High gain 800 Mhz NMO

[sonm10]

What is the difference between these antennas? Is there a difference between 1/2 over 1/4 VS 5/8 over 5/8? Thanks

PCTEL Maxrad MUF8325 825-896 MHz 5 db Gain Mobile Antenna - 5/8 wave over 1/4 wave - NMO - 25 in

PCTEL Maxrad MUF8325 825-896 MHz 5 db Gain Mobile Antenna - 5/8 wave over 1/4 wave - NMO - 25 in

theantennafarm.com

806-866 MHz 5dB Gain 5/8W Mobile Two Way Radio Antenna TE Technologies B8065C

Laird TE Connectivity B8065C 806-896 MHz 5dB Gain 5/8W Mobile Two Way Radio Antenna

theantennafarm.com

PCTEL Maxrad MUF8005

806-866 MHz 5 dB gain trilinear low profile heavy duty base, antenna only. Maximum Power 200(Watts), Whip Length 25

theantennafarm.com

 

[mmckenna]

The MUF8325 and the MUF-8005 are for different sections of the band.

The 8325 is geared more towards the SMR/Cellular band.
The 8005 is geared towards the LMR band.

The Laird is also aimed at the LMR band.

Different radiation patterns between the 5/8 over 5/8 and the 1/2 over 1/4.

 

[sonm10]

The MUF8325 and the MUF-8005 are for different sections of the band.

The 8325 is geared more towards the SMR/Cellular band.
The 8005 is geared towards the LMR band.

The Laird is also aimed at the LMR band.

Different radiation patterns between the 5/8 over 5/8 and the 1/2 over 1/4.

Can you explain the radiation pattern, please. I'm looking for more signal from the horizon.

 

[mmckenna]

Can you explain the radiation pattern, please. I'm looking for more signal from the horizon.

The radiation pattern has to do with how the antenna achieves 'gain'. Since it can't physically increase the amount of signal, it just focuses the power in a way that benefits the radio.

Depending on the application, the radiation of the pattern can send (or receive) better in certain directions. Since omni-directional antennas receive equally well in all directions around the antenna, they can focus how much energy is sent (or received) from the horizon.
1/4 wave antennas have a more spherical shape radiation pattern. It sort of blasts power below and well above the horizon. That can work great in mountainous locations where the repeater may be well above the horizon.
5/8th's wave antennas have more gain than a 1/4 wave, usually 3dB more. The way it gets that gain is by smashing down the radiation pattern more towards the horizon. That works great in flat terrains.

For your application, the 5/8th's over 5/8th's antenna will probably give you the better performance.

 

[prcguy]

All the antennas listed in the first post are rated 5dB gain. 5dB over what? I'm sure its 5dBi gain as you can't get 5dBd from such a small antenna. BTW, 5dBi gain would be 2.8dB gain over a dipole and that's about right. A 5/8 wave monopole has slightly more gain than a 1/4 wave monopole and when you stack them as in the examples listed in post 1 its not very effective, you don't get 3dB gain for adding the second 5/8 wave element. Partially because the spacing between the two 5/8 whips is not optimal and the bottom whip radiates some energy before it gets to the top whip. As far as the two 5/8 waves vs two 1/2 waves over a 1/4 wave, if they all have the same gain then its just different means to get to the same gain.

Antennas acquire gain by giving up signal in some directions and concentrating it in other directions. In this case the goal is to put the most signal at the horizon and that is where these antennas would have been or should have been tested for gain. I see the 5/8 over 5/8 is 19" long where the others are 25" long, so it appears for the size a 5/8 over 5/8 would be a better choice.

 

[sonm10]

Thanks for the responses. I will be going that route.