UHF radio in a D-Max

Submitted: Thursday, Jan 04, 2024 at 12:36
ThreadID: 146779 Views:2679 Replies:12 FollowUps:13
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Hello and I hope you all have a great year.
We have brought a new D-max.
Very happy with the vehicle.
My question is about fitting a UHF radio or more importantly if a high end 5W handheld would fit the bill.
Any thoughts please.
William
Always planning the next trip. VKS-737 mobile 1619

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Reply By: RMD - Thursday, Jan 04, 2024 at 13:00

Thursday, Jan 04, 2024 at 13:00
G'day William.
Just my experience with UHF over quite a number of years. Having the aerial up the highest you can get to on your vehicle is the best position. I use the option of two aerials ( not close together) for two radios. One for highway monitoring and the other for local use, calling caravan drivers not on 40. Aerial on bullbar is not the optimal position by a long chalk. Twice for life saving reasons, accidents encountered, the radio has performed well , with 70km transmit and receive quite common in both cases. Always disputed of course.
I also have two GME hand helds, with a 280mm approx, flex aerial which has been used and From Kyabram Vic to Bendigo Vic repeater, I can talk to the repeater. With a recent addition of a GME TX6150, it has a short aerial and is handy for contacting the vehicle from a distance. Used with an aerial adapter to feed a magnetic base aerial on roof of any vehicle is also convenient without an installation of gear. While wattage is important, the actual setup, ie aerial combination and position and type, which works, is equally important. Conditions and terrain play a role too in performance. There is a recent thread/posts discussing similar concepts.
AnswerID: 645024

Reply By: Stephen L (Clare) SA - Thursday, Jan 04, 2024 at 14:03

Thursday, Jan 04, 2024 at 14:03
Hi William

Hope you are enjoying your new D Max, they are a great vehicle and you should be very happy with it.

I was in the same boat as you, as I have not fitted a bull bar, so I went for a good quality 5w hand held unit and went with the Icom.

I was going to go with GME, but when I spoke to a specialist store in Adelaide they recommended the Japanese made Icom 5w, they said they were very reliable unit compared to the cheaper Chinese made GME which were prone to nagging issues.

GME do make a 5w Australian made handheld at almost double the price of the Icom, but they were honest enough to say it was not worth the extra dollars.

By going the handheld, you don’t have to worry about concealing the main unit under the consul and positioning the microphone and antenna.

Happy and Safe Motoring.
Smile like a Crocodile

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AnswerID: 645027

Reply By: Peter_n_Margaret - Thursday, Jan 04, 2024 at 17:01

Thursday, Jan 04, 2024 at 17:01
I have a hand held 5W Icom unit in the back of the OKA.. It is fitted with a power supply and external antennae which makes its performance identical to an installed unit. BUT I can take it out, fit the original antennae and go for a walk with it.
The antennae position is the most important feature determining performance.
Cheers,
Peter
OKA196 motorhome
AnswerID: 645031

Reply By: IvanTheTerrible - Thursday, Jan 04, 2024 at 19:17

Thursday, Jan 04, 2024 at 19:17
We have a D-Max with a UHF fitted in the pocket under the steering wheel. We have another D-Max that has a UHF fitted under the console, in front of the shifter. We also have two 5w Uniden hand held we use for
communication with people outside of the utes. ie when winching or bushwalking.

Fitted UHF is available always as long as the vehicles battery is charged. Better range.

Handheld. More flexible but you have to keep charging them
AnswerID: 645033

Reply By: Member - McLaren3030 - Friday, Jan 05, 2024 at 08:03

Friday, Jan 05, 2024 at 08:03
Hi William B,

The choice between fixed or handheld really comes down to your personal choice. I have both a fixed 5 watt in car unit and a pair of 2 watt handheld units. The fixed in car unit is paired with a 6 dBi antenna. The handheld units we use for comms when manoeuvring the car and caravan into tight spaces, or when out bush walking. Of course as they are only 2 watt, their range is limited.

