Date: Wed, 3 Aug 1994 00:27:46 -0700 From: Bob Wier Subject: Older dishes, testing... Here's what I look at with old dishes - 1. Mount condition - rusty? Homemade? Mount problems are difficult and expensive to fix. What you might want to do is to try to run the dish up/down and observe how smoothly it moves. Also, when it is near the top of the arc (due South), push on the lip of the dish, and observe if there is any looseness ("slop") in the mount - if so, you might have to replace hardware and add bushings/washers, etc. Listen closely as you move the dish over to the side for a "clunk" when the dish weight increases on the arm/jack. If you get a clunk, something has slop in it. 2. Look carefully at the surface if you live in a hail area. I've seen mesh dishes that look like someone took a ball peen hammer to it... 3. Try the string test. Take a bit of twine and some duct tape along. Strech the twine from lip to lip on the dish at 90 degree angles (if you can). See if the strings just barely touch in the center of the dish. If there is more than about 1/4" separation vertically, the dish may be warped (or "racked"). If you've managed to get the lines across the widest part of the dish (ie, at a right angle to the tangent at the edge), that should also give you an idea of whether the feedhorn support is actually in the right place (above the center of the dish)... 4. Small holes (bolts, bullets) don't seem to affect the dish performance too much. I've seen mesh dishes which are missing a panel which work fine, as long as the remaining panels are not distorted... 5. If you are planning on installing KU and are looking at a mesh dish, see if a #2 pencil can be fit thru the mesh holes. If so, the mesh is too coarse and won't work well for KU. Hope this might be of help... ===== Round Up the Usual Disclaimers! ====== Bob Wier, keeper of the Adobe Photoshop, Icom radio (WB5KXH), and Motorola HC11 mailing lists wier@merlin.etsu.edu currently in Ouray, Co at 8,000 ft. elevation (this is a *high level* system :-)