Dave, Depending upon the symmetry of the IF and detector component responses, there will be a difference in the apparent sensitivity with different deviation levels. The operative word is "apparent." If you intend to use the receiver for FM voice which averages about 3 kHz deviation, then you should use the EIA standard method of tuning to 12 dB SINAD with 3.0 kHz deviation of a 1 kHz tone. If you optimize the tuning on an unmodulated test signal, then the receiver's sensitivity to voice modulation will likely be poorer than it would be if tuned with a modulated signal.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Dave VanHorn Sent: Saturday, March 04, 2006 9:45 AM To: [email protected] Subject: [Repeater-Builder] Receiver Tuning I've noticed that I can get a lot better sensitivity on my receivers if the source I'm measuring against is either unmodulated, or I set the deviation to 1 or 2 kHz. When I get up to 3-5 kHz deviation, the apparent sensitivity of the receiver is significantly less. I notice this on many systems, where a weak station will be "in" until they talk a little louder, then they drop out. Is there a tuning method I can use to minimize this effect? 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/
