question for electronic wizards

I have a few open station tractors we use only in the summer for haying jobs. All spend most of their time in a tool shed, but may
sit outside for a rain or two during the summer if their shed space is needed for loads of small square bales waiting to be
unloaded. My issue is all the fender radios have developed bad reception. All would drag in FM stations really well when new. But
over the years each one has been reduced to nothing. I have A local FM country station that the tower is within eye distance, but
still I cant drag it in clearly. Does the antenna get rust or corrosion over time?? Each unit has the rubber type antenna and still
looks good. Not weather checked. I did notice a year ago I was listening to the radio while raking. Rain moved in with a cold front
and we had a wet few days that shut us down. When the sun and heat returned the radio would no longer bring in the station I was
listening to when I shut it off. I know something has to be up, but what?? I have a JD with a sound guard cab that had a very good
radio. This tractor will get pushed into the weather way more often than others because its cab is rain tight. Over the last
handful of years its radio is no longer as good as it was 20 years ago. Whats up, anybody know???

I used to fix tractor radios back when I was in high school. There are a whole lot of things it could be. The first thing I would look at is a bad ground, second the antenna, third the speaker fourth bad solder joint. You might have corrosion on the electronic components but that would cost more than the radio is worth to have it looked at. Sometimes just blowing the heavy dust off the components will solve your problem BUT DONT USE YOUR 120 PSI AIR HOSE TO BLOW IT OFF. Maybe more like 20 to 35 psi would be more gentle on the components. One problem Ill never forget was a mouse turd in a tuning coil. Every time the radio would was bumped the the turd would bounce and retune the radio.

I used to just use a copper wire about a 12 with a couple washers to hold it. I would clean them occasionally. It was AM so I would listen to stations like WBAP in Fort Worth TX ,WRVA in Richmond VA I think it was. And a lot of distant stations like that including WBZ in Boston or WABC in NY. Along with WSM at night. Most of these I would listen to at night working ground or planting. I had the solder crack in the circuit board once would make all kinds of weird noise then. These stations I could get in MI.

Have you ever looked inside those radios? Just a good (gentle) cleaning may help. Also check all places where metal contacts metal for good connections (grounds). The tuning parts (variable capacitors) can have a coating of dust that needs to be cleaned off. As others said low air pressure blowing is helpful.

One thing that comes to mind is the simple fact that water and electricity are not the best of friends, and they do not play well together. Corrosion, contamination, and moisture lead up to short circuits and electrical leakage.

I would lean towards the antenna first. I have found corrosion where it plugs into the radio to be a poor reception problem before. Mark.