Hard disk RF noise...
 

Hi there,

I've just setup a small recording studio in my room. It uses
my old Atari Falcon computer as a MIDI device, and all is to
be recorded to a 4 track high-quality Fostex deck using metal
tape.

The hard disk my Atari uses is a 1.2GB IDE disk of the usual
shape, but due to the original chassis of the Atari being able
to fit only a 2.5" laptop style drive I've had to run a power
and data cable out the back of the Atari, and sit the disk on
top of the computer chassis...where it gives off a large amount
of RF noise that is picked up very audibly by the Fostex deck.

How can I shield this RF? Should I need to earth any shield
device I might put around the disk?

Any thoughts welcome...

--
Kind regards,

Chris Wilkinson, Christchurch, New Zealand.
Remove spamblocker to send replies direct to my email...

Re: Hard disk RF noise...
 

On Mon, 22 Dec 2003 13:36:01 +1300, Chris Wilkinson wrote:

> How can I shield this RF? Should I need to earth any shield
> device I might put around the disk?

Use foil-wrapped cable. That's where the **** is being radiated from.

And thread it through a RF choke or 2.

Re: Hard disk RF noise...
 

Hi there,

Uncle StoatWarbler wrote:
> On Mon, 22 Dec 2003 13:36:01 +1300, Chris Wilkinson wrote:
>
>
>>How can I shield this RF? Should I need to earth any shield
>>device I might put around the disk?
>
>
> Use foil-wrapped cable. That's where the **** is being radiated from.
>
> And thread it through a RF choke or 2.

I've got the 40-way ribbon and a 4 way power hanging out the arse of
the Atari, so I'll try wrapping them in foil? I'll try a small foil
wrapped box for the drive itself, since I don't want that getting
too dusty...

Cheers...

--
Kind regards,

Chris Wilkinson, Christchurch, New Zealand.
Remove spamblocker to send replies direct to my email...

Re: Hard disk RF noise...
 

On Mon, 22 Dec 2003 15:04:55 +1300, Chris Wilkinson wrote:

> I've got the 40-way ribbon and a 4 way power hanging out the arse of
> the Atari, so I'll try wrapping them in foil? I'll try a small foil
> wrapped box for the drive itself, since I don't want that getting
> too dusty...

Cut a hole in an old cake tin, earth the tin and make it meet up with the
back of the atari ?

--

.... Brendan

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Holly: The North Western Electricity Board. They want you Dave.
Lister: Me ? Why, what for ?
Holly: For your crimes against Humanity.
Lister: You what ?!
Holly: Seems when you left Earth 3 million years ago, you left two half
eaten German sausages on a plate in your kitchen.
Lister: Did I ?
Holly: You know what happens to sausages left unattended for 3 million
years ?
Lister: Yeah, they go mouldy.
Holly: Your sausages, Dave, now cover seven eighths of the Earth's surface.
Also you left seventeen pounds fifty pence in your bank account. Thanks to
compund interest you now own 98% of all the worlds wealth. Because you
horded it for 3 million years, nobody's got any money except for you and
Norweb.
Lister: Why Norweb ?
Holly: You left a light on in the bathroom... Got a final demand here for
one hundred and eighty billion pounds.
Lister: One hundred and eighty billion pound ?! Ya kidding ?
Holly: April Fool.
Lister: But it's not April.
Holly: Yeah I know. But I could hardly wait six months with a red hot joke
like that under my belt.
Lister: So you just made it all up then ?
Holly: Yeah, bit of excitement for a while wasn't it ?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Note: All comments are copyright 2003, and are opinion only where not
otherwise stated, and always 'to the best of my reccollection'.

Re: Hard disk RF noise...
 

Hi there,

Brendan wrote:
> On Mon, 22 Dec 2003 15:04:55 +1300, Chris Wilkinson wrote:
>
>
>>I've got the 40-way ribbon and a 4 way power hanging out the arse of
>>the Atari, so I'll try wrapping them in foil? I'll try a small foil
>>wrapped box for the drive itself, since I don't want that getting
>>too dusty...
>
>
> Cut a hole in an old cake tin, earth the tin and make it meet up with the
> back of the atari ?

