HF Radio: what other uses?

As Chris mentioned "I would not rely on one completely for emergeny comms though".

To expand on what I believe that he is referring to; HF propogation, that is the path between radios that the signal takes, can be severly disrupted and even distroyed for hours by sunspot activity. Electrical storms can cause bad static. Bad enough at times for the audio to be unreadable until the storm passes on. Maybe even from storms over the horizon.

HF certainly has a good place but it should be supplemented with maybe a spot/epirb and backed up with HF and maybe in difficult situations such as mine, with a phone. We had to go down the satellite phone path because the doctors needed full duplex links and in fact requested it otherwise they would not give me their approval.

It really depends on what type of problem may arise for an individual or group and how much equipment, effort or funds are needed to cover that possible situation.

As an example of what Chris & Phil are saying, on one very stormy afternoon, back in the early '90's, I found UHF to more useful than the HF set that was installed in the vehicle.

I was about 100 kms from the station, and on a very high ridge, maybe 200 feet above the surrounding country. I called my wife on the HF, and while I could hear her reasonably well, she replied: "I know you're there, but I don't know what you're saying". The amount of static on the HF caused by the electrical storms was quite intense.

After a couple of frustrating attempts to relay my message, I then tried the UHF, and she was able to hear me quite clearly. Now this wouldn't work where one was out of UHF range, or perhaps bogged in a gully, but does illustrate that HF is not a panacea for emergency communication.

Bob.

Good example Bob. As an avid user of HF professionally and as a hobby (past that is) I have a lot of time for HF. Yes those times affected us even to the point that on several occasions we lost HF comms for hours to Vietnam while I was System Controller Officer. But for the most we got through. As does the 4WD HF service.

As an aside I used to make quite regular UHF contacts to Melbourne from Sydney. But then again that was using large arrays and heaps more power than we are allowed on UHF. But we cheated. We bounced the signal off high flying planes. Me cheat! Never?

UHF, HF, SPOT, Epirbs and even satphone all have their place. Even a sparking battery lead sending SOS.

Yes it can be done and that in fact was very close to Marconi’s first radio transmission in 1896, with coded signals. Tesla actually invented the radio four year earlier and Marconi was the first to actually make a transmission.

Hi PJR

2nd Sig Regt?? 1LSF???

Wombat S/No 216131

Both 2 and 5 then svn 110, 104 and then 1, 127 and then for 18yrs on to "special" and non corps units.

Take care mate

Yeah, Phil, I still get the "warm & fuzzy's" when thinking about my HF days.

The ability to, once multi-tap aerials came in, to talk to station staff on 2020 kHz, then switch to 5110 and send a telegram through Mt Isa base, to head office with say, some cattle numbers, and then, switch over to the radphone frequency(think they were 73XX & 76XX) and make a phone call to a Toyota dealer, to organise delivery of some parts. All from the driver's seat of a Landcruiser ute.

Once everyone got the phone on, Phil, by 1992, their use had started to wane by 1995. Think many stations still use them, but others, as we did, put in UHF repeaters, and sadly, dispensed with the HF's. Nothing like a bit of history, eh!

Bob.

I dropped in once when "testing" a "big" set I had just repaired, from Vietnam one day. The poor bloke thought I was pulling his leg when he heard where I was. The boss kicked me from one end of Vietnam to the other though. But it was worth it.

Catchya

Hi All,
Adding to the above, RFDSWA and RFDSQLD have an agreement with VKS using the HF network with Selcall to make Emergency and Help calls via the PSTN network and the 18 nominated sites, to the RFDSWA Operations Centre at Jandakot Airport in Perth and the equivalent RFDSQLD site, 24 hours a day. RFDS Doctors and Emergency Services are available for consultation as required.
This Emergency Service is available to "All HF users with SELCALL". Note: during "SKED" sessions voice contact should be used, Selcall should not be activated. Interested users of this service can down load VKS "Document 40" which is found under the "Document" Tab on the VKS site.

Cheers, Jerry C.

Hi Robin

125w output??? either things have changed or you must have yours tweaked up.

When we brought our Codan years ago, they were only 100w output and when I enquired about this, they told me that this was the greatest legal output available.

Cheers


Stephen

G'day Stephen - hope a radio expert drops in (or back) to clarify - my Barrett 950 is rated at 100W nominal and 125W PEP far as I know - the new Barretts are too. Seems that PEP (peak envelope power I think) is what the max output CAN get to at specific points in a transmission, while it might only average 100W across any time period....as I recall, the supply voltage needs to be up in the low 13's to achieve this though.

Think I might be the only Radio Engineer on this site now Darian - Years ago there were some others like Mike.

Yes Stephen the Barrett 950 is a unique product which has features not found on later models - like the 125 watt peak envelope power as Darian states and also the ability to transmit anywhere without restrictions (electronically that is , not legally).

The later models can't for instance tx on 27mhz.

As a radio amateur I can use a linear with the HF radio and transmit 400w PEP , only on cerain channels legally - but this wouldn't hold one back in a genuine emergency.

The Barrett 950 sort of reminds me of the Patrols I like - just enough technology to be with it, but still having the good old bits like live axles.

Not that it is significant in transmission terms, but I think the max power is 125W BUT as a Land mobile device it is limited to 100W by ACMA rules.

That's only about 2 db though.

During 'sked' times you can log in with a base operator your position and receive any recorded messages left with VKS's message service.
Many owners log in even if moving from city to city, it makes sure your equipment is working and gets you or your family used to operating the equipment I'm sure Darian can explain it better.
Cheers

On VKS737 skeds, 95% of contacts are simply log-ins from members letting the operator know where they are and where they will be the next day (just in case anyone back home needs to find them). Other issues covered at times include the following:
#Messages to the member (from whoever has been advised of their travel and given the network's messagebank number).
#Messages taken from the member and passed on to whoever.
#A simple radio check - to regularly make sure the hardware is all running well
#Requests for roads and weather info, to aid in trip planning en route
#Requests for technical advice and/or assistance re vehicle / trailer failure
#Requests for medical advice and/or assistance
#Requests to assist others found to be in difficulty (optional on our part)
#Requests to assist anyone at all with an emergency (an obligation in law)
#At this time of the year, queries on footy scores do feature :-o)

Members with mobile phones travelling inside phone cells probably have no vital need for their HF, but some still call other VKS members, or say g'day to operators in quiet times.
VKS have 6 skedding bases (and other stand by bases) across the nation and there are 7 skeds every day.
As mentioned above, the HF organisations in Australia all have varied practices and features - personal contact with other HF users is the fast track way of learning in my view - research on the web will get you part way.

G'day Bruce, Your link is to the members area of the HF Radio Club site. The correct link is HF Radio Club
Selcall 4350

Thanks Rod