We have remote receivers using Exec II conversions, with 2M receivers and 70CM link transmitters. Two of them are in unheated rooms. Today it is 0 degrees F, and both of them are having the same problem. This is not a new problem, but shows up whenever the temperature goes below roughly 15 degrees outside.
It appears that they have very low or non-existent output until *something* warms up enough to make them work again. This time period can literally be from 2-3 seconds up to several minutes after PTT activation, the longer times corresponding to the colder temps. I don't believe it is related to the crystals being off frequency. They really don't sound like they are off. It simply sounds like the output power ramps up, within several seconds typically, to what sounds like normal levels. (I can hear both of the links directly.) Today I attempted to get to one of them, but was not able to get into the driveway because of deep snow. I could hear the output at an EXTREMELY weak level in my mobile radio when about 200 ft. away, and it did not sound to be off frequency. So I have not been able to take measurements on them in their problem state. Both of them have their output turned down to low levels, around 2-4 watts, because it's plenty to make the path full quieting. Could the power control circuits be temp sensitive enough to act like this? What other areas should I look at when I get there? Hopefully Monday they will still be <not> working so I can diagnose them. I plan on being armed with test equipment to figure out what is going on, but I'd like an idea or two from others before I get to them. Thanks all. Laryn K8TVZ
