HF antenna mounting

**POD** · 13th February 2014, 05:55 PM

I posted a question about this in the communications etc section, but it has just about dropped off the page with no response, so hoping for more exposure here.
I've acquired an older HF radio setup via eBay, it includes a Moonraker brand auto-tune antenna, the rigid portion of which is a little under 1600mm tall. I've been looking at options on the 130 to mount the thing, and would appreciate some advice from those who know more about these things than I do- which probably includes most of the population.
I want to avoid mounting it on the bullbar, as the 'aerial view' is very obstructive.
Option 1, my preference in terms of protection from damage and not being too obtrusive, is behind the cab, with the entire auto-tuning section being in between the cab and the big aluminium box, this would have only the whip section above the vehicle roofline.
Option 2, mounting the thing on the sidestep (would involve mods to the step but that is no problem); same height as option 1 but this gets it further away from the bodywork but is somewhat exposed to damage on narrow tracks.
Option 3, on the rear bar next to where my second spare wheel goes; much more clear of bodywork, but the rigid section would be vulnerable to overhead damage.
I'm hoping for some advice in particular with regard to how option 1 and 2 would affect tuning and radio performance.
I emailed the antenna manufacturer, they have sent me a copy of the handbook for the antenna (or the one that superceded this model) but it is not very helpful on this point.
These photos show 2 views of option 1, 1 each of options 2 and 3.

**Bearman** · 13th February 2014, 07:29 PM

Just my preference but I have mine mounted on the bullbar on the passenger side where it doesn't obstruct the drivers vision. My reasoning it that if it is up front you can see anything that it is going to hit before it happens and alter course accordingly. With it mounted out of sight you tend to forget it is there and can have a costly mishap with it.

**123rover50** · 13th February 2014, 07:52 PM

POD your antenna seems to be different.
Bearmans and my Barrett have a plastic autotune housing that the whip mounts to. The top half of this housing radiates and should be clear of any bodywork.

**POD** · 13th February 2014, 08:06 PM

Yes it's a different style to the seemingly more common Barrett antennas, Moonraker are a Tasmanian manufacturer, this model was made in the early 1990s. They state in their literature that it can be mounted relatively closer to bodywork than other types, but I personally have no idea how close is too close.
I can mount it on the bullbar if necessary, but we're planning a 9 week trip this winter and my wife is not keen to look at this thing for 9 weeks. She got heartily sick of the sight of the rented multi-tap antenna we used for a 2-month trip a few years ago.
If I can mount it behind the cab, the only part of the antenna exposed to damage will be the stainless-steel whip, which has a spring base so I would think should be okay with the odd low branch.

**DeanoH** · 13th February 2014, 08:50 PM

Hi POD, don't know much about the Moonraker antenna. What HF set did you get ? If it's for the VKS-737 network which incorporates RFDS now a days you'll only need the main and secondary channels of 8022 and 5455 KHz to get you by, so you could even consider a multi tap antenna with a fold down mount that lives across the back (and behind) the bull bar.

By the looks of it your antenna is a bit like my Codan auto tune and radiates from the top whip section only so I'd definitely go with option 1 (between the cab and the box) as it offers the most protection for the antenna. I'd also remove the whip when not in use as vibration can make it fall off and a low hanging branch will soon bust it off. I lost mine on the Anne Beadell

but fortunately only had to back track 20 Km to find it

. It's a very good idea to carry a spare.

Here's what mine looks like on the back of the Oka. I mounted it here for the same reasons you are considering, protection and aesthetics. I'm not too worried about the roof rack impinging on the radiation pattern as HF mostly radiates up anyway.

Anyway the proof of the pudding is in the eating and we had no problem contacting VKS 737 at any time on our last central Australian jaunt.

