Hi Guys, W0INK studied and reported on that topic some time ago:
http://www.scomcontrollers.com/downloads/ctcsssreject&hpfilters.pdf 73, Bob Bob Schmid, WA9FBO, Member S-COM, LLC PO Box 1546 LaPorte, CO 80535-1546 970-416-6505 phone 970-419-3222 fax www.scomcontrollers.com -----Original Message----- From: Kevin Custer <kug...@kuggie.com> To: Repeater-Builder@yahoogroups.com Sent: Wed, Nov 18, 2009 9:54 am Subject: Re: [Repeater-Builder] Micor repeater audio Jeff DePolo wrote: I have had he opposite experience with the two most recent Micor UHF stations I ut on-line. Both have a peak very near to 400 Hz, and roll ff several B/octave above that. Setting for 3 in/3 out @ 1KHz, I get bt 4 out @ 00 hz, and abt, oh, 1.5 or so at 3K. nyone else noticed a peak around 400 Hz on a UHF Micor station? You're probably seeing the peak in the PL filter's response. If you remove he PL filter and config the A/S board for carrier squelch operation, you'll robably see relatively flat response up to about 2.5 kHz where the splatter filter" starts to take over. --- Jeff WN3A Jeff is right on the nose here.... I have swept the MICOR and MOTRAC PL filters and there is a defined peak around 400 Hz. It is likely caused by the self resonance of the 6 Henry chokes and associated support components which create the tuned network used in the filter. This can be tamed down (filter made to be flatter in response) to some degree by placing a 220K resistor across the choke(s). See Here: http://www.repeater-builder.com/rbtip/plf.html Kevin Custer
