Thread: HF Radios and antennas - need advice please

OK - starting simple

Take a look at VKS737: The Australian HF Radio & Radio-Telephone Network ! - once you join one of the providers you effectively become a joint licencee so there is no need to "get a licence". Sort of like joining an internet provider - gives you access to the system allowing you to transmit on a number of defined frequencies (which are probably in your radio).

There is a bit of jargon and protocol but it should be outlined on the website and it's mostly fairly simple.

If you have a tapped antenna (one with multi access points for the plug of a "wander wire") you don't need one of the large based aerials which are quite expensive. You manually change the frequency on the aerial to the one which you want to use. When the auto type is working correctly it "automatically" tunes to the frequency you are transmitting on.

Does your antenna have a base, and does it have any maker's name or model on it ?

Earthing the antenna base to the vehicle is quite important.

The power supply to the radio needs to be adequate - the power drain when actually transmitting is quite high.

Ahh - the antenna makes a bit more sense now - it is tapped type, but I couldn't figure out how it worked, or which tap to use. I'll have a look at the base tonight and see what says. The power supply is good and solid - it runs through some huge cable straight from the battery through a fuse and to the unit - which is mounted right next to the battery box, so a short run.

I'll have a look through the VKS website now so my future questions will be a little more informed.

EDIT - Just had a google and I think my antenna looks very much like this - Barrett communications: 914 which make sense as the radio is a Barrett unit. I didn't see any markings on mine for the frequencies, but I'll check tonight.

Cheers - Gav

What vehicle are you going to use it on? The interference from EFI engines plays havoc. Just use it once camped.

We need more details of the aerial. Or a pic. It's important that the frequency on the aerial matches that of the unit. You either jump out & do it manually, or via the autotune with a button press. The manual items are more robust & more efficient.

These things have the wavelength of a football field, and are only about 1% efficient. So, they blast out at 100 watts.

It's worth reading up on how they work, bouncing off the ionosphere etc. " The higher the sun the higher the frequency"

The older units work just as well. Or better. They're more repairable too. Mine's older, its a Barrett 250.

And as suggested, poke around VKS 737. Or one of the competitors. They'll issue you with a callsign.

Have fun!

Regards
Max P

It is set up in the back of the vehicle, so wouldn't/couldn't be used while moving.

Just been going through the VKS website - plenty of useful information, but one thing that I found was they make the times for thier daily radio skeds known only to members. While I can sort of understand that, it makes it hard for a newby like me to know when to listen in to see how it all works.

If it's not a closely guarded secret, can anyone tell me when the skeds are for the different frequencies?

I would like to listen in and see what it is all about...

Cheers - Gav

sent you a pm...

Thanks for the email

Now, I have some more detail on the antenna and a few questions. I think the antenna is a Barrett, but not sure of the model, as the current manual tap antenna on their website say it has 12 taps, but mine has 20...? It is 6' tall. Looks like this... There are no readable model numbers on the sticker at the bottom as it all has a coat of olive drab paint...



Sorry for the photo on its side, I couldn't fit it in otherwise.

Now for some questions on the markings. Some I think I can work out, but others I can't. From the bottom of the antenna, the taps are labeled like this...

The very bottom tap which is on its own by a fair way I am assuming is the fixed common point? It has 2 labels. One says '2020' and the other says 'WL-150'. The taps up from that read
RT12
VKS5
4980
RT13
5300/60
VKS1
RT22
6790/6845
RT14
7465
7899
VKS2
RT23
RT15
RT16/19
VKS3/RT2
RT24
VKS4
RT17/19/21/25

I am assuming that the VKS ones match the frequencies of the VKS channels? The 4 digit numbers are other frequencies? No idea what the RT ones are.

Can anyone confirm that the bottom tap if the fixed tap, or does it work different to that?

Cheers - Gav

Originally Posted by bacicat

Thanks for the email

ow, I have some more detail on the antenna and a few questions. I think the antenna is a Barrett, but not sure of the model, as the current manual tap antenna on their website say it has 12 taps, but mine has 20...? It is 6' tall. Looks like this... There are no readable model numbers on the sticker at the bottom as it all has a coat of olive drab paint...



......

I am assuming that the VKS ones match the frequencies of the VKS channels? The 4 digit numbers are other frequencies? No idea what the RT ones are.

Can anyone confirm that the bottom tap if the fixed tap, or does it work different to that?

Yes , that's correct, fit one end of your wander wire to that and the other end to the upper tap that you want to use ..... mainly needed on transmit

Originally Posted by bacicat

Now for some questions on the markings. Some I think I can work out, but others I can't. From the bottom of the antenna, the taps are labeled like this...

The very bottom tap which is on its own by a fair way I am assuming is the fixed common point? It has 2 labels. One says '2020' and the other says 'WL-150'.

2020 is an RFDS Channel

The taps up from that read
RT12
VKS5
4980 RFDS
RT13
5300/60 RFDS
VKS1
RT22
6790/6845 RFDS (I think)
RT14
7465 RFDS
7899 RFDS (I think)
VKS2
RT23
RT15
RT16/19
VKS3/RT2
RT24
VKS4
RT17/19/21/25

I am assuming that the VKS ones match the frequencies of the VKS channels? The 4 digit numbers are other frequencies? No idea what the RT ones are.

Can anyone confirm that the bottom tap if the fixed tap, or does it work different to that?

Cheers - Gav

Have a look above. Going by memory from a LOOOONNNNGGGGG time ago, when I built HF radios for Tracker Communications

The RFDS channels are good to listen into, especially if the School of the Air is operational. Do they still use HF??

The way we used to build them, the lower the frequency, ie: 2020, the lower the channel number, ie: chan 1. 4080 on chan 2 etc...

Disclaimer - this was back in the day when we used HAND CUT crystals in the radios. And they worked really bloody well. Adelaide to Brisbane no problems...