Redesigning CDE Rotator Control
Meter Scale for North-Centered Operation
April 8, 2007
I installed my MA-40 MARB rotating tower in Sept. 2004, the CDE
rotator control box had a south-centered scale. I never thought
about that till this week. Then, while looking at ads in CQ Magazine,
I suddenly realized that changing to a north-centered scale would
greatly reduce the turning required to work JA - EU - W/VE.
The original south-centered meter scale that came with my CDE rotator
CDE meter scale backplates have reversible North or South sides.
Mine did not. Imagine my disappointment upon opening
I had to make my own. I scanned the south-center scale as a 2400-dpi
image and used desktop publishing software to create new bearing
numbers along the arc lines, and S-W-N-E-S indications. Use any
software that allows you to make and rotate text boxes.
The redesigned north-centered meter scale.
tried various applications to create an arc line and add the text
of all bearings to that line, but found it was simpler and more
accurate to make individual text boxes, positioning them in the
right place and rotating them.
I was at it, I added ZL VK JA EU AF W SA labels to the appropriate
bearings for a custom job. Took three hours to meticulously redesign
the meter scale. I like the results very much, and readability is
the new meter scale on white paper and glued it to the "blank"
side of the plate. Getting the meter back into the CDE box is a
challenge, but take your time with the spring-retained clips and
it will work.
me, re-aligning the tower was as simple as loosening the tower in
the rotator's jaws at ground-level, turning the rotator to due south
(through W>SW>S), then hand-turning the tower due south and
tightening everything up. Spot-on alignment.
this helps someone else convert their CDE Rotator Control Box from
south to north centered operation, or vice versa.
image (Updated April 2011)
this meter scale as a very large .JPG (2.45MB)
is a large 2400-dpi .JPG image of the north-centered meter scale,
placed on the full-size meter plate. This version is improved from
the first attempt, with better placement of the numerals. The ZL,
VK, JA, etc. labels have been removed, allowing you to place your
own geographic labels appropriate to your own great circle bearings.
ready to print -- though you may need to place the image in a Word
document or other image-handling software to resize before printing,
depending on your setup.
to opening the CDE rotator control box:
these instructions are a general guide and are not intended to replace
the instructions provided in your CDE Rotator Control box manual.
Always follow the manufacturer's instructions. Failure to exercise
appropriate safety precautions could damage you, your control box,
the meter movement, or other things, such as your self-esteem.)
screws from sides of the box, and remove top and bottom covers
of the box.
the nut on the lamp support (it's a metal bar that goes from the
side of the transformer to the front of the box, above the meter),
then slide the lamp out of the way.
the nuts from the two terminal posts on the back of the meter.
There's not a lot of room for fingers to work in there, but it
will work. The manual recommends temporarily connecting the posts
together with a bit of wire to prevent damage to the meter (from
stray static charges, for example).
the circuit board off the two terminal posts.
the circuit board down through the hole so it's underneath the
This give you clearance to remove the meter from its holder.
push the two brass clips so they release the meter. The meter
will then be loose in its tracks and can be slid up and out. The
clips are held fast by springs, but can be pushed forward so their
ends release the meter. (You'll know what I mean when you get
a thin blade, you can pry off the clear cover of the meter. Be
VERY CAREFUL not to touch the needle or its movement. It is EXTREMELY
sensitive to even the slightest breath of air.
a thin blade, carefully work loose the meter scale metal backplate.
It has two holes that align with indexing pins on the meter housing.
Once the plate is clear of the pins, you can remove the plate
-- taking care not to damage the needle as you slide the plate
the back of the plate has the opposite (north-centered or south-centered)
scale, you can just flip it over and reinstall it. Some models
of the CDE controllers have these reversible plates.
If the back of the plate is blank (it'll be a
bare metal finish) you can now glue on your replacement meter
scale. The thickness of your paper sheet may actually cause the
needle to jam where it comes closest to the metal plate. To prevent
this jamming, ensure that the paper is trimmed so it is no closer
than 0.25 inch (0.5 cm) from the semi-circular cutout on the meter
plate. This gives plenty of clearance for the needle.
everything, and you're done.