[Boatanchors] Questions re rack mounting

[Rob Atkinson]

>
> Picked up a vintage two post 6' rack on steel base with casters.  Posts are offset from the center and supported by large triangular brackets.
>

By "two post" do you mean a relay rack as opposed to a box?

> From top to bottom:
>
> 270G-3  (are brackets are available?)
> 75A-4
> 20-A, 458 and MM-2
> 100V
> 600L  on wood riser directly on the base plate (and may I never have to lift it higher)
>

I don't know what all of that is, but generally the weight should go
from lightest to heaviest, top to bottom.  It appears that's what you
are doing.   you need to lock the rollers so the rack can't move
around while you are installing equipment in it.   When the rack is
positioned, I'd shim it or jam its base with door stops or something
so it can't get away from you.

> Given my tight space situation, I would prefer to use cantilevered shelves.  Potential problems?
>

You can do that, but I'd take all the units out of their cabinets and
set them on the shelves and back them up as far as possible to the
shelf ears, then secure them to the rack rails on each side at the top
most screw holes using long rack screws.  The 75A-4 has to sit on a
shelf because it wasn't made to be rack mounted.  I don't know about
that other gear.  I'm assuming most everything has rack handles and
rack ears.

Another method is to take a pair of rack screws and saw off the heads
and file a notch in the end for a flat head screw driver.   Drive the
resulting grub screws into the rack where you want to install
something.  Take your unit and place the top rack ear screw holes over
the grubs so the item has something to hang on while you drive screws
through the pair of bottom holes to secure it, continuing until it's
in, then remove and replace the grub screws.   Then you don't need
shelves for anything that can be rack mounted.

> Is it OK ground everything to the rack?
>
yes you should do that.

> The coax run from the 600L to the antenna tuner will be about 10'.  Potential issues?   (AT2KD  > 18" coax  >  4:1 balun > 600 ohm ladder line)
>

There's issues.  baluns are not the way to transfer from unbalanced to
balanced feedlines.   they are mostly reactive and generate heat which
means power loss.  Ditch the unbalanced tuner, the coax and balun and
employ a link coupled balanced tuner such as an EFJ KW Matchbox.

73
Rob
K5UJ