HF radio helps out

Submitted: Saturday, Jan 03, 2004 at 16:31
ThreadID: 9471 Views:2210 Replies:4 FollowUps:6
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Just got back from my trip to Esperance , on the way home we came via Fitzgerald River Nat Park ,out of Hopetown , about 40km into the park on a very hot day we came across a Surf on its roof with two ocupants ,luckerly they were shaken but uninjured ,as we could not get any responce on the UHF a call on the HF had us in contact within minutes and thanks to VKS737 we had help on the scene within the hour, this could have been a life saver if things had been worse ,the $700 I paid for this old 2nd hand radio was well worth it .DONT LEAVE HOME WITHOUT ITTelfer mines rd camp
Peter York 4x4
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Reply By: GTee - Saturday, Jan 03, 2004 at 20:17

Saturday, Jan 03, 2004 at 20:17
Hi Peter,

I am about to purchase a radio for my 4X4. Is it possible for you to outline the pro's and con's of both UHF and HF with approximate costs if that isn't too much to ask?

Thank you.
AnswerID: 41664

Follow Up By: Rowler - Saturday, Jan 03, 2004 at 21:07

Saturday, Jan 03, 2004 at 21:07
Check out the communications section on this site it's under vehicle requirements at the top of this page

Cheers rowler (dave)
FollowupID: 304128

Follow Up By: Bonz (Vic) - Sunday, Jan 04, 2004 at 08:02

Sunday, Jan 04, 2004 at 08:02
And...do a search on this forum site under "HF" theres lots of information there too!Laterally Literal
Seriously Cerebral
FollowupID: 304144

Reply By: Chris (W.A.) - Sunday, Jan 04, 2004 at 07:18

Sunday, Jan 04, 2004 at 07:18
Hi Peter,

Not baggin...too much. Up on Mitchell plateau and HF was useless even with autotune type. Switched on the good ol AM/DSB and picked two blokes in eastern states straight away.
Admittedly, it was for experimental purposes only but it proved something.

We now have EPIRB and DSB plus portable HF for the novelty.

Go Yorky!!Nice southerly coastal fishing trip someday.
AnswerID: 41694

Follow Up By: Mad Dog Morgan (Vic) - Sunday, Jan 04, 2004 at 08:22

Sunday, Jan 04, 2004 at 08:22
Hmm, Do I read you correct. You recommend a 27meg AM radio over a ssb radio on the vks737 or flying doc freqs ?I may be mad but I'm not crazy
FollowupID: 304146

Follow Up By: Member - Eskimo - Sunday, Jan 04, 2004 at 10:31

Sunday, Jan 04, 2004 at 10:31
Mad dog,
Chris said "portable HF" ....or does he mean portable UHF?

Cant believe that HF was inferior to 27 meg Wow! am I cute
If yer ain't fishing, Yer ain't livin
FollowupID: 304156

Follow Up By: Mad Dog Morgan (Vic) - Sunday, Jan 04, 2004 at 12:52

Sunday, Jan 04, 2004 at 12:52
Well, 27 meg is also included in the hf spectrum but exhibits some different characteristics than the lower freq's. Propagation over long distance on 27 meg happens frequently especially in summer and at the peak of the sunspot cycle but it is fool hardy to rely on it too much. To get the best from ones HF radio at least a basic understanding of radio signal propagation and how it varies between summer/winter, the time of day and the sunspot cycle is paramount. Plently of info on the web.I may be mad but I'm not crazy
FollowupID: 304172

Follow Up By: Chris (W.A.) - Sunday, Jan 04, 2004 at 15:09

Sunday, Jan 04, 2004 at 15:09
Nah, meant "HF". The type that you throw a aerial up a tree or even along the ground.
I'd never recommend relying on a AM/DSB unit by itself. It was just ironic at the time that it picked up people compared to another bloke that couldn't raise anybody on his mobile HF unit.Nice southerly coastal fishing trip someday.
FollowupID: 304175

Reply By: Member - Peter- Sunday, Jan 04, 2004 at 09:02

Sunday, Jan 04, 2004 at 09:02
What you must remember with HF is that signal propagation is very dependant on atmospheric conditions and the correct frequency is required at different times of the day and also your physical location.
The Kimberley is notorious for poor HF comms especially if you are trying to go east west. HF signals always travel better in a north south direction than east west.
As a rule of thumb the higher the sun the higher the frequency but bear in mind the distance you are trying to cover/reach may in fact be too short for a high frequency.
Use the base station beacon to establish what is best for your location at that particular time of the day.
Conditions will and do change dramatically even on a minute by minute basis. I can remember talking to Penta comstat when they were a VKS base about 5.30-6 am WA time from up on the Mitchell Plateau, as the sun came up through the trees the signal dropped off over about 5 minutes to go from loud and clear to unusable.
Also in the northwest and northern parts of Oz there is a lot of interference from our northern neighbours who don't give a stuff about using someone elses frequencies or even blasting over the top of emergency comms, no enforcment of transmitter power, licencing etc up there.
Another problem is that with any vehicle that has electronic fuel injection either petrol or diesel (TD5's and Nissan's especially) an HF is unusable if the engine is running due to interference from the electronics.
Most vehicles will cause interfernce as will accessories like frigs GPS (if connected to vehicle power), fans, other radios and sound equipment but most of these can be shielded/switched off unlike the EFI.
Antenna mounting can also cause problems especially when they are mounted on the rear of a spare tyre carrier below the top of the tyre, the tyre has a lot of steel belts running in a ring around the tyrs case, doesn't do much for reception when it is beside the antenna. It will possibly prevent an auto antenna from tuning particular frequencies.
Lastly relying on am/ssb cb for comms is asking for trouble but yes under the right conditions long distances are possible ask anyone who had one 20 years ago and was DXing around the world.
AnswerID: 41706

Reply By: Mike - Monday, Jan 05, 2004 at 22:56

Monday, Jan 05, 2004 at 22:56
For my 2 bobs worth, (or 2c), on our 4 month jaunt which took in outback Qld, Simpson Desert, the Red Centre and up to the top end, the Kimberly and the west coast of WA, we were constantly glad of our HF radio. Apart from organizing assistance and recovery for us a couple of times and getting messages from home, the camaraderie devoloped listening to regular radio skeds each evening or morning, was priceless. Our progress was regularly logged as well so that if we did encounter long term probs, someone knew where we were.
My hat goes off, in a big way to the operators on the VKS737 network, we would never do another trip without the comfort of having them along for the ride.
Yes, we carry an EPIRB and UHF and are very experienced in outback travel, but my mates on VKS737 go with us as well.

Happy trails, Mike.
AnswerID: 41879

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