Coy; I would suggest that you add the following after "--- million." in you descriptions of the 5C and 2C ICOM's; " over the temperature range of -40 Deg.C. to +70 Deg.C. providing you set the initial frequency of the ICOM as described in the GE MASTR II manual." Less you move the crystal's "S" curve up/down on the temperature curve and then the ICOM will not meet the speciation at the extremes of the temperature range. Thanks Fred W5VAY
----- Original Message ----- From: "Coy Hilton" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, January 27, 2005 10:13 PM Subject: [Repeater-Builder] Re: Starting out with a Mastr II > > > Actually a 2C ICOM is internally compensated and will not compensate > any other ICOM it's Compensation pin is not connected internally. > All ICOMS will stay with in 2 parts per million with in the " > normal temp range". It's when you get to the "extreme" rang of temps > that the compensation takes over. Before you slam me read your > manual carefully. > Here is what it all means: > EC = "Externally Compensated" > 5C = "Internally Compensated to remain with in 5 Parts per million > and will compensate all other ICOMS except 2C. > 2C = "Internally Compensated only and will not compensate external > ICOMS and will keep it's frequency with in 2 parts per million" > 73 > AC0Y > --- In [email protected], "edctexas" <[EMAIL PROTECTED]> > wrote: > > > > --- In [email protected], "kg4wmp" <[EMAIL PROTECTED]> > wrote: > > > > > > I could find nothing > > > specific on why a radio whould need 4 (or more) 5C's and 1 EC. > Do > > > they take an average over several crystals or something or was > this > > > a function of multiple channels? > > > > > > Normally a mobile set only needs one 5C or 2C ICOM. The EC units > are > > slaved to the correction that the 5C creates for itself. The radio > > could have the buss cut and use separate Master and slaves for TX > and > > RX. It is not normally recommended to use multiple 5C units. > This > > will cause the units to fight each other. Theeir temp. comp. will > > not be correct. But on low band and for ham use, put in what you > got > > and use it. Some of the MII repeaters in this area don't bother > with > > any temp. comp. at all. > > > > The master ICOM has a selected thermistor and resistor combination > > which produces a correction voltage to a tuning diode (varicap). > If > > I remember right the 2C units have to have the parts selected, but > > the 5C units don't. The EC units have the tuning diode and get > the > > correction voltage from the master. If two masters are tied > together > > the voltages fight. > > > > Some guys use EC ICOMs and modulate the varicap. Its good FM but > > generally low deviation. Most repeaters source their +10V from a > > separate source for TX and RX. This separation prevents any RX > side > > noise from adding spurious to the TX. Simplex transmitters don't > have > > the problem as the RX is off during TX. Repeaters do have the > > problem without this extra separation. > > > > More GE trivia! WE can take this off line if you'd like more poop. > R- > > B website that Kevin has is a great source book. Once you get a > > manual your off. Many mobile use the same key. I'm not sure if > the > > station key or the mobile key is stamped BF-10 anymore. Nearly > any > > 2way shop has a ley to unlock it. I'd just use the master key > > (electirc drill). Then vaccuum the mess out of the radio. > > > > 73 Ed K3SWJ > > > > > > > > > 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/
