[TowerTalk] Yaesu GC-048 mast clamp: anyone try it on a G-1000?

[Kevin Normoyle]

Okay, I got my answer. From myself! I think this is a pretty
nice solution to anyone having clamp problems with Yaesu G-800/1000's,
for about $50 cost, so I wanted to share it.

 (see my prior post when I posed the question).

I ordered a GC-048 (Gigaparts had a sale), the bigger "lower" mast clamp 
for the G-2800,

Got it the other day and proceeded to install as the top (normal) mast 
clamp on a  G-800
(which is the same as a G-1000, mounting wise.. I also have a G-1000SDX, 
I lined it
up there too to see if it would be the same there. Is)
 

MAN this clamp is hefty compared to the mast clamp that
comes with the G-800 or G-1000. The aluminum is really thick everywhere,
it's larger, and it had 6 bolts for compressing to the mast, not 4. It's got
some extra ribs in the casting also. I could see that Yaesu might have been
trying to save weight on the normal clamps (for non-tower installs). But 
this clamp
has heft!

Tried it on the rotator and realized there was a issue, (so it doesn't 
"just work")
but it was easily fixed.

There is a center rib on the top of the G-800/1000 rotators. The smaller
standard clamp doesn't hit the rib, when you tighten the the two clamps 
onto a 2" mast.

When I put the GC-048 on, it hit this center rib, before fully 
tightening on a 2" mast.
You don't want the clamp to slide on top of this rib. You could do that, but
then it's cocked. Don't want that.

Takes some visualization here.

Think of the mast clamps as "L"'s. If you put the bottom of the L of the 
GC-048
up against the standard clamp, and align the holes, you can see it's larger
(base of L is longer) which is why it hits the center
rib.

If you compare the two clamps, and look at the top of the rotator and
play with the two on top of the rotator, you'll see the issue.

Fix: I ground the offending lip on the bottom of the GC-048 at a 45 deg 
angle.
Only needed to grind off about 3/16"  to 1/4", for about 4"? (Basically 
taking the edge
of the 90 deg offending lip, so material is removed
3/16' vertically and horizontally, with a single grind.

This only took a couple minutes.

Just need to be able to mate the two clamps a little closer than needed 
for a 2" mast
and not have them hit the rib (you want to dry run this, not find out 
you don't
have enough room on the tower).

The aluminum will get in your grindstone (cause it's soft) so you may want
to use a big double mill bastard file. A little slow but will do the 
job. Make
sure you clean the file often with a file card because of the aluminum 
getting
stuck in the file. I also sprayed the exposed aluminum after filing with 
some krylon
acrylic for oxide protection, when done.

I'd take a picture, but no camera here at this QTH.

Note you don't have to grind the full width, just the lip that will hit 
the rib, which
is about the width of the mast opening in the clamp.

I know this sounds like weakening the clamp, but it doesn't. There is SO
much aluminum on this one, and there's no aluminum at all in this area 
on the standard
clamp.

It really looks nice. I didn't want to pin the mast, but wanted to make 
sure it didn't
spin. Just needed more clamping force/friction, and this GC-048 (with 
modification)
is really nice. I actuallly put it on a G-800, because of a current 
project.

I suppose by definition, this boosts the clamping force up to the torque 
that
a G-2800 can supply, minimally.

(ps. I've seen another mod by Phil AC6HY for improving the clamping 
force on the
standard mast clamps, which got me thinking about using the GC-048 instead).

-kevin
KE6RAD