Antenna for 450-490 MHz band question

[EasternMassScanFan]

Looking for the best NMO antenna from that covers the 450-490 MHz. I monitor PDs in the 450 to 460 range and in the UHF T-Band and I was wondering if an antenna that covers 450-470 Mhz would work fine in the T-Band also. The antenna I am looking at is linked below. Just wondering if the antenna linked below would work fine for my application.

B4503: 450-470 MHz Mobile Base Coil NMO Mount Antenna- Metalic Ground Plane Required | Arcadian Antenna

Try ArcAntenna.com for Laird/Antenex B4503 antenna speicification, techical assistance or to buy now.

www.arcantenna.com

 

[nd5y]

The matching network in the base of that antenna probably limits the bandwidth.
For receiving only a 450-470 straight 1/4 wave whip (no matching network) will work from 400-500 MHz or more.

 

[mmckenna]

1/4 wave UHF antenna. About 6 inches tall. Will cover the entire UHF band with ease.

The antenna you linked to will give you some more gain, but unless you are really on the fringes, that's not going to be necessary.

 

[EasternMassScanFan]

1/4 wave UHF antenna. About 6 inches tall. Will cover the entire UHF band with ease.

The antenna you linked to will give you some more gain, but unless you are really on the fringes, that's not going to be necessary.

As I was curious, I picked up a B4503. Despite the longer length of this antenna, my Laird UHF quarter wave 450-470 seems to perform better while in motion. Is it because the B4503 is cut for a specific range/it is not a quarter wave antenna?

 

[mmckenna]

As I was curious, I picked up a B4503. Despite the longer length of this antenna, my Laird UHF quarter wave 450-470 seems to perform better while in motion. Is it because the B4503 is cut for a specific range/it is not a quarter wave antenna?

the Laird B4503 is a 5/8th's wave antenna. It has about 3dB of gain. That extra gain comes by compressing the pattern. That compressed pattern can work against you in some applications. It also has narrower bandwidth, so depending on the frequencies you are listening to, it might be outside the range.

Not surprised. I've found 1/4 wave antennas usually work just fine for my own use. I've gone through the all the various types of antennas, 5/8, 1/2 wave, etc. I usually end up back with 1/4 waves.

 

[Ubbe]

I had a taxi cab customer that complained about poor VHF radio performance when on the highway. Another company had put 5/8 antennas on the cars which bent from the wind resistance at highway speeds. It was enought to make the antenna perform very poorly. I switched to 1/4 wave antennas on all cars and no more problem. There's not enought gain difference between antennas to make it wortwhile in most cases to switch to a bigger antenna that flex in the wind.

/Ubbe

 

[jcemt]

I always use the Maxrad MLPV450 salt shaker style antennas for this type of application as they have a huge bandwidth and work great.

 

[speedway_navigator]

A dealer in TX has gone back to 1/4 wave from gain after switching to DMR, the extra coverage from DMR eliminated the need for gain antennas. He's in a hilly area so I was wondering if the compressed horizontal pattern from a gain antenna might have been pointing too low or high over the horizon depending on the vehicle's orientation when the radio keyed up.

 

[freddaniel]

The amount of gain in the larger antenna would not cause a noticeable effect on the horizon, relating to the up-hill or down-hill position of the car, as the gain is typically less than 3 dB. The difference most likely occurred with the complete analog system was replaced with DMR and the faulty cable or water-filled connector was replaced. Mobile gain antennas improve mobile receive by increasing the "capture area" of the antenna when traveling in fringe areas, or on tree-lined streets which cause picket-fence flutter, or if the antenna is not on the roof but on the trunk lid. Typically, a normal person cannot easily identify signal level changes less than 6 dB by ear.

 

[Project25_MASTR]

Maxrad/PCTEL wideband knobs FTW. My professional opinion, a roof mounted unity gain knob will outperform a 1/4 wave whip in digital applications above 430 MHz. Granted, there are some applications where you just don't put knobs (like when you know the antenna may hit something such as on the roof of a school bus). Other than that, I typically will only use gain antennas when a roof mount is unacceptable (per the customer)...then again I've also been known not to guarantee coverage for anything other than a unity gain antenna solution.

 

[jcop225]

Looking for the best NMO antenna from that covers the 450-490 MHz.

PCTel MWU4002S

https://www.pctel.com/wp-content/uploads/2018/11/Product-Datasheet-1.pdf