You said, "Any insight is appreciated." This might be to late for you, but help some others. 1. This is the very reason I stopped using the more "economical" crystal companies. While their prices look attractive, there is usually just to much rework, lost time, frustration, delays, and poor performance. 2. Send the ICOM / Channel Element in with your order and pay the cost for xtal installation, testing, and compensation, I'm now 28 for 28, worked right out of the box the first time, zero problems or failures using this approach and dealing with ICM. Yes, it costs more, but its been done right the first time, every time.
Good Luck, Rob K7EI -----Original Message----- From: kk2ed [mailto:[EMAIL PROTECTED] Sent: Wednesday, December 03, 2003 11:06 AM To: [email protected] Subject: [Repeater-Builder] Micor UHF TX channel element/crystal issue Hi all, I have a peculiar situation here - I just received two new crystals from Bomar (NJ) to refreq' two elements to 440 ham freqs. The channel elements are virgin KXN1052's as prepared by Motorola. I installed the crystals, and after attempting to adjust the warp capacitors, both elements come up by about 12-15KHz on the high side. I then went and placed aprox. 12-15pf caps in parallel with the warp cap, which allowed me to trim the element on frequency, with a swing of + or - 7 KHz or so, to allow for adjustments either way as the crystals age. Now the fun part - The original Moto factory 460 crytals yielded a maximum deviation setting of 8KHz or so, so there was no problem setting the IDC for clipping at 4.5 or 5KHz. HOWEVER, the new crystals will only achieve a Maximum Deviation of 3.75KHz or so, even with the IDC control at max. I then pulled the caps I placed in parallel with the warp cap, and although the elements were 12KHz high in operating freq, I was able to obtain a max deviation of 4.5KHZ, but still not 5KHz as desired. Question - is it possible that the crystals were cut with too much parallel capacitance to start with, then my adding the caps to get them to center freq just compounded the issue? Is the max freq deviation factor of the crystal proportional (or inversely proportional) to the crytal's internal capacitance? My calls to Bomar have been less than fruitful. I am still waiting to speak to their "tech". They have offered to replace the crystals, but I am afraid that the next set will be the same, as they seem to think they are making them correctly. Any insight is appreciated. Eric KE2D Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
