Laryn, Your channel element was previously compensated for the crystal that was in it; that is, a "used" channel element may be far from a nominal unit that ICM or any other manufacturer must assume when you order just a crystal. Therefore, it is only blind luck that will allow a new crystal to perform properly in a previously-compensated holder.
This topic has been covered many times on this list, but it bears repeating: Always send your channel element to the crystal house for precise compensation with the new crystal. This is especially true when the original element and crystal were actually made by Motorola, because Motorola had their own crystal plant and used processes that were different from those used today by ICM and other crystal houses. In such channel elements, new raw crystals from any other crystal source will seldom work properly. Only when you send the channel element to the crystal house for proper compensation can you be assured that all the four important crystal factors will meet specs: Amplitude, center frequency, temperature stability, and deviation sensitivity. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Laryn Lohman Sent: Friday, January 26, 2007 9:03 PM To: [email protected] Subject: [Repeater-Builder] UHF Micor Off Frequency I just installed a new TX crystal into a KXN1052 channel element on a Micor exciter today. The crystal is from ICM. It will not come on channel. The ordered frequency is 445.125; it comes no closer than 445.1375. The crystal arrived late Friday PM, and upon installation Friday evening, the problem was discovered. I realize I may need to contact ICM when the office opens on Monday since this is a new crystal. But, is there an easy and reliable way to warp it down without the need to perhaps send the crystal back? A small cap across the crystal? Related question--why would a crystal from a reliable manufacturer be off in the frist place. Are there tolerances in the channel element that can sometimes add up the wrong way? I have some other elements of the same number; is it worth trying the crystal in another one? Laryn K8TVZ
