HF Radio Installation Feedback

Submitted: Sunday, Sep 14, 2008 at 15:03

ThreadID: 61659 Views:3227 Replies:3 FollowUps:5

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HF Radio Installation

In this article, we discuss the procedures for installing a HF radio and the modifications that can be considered for a successful installation.

Member - bungarra (WA)

To the author.. Interesting and well written article...would appreciate your comments on my current experience with instalation of the Barrett 950 auto tune antenna . I have installed the same radio on 3 of my previous vehicles (antenna on the bullbar)...always perfect performance.......In this latest vehicle a tray top landcruiser I installed on the front of the cab guard (see pictures in my rig ) this has been an absolute disaster for transmission despite the top of the whip thread being slightly above the roof line.... that is above the highest metal part of the vehicle. Reception is brilliant but transmission woeful. I now have a second bracket mounted on the very top of the cab guard (bottom of plastic housing above the roof line) that I use when bush and it works perfectly except I hate having it there as it is very vulnerable...the original postition as shown in the rig picture is now its "home" position when not out bush. As I understand your article my original low down antenna placement should work but definately does not. Any comment appreciated thanks

Life is a journey, it is not how we fall down, it is how we get up.
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Reply By: Member - Graham H (QLD) - Sunday, Sep 14, 2008 at 15:11

Sunday, Sep 14, 2008 at 15:11

Might seem a stupid question but is it earthed correctly.
My 9350 has a strap back to the chassis.

Just a thought

AnswerID: 325243

Follow Up By: Member - bungarra (WA) - Sunday, Sep 14, 2008 at 18:49

Sunday, Sep 14, 2008 at 18:49

G'day

Yes earthing is something that I am very concious of and it has been throughly and effectively earthed to both chassis direct, cab as well as back to the radio.

I am very confident that earthing is not the issue

Thanks

Life is a journey, it is not how we fall down, it is how we get up.
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Reply By: Member - Mike DID - Sunday, Sep 14, 2008 at 16:01

Sunday, Sep 14, 2008 at 16:01

Although Codan and Barrett Autotunes look similar (whip on top of a plastic housing) they work quite differently.

The Codan has a long adjustable coil inside the plastic which forms part of the aerial - if it's shielded it will affect performance strongly.

The Barrett contains small coils which don't radiate greatly so there will be less impact on performance if there is metal nearby.

So if your Barrett is not working well, I would look for causes other than shielding - earthing, coax connectors, cable problems.

AnswerID: 325253

Follow Up By: Lex M - Sunday, Sep 14, 2008 at 16:46

Sunday, Sep 14, 2008 at 16:46

I was thinking of mounting mine similar to this. See thread59384.

The installation guide (page two doesn't seem to agree with this - or am I missing something.

FollowupID: 592364

Follow Up By: Lex M - Sunday, Sep 14, 2008 at 16:50

Sunday, Sep 14, 2008 at 16:50

hmm. That link to the guide worked in preview. let's try again

guide link

(http://www.barrettcommunications.com.au/pdf-files/INSTALLATION%20GUIDES/910-antenna-in-BCM9100-2.pdf)

FollowupID: 592365

Reply By: Member - Phil G (SA) - Sunday, Sep 14, 2008 at 17:13

Sunday, Sep 14, 2008 at 17:13

I have to disagree with Mike (pretty unusual!!) Your Barrett autotune is too close to the metalwork.

Barrett specify a minimum of 160mm clearance - this is at the join of the 2 pieces of plastic housing. You need more clearance upwards from this point at roughly a 45 degree angle. Any metalwork within that area will affect transmission. This information was provided to me by the Barrett dealer in Adelaide.

I know a couple of people who have installed Barretts in the same position as yours. Both have made up swing brackets to allow the autotune to swing away from the bodywork when transmitting and swing in when driving.

I installed mine on the back of the canopy, so it would be well protected. To achieve the necessary clearance, mine can be tilted backwards and raised. I get very good transmissions when I adjust my bracket for the extra clearance.

AnswerID: 325265

Follow Up By: Member - Phil G (SA) - Sunday, Sep 14, 2008 at 17:15

Sunday, Sep 14, 2008 at 17:15

I'll also ditto the earthing comment above. I have thick earth straps going from the autotune base to both canopy and chassis.

FollowupID: 592366

Follow Up By: Member - bungarra (WA) - Sunday, Sep 14, 2008 at 18:58

Sunday, Sep 14, 2008 at 18:58

Taking on board all of the above I am now convinced that Phil G is spot on as to the placement of my housing.

My earthing straps are very solid and very well connected to three seperate points including direct to Chassis. This followed advice that Mike Harding gave to my post some mnoths ago.

Secondly when I remove the antenna and place up higher my earthing points don't change but performance improves hugely. So I guess I have answered my own question to the extent of the above observation.

I posted because I have taken note of a lot of different placements in the last 5 months or so and many of them appear to contradictory to the "rules" and yet when I question the owners they all state that it works fine in their position!

I will go ahead and modify the current one to a swing out bracket for transmission only and tuck back in for travel

Thanks all for your help

cheers

bungarra

Life is a journey, it is not how we fall down, it is how we get up.
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