The most important thing with a UHF radio when travelling is to have it switched on and monitoring the highway channels (40 for the majority of highways, or 29 on the Pacific Motorway). These are the channels that the majority of trucks, and Pilot vehicles use. Whilst many caravaners use channel 18, you will not hear important information regarding oversize loads coming towards you from either direction, or potential hazard information. I have found that the majority of foul language or the abusive idiots who just like to try and have an argument with anyone are usually around the major cities. Once out on the open highway, it tends to disappear.

The next important thing to remember with any UHF Radio is the choice of antenna and more importantly it’s position relative to the centre line of the vehicle. Even the best UHF Radio will not perform as well as it could if you have a poor quality antenna.

Ideally the best position for the antenna is the centre of the vehicle at its highest point. Not always possible or practical especially with roof racks, or low hanging obstacles. You can get adjustable antenna bases that can be attached to the side of a roof rack, and can be adjusted so that they lay flat, or on an angle when negotiating low lying obstacles such as underground carparks etc. However these can be inconvenient as you have to get out and make the adjustment manually. Of course you lose transmission range by having it in the lowered position.

The next best position, in my opinion, would be the centre of the Bull bar. I have chosen to have mine mounted to the passenger side of the Bull bar utilising an existing mounting bracket on the Bull bar. Not the most ideal position, but I have a light bar fitted to the centre of the Bull bar, so it was the next best position. If you do not have a Bull bar, you can get a “Z” bracket to attach it to the top of the mudguard where the bonnet comes down. Not ideal, but it is an option.

Macca.
Macca.

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AnswerID: 645037

Follow Up By: Allan B (Sunshine Coast) - Friday, Jan 05, 2024 at 12:52

Friday, Jan 05, 2024 at 12:52
.
Actually Macca, antenna mounting with a "Z" bracket at the left/rear point of the bonnet seems a reasonable location. It gets a ground-plane benefit from the bonnet better than being on the bullbar and is not in the front of your vision. I do appreciate however that in the centre of the bullbar is further from damage from scrub than at the side.
Cheers
Allan

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Reply By: Gbc.. - Friday, Jan 05, 2024 at 18:04

Friday, Jan 05, 2024 at 18:04
I have the new BT50 and went with the 5w GME handheld with the in car adapter kit. Works just fine. UHF is more for convenience these days rather than worrying about ultimate performance.
AnswerID: 645040

Reply By: Rob J8 - Saturday, Jan 06, 2024 at 22:39

Saturday, Jan 06, 2024 at 22:39
When I bought the GX 200 series new in 2018 I swore I would never have another bulbar because I don't drive at night much anymore so installed the CB with the aerial on a Z mount. works really well, Did fit a bull bar in April 2023 as we are travelling the East coast and there are many wild animals over here !
The aerial is still on the Z mount; the executive director of housekeeping likes the better vision.
AnswerID: 645045

Reply By: Croc099 - Sunday, Jan 07, 2024 at 00:37

Sunday, Jan 07, 2024 at 00:37
MU-X instead of DMAX but close enough. I use a GME XRS-370 with an on-glass AE5002 antenna. It is mounted high up on the front windscreen out of the way. Coax is hidden behind the pillar cover and the excess cable shortened and re-terminated. Works very well. The GME CP50 5W handhelds are just used out of the vehicle.
AnswerID: 645046

Follow Up By: IvanTheTerrible - Sunday, Jan 07, 2024 at 10:23

Sunday, Jan 07, 2024 at 10:23
I hope the lead isn't going to foul the airbag. :-)
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Follow Up By: Croc099 - Sunday, Jan 07, 2024 at 10:49

Sunday, Jan 07, 2024 at 10:49
A snowball's chance in hell.
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Follow Up By: RMD - Sunday, Jan 07, 2024 at 12:59

Sunday, Jan 07, 2024 at 12:59
While those STICK ON through glass systems can transfer radio frequency signal, I doubt it is very effective over a distance. Nothing like a piece of wire connected to the radio input and output stages to get performance. Yeah yeah, GME has tested them and they work satisfactorily to be able to sell them.
2.1 DBi according to GME and the normal aerials are 4DBI with some being 6 and 8. Ok for convoy's where
you can see them or thereabouts.

