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brownpage · 11-23-2003, 10:47 AM

Quote: Originally Posted by Naamanf

FM radio is in the 90-110 mhz range. The size of the radio waves is very different. And in simple terms the size of the wave (due to it's frequency) will determine the size of the antenna. The lower the frequency the larger the antenna.

Thanks a lot for the explanation. Yes, FM radio is 90-110mhz range. And that means FM wave has a wavelength of about 3 meters. And for normal AM radio, the range is 535khz-1.7Mhz, that means AM wave has a wavelength of about 300 meters. So we need to pull out car antenna to get better reception of AM signal, which is often not so good.
Then, for GPS, which has a frequency of 1575.42Mhz, that means a wavelength of about 0.2 meters. This is not a so small length compared with the size of car antenna. As we can pull out the antenna to get better reception of AM radio, we may also retract the antenna to get better GPS signal. And, actually I often let my antenna stay very short and the Fm reception is still fine.

no intention to bother. THanks a lot for reply. That makes me more practical on the antenna issue.

11-23-2003, 10:47 AM	#5
brownpage Newbie Join Date: Nov 2003 Posts: 6 My Photos: ()	Quote: Originally Posted by Naamanf FM radio is in the 90-110 mhz range. The size of the radio waves is very different. And in simple terms the size of the wave (due to it's frequency) will determine the size of the antenna. The lower the frequency the larger the antenna. Thanks a lot for the explanation. Yes, FM radio is 90-110mhz range. And that means FM wave has a wavelength of about 3 meters. And for normal AM radio, the range is 535khz-1.7Mhz, that means AM wave has a wavelength of about 300 meters. So we need to pull out car antenna to get better reception of AM signal, which is often not so good. Then, for GPS, which has a frequency of 1575.42Mhz, that means a wavelength of about 0.2 meters. This is not a so small length compared with the size of car antenna. As we can pull out the antenna to get better reception of AM radio, we may also retract the antenna to get better GPS signal. And, actually I often let my antenna stay very short and the Fm reception is still fine. no intention to bother. THanks a lot for reply. That makes me more practical on the antenna issue.