We have two ExecII mobiles in the same set up 2 mtr Rx 70cm Tx. One of them will quit working when it gets cold. I have seen both low Tx audio and low power output until it warms up. I haven't been able to be at the site when it isn't working to try and figure anything out.
John Lock kf0m at arrl.net > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] Behalf Of Laryn Lohman > Sent: Sunday, February 10, 2008 5:28 PM > To: [email protected] > Subject: [Repeater-Builder] Cold Weather Exec > > > 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 > > > > > > > > > > > Yahoo! Groups Links > > > >
