UHF aerial mount position?
Submitted: Sunday, Aug 11, 2024 at 18:22
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Member - bungarra (WA)
I have always mounted these on the bullbar of successive vehicles over the years.
The last 10 years the bar has been decorated with both the UHF and a mobile phone antenna, one each side...have been told that's not legal in some states but never had an issue and after a while you don't even notice them through the windscreen.
I am now changing vehicles and the new GME antenna that came with the XRS pack is only ~ 600mm. Half the length of previous ones...I assume GME know what they are doing and that its functionality is not compromised.
I have seen some on a triangular mount near the window / mirror on the driver's door on a 300 series, keen to hear opinions if this position would impair their performance?
My thoughts are that perhaps it might be a small improvement for signal behind and in front of the car as it might be an advantage that time when vehicles are travelling basically straight behind and reception is static or weak when compared to vehicles in front when you can hear transmissions for ages coming towards you long before they come in view. Being on the side of the vehicle perhaps it might be a small improvement for those behind ...... unless the proximity to the vehicle mass is a negative?
If others have no negative comments, I might consider the UHF there and the mobile phone on the passenger's side bullbar.
Appreciate hearing from you
Reply By: RMD - Sunday, Aug 11, 2024 at 18:40
Sunday, Aug 11, 2024 at 18:40
bungarra.
This only my opinion and experiences in the past. I think antenna's on the bullbar restrict rearward transmission of signal to some degree. I have had antennas/aerials destroyed by vibes a couple of times at the side of the vehicle might be convenient to some degree but transmitting though the vehicle isn't proper to me. Even antennas closer than 300mm to each other, or so, can cause loss. My preference is above roof level, ie on roof bar or gutter bracket maybe. Since having my two antennas above the roof they seem to be far better. No quantifiable data on that but some transmissions and received communications have been over quite long distances, compared to previous positions.
AnswerID:
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Reply By: Garry L - Sunday, Aug 11, 2024 at 19:27
Sunday, Aug 11, 2024 at 19:27
G'day Bungarra
I got the number 2's looking at aerials on the bull bar and when I got a 200 series a few years ago I bought one of those triangular mounts you are talking about but on the LHS and mounted a 600mm aerial on it and I have found there is absolutely no loss off performance whatsoever !
It might vary with different aerials I'm not sure
Cheers
Gazz
AnswerID:
646326
Reply By: Member - McLaren3030 - Monday, Aug 12, 2024 at 07:05
Monday, Aug 12, 2024 at 07:05
Hi Bungarra,
Firstly, let me state that I am not a “Radio expert”, and there are others on this
forum that are.
In the days of AM CB Radio, the ideal position of the antenna was in the middle of the roof of the vehicle, with UHF radios, the same principle applies. Having said that, it is not always convenient to place an antenna in the middle of the roof.
If you take the option to mount the antenna on the Bull bar, the centre of the bar is probably the best location as there is certainly less movement in the centre of the bar than there is on the outside ends of the bar. You can also get “folding” antenna mounts that can be placed on a roof rack, gutter or Bull bar.
Remember, the length of the mast is not as important as the length of the antenna wire that is wrapped around the mast. Having said that, it is important to have the top of the antenna above the top of the vehicle.
Macca.
AnswerID:
646330
Reply By: Tony W - Monday, Aug 12, 2024 at 08:10
Monday, Aug 12, 2024 at 08:10
"I have seen some on a triangular mount near the window / mirror on the driver's door on a 300 series, keen to hear opinions if this position would impair their performance?"
Yes it will.
It is about as bad a spot as it can get. But it does sell aftermarket accessories becasue it looks pretty cool. These are all designed by metal work companies, not radio companies for a reason. On a bull bar is a bit, but not a lot, better. UHF CB antennas should be at least a wavelength away from metal ( about 70 cm) or you will drive the SWR up. Bad Ju Ju.
