably
been FCC approved, which simply means that if it is to be SOLD as an
integrated system it must meet certain vague EMI radiation standards.)
->      If I went to D.C. , would it decrease?
Not a drop!  The power cable exiting your system is probably the best
filtered (For RFI) conductor on there. If the case/power supply, and
power cable are bonded properly, substantially _no_ RFI leaves via the
power wire.  DC powering would quite likely allow _more_ RFI to escape.
->      2) How would RF be affected in an RV type use.
Assuming it's a metal RV, shutting the RFI up inside it _with_ the TV
might make the situation much worse.  If, on the otherhand, the TV has a
well shielded tuner, etc, and the antenna lead-in were Co-ax to an
antenna _external_ to the RV's  metal shell, the problem might be
improved immeasurably.  (Using the RV shell as a sort of Faraday shield
against the computer's EMI.)
->      I am contemplating
->      placing a MB in the base of a wood(multi-purpose) RV TV type
->      cabinet, with a large computer fan venting through the wall or
->      into the "basement" of the RV to muffle sound.
I have two such systems (NOT in an RV but in my house) and they radiate
RFI like crazy!  UNTIL, proper shielding using aluminum wrap is placed
inside the cabinet to keep the EMI _inside_ where it belongs, along with
_careful_ bonding of all cables EXITING the cabinet which might radiate
the interference.
->      Are longer IDE cables made for connecting floppies or
->      wouild I have to hack one?
And _here_ is where your REAL problem starts to show up!  Since they
plug almost directly into the PC buss, (Which of course has all the
clock signals and rampant harmonics thereof on it) floppy and hard drive
cables are the worst offenders of all at diseminating the dread RFI!
They too can be shielded with aluminum foil wrap, but it takes _careful_
care and tuning of the shielding to keep their EMI radiation within
reasonable bounds.  EIDE cables come in various lengths and can of
course be hacked to totally unreasonable dimensions, but there is a
practical limit to how much you can reasonably tolerate.  Careful
positioning of drives, MB, CD's etc are a better solution when you start
planning such a system.
-> Is their any more of a fire hazard with wood rather than with those
-> ugly flymsy plastic cases?
Not IMHO. Common sense and a little care should prevent _any_ fire
hazard problems.  Besides which there are no naturally occuring high
temperature areas _in_ a PC that's properly vented. The power supply
fan is more than adequate to remove any heat that might reasonably be
expected to be generated and can easily be vented to some _other_ area
to prevent "noise pollution" of your living environment.
-> Thanks for the idea and suggestions.   gary.collier@omnibbs.com
Hope I've helped.  Otherwise I've wasted a lot of your time and mine,
and probably handed the rampant theorists a wonderful assortment of new
rocks to throw.
 ^..^
--- FidoPCB v1.5 beta-'j'
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