UHF antenna placement and "ground"

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Re: UHF antenna placement and "ground"

Post by mahna » 07 Oct 2014, 9:40 am

Well the roof is out...

I guess I'm going with regular quarter panel mount to keep it above the bonnet then.
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Re: UHF antenna placement and "ground"

Post by Chronos » 07 Oct 2014, 10:04 am

BBJ wrote:
Apollo wrote:It's already been said..... ;)


Bah, I had the window open and left the computer for a few hours.

When I got back I did my reply and a bunch had come in without me seeing.

Need to learn to refresh.

"I have HF, VHF & UHF Antennas mounted in positions that are not ideal but the best I am going to do as I'm not drilling holes in a roof."

That's why I said what I said. Everyone says centre of roof is the answer when they don't do it themselves because they know it's not practical. So... Yeah, not useful advice really?

2c.


Yeah it's about how you read the op's question

"I've got a UHF radio on the way for the ride, looking for advice on the best mounting position"

There's no argument the center of the roof is the best position as far as signal strength goes but for most it's not practical.

I hate front bar mounts but installers love them because the mountings are usually already there and cable running is easy because it runs through the firewall and there's no fiddling with roof linings or trim

I don't have a front bar so I mount mine on the roof using a magnetic base when I need it, it usually lives on the back seat and works fine there for vehicle convoys

If people put more effort into writing an informative post and answering the op's question instead of taking the opportunity to put sh1t on other forum members these threads would be a great source of reference for others.

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Re: UHF antenna placement and "ground"

Post by Warrigul » 07 Oct 2014, 11:14 am

Combat_Wombat wrote:Knowing the theory on a topic is always important but at the end of the day there is ground truth...

Just like against all aparent odds my set up worked just fine.

I'm a sparky and out of all the engineers I've dealt with the only ones with a clue at all all did their trade first.


Yep, the great majority of Uni engineers are d**kheads.

Engineers were originally weaned with dirty hands and their knowledge was borne out of what worked in practice but somehow it has turned around and it is now okay to say that book learning is a substitute for nouse.
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Re: UHF antenna placement and "ground"

Post by Lorgar » 11 Oct 2014, 10:29 am

Warrigul wrote:Engineers were originally weaned with dirty hands and their knowledge was borne out of what worked in practice but somehow it has turned around and it is now okay to say that book learning is a substitute for nouse.


I work with a guy who is an engineer (now businessman) who worked for ExxonMobil for years doing a lot of their on-paper stuff.

Smart guy, utterly useless at anything that vaguely resembles the "hands on" side of it though.
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Re: UHF antenna placement and "ground"

Post by tom604 » 11 Oct 2014, 9:16 pm

i mounted mine on my roof rack and the short one is 6db or something like that the long is 9 whatevers, short for hills long for flats. just use the short one on mine. sorry i missed the start of this thread it seemed like it was fun :lol: :lol:
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Re: UHF antenna placement and "ground"

Post by Jack V » 12 Oct 2014, 8:29 pm

A radio is an emergency piece of equipment in addition to any other use so why put the antenna where it could be destroyed in a crash or if you hit a cow , roo or deer and I have seen them shot off!

A short stainless whip on the roof will transmit just as well as a longer antenna mounted on the bull bar with a better radiation pattern. It can be taken off quickly when navigating low trees etc. On a magnetic mount it will knock over and usually re clamp if it gets a bad nock as long as some slack is in the cable .

Stick a thin film of rubber under the magnet to stop it scratching the paint job. Seal the cable connections with silicone. In thick bush I would take mine down and stick it on the bonnet , still works about 75% as good.

