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I am talking the antenna up front, center above windshield. I know on my Smart, the short stubby antenna messed up my reception and I only need to gain about 4 or 5 miles in reception. Numerous sites quote a 30% decrease in range when changing to a short stubby antenna, and the optimal length for FM reception is around 31 inches. Since I am in a relatively small town and my commute is across open countryside, that will make a difference. I guess I will know when I change antennas and try it out.
I will try for some pics tomorrow as it is a bit dark outside now. The 2M antenna will probably be a mag mount and since I am active in storm spotters and the local radio club, I am used to having my ham radio in the car (and truck) KE0JRT
The WIRE is optimally 31-39 inches depending on the frequency. The length of the MAST does not matter, except for line of sight. You could coil the wire up and get the same result or divide it into multiples of the frequency; i.e.: 1/3, 1/2, 1/10 , 2, 3 ,4, 10 etc the frequency. FM is in the 33cm band, so the length of the wire could be any multiple or divisor of 12.9 inches(33cm) usually 3*33 cm= 1M Multiples are better than divisors because they catch the wave multiple times..
The stubby after market antennas are of dubious quality and probably divides too small or not accurately, since the band stretches between 902-928 MHz they approximate somewhere in the middle; the shorter the more accuracy you need (a bit less than 1 cm is not as critical as a bit less than .5 cm). If a desired station is over the horizon raising the height of the wire can be beneficial if it makes the line of sight better, an inch or 2 does not make a lot of difference to the horizon.
The OEM antenna mast is about 16 inches with a 31-39 inch wire wrapped around it. But it only stands a few inches above the ground plane. There is an amplifier built into the antenna base that needs to be accounted for when tuning because it changes the shape of the reception "cone" (you might find that reception is better while travelling in one direction than the others.
I would expect a ham to know all of that, but things have changed to a "buy it and replace it" rather than build it yourself culture. My brother designed and built his first transmitter in the early 60's (13 years old) and fought with my father to hang a 20M wire between trees in the backyard. These days you don't even need to go to a major city to take the test for a license, he had to talk dad into driving 100 miles to Savannah, GA and know all of the math and Morse code involved. I picked a lot up from osmosis and age, not an expert.
I would not depend on info from "many sites" unless you understand the reasoning.
Kind of insulting remarks, but I have been in Ham radios for a number of years and I have made countless antennas over the years, many I still use daily. you are correct in what you stated, but the line of sight makes a big difference, and on a receiving radio, a few inches can make a big difference, as does the construction of the antenna. a 3" antenna is not as efficient as a 16" antenna. the WIRE inside is at a lower elevation on the stubby antenna and therefore loses it effective efficiency to detect a radio wave. The ideal length of the antenna (wire or whip if no wire is used ) is 31.234705228031146 inches. This is mostly for transmitting. I currently have 5 antennas mounted and active covering everything from 70cm to 160M and all but one I made myself. I have no problem getting out to countries across the world. farthest is Australia. I have a number of HT radios and they all work better getting rid of the stock 'rubber duckie" antennas and using a slightly taller whip. None are over 12-13 inches and it does make a big difference. my latest project is mounting a tri-band antenna on a 43 ft tower It is modified to pick up more bands than just 10m-40m. Antenna is roughly 30ft x 18ft and is a beam type with a rotor mounted on the tower to direct direction. Ran out of summer to get it put up.
In the spirit of Ham radio, I am always striving to make things a little better which is why I asked about installing a longer antenna. I have seen a number of HHR's with a longer antenna and wondered if the made a difference, thus my original post. I thought I could draw on some of the experiences on here rather than to start spending time on reinventing the wheel.
current antenna. As you can see in the first photo, it doesn't thread all the way down on the mount so I assume someone went for looks and not function. Vehicle came from a larger city which has a number of radio stations close by. I live in a smaller community 53 miles from there, and drive 43 miles to a larger city for work. After about 3-5 miles, I can pick up the destination radio station, so a bit more of an antenna could make a difference.
And yes, the sun roof is sealed for the winter until I can get the dented roof fixed so it will seal.
The stubby probably came with adapters Like this , possibly that’s why it doesn’t seat all the way down
I see corrosion on the threads with the stubby removed, could be water damage. Also the may be why the other antenna you purchased won’t fit in , that adapter has a larger thread.
The threads on the base don't look to be removable, and are clean. The antenna i ordered (that doesn't fit) did not have any adapters and has a 10-32 thread sticking out, much smaller than what is sticking out of the base, and is not removable. The new one I ordered has different adapters that can be crewed into the antenna, 4mm, 5mm, and 6mm which looks like a straight thread. I am guessing it will thread directly on to the base. I might pick up some rubber washers.
12-14-2021, 03:20 PM