When at the top of Newcastle range in QLD, see if you can readily talk to UNDARRA reception 97 km away on a wet day! Worth a try to see the effectiveness of the AE5002.
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Follow Up By: Stephen L (Clare) SA - Sunday, Jan 07, 2024 at 13:56

Sunday, Jan 07, 2024 at 13:56
As we know, without a repeater tower, UHF is line of sight, and GME have used their db gain diagram for years.

Generally a lower db gain are better for hilly conditions, while a higher db gain antenna is better in flatter terrain.
Smile like a Crocodile

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Follow Up By: Croc099 - Sunday, Jan 07, 2024 at 14:00

Sunday, Jan 07, 2024 at 14:00
The capacitive coupling works fantastic with stuff all loss at 477MHz. I have no trouble with range. The extra height attained more than compensates for the 4dB lower gain and is more effective in the mountains as hills. I have no need to chat with someone 97kms away. Less loss with the shorter coax feed as well. Like most things, it depends on your application.
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Follow Up By: Croc099 - Sunday, Jan 07, 2024 at 17:20

Sunday, Jan 07, 2024 at 17:20
RMD, I don't live anywhere near the Newcastle ranges so can't do a live test. Just out of curiosity I thought I'd try the numbers. 97kms at 477Mhz has a free space path loss of around 126dB. 5W is equivalent to +37dBm and a typical CB sensitivity is around -123 dBm. Subtracting the path loss leaves me with 34dBm up my sleeve ( 37 + 123 - 126 ). I'd fully expect a loss in gain of only 4dB to be insignificant and the AE5002 would not have any problem.
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Reply By: qldcamper - Monday, Jan 08, 2024 at 07:54

Monday, Jan 08, 2024 at 07:54
I use UHFs but they are very limited and get used as such. Don't ever consider them as a reliable form of emergency communication.
Don't waste money on big heavy "look at me" antennas, a 150mm on a elevated feed ground independant base with no spring will do all you will want and not destroy itself from excessive movement like the heavy ones. 12 years in mining and rail construction keeping UHFs working as reliably as possible had proven this to me.
If you want a little more range from time to time unscrew the 150mm whip and screw on a longer stainless antenna.

Installed or handheld?
Answer to that is both.
Handhelds work well but an installed set is always there, not the battery is flat or its in the van or the glove box or anywhere else other than in arms reach. I use both but while driving there is only one "best" choice.

Antenna position?
It has been proven that as high and smack in the centre of the ground plane (metal structure of the vehicle) IS the best but rarely practical. But once you accept the fact that reliable long range operation isnt the nature of this band then spending too much time trying to achieve perfection is just a waste of time, cover the basics, free space for 300mm around the antenna and your good to go. The performance difference from poor antenna position is most often caused by the radio derating because of a poor SWR because of surrounding metal objects close to the antenna.
If you can reliably get 10km in all directions out of your in car it will do everything this class of radio is designed to do in a legal mobile application.

If your going bush and need reliable comms take a sat phone or at least an airband handheld. The sat phone will also transmit your exact co ordinantes in an emergency.
AnswerID: 645056

Reply By: qldcamper - Tuesday, Jan 09, 2024 at 07:57

Tuesday, Jan 09, 2024 at 07:57
Antenna debates always boil down to the practical side and the theoretical side.
Which is right?
Answer both, and neither.
Only theoretical antennas can be the same.
There are too many variables in practice for any two antenna systems to be the same. Even the same antenna on different days will perform differently.
Debating in forums is pointless because most of the time those that say the most only know what they repeat off the net.
This come up around a campfire one night and as a test I asked a simple question and none of the "experts" had Google to fall back on. The most basic principle of gain and nobody had a clue but they were all convinced that their choice of antenna was the best.
Antennas are a science and what most of us, including myself, know is like comparing a fire cracker under a baked bean tin to the launching of the voyages spacecraft's.
AnswerID: 645058

