Modify CM-3672 ?

[300ohm]

What size SM mesh corner reflector do you want ? Ill make up an example.

[kc2cbd]

I was trying to do a 36 inch wide by 2 foot on each panel using 2 x 4 inch mesh.
For some reason those mesh corner reflectors won't do frequency sweeps on my computer. If there actually running then I would assume it will take a day to run a sweep just to check gain and swr.
I have no problem running AGT tests with them but I don't get any indicator movement running sweeps.
I was hoping the SM mesh would run almost as well as using just horizontal elements.
I could probably just use those, but I was trying to grasp the SM and SC cards.

[300ohm]

but I don't get any indicator movement running sweeps.

The program is running, its not locked. Mesh makes for very long calculations.

Yep, after a certain calculation time figure, there is no indicator. After 10,000 seconds, youll get the 1 e4 times, which can be anything over 10,000 and below 20,000 heh.
Resegmentation of the mesh section to 1 segment per wire will cut calculation time a lot without affecting the results. The NEC Editor (new) is good for that.

I was trying to do a 36 inch wide by 2 foot on each panel using 2 x 4 inch mesh.

Here ya go, its deceptively simple, heh.

CM Corner Reflector using SM and SC cards by 300ohm
CM Basic Corner Reflector
CM SM panels
CM Density = 2 inch by 4 inch mesh
CM Size = 36 inch wide by 24 inch high panels
CE
SM 12 9 16.9706 -18 16.9706 0 -18 0
SC 0 0 0 18 0
SM 12 9 0 -18 0 16.9706 -18 -16.9706
SC 0 0 16.9706 18 -16.9706
GS 0 0 0.0254 ' All in in.
GE 0
GN -1
FR 0 1 0 0 585 0

but I was trying to grasp the SM and SC cards.

Basically, youre defining each of the X, Y, Z coordinates of the top left, bottom left, bottom right corners of a rectangle, which makes up the outside dimensions of 1 panel. Thats done with one SM and SC card combo. The SM card describes the top left and bottom left coordinates, while the SC cards describes the bottom right coordinate. You need two combos for the two panels of a corner reflector.
And you define how each panel is split up, vertically and horizontally, which is your mesh size.

The easiest way to get the coordinates is to make a wire model first, which you should do anyway at the end of optimizing for finer accuracy. SM/SC cards are accurate enough for the quick calculations and optimizations though.

In the above example, the +/- 18 numbers are the width of the panel, the Y coodinates, making 36 inches. The +/- 16.9706 numbers are the X and Z coordinates of the 24" panel height, which are the same number (1/2 of (24 * SQRT 2)) because its a 45 degree angle. The 0 number is at the apex.
There are twelve 2 inch sections in the 24 inch height, and nine 4 inch sections in the 36 inch width.

Surface patches are not usable in Geometry Edit, so you have to enter them thru NEC Edit.

[kc2cbd]

Finally got a UHF antenna I built from the CM-3672 UHF active element up this past weekend. So far it has been performing quite well. It even rejects signals from the rear really well. Now I just have to build a small antenna for the channel that is about 13 miles away. At present I have the 4251 pointed at it but I think that antenna is over kill for that channel but it is working really well and both antennas aren't interfering with each other.

[300ohm]

So what did you finally do to it ?

[kc2cbd]

Did an all band UHF antenna on a 10 ft mast with a 2ft x 3ft CR. reconfigured the CM3672 with those winged elements. The new UHF is on top then the 3672 below that and the 4251 is just above the tripod. Wired the both UHF antennas into a 2 way splitter as a combiner into the uhf side of a uvsj and the modified 3672 wired into the vhf side then into my pre-amp. It is feeding 6 tuners and so far very reliably. I will get a picture of the setup sometime today.

[kc2cbd]

Pic of whole system


Closer pic of new antenna above modified 3672

[300ohm]

Looks good, as does the CM3672 with the cross fire directors on it. How well is it doing ?

[kc2cbd]

Still works good..but the Hdhomerun is picky so it still doesn't like channel 23, and I'm going to have to make a small channel 22 antenna to take the place of the 4251. The 4251 is working right now but it doesn't have a good enough rejection of rear signals. But I can't complain as right now it pulls in that channel good enough till I get a small one built.