Type of antenna?

[kyparamedic]

We have some UHF M1225's and CM300's that were given to us from an agency that has gone to 800 MHz. What antenna do we need to get, HAE4003A or HAE4011A? We have rolling terrain. Some flat areas but also a lot of hills and valleys. Some of the places we may need to talk to could be 25-50 miles away. Also, will the cabling that comes with it connect directly to the radios or will we need some sort of adapter?

Thanks.

[FireCpt809]

Use the gain antenna. With the terrain being hilly every extra db of gain wont hurt.

[Motoboy]

The antenna kit comes with everything you need to connect to the radio, including the Mini-UHF connector. It is supplied loose, though, and you will need a coax crimper to install it, with the correct dies for that cable / connector.

[FireCpt809]

You can order kits from Tessco any one of many suppliers that have the Mini UHF attached. It may even be cheaper than what M charges

[rocketman]

Before you order any antennas, you need to check your license to verify: 1. allotted power output per the license, and 2. ERP as allowed by the license.

[AEC]

Antenna gain can play against you in hilly terrain, as the signals radiated from a standard 1/4 wave will actually work better in such terrain, while a gain antenna will surpass the 1/4 wave in level(urban) terrain in most cases.
The same applies to dense urban jungles where the majority of systems are on high buildings, Driving about in such areas with a gain antenna will actually perform poorer than the ubiquitous 1/4 wave, due to the radiation pattern of both antennas.
The 1/4 wave radiates better upward, covering a larger section of the higher buildings, and a 3dB agin antenna provides a better radiation pattern closer to ground, where it's needed more for distant systems.

A simple drive test will confirm the results you will obtain...

E.R.P is a license classification, and no matter the gain(within actual reason) will a 3dB (VHF) antenna step into the bounds of excessive E.R.P for a given license class.
If one worries about a mobile doing such, then program the output to never encroach into such troubled areas, then you are safe, no matter what type of antenna you select to utilize.

[rocketman]

I totally concur with the above post regarding radiation pattern characteristics. Have done extensive testing with a similar situation and we finally found that the 1/4 wave was the antenna of choice. In valleys and behind hills, the 1/4 wave shines....the gain antennas were just dumping signal into the hillside. causing multipath issues....we had more deadspots with the gain antenna than the 1/4 wave in the hilly terrain...we eventually added some voting receivers to make portable coverage 100%, but still use the 1/4 wave mobile antenna

[RadioSouth]

Didn't see any mention of a repeater ? The 25-50 mile range you're looking for isn't attainable direct mobile to mobile.

[rocketman]

The original poster stated UHF....and judging by his description of the terrain, one would have to surmise some sort of repeater would have to be employed in the mix...25 to 50 miles on UHF simplex under the stated conditions won't happen

[Bill_G]

As already mentioned, antenna gain can work for and against you in hilly and mountainous terrain. It's a double edged sword. 3db boost on the receive side might mean that last mile that you wouldn't have with a unity gain antenna. For those that understand the problem, having both in your car is an option. You can switch them when appropriate.

From the plots I've done, I think I prefer mountainous terrain over the wash board hills I've seen back east. We have very distinct coverage zones with almost complete isolation between valleys. It also means that coverage in one area may be only five miles, and in another more than twenty.