Follow Up By: Allan B (Sunshine Coast) - Tuesday, Jan 09, 2024 at 09:39

Tuesday, Jan 09, 2024 at 09:39
.
Yep QC, I agree with your sentiments.
Propagation of radio signals is a complex science and often does not conform to theory.
So as I often say…. "Whatever works for you, works".
Cheers
Allan

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Follow Up By: Briste - Tuesday, Jan 09, 2024 at 09:41

Tuesday, Jan 09, 2024 at 09:41
FWIW, here is a test that Ronny Dahl did few years ago, that seemed to demonstrate that practical differences are not always as clear-cut as the the theory would suggest.
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Follow Up By: Member - Mark (Tamworth NSW) - Tuesday, Jan 09, 2024 at 12:10

Tuesday, Jan 09, 2024 at 12:10
Physics is theoretical science, engineering is physics in practice.
I guess that's why we have more engineers than physicists!
Mark
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Follow Up By: Briste - Tuesday, Jan 09, 2024 at 18:31

Tuesday, Jan 09, 2024 at 18:31
Sounds like a variation on the difference between an applied mathematician and a theoretical one - the applied mathematician can find the solution to any difficulty, whereas the theoretical mathematician can find the difficulty with any solution.
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Reply By: RMD - Wednesday, Jan 10, 2024 at 19:40

Wednesday, Jan 10, 2024 at 19:40
William.
Are you know confused and can't make a decision.
If a recognised quality unit or a high end, high price unit is purchased, both will work the same with a decent aerial. You decision as the the outlay. Not sure if most who have replied have actually used one over a large distance or relatively short distance. Hard to sort out reality.
AnswerID: 645071

Follow Up By: Allan B (Sunshine Coast) - Wednesday, Jan 10, 2024 at 20:37

Wednesday, Jan 10, 2024 at 20:37
.
William, To answer your original question….. "if a high end 5W handheld would fit the bill"
If you just want to listen/talk to near vehicles then yes, a good handheld will do fine.
I had an installed UHF in the Troopy for many years but almost never used it. Now, with the Sprinter, and not going remote, I carry a handheld, but in two years have not used it. I am out there for the environs, not to listen to others.
The UHF may be useful to talk with companion travellers but not much value to 'radio ahead' when crossing the Simpson etc. There is no guarantee that the next vehicle coming at you over a dune ridge even has a UHF to hear you so you need to drive as though you are the only responsible person on the track.
So unless you have a burning desire to display your comms I would recommend a handheldUHF.
Cheers
Allan

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Reply By: Member - William B - Saturday, Jan 13, 2024 at 19:05

Saturday, Jan 13, 2024 at 19:05
Thank you every one for their replies.
I don't need the radio for emergency comms and am aware of antenna placement.
UHF for me is while travelling to be able to hear from oversize convoy drivers and such and in the deserts to broadcast and listen for other vehicles. ( even though some desert travellers seem unaware of the need for this).
I am interested in the hand held option with a fixed antenna or magnetic mount.
Once again thank you every one for sharing their thoughts on this subject.
If I am missing something obvious please post your thoughts, I'm not going to discount any thing.
William
Always planning the next trip. VKS-737 mobile 1619

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AnswerID: 645092

Follow Up By: qldcamper - Saturday, Jan 20, 2024 at 10:00

Saturday, Jan 20, 2024 at 10:00
Handhelds work well as handhelds.
As soon as you start adding external antennas they start being difficult to use so then you get a speaker mic and mount cradle with a battery eliminate kit and so on. The antenna is the most difficult part of the install and about 25% of the cost of a fixed unit so sort of defeats the purpose of the handheld concept.
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