Johnny, The transmit crystal in your repeater is supposed to operate at a regulated temperature of about 176 degrees Fahrenheit, or about 80 degrees Celsius. The crystal should be ordered for operation at that temperature. If the radio shop technician disconnected the heater resistor but installed the correct (oven-rated) crystal, it will be *way* off frequency. The heated TX crystal is mandatory, in order to achieve the +/- 2.5 PPM stability specified by Uniden. Note that the receive crystal has a heater that kicks in only when the ambient temperature falls below about 14 degrees F.
The TX crystal heater is a 47-ohm 2 watt resistor. Once it is installed and working correctly, wait at least five minutes after turning on the radio before attempting to tune the TX frequency. I'd let it settle for a half-hour or more. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of bama_guy1965 Sent: Sunday, May 07, 2006 2:46 PM To: [email protected] Subject: [Repeater-Builder] Re: Uniden ARU251 Repeater ---well I checked the crystal htr and I suspected he d/c the thing and I have no idea where to reinstall it. I didn't see anything on the diagram where you can do it, but I have a manual here I will find in min but I bet that's the reason why my transmit is drifting off. Johnny 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/
