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How Would You Diagnose This Signal Loss?

Remember not to jump to conclusions when troubleshooting

The author is principal of Eberhart Broadcasting in Dallas, Texas.

Our station KGAF in Gainesville, Texas, is a 1,200-watt AM daytime and 250-watt nighttime non-directional station.

Our upgrade to 1,200 watts a year or so ago was a big improvement for us expanding our reach quite a bit from our previous 250 watts day and night. Indeed, our signal now reached to my home in Dallas, some 70 miles away.

Recently, I noticed our station was not being received as well as it had before as I drove around north Dallas. In fact, I almost couldn’t hear it at all. Even in Denton, only 30 miles from our tower, I was having trouble picking up the station. I could hear all of the Dallas stations just fine, loud and clear.

Concerned, during my next day at the radio station I went to the transmitter and checked to be sure our power output was correct. It was dead on 1,200 watts. Zero reflective. Modulation was peaking 95–98-percent negative, 100–120-percent positive — clearly plenty loud.

Next, I went to the tower shack and checked the base current reading. It was exactly correct, as it had been when we initially set everything up a year ago with the upgrade.

I kept scratching my head, trying to figure out why our signal was so poor. It came out great within the county we are in, but almost the moment I drove out of the county, it dropped to almost nothing.

A large new development is being built in what used to be a large open field next to our transmitter site. They are unearthing an extensive area, and I feared that perhaps we had buried ground cables there, and they might have disrupted them or something. Unlikely as it might sound, back in 1947, when the station originally went on the air, who knows what might have been done.

A new ground system was put in in the mid-1980s, but again, it’s really anyone’s guess how it might have been done. As is often the case, we found numerous curious technical issues in our plant when we did the recent upgrade, and I can assure you nothing would surprise us at this point!

It was the only thing different about anything near our transmitter site, and I became obsessed, wondering how on earth (bad pun) that could so adversely affect our ground system as to cause our signal to weaken.

Every knowledgeable person I talked to assured me that was not likely the cause, as ground systems wouldn’t normally extend that far — and surely not on adjoining property owned by others. I agreed it made little sense, but the dirt clearing next door was literally the only thing different anywhere near the site.

I asked if disrupting earth near a ground/tower site could cause an issue. Again, no one believed it could.

One thing I’ve learned about engineering issues is that most can tell you what likely is or isn’t the issue when problems arise, but most agree that they can’t and won’t rule out anything when it comes to this kind of stuff. Just because one has never heard of it happening or seen it, doesn’t mean it couldn’t possibly be so.

I left the station still bewildered, wondering why the station’s signal is dropping off in areas that only weeks ago it was booming into.

I stopped for gas on the way back to Dallas from Gainesville. As I stood there, filling up, I looked over the top of my car and noticed … my car’s radio antenna was missing! A true OMG moment! Are you kidding me?! Apparently, someone helped themselves to the little foot-long radio antenna on the roof of my car.

I felt like such an idiot. I had been fearing some expensive engineering fix on the horizon and all along my stupid car’s antenna was missing.

I could get all of the Dallas stations because most of them are 50,000-watt blow torches that obviously didn’t require an antenna to hear loud and clear. My 1,200 watts with no antenna got me about 25 miles without an antenna.

I stopped at the local car dealership and replaced the screw-on antenna, hopped in the car and boom! KGAF loud and clear in north Dallas.

Those little antennas aren’t cheap ($60), but the removal of the stress the past two weeks produced was priceless.

Word to the wise: Before you think your transmitter or tower is failing, check to see if your car still has its antenna.