Up as high as possible without any obstructions in the horizontal plane is the right approach. Independent ground antennas don't need to be in the middle of the roof. Cheap, or even homemade fold-down brackets solve the problem of hitting car park roofs.
If you do go ahead it will work but with limited range.
You can see how large the effect is. FInd a local repeater to
test the antenna on the roof. You'll ge much better range.
But if you just want to talk to buddies in a convoy 1km or so apart then you probably wont notice it.
AnswerID:
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Follow Up By: RMD - Monday, Aug 12, 2024 at 09:58
Monday, Aug 12, 2024 at 09:58
I am puzzled as to why people think having a transmitting aerial obscured from being able to do it's task of RADIATING a SIGNAL and receiving it too, is OK. IT ISN'T.
If anything metal is in the path then it cannot be as it should be. Bullbar mounted only transmits best sideways and front. Forget rear. At side of vehicle, the aerial gets immediate signal reflection from the VERY close vehicle, and really only shines out one side.
You can make a folding bracket out of a LARGE HINGE and have an R clip to make it easily removed so as to fold the whole lot rearward, ie, within 10 seconds.
Mine is a piece of angle aluminium held with a 6mm socket head screw. If needed to be down, I use a T handle hex driver to remove the screw and fasten it in the down position. takes more than 10 seconds though. Hardly ever have to do it.
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Reply By: kgarn - Monday, Aug 12, 2024 at 08:47
Monday, Aug 12, 2024 at 08:47
Here is a link to a GME video which discusses antennas..
GME Antennas
Ken
AnswerID:
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Reply By: qldcamper - Monday, Aug 12, 2024 at 10:51
Monday, Aug 12, 2024 at 10:51
This is a regularly visited can of worms.
So as not to intentionally contradict other replies I have not read them ...yet.
My answer is put it anywhere that it is not close to anything metal above its base.
UHF is not intended for long range comms,
A 600mm antenna will work as
well as a hollow tube with a 600mm bit of wire inside it no matter how long the tube is, some only have 300mm of wire inside.
The best position for it is where ever it's practical for your particular set up, it won't be the electrically perfect position but for all intensive purposes it will do what you want it to do unless your expecting more than the mode is designed to do.
If you think it's going to come in handy to save your life then get something else, if you just need it to talk to other traffic within say 10km then antenna position won't make a big difference as long as it's in free space and not lower than the surrounding metal structures within about 300mm.
AnswerID:
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Reply By: Member - Broodie H3 - Monday, Aug 12, 2024 at 11:58
Monday, Aug 12, 2024 at 11:58
Good morning Bungarra, Just as thought in my 200 series, I have a GME radio and the antenna is stuck on the inside of the wind screen. It still works exactly the same as it did when the radio was in the ford
ranger with the antenna on the bull bar, same range same good reception. we have not had any transmission or reception issues with it. I don't have a bull bar on the cruiser as I don't do the night drives that I use to do, and we are generally parked up by 4pm. so the position of the radio antenna is only used for taking to truckies, and if we are travelling with friends . we were in convoy coming back from Carrawine
Gorge , and spaced about a Kilo meter apart there were for in the convoy and we were tail end Charlie, and we had no problem talking to the leader even when going through the hilly country. the best part about having the antenna on the screen nobody knows that you have a radio in your car, until you talk to them. we tow a 23ft caravan, even when we were leader we had no problems talking to tail end Charlie. now we don't have any antenna problems. just to give you another option for your antenna
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Reply By: Gronk - Monday, Aug 12, 2024 at 17:04
Monday, Aug 12, 2024 at 17:04
Just bought a new cb radio ( Uniden )with a 640mm antenna ( 5db )
The 600mm one you bought may
well be a 2.1db one, which is good for hilly terrain, but less good for long range.
Mine will be going on a bonnet hinge mount, so yes, most of the rearward signal may be compromised, but for a 4wd that isn’t going to be used just for outback travel, and also doesn’t have roof racks, a roof mounted one is out of the question.
