You most certainly do need a groundplane with a 1/2 wave antenna, you just need a smaller groundplane than with a 1/4 wave design.
Rege
This doesn't match my observations using a commercial 1/2 wave antenna with & without a ground plane on a 3 meter antenna test range.
fp
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I do "Ignore" those who consistently make outrageous or erroneous posts, you know who you are.
It all depends on the actual 1/2 wave antenna as to what "ground plane" means. A "coaxial" antenna, sometimes called an "elevated feed" antenna, incorporates the "other half" of the antenna which is separate from any "ground plane" and therefore does not require anything else. This is basically a dipole type of antenna in which the coaxial feedline goes through the counterpoise to the primary radiating element.
Antenna Specialists made a highband (basically 2-meters) mobile antenna for decades that was available in both unity gain (1/4th wave radiating element) and a 3 dB gain version. Maxrad now makes a 3 dB gain version of this same antenna. See for details
As far as I know, the quarter-wave radiating element version is not being manufactured commercially at the present time for highband. However, elevated feed antennas incorporating the same basic design are available for the 70 cm band, 800 MHz, and 900 MHz from several different sources.
I find that for local use, which is what most 2 meter stuff is, a 1/4 whip is fine. Mounted right, it will certainly fit under your garage door.
Now, for 'road trips' I have a double 5/8 antenna that's quite tall. That's because typically, the taller the antenna, the better off you are, when talking about 2 meter mobiles. I've also had great luck with 3/4 wave antennas out here in the corn fields, even though the 3/4 wave whip is alleged to be inferior to the 5/8.
Years ago, someone made an element that you could clip onto a standard 96 or 108" steel whip, typically used for 10 or 11 meters. This added element would turn the top end of the long whip into a 2 meter J-Pole. It looked a bit strange to see that matching element and a separate piece of coax, but the result was a 1/2 wave J-Pole about 10 feet off the ground - a 'killer' 2 meter mobile antenna! With a little effort, the 10 meter whip would still work on 10 but you didn't want to transmit on 10 with the 2 meter rig in place!
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So Max height probably means I will have to cut it myself.
All it means is that the base coil is the same height. Each of these comes with a 49" whip that must be cut for the frequency range you want to operate. 49" + 2.5" for the coil = 51.5"
It would actually be about an inch shorter when the 5/8 is cut, and about 9" shorter when the 1/2 wave is cut.
Joe
__________________ "FCC whacker": "A wannabee FCC agent who lives to find violations (real or imagined) anywhere he can. He will use the most narrow definition of the rules, if it suits him. He wants to enforce his interpretation of the FCC rules onto everyone."
If you buy an antenna from Larsen it will include a cutting chart that will give you the length to cut the whip for your frequency. You measure the whip.
You can download the Larsen cut charts from their web site.
It all depends on the actual 1/2 wave antenna as to what "ground plane" means. A "coaxial" antenna, sometimes called an "elevated feed" antenna, incorporates the "other half" of the antenna which is separate from any "ground plane" and therefore does not require anything else. This is basically a dipole type of antenna in which the coaxial feedline goes through the counterpoise to the primary radiating element.
Antenna Specialists made a highband (basically 2-meters) mobile antenna for decades that was available in both unity gain (1/4th wave radiating element) and a 3 dB gain version. Maxrad now makes a 3 dB gain version of this same antenna. See for details
As far as I know, the quarter-wave radiating element version is not being manufactured commercially at the present time for highband. However, elevated feed antennas incorporating the same basic design are available for the 70 cm band, 800 MHz, and 900 MHz from several different sources.
Glen, K9STH
There is a difference between a vertical 1/2 wave dipole,where the feed line is run thru the center of the bottom element to the feedpoint in the center of the antenna, and a 1/2 or 5/8 end fed vertical without a counterpoise.
The first uses a naturally balanced antenna, the second relies on the stray capacitance at the (usually hand held) transmitter to provide the "other half" of the antenna.
The first is good radio engineering.
The second is poke-and-hope.
Another problem, is many unsavvy users cannot differentiate between a 440mhz halfwave that works fine with "stray" coupling to the groundplane, and a 3.5mhz version where the "stray" coupling is hopelessly inadequate.
Anyway, back to the OP's Q, It's advertising, and we all know advertisers always tell the truth. LOOK at the antennas, the better built one (mechanically speaking) will almost always be the better working one.
Antenna electrical design was figured out over 100 years ago.
Rege
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Yaseu FT-2900 and 2 Larsen antennas one for mobile on a permanent NMO mount, and the other for the house on a base NMO mount on the roof.
I have 2 of the FT-2800M, which the FT-2900R has replaced. I don't move one radio back and forth. I have one in my vehicle, and the other in "the shack".
I'm not sure that trying to use a mobile antenna for your base will be beneficial. I'm using a B-Square Engineering J-pole on the top of 20' of TV mast, and it is giving me very satisfactory performance.
We appreciate your support.
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