Originally Posted by ORBIT
I have the Antenna.com model. Have had no problems at all with it. just went on a trip approx 100 mile from radio station with no issues.
The only issue with a shortened antenna is what happens in the fringe area of the radio station. Just because you were able to travel 100 miles from the radio station doesn't mean that you reached the fringe area. Stations that have their antennas up at a few thousand feet and are transmitting with upwards of 50,000 watts of effective radiated power means that even with a dinky antenna at 100 miles you can still do well. However, add in a competing strong local station and the distant station will be gone or as you travel away, you may have been able to drive 200 miles with the stock antenna vs the 100 miles with the stubby.
The only way to rate an antenna is to see its performance against the standard 1/4 wave antenna measured in decibels. To be a true measure, both antennas would have to be measured against the standard. Most antenna manufacturers who sell snake oil including the ones for the jeep fm antenna or especially CB antennas because there is a lot of money to be made in snake oil will hide the true gain figures for their product. Ham radio operators are mostly informed about snake oil and so antenna manufacturers will usually post the gain of the antenna. But even then, they try to inflate values using "tricks" to get you to spend money on their antenna vs the competition.
The best rule of thumb regarding fm antennas for vehicles is that the antenna that approximates a 1/4 wave antenna would be best. Absent that, the conductor in free space (actual length) being longer (up to 1/4 wave) would have better reception.
So, if you see this type of thread with short antennas, and are wondering if it is for you; you have to evaluate if shortening the antenna from stock is worth the degradation in reception or the price of the shorty when you already have a fine antenna on the jeep.