Everything is a compromise, so we just have to make do with what we have.
AnswerID:
646335
Follow Up By: qldcamper - Tuesday, Aug 13, 2024 at 07:31
Tuesday, Aug 13, 2024 at 07:31
If it works it works.
Compromise is something social media forgot long ago......it has to be 200% perfect these days.
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926874
Reply By: RMD - Monday, Aug 12, 2024 at 19:11
Monday, Aug 12, 2024 at 19:11
I am surprised people use gear which , yes, contacts the leader of the convoy and along and through a few hills, but I would have thought most people would want something which performs quite a bit better than the convoy minimum.
My half wave antenna on my handheld has triggered and talked through a repeater 100 km away. Same unit over water 140 km confirmed by where the receiving person was stationed. Vehicle UHF had similar results. To me, best to have something a bit better than just enough.
AnswerID:
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Follow Up By: Gronk - Wednesday, Aug 14, 2024 at 19:35
Wednesday, Aug 14, 2024 at 19:35
And, what setup do you have ?
Can you drive your 4wd in 2.2m high underground car parks ?
Have you got the aerial mounted on a bullbar or roof ?
Where would you mount the aerial if you had neither of the above ?
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Follow Up By: RMD - Wednesday, Aug 14, 2024 at 20:55
Wednesday, Aug 14, 2024 at 20:55
Gronk
If reading what I said , the antenna's are able to be, within seconds, lowered IF EVER NEEDED TO BE. How many underground 2.2m height carparks are there in the general countryside or outback?.??if in a town simply lower it or remove it. Not hard to do! I have solar panels on a dual cab roof and one on the canopy too. The antennas are between the panels above
the gap on part of the solar panel.mount frame. The 2.2m thing is not applicable, really! There are many ways to fit antennas apart from using proprietary factory made gear.
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Follow Up By: Tony W - Thursday, Aug 15, 2024 at 07:37
Thursday, Aug 15, 2024 at 07:37
You can get a wide variety of fold down / knock down mounts that need no extra height. Or you can make one with aluminium extrusions from bunnings for about $15 easily.
Fold down antenna bracket
Can you drive your 4wd in 2.2m high underground car parks ?
- Yes - 2.1 including antenna and roof rack.
Have you got the aerial mounted on a bullbar or roof ?
- Roof. Never on the bullbar since I tested the difference in performance between bullbar and roof. Wit a bonus of the antenna lasting longer from less vibrations and better visibility.
Where would you mount the aerial if you had neither of the above ?
- None
I think ARB has done a fantastic job in marketing to convince people that they need a $3000 bullbar as a mount for a $50 CB antenna.
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Reply By: Lakers - Monday, Aug 12, 2024 at 19:32
Monday, Aug 12, 2024 at 19:32
I used to have the UHF antenna on the bull bar, but changed vehicle to one which did not have a bull bar. I have now mounted the antenna on a folding mount on the roof rack bar. Works
well and out of the way. Cheers...
Roof rack UHF mount
AnswerID:
646339
Follow Up By: Member - John - Tuesday, Aug 13, 2024 at 07:38
Tuesday, Aug 13, 2024 at 07:38
Lakers, can you supply details of the mount please? Thanks in advance.
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Follow Up By: Lakers - Tuesday, Aug 13, 2024 at 11:09
Tuesday, Aug 13, 2024 at 11:09
Hi
John, This was a gutter mount I bought years back and have 'modified' it a few times to suit what I needed at the time. From memory, it came from ebay, but any manufacturer name (if it had one) has long gone. Prestige Communication in Malaga (WA) have some on line, but I have no experience of them. Cheers...
https://www.prestigecom.net.au/uhf-cb-antennas/mounting-hardware-1
Folding antenna mount
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Follow Up By: Nomadic Navara - Tuesday, Aug 13, 2024 at 23:54
Tuesday, Aug 13, 2024 at 23:54
If you are wanting something to bolt onto ladder bars, look for marine units. They have deck mount folding units that can be adapted.
