I have heard that many out there are looking for a company that makes good Crystal Band-Stop or related filters. We were too for our casino UHF LTR system. We found a place called Filtronetics http://www.filtro.net out of Kansas City.
They really are good at what they do. We sent them our TX Freqs for analysis and they faxed us a Tracking Gen sheet for each sheet with path loss and all the db specifics.
Takes about a month to grow, test and certify the filters. But they are worth it! The tracking gen results they sent with each filter matched our HP-8921A Service Monitor TG perfectly. Stay tuned on the repeater performance results.
