• To anyone looking to acquire commercial radio programming software:

    Please do not make requests for copies of radio programming software which is sold (or was sold) by the manufacturer for any monetary value. All requests will be deleted and a forum infraction issued. Making a request such as this is attempting to engage in software piracy and this forum cannot be involved or associated with this activity. The same goes for any private transaction via Private Message. Even if you attempt to engage in this activity in PM's we will still enforce the forum rules. Your PM's are not private and the administration has the right to read them if there's a hint to criminal activity.

    If you are having trouble legally obtaining software please state so. We do not want any hurt feelings when your vague post is mistaken for a free request. It is YOUR responsibility to properly word your request.

    To obtain Motorola software see the Sticky in the Motorola forum.

    The various other vendors often permit their dealers to sell the software online (i.e., Kenwood). Please use Google or some other search engine to find a dealer that sells the software. Typically each series or individual radio requires its own software package. Often the Kenwood software is less than $100 so don't be a cheapskate; just purchase it.

    For M/A Com/Harris/GE, etc: there are two software packages that program all current and past radios. One package is for conventional programming and the other for trunked programming. The trunked package is in upwards of $2,500. The conventional package is more reasonable though is still several hundred dollars. The benefit is you do not need multiple versions for each radio (unlike Motorola).

    This is a large and very visible forum. We cannot jeopardize the ability to provide the RadioReference services by allowing this activity to occur. Please respect this.

antenna help

Status
Not open for further replies.

alex288288

Member
Joined
May 9, 2015
Messages
61
Location
oakville
so i tried looking through the forum before posting. and i cant find anything with what i am requiring,

First thing, i am looking for a car antenna, needs to be UHF 450mhz area... my question is:

If i purchase an antenna that states it will support 450 mhz, does this support the whole range?

example: my tx is 451. and rx is 456. will this 450 mhz antenna support these or do i need to look for a higher antenna rating like 470/480mhz?


Also does anyone have any where i can order a Car mount UHF antenna, from Canada area. thanks
 

mmckenna

I ♥ Ø
Joined
Jul 27, 2005
Messages
23,615
Location
Hiding in a coffee shop.
Depends on the exact type of antenna you get, but in basic terms, yes, an antenna advertised as "450MHz" will usually cover quite a bit on either side.

Different designs of antennas will have different useable bandwidths. Usually higher gain antennas have narrower useable bandwidth, lower gain antennas have wider useable bandwidth.

What you need to look at is the antenna specs. Usually there will be something like "30MHz bandwidth at 2:1 SWR" That says that you can expect nothing over 2:1 swr (pretty acceptable) over a 30MHz wide area, so 445MHz to 465MHz.

The exact type of mobile antenna you need depends on your mounting, local terrain, where your repeater is, and most importantly, what your license allows.

You'd need to look at your license and see what the maximum power you can run in your mobiles. It'll either be listed as TPO (Transmitter Power Output), which is the measured transmitter power off the rear connector when terminated to a 50Ω load, or it'll be listed as ERP. ERP is the total of the transmitter power, minus cable loss, multiplied by antenna gain.
Running a high gain mobile antenna can potentially put you over the allowed ERP. While this may seem trivial, it can actually cause lots of issues for other users on the frequency. Your "footprint" might exceed your allowed area of operations and cause someone else licensed on the same frequency but in another area to have interference issues.

As for antenna designs:
- Go with an NMO mount. This is the de facto standard in the commercial/public safety two way radio industry. Using the standard NMO mount will let you use a wide range of antennas from many different manufacturers. The NMO mount is designed to be used in mobile environments.
- Go with a known good brand. Larsen, ComTelco, Laird, etc. Avoid the cheap Chinese/Taiwanese knock off antennas from Browning/Tram. You might save a few dollars, but you'll pay in the long run. Get a good antenna/mount now and it'll easily outlast your vehicle.
- Think carefully about your antenna choice. High gain antennas, besides the ERP issues, can work against you in mountainous terrain. I know you are in Hamilton, and that's pretty flat, but you said in your other post that the system is going somewhere else. High gain antennas work by focusing more power at the horizon. That can work well in the flat lands, but in high mountains, it can cause coverage issues.
Sometimes lower gain antennas will work better. Also, they are shorter and lower profile.
- Drill the hole and install the antenna correctly. It'll work a lot better and avoids the drawbacks of magnetic our temporarily mounted antennas.

Not sure where to order up there, but most amateur radio dealers will often carry a few of the commercial antenna brands. A simple 1/4 wave Larsen NMO mount antenna should run you less than $20.
 

jwt873

Member
Premium Subscriber
Joined
Dec 1, 2015
Messages
1,620
Location
Woodlands, Manitoba
example: my tx is 451. and rx is 456. will this 450 mhz antenna support these or do i need to look for a higher antenna rating like 470/480mhz?

Also does anyone have any where i can order a Car mount UHF antenna, from Canada area. thanks

Just to add.. The antenna has to be resonant at your transmitting frequency. As mmckenna points out, the SWR should be less than 2:1. But, this is not so for receiving. You're not dealing with any power on receive, so SWR doesn't come in to play. You're using a standard 5 Mhz repeater split so you definitely won't need any special sort of antenna. Just get one cut for your TX frequency.

I shop at ham radio stores... Radio World - https://radioworld.ca and Durham radio - Durham*Radio*Sales*and*Service*Canada But, any outfit dealing with commercial mobile communications can help. (I agree with mmckenna. Go for an NMO Larsen mount. They are professional quality).
 
Status
Not open for further replies.
Top