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Follow Up By: Member - McLaren3030 - Wednesday, Aug 14, 2024 at 06:55
Wednesday, Aug 14, 2024 at 06:55
John and Jan,
Hi
John, just “Google” folding UHF Antenna Brackets and it will show a range of brackets.
Macca.
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Reply By: Peter_n_Margaret - Wednesday, Aug 14, 2024 at 20:09
Wednesday, Aug 14, 2024 at 20:09
I use the little rubber zero gain antennas that are about 250mm long. I want good quality SHORT range reception/transmission. They are bullet proof (and cheap).
I have no interest to hear every dh who likes the sound of his/her own voice for a radius of 30km++.
If I want long range performance in an emergency, I carry a spare high gain antenna just for that that I can fit. Never used it in 20 years.
Cheers,
Peter
OKA196 motorhome
AnswerID:
646344
Follow Up By: RMD - Wednesday, Aug 14, 2024 at 20:46
Wednesday, Aug 14, 2024 at 20:46
Peter. That is all very nice, but twice I have arrived at a motorcycle crash
Oodnadatta track sth of Oodna and the other in the
Newcastle range near
Georgetown Qld. A really bad truck crash. Both times I used the UHF to call for ambulance and Police. At the truck crash, the driver died, but a UHF call 70 + km to Undarra Lava reception meant all
services arrived asap and the surviving truck passenger received lifesaving treatment on
the spot which saved his life. Similar at Oodna mcycle situation. If not straight away, probably both would have also died. On the way to hospital. Better is good!
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Follow Up By: Peter_n_Margaret - Wednesday, Aug 14, 2024 at 20:56
Wednesday, Aug 14, 2024 at 20:56
I don't have UHF for emergencies and nor should it ever be relied upon for that purpose, in my opinion.
I reckon you experience would be exceptionally rare.
Cheers,
Peter
OKA196 motorhome
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926888
Follow Up By: RMD - Thursday, Aug 15, 2024 at 12:55
Thursday, Aug 15, 2024 at 12:55
Peter.
I think you missed the point, Stating using "UHF for emergencies and nor should it be relied upon for that purpose" is NOT WHAT HAPPENS AT ALL! It is Simply the fact that UHF WAS used for those two incidents/accidents!
Every time someone mentions as having used UHF over a distance more than normal short distance for a communication reason, there is ALWAYs a person who says UHF shouldn't be for emergencies or relied UPON. It seems to be a standard reply on OE in this situation. I think everyone knows limitations of UHF already!
If it is what you have at that instant of need, OF COURSE you use it!
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Follow Up By: Peter_n_Margaret - Thursday, Aug 15, 2024 at 18:56
Thursday, Aug 15, 2024 at 18:56
No point missed.
Certainly use it if it works. I stand by not RELYING on UHF for emergencies in the first instance.
It can be very useful for talking to an aircraft that has responded to a PLB, for example.
My question is, what do YOU use when it does NOT provide contact with someone who can provide assistance in an emergency.
Cheers,
Peter
OKA196 motorhome
FollowupID:
926892
Follow Up By: Nomadic Navara - Thursday, Aug 15, 2024 at 18:59
Thursday, Aug 15, 2024 at 18:59
RMD despite your protestations, CB radio can not be relied upon for emergency response for emergency
services. Many people have reported chance or anomalous communications. In both cases, a couple of kilometres down the road you may not have been able to get any communications even with super antennas and high power transmitters. The way you are promoting top-notch equipment can get through anomalous propagation does make some people with little knowledge of how
UHF radio work think they probably get communication when they want it. Peter and I are just reminding those people that CB radio can not be relied on in the outback any time someone how their crash hot equipment has saved the day.
