Three questions

Thanks Roachie for the info.Also thanks to Kiwi Ray.

I'm just wondering how having the aerials mounted on the front compared to say having them them mounted on a rack in the centre of the the vehicle would effect the groundplane and the transmission range of the radio

Merv..

Merv,
Most aerials these days are ground plane independant, so it doesn't matter much where you mount them. However, in the middle of the roof would be better simply because the vehicle itself would not be impeding a signal coming from behind you. I have my UHF on the b/bar and I don't seem to get as good range as other blokes in our club, but that could just be the fact i have an old Uniden (I believe the majority of forumites who say that GME are a better radio....so if mine ever packs up it'll be replaced by a GME). The others who get better/longer-distance reception than me also have b/bar mounted aerials, but different brands; so it could be that too.

It's not a huge problem, but it is a bit frustrating when someone else in our convoy is talking to another vehicle, say 6 klicks away, and I'm the only one who has to ask "what'd he say???"

Cya mate.

Merv

UHF Aerials (Non tech Stuff)

In essence the aerial is the 'core business' end of your radio setup. It will make or break the efficiency and effectiveness of what you hear and speak on radios (GME, Uniden, Icom) ,that for the sake of this thread we will ACCEPT are in 100% functioning mode, equal in output etc etc (Yep I know there are big differences, but we are talking aerials) .

Roachý is correct that unimpeded on top of the vehicle is best, however it will cause major headaches with over head object strike. If you don't wipe it off, it will bend over and not return to the perpendicular. I have experienced this twice with bullbar mounted aerials. Of course it depends on how far they get bent over and the quality of the spring base.

If you mount them on the bullbar, try and use the left side so that there is no argument that it is interfering with drivers line of sight.

Make sure that the mounting platform is on the vehicle side of the bullbar and not protruding on the front of it.

Avoid placing it side by side with another aerial (Eg CDMA) because contrary to popular opinion they will interfere with each other, regardless of being on different frequencies.

Now the next trick is to select the correct DBF gain for you situation. I am not going to recommend anything here, however what ever you choose will have a direct impact on the product your radio generates. So seek advice re same concerning the conditions you will be operating in and select wisely.

Now the last thing that is critical is the the method that is used to connect the coax cable into the antenna base.

Don't select anything that is not hard soldered or machine crimped into the base.

There is one type that has a little brass do-da that just slips in and is basicaly held there by friction. Cause more problems than a copper in a brothel.

Also don't buy the wire 'coat hanger' type as corrugated roads give them metal fatigue and they regularly breakoff . I had one of these. Good antenna, however I had to replace the aerial section twice because of the metal fatigue thing, so I went to a fibreglass one.

This will give you something to chew on so to speak.

Regards

Ken Robinson

Ken,

Am interested in your commentary on UHF antennas. Have a Mobileone 4dB gain antenna base mounted on the bullbar 200 mm from a CDMA antenna. The 4 dB antenna original failed in the first few months and I have replaced it with a 6 dB glass fibre stick, thinking it would reach further.

On the Simpson crossing we found out UHF would not perform any where near as well as our friends UHF of the same brand, same as original antenna. It has me in a quandry as to which way to go at the moment. Noticed it had not performed as well in the mountains earlier too.

I agree with you on the wire types almost entirely but has gone well on a bonnet mount on Falcon ute.

Make sure that you look at the fine print. It says

Please Note:
The contents of this publication are a guide only and cannot
be used as a reference to a point of law. For a detailed
explanation, refer to the Transport Operations (Road Use
Management - Vehicle Standards and Safety) Regulation 1999.