UHF CBRS to expand to 60 channels

The following announcement was broadcast on the WIA news on 24th May 2009

Expanded UHF Citizens Band proposed
The Australian Communications and Media Authority is raising the possibility that the current 40 channel UHF band could, with some changes, accommodate up to 60 channels.
The band began in the late 1970s with the Australian Government's plan that it would be the only CB band in Australia and everyone would switch from 27MHz (AM/SSB) to UHF (FM). That did not happen.
The ACMA acknowledges that the Class Licence CB band 476.4125 to 477.4125MHz is well used by not only hobby communicators but also private, commercial and government users.
An expansion needs a reduction in the simplex channel bandwidth from 25kHz to 12.5kHz and a lifting slightly of the band's upper frequency limit.
However 25kHz channels would be retained for the existing eight repeater pairs the 5/35 emergency pair and the 22 and 23 telemetry/telecommand channels.
The proposals require new transceivers programmed to automatically switch between 12.5kHz and 25kHz as required.
The ACMA recognises that interference is likely between the current and new transceivers, but under the Class Licence no protection is available from interference.
The proposals are part of the ACMA's review of the so-called 400MHz band used by land mobile, defence, government and others users.
The ACMA welcomes written submissions on the proposal by Friday, 29 May.

To read the entire ACMAs proposal for 400 to 520MHz, click here. Skip down to chapter 5 for UHF CB Radio.

It would appear UHF CB will expand to a 60 channel system. The fact that the ACMA has requested written submissions will make no difference. Some of you may remember nine years ago when the ACA (as the ACMA was then) requested written submissions on their proposal to introduce CTCSS on UHF CB. 94% of those who submitted their views did not want CTCSS on CB, but the ACA introduced it anyway. When the Australian Association of CB Radio Operators approached the ombudsman to see if there was reason for complaint, the ombudsman said "The ACA is legally required to ask for public opinion. They are not required to act on it". So if the ACMA has suggested a 60 channel UHF CB system, its safe to assume we are getting one, whether we want it or not.

The new system will retain some of the established 25KHz spaced channels with + or - 5KHz deviation (hereafter known as "wide channels"), but reduce some of the existing wide channels to 12.5KHz spacing with presumably + or - 2.5KHz deviation (hereafter known as "narrow channels"). An additional 20 narrow channels will slot inbetween the existing channels.

At this early stage we have to assume that the ACMA will take the sensible approach (?!?) and retain the original 40 channel numbers as they have always been, and not re-number the band in frequency order. Making that assumption, the UHF CB band will look something like this-

Retained wide channels	Old wide channels now narrow	New narrow channels	Use	Frequency
1			Repeater output	476.425
2			Repeater output	476.450
3			Repeater output	476.475
4			Repeater output	476.500
5			Repeater output emergency use	476.525
6			Repeater output	476.550
7			Repeater output	476.575
8			Repeater output	476.600
	9			476.625
		41		476.6375
	10			476.650
		42		476.6625
	11		Calling (rarely used)	476.675
		43		476.6875
	12			476.700
		44		476.7125
	13			476.725
		45		476.7375
	14			476.750
		46		476.7625
	15			476.775
		47		476.7875
	16			476.800
		48		476.8125
	17			476.825
		49		476.8375
	18			476.850
		50		476.8625
	19			476.875
		51		476.8875
	20			476.900
		52		476.9125
	21			476.925
22			Telemetry	476.950
23			Telemetry	476.975
	24			477.000
		53		477.0125
	25			477.025
		54		477.0375
	26			477.050
		55		477.0625
	27			477.075
		56		477.0875
	28			477.100
		57		477.1125
	29		Trucks and road channel pacific highway only	477.125
		58		477.1375
	30			477.150
31			Repeater input	477.175
32			Repeater input	477.200
33			Repeater input	477.225
34			Repeater input	477.250
35			Repeater input emergency use	477.275
36			Repeater input	477.300
37			Repeater input	477.325
38			Repeater input	477.350
	39			477.375
		59		477.3875
	40		Trucks and road channel	477.400
		60		477.4125

So what difference will this make to you and I? ie, Mr average CB user.

It is very unlikely that many exisiting CBs will be converted to the new channel width. If the proposed system had been for 80 channels and required all wide channels to become narrow, conversion would have been easy. But because some channels need to stay wide and some need to become narrow, conversion of older sets will be difficult if not impossible. So its more than likely exisiting sets will not be altered at all. Add this to the often agressive desire of some CBers to maintain their ignorance of anything that they dont understand (have you ever tried to explain to a non-enthusiast CB operator that he was blocking a repeater input?) and we soon realise that there is no hope of a smooth transition to the new system. The ACMA predict exactly this scenario by stating clearly that they will offer no protection from interference from other users.

The ACMA optimistically suggest a 5 year "migration" period after 60 channel sets become available. But as we know, there are heaps of UHF CBs over 20 years of age in daily use so users are unlikely to be scrapping 5 year old sets.

However, there will be diligent CB enthusiasts who will make sure they can operate to the new specifications. Many will be operating converted commercial or amateur equipment which can be easily re-programmed to the new channel widths. Its funny how on CB its usually the operators with illegal non-type approved equipment (and therefore "pirates") who are the best operators.

What of the future?
I'm certain the manufacturers will produce new 60 channel radios fairly quickly. Actually they will be 58 channel radios, channels 22 and 23 are disabled in all new CBs, effectively gifting them to commercial operators. Both GME and Uniden already have 60 channel CBs available with an additional 20 recieve only channels, which suggests they may have known about the proposals before the public did.

Once 60 channel radios arrive in the market place the confusion will start when it is discovered that old wide radios will sound distorted on new narrow radios. That narrow radios will sound quiet on wide radios, that wide radios will break through to adjacent narrow channels, and since its not a numerically adjacent channel nobody will understand why. Get ready for a nation wide bun fight folks! :o)

Actually...  if we consider the theory of fitting a narrow channel between two wide channels, they might fit. Assuming that wide channel sets have + or - 5KHz deviation and a recieve filter width of 15KHz, and narrow channels sets have + or - 2.5KHz deviation and a recieve filter width of 6KHz (as is more or less the industry standard) then there is no cross over between the channels. There is almost no space between them, but they dont meet.
So... if both CB stations had decent quality, well aligned recievers, it is possible that a wide channel and an adjacent narrow channel could operate at the same time and not hear each other.
However... this is in an ideal world and we all know that many CBs leave rather a lot to be desired in reciever quality and even good quality commercial equipment would never have channels spaced so closely. So no matter how hopeful we are that it'll work, we have to expect break through onto adjacent channels.

Who benefits from 60 channel CBs?
The manuafacturers will sell more radios to those updating to get the extra channels. The ACMA will get more free-to-air frequencies to recommend to small businesses who could not afford a private channel. But Mr average CB user wont see much difference. In the places where more channels are needed, like the RF congested inner city areas, the new narrow channels will suffer interference from old wide sets making the new channels unusable for most of the time. 

When more info is available, you'll read it here.

Cheers all
Jack VK2CJC
(all views expressed are entirely that of the author and do not reflect the views of any particular organisation)