How do I know what antenna to use?

[streaky]

My incar set is a UHF and VHF Icom unit that's been using a roof mounted mag-mount antenna.
For various reasons I can't use the roof anymore so I need to find another solution to mount the antenna.

I have accumulated a number of different antenna's over the years....how do I know which one is suitable for my set without damaging it?

Thx.

[LowRanger]

Do any of the antennas have anything written on them anywhere?

Usually,UHF will be smaller than VHF

[Lotz-A-Landies]

UHF antenna often have blue caps or blue stripes around the lower end.

HF CB usually don't have anything while GME usually have the model on the lower end.

If you're still not convinced go to your local amateur radio club (usually on a Saturday) and see if someone will test the antenna for you.

[michaelp]

Or post 1 good photo of all your antennas side by side and i should be able to tell which is what.

[wrinklearthur]

If you're still not convinced go to your local amateur radio club (usually on a Saturday) and see if someone will test the antenna for you.

What you need is a person with some antenna tuning equipment, I would look for a radio hobbyist that has a lot of aerials above their house roof.
Ask if they can help out with a VSWR* meter for UHF and VHF.

A nice example of a dual band VHF / UHF antenna.

http://www.aulro.com/afvb/attachment.php?attachmentid=55723&stc=1&d=1358473757

ref; Comet Mobile VHF/UHF Vertical Antennas SBB-1 - DXEngineering.com (http://www.dxengineering.com/parts/cma-sbb-1/media/images)

*( Voltage standing wave ratio )
.

[HowardSmall]

If it is a dual band transceiver do NOT use an antenna for a single band as it will be incorrect for the other band and could lead to damage.

You need to buy a dual band antenna but it must cover the frequencies you intend to operate on. There are plenty available from places like 409Shop.com HONGKONG RADIO sale Company ?????? www.409shop.com ?? ??KG-UV6D KG-UV920R UV-5R KG-UVD1p UV-3R VX-8R VX-3R VX-7R VX-170 KG-699E KG-669 KG-689 PX-777 PX-888 FT-897 FT-857 VX-177 VXA-300 KG-679 VEV-3288S V-1000 TG-UV FT-817ND FT-60R FT-897 (http://www.409shop.com) but they are usually for the amateur bands.

If you intend to use it on some frequency outside of the amateur bands then you may not be able to get a suitable dual band antenna. In that case get one for the frequency you will use but ensure the radio is not used on the other band.

Howard


My incar set is a UHF and VHF Icom unit that's been using a roof mounted mag-mount antenna.
For various reasons I can't use the roof anymore so I need to find another solution to mount the antenna.

I have accumulated a number of different antenna's over the years....how do I know which one is suitable for my set without damaging it?

Thx.

[streaky]

Howard.
Noted your comments on not using a single band antenna for my dual band set...but just to confirm......what if I only intend to use the UHF band ONLY using a single band antenna? Will this harm my set?

For those not familiar with life in the UAE and many other middle east countries...any sort of airwave communication by walky talkies, in-car mounted sets, home HAM radios is strictly forbidden and licences are not given to ex-pats unless they can prove it's for a legitimate business use or mobile phones can't be used. They are also extremely expensive and only given on a yearly basis.
There are places in Dubai that sell these items but only to local licence holders. I can't even buy antenna without a permit!

So we have our comms well hidden inside the car and only mount the antenna when we get outside of the city limits.
Even the tiny FRS walkie talkies for kids are banned here and you can face a hefty fine if you're caught using them.

[HowardSmall]

Clearly you have some problems! First up, if you are only going to operate on UHF then a UHF antenna will be fine.

More importantly is the issue of not drawing attention to your use of radio. You can buy disguise antenna that are used for surveillance vehicles. Generally they replace the car radio antenna and have connections for both the car radio and two way. You can also buy antennas that do not look like conventional antennas.

Another neat trick is to put a UHF quarter wave antenna on the rear parcel shelf. That will be about 15 to 20cm tall. Then put a felt hat or similar over it. It will still work fine but not be seen.

Finally there are multi purpose antennas. RFI in Australia manufacture some that will work for GPS, GSM phone and UHF. They look like the aerodynamic antennas you see on BMWs and the UHF antenna is very broadband, i.e. it will work over pretty well all of the UHF band.

Howard

[streaky]

Thanks for that info...it's very useful but in general I'm a complete nitwit when it comes to comms and simply expect to buy the gear...plug it all in and everything will be perfect no matter what!
Another issue I'm trying to overcome is my Discovery has a full length Autohome Roof tent so I can't mount an antenna directly onto the roof and neither can I use a Mag-Mount antenna.
My unit is an 'under the counter' sourced Icom IC-2720H and I have a gutter mounted antenna which basically just isn't getting any range past a few hundred feet. We use the channel freqs ranging from 462.5625 MHz upto 467.7125 MHz.
Which of the UHF low profile antennas would you recommend I get to work with my radio?
Should I go for this one? UHF Low Profile 450-470MHz - UHF Mobile - Mobile Antennas - RFI Wireless (http://www.rfiwireless.com.au/mobile-antennas/uhf-mobile/uhf-low-profile-tla600-70.html#.UREqBR2siSo)
I could mount it to the fiberglass shell of my roof tent?

Thanks again...I hate this kinda stuff.

[HowardSmall]

That will work. I have one on my defender and use it for UHF CB - works well.

It has an N connector on its base so you will need to cut a hole in whatever it is mounted on and have someone put an N connector on that end of your coaxial cable that connects to the radio antenna socket.

Howard

[streaky]

I received the quote for the UHF Lo-Profile antenna.

Next question is can they be mounted in any position... Vertically instead of the usual horizontal position?
How would it perform if it was mounted inside the car?

Thx.

[HowardSmall]

Best to mount it horizontally as that will give vertical polarisation which is what other vehicles will be using. You can mount it anywhere you like but the normal rules apply: best performance is obtained when it is high and clear, so on top of the vehicle is the place to go. The lower and more obstructed it is, the worse the performance. Of course this will not be an issue if you are only after short range comms. But if you are going to do that then maybe you should save money and just go for a ground plane independent antenna and camouflage it (back to the hat over the antenna idea).

Howard