You can get short Broadband dipole antennas for UHF that are ground independent for a bull bar .
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Re: UHF antenna placement and "ground"

Post by Hugh » 12 Nov 2017, 1:32 pm

WOW Ok flame suit on,Middle of roof is best place of course,i have found in the real world being interested in radio comms and having one in car since my 20s both hf and uhf that where ever you put it ,ground independent or not a good earth is always a great idea.The other is the longer the better,a know everybody says the smaller ants are better for hilly country because of different angle of radiation but I have found the extra gain more than makes up for it.I have had all different types on my car over the years mostly bulbar mounted.All I know is when up in hills deer shooting I'm the always the one relaying messages between different 4wds when they cant hear each other.I run the six foot fiberglass type.Not saying anybody is wrong or right,just my experience.Having said all that running the 6 ft around town not just for parking underground ,but the amount of traffic that comes in to it from Suburbs,ballarat and Bendigo if you have right weather conditions can be a pain but that's what the sq is for.
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Re: UHF antenna placement and "ground"

Post by SendIt » 13 Nov 2017, 12:35 pm

I'll jump into the fire here too.

About mounting a UHF antenna in the middle of the roof...

Someone find me a picture of someone, anyone, who's actually done it.
Last edited by SendIt on 13 Nov 2017, 3:49 pm, edited 1 time in total.
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Re: UHF antenna placement and "ground"

Post by Hugh » 13 Nov 2017, 2:35 pm

Here you go
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Re: UHF antenna placement and "ground"

Post by SendIt » 13 Nov 2017, 3:53 pm

I'm going to say no.

We're talking about mounting a UHF radio antenna here.

Not accessorizing your car to match your tin foil hat.
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Re: UHF antenna placement and "ground"

Post by Daddybang » 13 Nov 2017, 3:54 pm

Mines on the bull bar and never had a problem with it. I spend A LOT of time on overgrown tracks with trees etc hanging down and getting out to remove one from the roof all the time would just be a pain in the rear!!! :drinks:
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Re: UHF antenna placement and "ground"

Post by on_one_wheel » 13 Nov 2017, 5:56 pm

At the end of the day, a uhf is only good short range communication with the exception of those very limited areas where you can hit a repeater. They shouldn't be relied on for emergencies, that's where satellite phones and HF radios are good.

Most people mount antennas on the bullbar, that's where mine is and it works just fine.
If it were on the roof the tip woukd stand 3.3 meters from the ground, I'd smash that on a tree within the first hour of driving... that's somewhat impractical.

Mounting it on the bar will just make your signal directional.
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Re: UHF antenna placement and "ground"

Post by Hugh » 14 Nov 2017, 3:27 pm

Uhf is fairly short range but if you get enough height you will be surprized how far it will go,get a descent ant and set and you could punch out a long way,when I lived up in the hills[Dandenong ranges] I could most of the time talk to some stations in Devonport and Launceston,and in right weather conditions you could get something called ducting and it would come in from different parts of au.
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Re: UHF antenna placement and "ground"

Post by doc » 14 Nov 2017, 3:31 pm

SendIt wrote:I'll jump into the fire here too.

About mounting a UHF antenna in the middle of the roof...

Someone find me a picture of someone, anyone, who's actually done it.


I don't have photo's but I know of 2 people who have done it - drilled holes the works. It's uncommon but still done.

The OP said that he was "looking for advice on the best mounting position". Depending on how you translate 'best' but if you mean best gain then that is the most accurate statement.

When I see most people talk about UHF's and good reception I'm reminded of Jeremy Clarkson yellowing "POWER!!!!" whilst plowing ahead full steam getting little to no where. :lol: Power only helps with transmit.

Antenna gain is far better than power gain in most situations - as it works in both directions. Talk to HAM radio enthusiasts and they'll give you a 3hr conversation about it. 8-)

Obviously for most - 'best' will be a combination of antenna gain, practicality, amount of work involved, and aesthetics. For some - antenna gain trumps the others, but for most of us - our pride and 'looks' tend to come into a big play. "I'll never be caught dead with that looking like that" :lol:
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Re: UHF antenna placement and "ground"

Post by Blackened » 14 Nov 2017, 8:56 pm

doc wrote:Talk to HAM radio enthusiasts and they'll give you a 3hr conversation about it.


Sounds riveting :sarcasm:
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Re: UHF antenna placement and "ground"

Post by Gamerancher » 15 Nov 2017, 9:16 am

Who wanted a picture of one mounted in the middle of a roof?
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