Deano

**POD** · 13th February 2014, 09:37 PM

The HF set is a Codan 8525. I'm going to have to get the VKS-737 channels programmed, the printout that lists the channels programmed into the unit doesn't show any of the frequencies listed on the VKS-737 website. Hopefully whoever I get to do the programming (recommendations??) can give me a bit of a tutorial on the operation of the unit. The ebay seller had never used it, said it had been in his vehicle from a previous owner. Here's hoping it all works!
A fourth mounting option that I've considered is to have a folding mount, as I don't anticipate wanting to use the HF set whilst on the move. Having to fabricate a folding mount would make things much more complicated though.
The OKA looks like a great setup.
I backtracked 40km of the Anne Beadell to pick up a bag of rubbish that had bounced out of the wood bin on our camper trailer. Ahh the memories.

**Bushy049** · 13th February 2014, 11:46 PM

A word of advice. Find a comms shop that knows about hf radios, have the radio serviced and tunned, make sure it's working right as you want it work in an emergency. Have the latest land pack software installed. There has recently been a new program updated with all current australian hf networks and the new Rfds arrangement with vks and new vks channels. U need to mount your antenna away from metal objects like you cab. If you mount it between the cab and tray I recon you will have issues. That antenna you have would better be replaced with a tap antenna or newer codan auto tunner (sorry). And remember your fitting a hf for safety do it right it will save your life if you need it.

Sent from my HTC_PN071 using AULRO mobile app

**Bushy049** · 13th February 2014, 11:49 PM

Oh and one golden rule what ever antenna you mount, make sure it is mounted with a good earth strap to the body of the vehicle

Sent from my HTC_PN071 using AULRO mobile app

**POD** · 14th February 2014, 08:31 AM

Originally Posted by Bushy049

A word of advice. Find a comms shop that knows about hf radios, have the radio serviced and tunned, make sure it's working right as you want it work in an emergency. Have the latest land pack software installed. There has recently been a new program updated with all current australian hf networks and the new Rfds arrangement with vks and new vks channels. U need to mount your antenna away from metal objects like you cab. If you mount it between the cab and tray I recon you will have issues. That antenna you have would better be replaced with a tap antenna or newer codan auto tunner (sorry). And remember your fitting a hf for safety do it right it will save your life if you need it.

Sent from my HTC_PN071 using AULRO mobile app

Thanks, will definitely take the advice about servicing, also was not aware of new arrangements with VKS / RFDS, I am a complete newbie with this, so any advice or knowledge is welcome. Would also welcome recommendations for a HF specialist who can offer me some training as well as doing the necessary servicing and programming.
Wondering why you say replace the antenna, is it likely to not work, not compatible with current networks or some other reason?

**DeanoH** · 14th February 2014, 10:06 AM

Hi again POD, this site is a mine of information for all sorts of things Codan and Barrett.

Hf-Radio.com.au Online Store - Home

An up to date EPROM is available for $79 with all the channels you'll need.

Codans agent is in Lara is Peter at Lara electronics, I've spoken to him before and he was very helpful.

I'm with Bushy049 here and am of the view that the 8525, whilst a very good set in its day is a bit long in the tooth for something to rely on to save your life. The Moonraker antenna is also pretty old and considering this has a long tapped worm drive internally (ie moving parts sealed up and probably not serviced/lubricated for a long time) I'd be pretty chary of its reliability.
We also carry a portable Sat Phone as a plan'b' if case the Codan 9323 (a very good set) HF packs it in.

I've got a (spare) Barrett SB 250 LC and multi tap antenna/base in very good condition if you want to borrow them for your trip.

I saw a folding mount for a spring base multi tap when I was in Alice springs last year, so they are available. I also concur with Bushy049 about the earth strap from the antenna base to the body and chassis. You can't just assume a good DC connection like you'd need with a set of driving lights is good enough, RF energy is funny stuff and 100 watts of it can cause definite injury. Correct earthing is important to avoid this.

Peter Trewearn (I think I spelt that right) is a very good radio tech. I'm not sure if he's retired now but his home/workshop is in Normanby St Warragul on the LHS just past the old Telstra Depot when heading North. You can pick it by the antennae hanging off the workshop roof.

If you want a run through of the gear and its capabilities and use, drop me a PM and I'll give you a demo.

Deano

VKS-737 Mobile 1366

Thread: HF antenna mounting

Thread Tools

HF antenna mounting

Bookmarks

Bookmarks

Posting Permissions