Sirio CX455 455-470MHz UHF GMRS Base Antenna range question

[wpwx694]

I bought Sirio CX455 455-470MHz UHF GMRS Base Antenna
For the house

3/4 Wave UHF antennas for base station service made of hi-quality materials to get the maximum efficiency and the best performance.

Features:

Base station antenna, Mono-band
Low-gain, Omnidirectional
Protection from static discharges DC-Ground
Made of aluminium alloy 6063 T-83
Electrical Data

Type: 3/4 Wavelength coaxial J-pole
Frequency range 455-475 MHz
SWR less than 1.5: 455-475 MHz
Impedance: 50Ω
Radiation (H-plane): 360° omnidirectional
Radiation (E-plane): beam width -3 dB = 60°
Polarization: linear vertical
Gain: 2dBd - 4.15 dBi
Max. power (CW) : 250 Watts
Grounding protection: All metal part are DC-grounded, the inner conductor shows a DC-short
Connector: N-female

The Carlos, TX Repeater is 27mi from my house (Navasota, TX)

Height: 170′

And

Montgomery, TX repeater
26mi from my house (Navasota, TX)

Height 200'

Can I hit iit with this antenna at my house (Navasota) with a 50 watt radio

 

[mmckenna]

Without knowing EXACTLY where your antenna is located, how high it is, what kind of coax, sensitivity of your radio, quality of the repeater, it would be a total guess on our part.

The easiest way to check is for you to try it yourself.

Distance to horizon starts to play into things here. The curvature of the earth will work against you beyond a certain range. At 200 feet high, the Montgomery TX repeater will have about 17 miles to the horizon. You can add range by raising your antenna up higher. But you need to consider that the ground is not flat between you and the repeater.

There is software that will figure this out, but you would have to supply a lot of very specific details about your installation, some, like your street address, you may not want to share.

 

[wpwx694]

Without knowing EXACTLY where your antenna is located, how high it is, what kind of coax, sensitivity of your radio, quality of the repeater, it would be a total guess on our part.

The easiest way to check is for you to try it yourself.

Distance to horizon starts to play into things here. The curvature of the earth will work against you beyond a certain range. At 200 feet high, the Montgomery TX repeater will have about 17 miles to the horizon. You can add range by raising your antenna up higher. But you need to consider that the ground is not flat between you and the repeater.

There is software that will figure this out, but you would have to supply a lot of very specific details about your installation, some, like your street address, you may not want to share.

cm 400 with n Connectors and 20 ft in the air

 

[wpwx694]

Without knowing EXACTLY where your antenna is located, how high it is, what kind of coax, sensitivity of your radio, quality of the repeater, it would be a total guess on our part.

The easiest way to check is for you to try it yourself.

Distance to horizon starts to play into things here. The curvature of the earth will work against you beyond a certain range. At 200 feet high, the Montgomery TX repeater will have about 17 miles to the horizon. You can add range by raising your antenna up higher. But you need to consider that the ground is not flat between you and the repeater.

There is software that will figure this out, but you would have to supply a lot of very specific details about your installation, some, like your street address, you may not want to share.

Laird TE Connectivity CRX450B is this better

 

[mmckenna]

UHF is line of sight. It's not going to bend around hills very well.

20 feet high is going to give you a bit over 5 miles to the horizon. Add in the 17 mile line of sight for the repeater, and you might come up a bit short.

The easy answer is for you to put the antenna up and give it a try. Like I said, without having the exact locations of the repeater and your home, anything we do is going to be a guess. Also, what works for someone in another part of the country is not going to mean it'll work for you. Your local topology is going to be different than everyone else's. There is coverage plotting software that would tell you for sure, but it's expensive. You might find some online tools that will give you an idea of range, and won't require you posting your home address here.
Try this site:

RF Line of Sight - SCADACore

RF Line-of-Sight provides radio path information for mapping long distance SCADA radio communications by using antenna height and topography.

www.scadacore.com

The Laird has some more gain, but gain isn't going to magically pull the signal through the hills.

 

[mmckenna]

Using the above website and using the center of both towns, it looks like:

No straight path between your town and Montgomery TX. You'd need a 140' tower on your end to get over some hills that lay between you and the repeater.
There are some funny things that happen with RF, called "Knife Edge Diffraction", but it's not likely to be reliable enough to make for a good path with your current setup.


No straight path between your town and Carlos, TX, either. You'd need a 190' tower to get over obstructions.


But, again, try it and see if it works. Computers/math can be wrong and won't take into account all the variables. I wouldn't rely on it working, though. One of the problems with terrain such as yours.

 

[wtp]

if you have a radio/scanner, can you hear it ?

 

[wpwx694]

if you have a radio/scanner, can you hear it ?

Yes

 

[wtp]

so if you hear it, it should 'hear' you.

 

[wpwx694]

I decided to send it back and get a

Comet CA-712EFC​