At 03:33 PM 08/03/10, you wrote: >Hello all, > >I have having a severe drift problem on my GE Mastr II 2 meter >repeater. The transmit freq will drift nearly 2 KHZ over a 5-10 >minute period. I have changed exciters and used a different ICOM but >no improvement. The building that I am in is not ventilated and is >very very hot. I put a high/low thermometer in and one day the high >temp in the building was 114 degrees. Is this the problem? > >Thanks for any help. > >Steve W4SEF
Can you elaborate on the situation? Is it an FM exciter or a phase mod exciter? Is it an EC, a 5C, or 2C Icom? Have you read <http://www.repeater-builder.com/ge/m2icoms.html> especially the paragraph that starts with "Any voltage change on the +10vDC power supply line will change the frequency on the Icom..." ?? You will also what to read the page at <http://www.repeater-builder.com/tech-info/temperature-compensation.html>. An idea on cooled down a building before you set the frequency... I once took a couple of cheapie box fans and setting one to blow in (at floor level) and the second stacked above it to blow out (at the top of the door level), and with a piece of cardboard in between them as an air dam. The cardboard was cut from the side of a large cardboard box that was used to ship a washing machine (ask for one at any appliance store). You could do something similar for the time period needed to set the frequency - your target is 75 to 80 degrees F for about an hour. Look at page 5 of this: <http://www.repeater-builder.com/ge/lbi-library/lbi-38505a.pdf> Yes, it's a receiver LBI, and you have a drifting transmitter, but the temperature notes apply. Mike WA6ILQ
