Thread: Questions about HF in Aus.

We have different versions of HF many still use 27mhz cb but there is also dedicated 4x4 hf radios for long distance comms in remote areas. dedicated Hf costs more then 27mhz but is much more reliable.Where are you looking to use youirs here or at home, if you are looking for long range comms from the US 27mhz is probably what you want. many truckies over here have both UHF and 27mhz in thier trucks range varies HF thousands of km if conditions are right.

PS: we do have heaps of cell towers cover most cities and towns, highways ect supposed to cover 98% of the population

Originally Posted by THE BOOGER

We have different versions of HF many still use 27mhz cb but there is also dedicated 4x4 hf radios for long distance comms in remote areas. dedicated Hf costs more then 27mhz but is much more reliable.Where are you looking to use youirs here or at home, if you are looking for long range comms from the US 27mhz is probably what you want. many truckies over here have both UHF and 27mhz in thier trucks range varies HF thousands of km if conditions are right.

PS: we do have heaps of cell towers cover most cities and towns, highways ect supposed to cover 98% of the population

Thank you for the input regarding your radio gear. I am looking to use one here in the U.S (Calif, Nevada, Arizona etc). After talking with others here about their use, they generally use repeaters to get across longer distances.

Once you get away from major highways and the popluated regions here in the US cell phone use is limited - That is why I was thinking of getting an HF radio. I have also considered a Sat Phone - primarily because much of my driving is in and around tall mountain ranges and even HF would have a hard time getting out of some of the narrow canyons we pass through. I have friends who lease Sat phones for there longer trips.... I must admit it is pretty convientient when we are out wheeling together and they want to get a hold of someone... but use is costly.

I had some friends who drove around the world with four Discos back in 2004-05. I almost joined them for the leg of the trip when they crossed Austrailia. I had just started a new job and could not take a month off for the trip. When they were in Au they drove from Cairns to Perth via Alice Springs. I really missed a good drive....

Sounds like a satphone might be your best option.

The HF radios with the really big antennas aren't an option. Who are you going to talk to?

They don't bounce off the moon, but they do reflect off the ionosphere. Bit of an art form picking the right frequency. If conditions are right we can get across the country, say 3000 miles. Go for a higher frequency and yes you can get sailors in the middle of the Pacific.

The antennas are huge because they're only 1% efficient. The ground plane is the size of a football field. So they blast out at 100 watts.

Depending on the set we can turn them back to 10 watts for vehicle to vehicle, but that's frowned upon. Conventional UHF is far better for convey use.

And the big sets need a licence. Eay enough to get but conditions of use are imposed.

Have a look around www.vks737.on.net

Regards
Max P

Len

If I'm understanding you correctly you are talking about HF use in the USA and Canada.

In Australia HF has been the mainstay of remote communications for about 70 years. They have been used for regular communication between stations and their outstations or workers in the field, used for contact with the Royal Flying Doctor Service and even for schooling children in remote areas, although some of these functions are being replaced by Sat Phones. Although Sat Phones are expensive to place calls and can often have problems of traffic and disconnected calls.

In Australia for vehicle to vehicle comms within a group we usually use UHF CB and yes we do have repeaters along the coastal strip and in some places inland.

The reason that we have such large HF antennas on some of our vehicles is related to the wavelength being used and not the 1% efficiency. The distance covered by any RF transmission is a function of the wavelength used, output of the transmitter, antennae system/s, terrain and atmospheric conditions particularly for long wavelengths.

In Aus the mobile HF sets that are used for remote area travel are usually between 25 and 100Watts PEP. Coastal maritime units usually go up to 125Watts while ships and base stations can transmit on anything between 400 Watts to 1 Kilowatt. The lower the frequency the longer the distance covered and the less terrain effects will have. Remember your HF CB are in the 27MHz range while we are using sets often capable of frequencies between 2MHz and 30MHz (hence antennae systems that sometimes need to modify their electronic length by metres when switching between channels).

VKS737 is a community organisation which maintains a network of transmitters around the country. Members of the organisation are allocated a callsign and their membership is their licence to use the spectrum under VKS737's master licence. There are other similar organisations. I can regularly switch on my Codan set in Sydney and talk to the VKS737 base station in St Marys Tasmania, other times I will talk to friends travelling in Western Queensland, it all depends on the frequency used, the location of the two stations and the current atmospheric conditions.

There are also organisations (VKS737 being one) that will allow TelCall equipped sets to dial landline telephones by the use of their numeric mic keypad. For non-TelCall equipped sets VKS737 can make the connection or relay the calls for you. VKS737 also log the location of members travelling in remote locations (when the member calls in) which can assist locating the member if they fail to arrive at a destination or they fail to make a radio schedule.

If you want the same sort of emergency communication in the US and you travel in remote locations away from CB repeaters then you can consider the use of Maritime HF Radio which are monitored worldwide, although you will need to contact your local authorities about the legality of a land station using the maritime system.

HF ( not talking 27Mhz, but the real HF ) is good for a traveller who likes to chat - you can put out a call or get on a "net" and find out about conditions in the next few places you are going to, meet up with people etc. I think however that the numbers out there with HF sets is decreasing, so it may be harder to find people to talk to.

It will take a bit of room in your vehicle and then there's the little bit of maintenance and care required. It also ( depending on the set you choose ) requires a bit of expertise to drive an HF as opposed to a Sat Phone.

Thanks guys for the info - It sounds like Australians have long distance communication dialed in pretty well. I don't need the level of radio hardware you folks are using. I would like something that will be useful in the 40 to 60 mile range. My cb does well for truck to truck comms. For my own education I'll look over the link you past on to me. I may still go ahead and study for, then get my Ham license. Then further compare the costs/pros/cons of a sat phone vs a simple dual band mobile ICOM radio....

Len

Len

60 miles is getting outside of the groundwave propagation of a 100 Watt HF set and probably sitting in the "skip zone" which is like a black hole for the signal.



However by modifying the antenna into a NVIS configuration you can reduce the distance the skywave travels in one direction where the station you wish contact is located.



NVIS antenna configuration look like the looped over whip antennae frequently seen on US Law Enforcement vehicles working in remote locations such as Nevada, Arizona or Texas etc.

Cheers
Diana

Originally Posted by Lotz-A-Landies

Len

60 miles is getting outside of the groundwave propagation of a 100 Watt HF set and probably sitting in the "skip zone" which is like a black hole for the signal.



However by modifying the antenna into a NVIS configuration you can reduce the distance the skywave travels in one direction where the station you wish contact is located.



NVIS antenna configuration look like the looped over whip antennae frequently seen on US Law Enforcement vehicles working in remote locations such as Nevada, Arizona or Texas etc.

Cheers
Diana

Diana -

Thanks again - it looks like you provided an ideal radio/antenna solution for the areas I drive - and saved me a lot of time!

Len