Hi Guys, Any of you ever hear of Modulation Acceptance? Test the receiver and find out. No receiver made has a linear Pass Band and sometimes by running the if cans to the second resonant point, you can find a more linear point. Another trick is to change the 2nd conversion xtal above or below the if. Bottom line is test the Receiver. Clean up the mixers, Birdies out of the oscillator will kill you. Ron wa6unm
-----Original Message----- From: Steve S. Bosshard (NU5D) [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 7:34 PM To: [email protected] Subject: RE: [Repeater-Builder] Help on Interference Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. Reply: Please refer to modulation index and Bessel functions. The frequency response is 300 to 3000 hz emphasized at 3db per octave. Transmitter instantaneous deviation is supposed to be limited to +/- 5 kc deviation from center. Significant sidebands in FM extend beyond the deviation limit, hence emission designator 20K0F3E that equates to about 16 khz occupied plus a guard band on either side. They share part of the same channel (honest - I would not kid about something like this). Has nothing to do with receiver - both transmitters share common ground. Very truly yours, Steve Bosshard AR SK Steve Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
