Antenna vibration

[Doug32 Member Find all posts View Profile Close Doug32]

Hi all
I am fitting out my first Prado dedicated for traveling and I have a question about antennas and vibration. I have been told vibration is a real killer of antennas and am not surprised after seeing what happens when doing rough tracks in my mate's Land Cruiser. It's the very high frequency type of vibration that would be the most damaging.

I am now a bit concerned about fitting a UHF antenna to the bullbar owing to the vibration factor as the bar is an unsprung mass. When I bought my current antenna I was told by the sales guy it makes sense to carry a spare owing to vibration if mounted on a bullbar. Instead I have been thinking of making a bracket that is bolted to the body (sprung mass) where high frequency vibration should not be a problem. (If it was you would feel it throughout the vehicle.) Yet on saying all of this, am I concerned over nothing? After all it's more common than not to mount antennas on the bullbar. I also wonder about driving lights mounted on the bar and the effects of vibration? Vibration must not be good for wiring and filaments etc.
Regards
Doug

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Its certainly possible to break the whips on bullbar mounted aerials, I know I have. The type of aerial will play a big part in that, I had a thin GME fiberglass one that lasted quite a few years before it broke up the Cape, the guy at the radio place in Weipa told me to get a stainless whip as these were the only ones that handled the corrugations up there. That one lasted less than 24hrs before it broke

I now run GME AE4705 Broomstick aerials and touch wood they have handled the vibrations for quite a few years without issue.

Cheers Andrew

[OldGreyFart Advanced Member Find all posts View Profile Close OldGreyFart]

I would be more worried about the impact of vibration on your driving lights. My antenna is a Uniden and on the bar and has coped so far with a lot of vibrations over 2 years but one of my driving lights supports failed in Arkaroola from metal fatigue and it cost me $over $400 to replace it as not covered by warranty.

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Bushcomm Stinger is the go
http://www.bushcomm.com.au/brochurel...%20Stinger.pdf

[JimmyC Advanced Member Find all posts View Profile Close JimmyC]

I have a GME AE4703 and it has copped a hiding and still going strong. What I like is that is 5cm or so higher than the roof racks so I can use it as a good height gauge

[hulbyw Senior Member Find all posts View Profile Close hulbyw]

My experience with 2 Prados and 3 different bullbars is that if you are going over severe corrugations you need a broomstick antenna (like the Bushcomm mentioned above or something similar. I use a ZCG broomstick and it is quite tough.
Cheers

[Doug32 Member Find all posts View Profile Close Doug32]

Thanks Guys. I have a 1.2 metre GME broom stick and looking at options rather than bullbar mountings. This weekend I hope to get time to check out the front of the Prado and see if I can install a purpose built bracket. If none exist, then on the bullbar she goes.
Doug

[Guest Close Guest]

Note that the bullbar is sprung mass. The only major items that are unsprung are things like the tyre, rims, rear diff.
The reason why the antenna may vibrate more is because it is further away from the source of vibration.

I installed my antenna on the awning on a knockdown bracket. It has better performance up high meaning less of a need for high gain antennas. a shorter antenna has less tendencies to break.

[404pug Avid PP Poster! Find all posts View Profile Close 404pug]

Whatever you do don't get one of the stainless ones with the springy bit in the middle. A day or 2 on corrugations will kill it. I have a 4.5 [short] and a 6 [long] db. GME fiberglass and they have been fine for 5 years until on the last trip the fiberglass whip came a bit loose and buggered the thread but that could happen to any of them. They are mounted on a 120 Sovereign bull bar [which has to have all sorts of bolts done up after a day or 2 on dirt- crap design.]

[Doug32 Member Find all posts View Profile Close Doug32]

Thanks for that. I thought as the bullbar is mounted on the chassis it would be unsprung mass - the sprung mass is everything above the springs. Anyway, I like the idea of the antenna fitted to the awning bracket when travelling in open areas.

[Doug32 Member Find all posts View Profile Close Doug32]

The advice about avoiding the 'stainless ones with the springy bit in the middle' was exactly the same advice given to me by the GME guy.

[Guest Close Guest]

The chassis is sitting on the springs, so it is sprung mass.

[r4ndll Avid PP Poster! Find all posts View Profile Close r4ndll]

The advice about avoiding the 'stainless ones with the springy bit in the middle' was exactly the same advice given to me by the GME guy.

And to me by a tour guide who does two desert and two high country trips a year.

[Richoson Avid PP Poster! Find all posts View Profile Close Richoson]

Well it is all very interesting, I have used the thin stainless one with the ballast in the middle no springs at all for years (18 to be precise), mounted to the aerial tab on the bullbar and only had one break at the ballast, the replacement part is $20.00 from any decent comms shop. I don't have a picture sorry, but I have seen plenty of the large fibreglass ones break.

See ya on the tracks, Richo.

[AussieAndy Find all posts View Profile Close AussieAndy]

It is funny Richo, cause I always used to run the ones you're talking about. They look good and work effectively. However I broke two on my Pajero, one on my Landcruiser and two on my current work ute. They all broke as you explained, right where the stainless meets ballast half way up, usually on the underside of it. Easily and cheaply fixed sure, but not so the dings they put in the bonnet every time they broke. When we bought the Prado I spoke to the GME rep at the 4wd show for a fair while, not just about radios but also places we had visited and what not, and he came up with the AE4705 being the best for us. Since getting one on the Prado I have also replaced the one on the work ute with one when the last stainless one broke. Just my experiences so far, I guess it differs for everyone.