Might give it a try, but I've discovered that the RF being picked up is
only being picked up by the headphone/line-out stage, not the line-in
stage, so it doesn't get recorded...phew! Once I've recorded the MIDI
I need I can switch the Atari off and not worry about the RF annoying
me, cos it surely would after take 23 of my acoustic guitar part being
bumbled yet again! :-)

--
Kind regards,

Chris Wilkinson, Christchurch, New Zealand.
Remove spamblocker to send replies direct to my email...

Re: Hard disk RF noise...
 

Chris Wilkinson <misterblobby@NOSPAMsnap.net.nz> wrote in
news:1072168863.145751@kyle.snap.net.nz:


> Might give it a try, but I've discovered that the RF being picked up
> is only being picked up by the headphone/line-out stage, not the
> line-in stage, so it doesn't get recorded...phew! Once I've recorded
> the MIDI I need I can switch the Atari off and not worry about the RF
> annoying me, cos it surely would after take 23 of my acoustic guitar
> part being bumbled yet again! :-)
>

You could try threading 2 or 3 or more turns of the headphone cable through
an RF choke at the plug end as it sounds like the headphone cable is acting
like an aerial.

--
Chris

"Two men walk into a bar. You'd think the second one would've ducked..."

Re: Hard disk RF noise...
 

On Tue, 23 Dec 2003 21:41:46 +1300, Chris Wilkinson wrote:

> Might give it a try, but I've discovered that the RF being picked up is
> only being picked up by the headphone/line-out stage, not the line-in
> stage, so it doesn't get recorded...phew! Once I've recorded the MIDI
> I need I can switch the Atari off and not worry about the RF annoying
> me, cos it surely would after take 23 of my acoustic guitar part being
> bumbled yet again! :-)

Woger suggests you stick the drive on the end of a 12 meter cable and sit
it outside. Apparently it'll be cooler also ;)

--

.... Brendan

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Holly: The North Western Electricity Board. They want you Dave.
Lister: Me ? Why, what for ?
Holly: For your crimes against Humanity.
Lister: You what ?!
Holly: Seems when you left Earth 3 million years ago, you left two half
eaten German sausages on a plate in your kitchen.
Lister: Did I ?
Holly: You know what happens to sausages left unattended for 3 million
years ?
Lister: Yeah, they go mouldy.
Holly: Your sausages, Dave, now cover seven eighths of the Earth's surface.
Also you left seventeen pounds fifty pence in your bank account. Thanks to
compund interest you now own 98% of all the worlds wealth. Because you
horded it for 3 million years, nobody's got any money except for you and
Norweb.
Lister: Why Norweb ?
Holly: You left a light on in the bathroom... Got a final demand here for
one hundred and eighty billion pounds.
Lister: One hundred and eighty billion pound ?! Ya kidding ?
Holly: April Fool.
Lister: But it's not April.
Holly: Yeah I know. But I could hardly wait six months with a red hot joke
like that under my belt.
Lister: So you just made it all up then ?
Holly: Yeah, bit of excitement for a while wasn't it ?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Note: All comments are copyright 2003, and are opinion only where not
otherwise stated, and always 'to the best of my reccollection'.

Re: Hard disk RF noise...
 

Hi there,

Chris wrote:
> Chris Wilkinson <misterblobby@NOSPAMsnap.net.nz> wrote in
> news:1072168863.145751@kyle.snap.net.nz:
>
>
>
>>Might give it a try, but I've discovered that the RF being picked up
>>is only being picked up by the headphone/line-out stage, not the
>>line-in stage, so it doesn't get recorded...phew! Once I've recorded
>>the MIDI I need I can switch the Atari off and not worry about the RF
>>annoying me, cos it surely would after take 23 of my acoustic guitar
>>part being bumbled yet again! :-)
>
> You could try threading 2 or 3 or more turns of the headphone cable through
> an RF choke at the plug end as it sounds like the headphone cable is acting
> like an aerial.

After experimenting I've found the best way to shield the disk is to
grab the sucker in my hand. Only problem is that one-handed guitar
is not for beginners or genii alike... :-)

--
Kind regards,

Chris Wilkinson, Christchurch, New Zealand.
Remove spamblocker to send replies direct to my email...