Has anyone mounted an Autotune HF Arial to a Mux bullbar, if so can I ask how it was done..?, Does it affect airbag compatibility or any regs, I'm in Queensland...
Greg 1 said
02:04 PM Jan 11, 2020
I very much doubt that an ariel will have any effect on correct airbag deployment as the air bag sensors are behind the bumper. I don't think you will have issues either with registration provided the brackets fitted face rearward and not forwards so to make a dangerous projection.
As far as fitting goes, there are aftermarket brackets for this purpose. Try someone like Jaycar or a good automotive shop.
Possum3 said
03:42 PM Jan 11, 2020
Welcome Wandy,
Are you talking about a full "Bull-Bar" or, a "Nudge Bar"? - I only ask as most bull bars have mounting lugs welded to the inside top rail of the bar.
Mike Harding said
05:17 PM Jan 11, 2020
HF autotune? So I assume you are talking about a Land Mobile system? VKS737 or the like with a Codan or similar radio putting out up to 125W (iirc)?
I would not mount it on the bullbar for a few reasons:
There is no significant (or even insignificant) ground plane in this location.
125W of RF that close to the vehicle electronics is a bad idea.
During tuning there will be serious mismatches (albeit probably lower power) - this is not good for the vehicle electronics.
Those antennas are large and will obscure vision and be distracting.
Hylife said
03:37 PM Jan 16, 2020
Whilst many folks mount all sorts of things such as spot lights, LED Light Bars, and antenna to their bull bars, it is in fact "100% absolutely illegal" to have anything mounted to your bulbar that protrudes above the bonnet and that includes antennae.
FYI, UHF CB is 477 Mhz which means a full wavelength of 63cm. A quarter wave whip antenna at that frequency is only 15.7cm.
There is absolutely no reason to mount to your bull bar an oversized whip that only has a shielded wire running up the insides with a tiny 15cm spiral wire at the top and a half wave whip without a ground plane is worse than a quarter wave.
Mounting an omnidirectional whip antenna to the middle of your car roof forms a mediocre ground plane and improves radiation at lower HF groundwave frequencies such as the old CB 27Mhz we used to use where a full wavelength was 11 meters with a 2.8M quarter wave and the quarter wave whips were huge spiral wound beasties mounted on springs.
At 477Mhz you are radiating and receiving almost exclusively as "strictly line of sight".
A 5watt UHF hand held with a straight quarter wave rubber ducky on top will cover the same distance as a 5watt dash unit with an oversized bull bar mounted whip.
Oh, and remember that every metal surface will act to reflect your signal in the opposite direction, so if your full height van is in tow then approximately 60% of your immediate rearward signal is reflected forwards and if your bull bar whip is corner mounted you now have enlarged by approx. 25% the radiation lobe to that corner, ie, more directional to that direction.
Guys, please go talk to a HAM who has many years of antennae design and building up their sleeve instead of believing all the 4x4 TV shows and their marketing nonsense.
Has anyone mounted an Autotune HF Arial to a Mux bullbar, if so can I ask how it was done..?, Does it affect airbag compatibility or any regs, I'm in Queensland...
Are you talking about a full "Bull-Bar" or, a "Nudge Bar"? - I only ask as most bull bars have mounting lugs welded to the inside top rail of the bar.
HF autotune? So I assume you are talking about a Land Mobile system? VKS737 or the like with a Codan or similar radio putting out up to 125W (iirc)?
I would not mount it on the bullbar for a few reasons:
There is no significant (or even insignificant) ground plane in this location.
125W of RF that close to the vehicle electronics is a bad idea.
During tuning there will be serious mismatches (albeit probably lower power) - this is not good for the vehicle electronics.
Those antennas are large and will obscure vision and be distracting.
FYI, UHF CB is 477 Mhz which means a full wavelength of 63cm. A quarter wave whip antenna at that frequency is only 15.7cm.
There is absolutely no reason to mount to your bull bar an oversized whip that only has a shielded wire running up the insides with a tiny 15cm spiral wire at the top and a half wave whip without a ground plane is worse than a quarter wave.
Mounting an omnidirectional whip antenna to the middle of your car roof forms a mediocre ground plane and improves radiation at lower HF groundwave frequencies such as the old CB 27Mhz we used to use where a full wavelength was 11 meters with a 2.8M quarter wave and the quarter wave whips were huge spiral wound beasties mounted on springs.
At 477Mhz you are radiating and receiving almost exclusively as "strictly line of sight".
A 5watt UHF hand held with a straight quarter wave rubber ducky on top will cover the same distance as a 5watt dash unit with an oversized bull bar mounted whip.
Oh, and remember that every metal surface will act to reflect your signal in the opposite direction, so if your full height van is in tow then approximately 60% of your immediate rearward signal is reflected forwards and if your bull bar whip is corner mounted you now have enlarged by approx. 25% the radiation lobe to that corner, ie, more directional to that direction.
Guys, please go talk to a HAM who has many years of antennae design and building up their sleeve instead of believing all the 4x4 TV shows and their marketing nonsense.