Thread: VHF or UHF

Originally Posted by Deffy

I got a licenced VHF unit from overseas, but it seems that most places only sell UHF. What the deal with that? What are most drivers using?

Regarding licenced VHF,

For 4wd use, HF and UHF are the most useful in Aus. VHF is not very useful for the average 4WDriver who does not have an amateur licence.

The cb frequencies on UHF (476.425 to 477.400 MHz and HF (27MHz) are free to use.

To transmit on any other frequency (except amateur frequencies, where a special amateur licence is required), you need a spectrum licence from Australian Communications Media Authority http://www.acma.gov.au ($k for each frequency).

HF is useful for long distance communications from remote areas. For this you can become a member of a network such as VKS737 (the 4wd network) and use the frequencies that they have licences for.

To use your VHF radio, you will need to purchase a spectrum licence. This is an expensive exercise and there may not be any available - AFAIK, when a frequency is surrended, the current practice is to auction them off.

Originally Posted by Cul

I agree. The language has become an issue. There's not much you can do about it though. The only thing that had annoyed me recently is the availability of the UHF's on the market, and the fact being that kids are buying these handhelds and just being idiots on there by intimidating other users and trying to get an angry response out of them.

How many people communicate using VHF these days?

I think you mean 27MHz CB which is HF not VHF (The definition of HF is any radio frequency between 3 MHz and 30 Mhz).

The definitions are:

ELF 3 Hz - 30 Hz (Used for submarines)
SLH 30 Hz - 300 Hz
ULF 300 Hz - 3 Khz
VLF 3 KHz - 30 KHz
LF 30 Khz - 300 KHz
MF 300 Khz - 3 MHz
HF 3 Mhz - 30 MHz
VHF 30 MHz - 300 MHz
UHF 300 Mhz - 3 GHz
SHF 3 GHz - 30 GHz
EHF 30 GHz - 300 GHz

Why multiples of 3?

Simple, that gives wavelengths in the multiples of 10 owing to the speed of radio waves being approximately 300,000,000 metres per second (actually 299,792,458)

See also http://www.vlf.it/frequency/bands.html

Ron