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Follow Up By: Member - Ups and Downs - Friday, Aug 16, 2024 at 07:20
Friday, Aug 16, 2024 at 07:20
Agreed, you can't rely on a UHF for emergency communications.
Nor will it keep your beer cold, or make bacon and eggs.
I thought this post was about getting the most out of the equipment, not what it can't do.
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Follow Up By: RMD - Friday, Aug 16, 2024 at 08:13
Friday, Aug 16, 2024 at 08:13
This is almost funny with the responses. I HAVE NEVER SAID I "RELY" on the UHF for distance communication, NEVER!!!!!!! Someone started saying that and the chorus joins in for some reason. Simply that it WAS used in those circumstances. What are these people on about? Sheep following sheep!
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Follow Up By: Peter_n_Margaret - Friday, Aug 16, 2024 at 10:02
Friday, Aug 16, 2024 at 10:02
Resorting to personal insults doesn't help.
Cheers,
Peter
OKA196 motorhome
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926896
Follow Up By: RMD - Friday, Aug 16, 2024 at 13:32
Friday, Aug 16, 2024 at 13:32
No insult there,. You explain why when one person, in this case it is you, started the YOU CAN'T RELY on UHF tack and others followed. If they are not sheep in doing that, why do they all join in as a collective mob all claiming the same when it ISN'T the situation at any stage anyway.
Always, if someone says something others don't like they start the INSULT rubbish. and cry foul for some reason.
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Follow Up By: Member - FSH00 - Friday, Aug 16, 2024 at 15:14
Friday, Aug 16, 2024 at 15:14
Your making me feel uncomfortable now (-:
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Follow Up By: Tony W - Saturday, Aug 17, 2024 at 07:23
Saturday, Aug 17, 2024 at 07:23
Those DH's 30km away that you could have communicated to, may have a sat phone, a mechanic, or medic on board, an opportunity for a lift ot tow, or a vehicle that may come over a
sand dune head-on after announcing their position and direction 30 mins ago which would be missed with poorly designed or implemented antenna.
It is not a guarantee - clearly, but UHF's can a meaningful, improved chance of assistance in a short time frame.
Not every situation calls for, or is best serviced by an EPIRB or Sat Phone.
When travelling, it is useful to keep all options open, not just the simple ones, by giving proper design some thought in the first place. Setting up a UHF antenna properly like the OP asked about is easy and cost effective, so there is no need to compromise if informed properly.
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Follow Up By: RMD - Sunday, Aug 18, 2024 at 16:55
Sunday, Aug 18, 2024 at 16:55
Tony W
I agree with your above response.
When I called at the
Newcastle range near
Georgetown QLD, and contacted Undarra Lava Tube reception 72KM away and told of EMERGENCY. The Mt Surprise Police knew about it less than 4 minutes after it happened. and started the response immediately and within the 4 mins they were on their way. THAT SAVED A LIFE! Now where is my sat phone? is it charged? will it connect soon? Oh, my UHFantenna is a bit short for this. Simply switch on the EPIRB and Wait while someone dies, That might be what some do, I don't know.
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Follow Up By: Peter_n_Margaret - Sunday, Aug 18, 2024 at 18:10
Sunday, Aug 18, 2024 at 18:10
Not that simple.
Your high gain, long range antennae might just not receive the signal from the approaching vehicle that is the other side of the NEXT dune, where-as the low gain short range antennae probably will.
My view is to use equipment for what it is reliably good at.
Your lucky connection is unlikely to happen next time, but in the mean time (all of the time) you need to put up with 5 times the useless chatter with no concept of what is close and what is not.
For the odd time when long range might be useful, carry a high gain antennae for that purpose. I do, but I have never needed to use it and maybe I never will.
Cheers,
Peter
OKA196 motorhome
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Follow Up By: RMD - Sunday, Aug 18, 2024 at 22:49
Sunday, Aug 18, 2024 at 22:49
The problem there is. I do have a high gain antenna but hardly ever use it, and it wasn't what was used in both cases.
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