Finally, at last, about time - 80ch

Thanks jd patrol

Gooday olcoolone,
The documentation clearly states it comes into effect the day it is published in the gazette (as does all legislation unless a specific rider is attached).
regards

Yep it is law alright. Done and dusted. There is also a similar amendment about the specs of the equipment. ( it's law too)

Agreed on the probable inability of government/regulators to have the gonads and resources and will to remove the 25mHz units out there that would be unable to be reconfigured.

Should also be more interesting out there with the amatuer CB'er's who have needed to upgrade their power outputs to say 25 watts to get their voices and messages shouted out into the stratosphere, while drowning out the legitimate 5 watt users for tens and tens of kilometres.

If you don't need it then don't get it. Simple. \

Others DO have issues with crowded channels which this goes some way to resolve.

There are no extra fees so how can you think the government is in the interests of the Feds as you say.

I think you missed my question!! Michael

Sorry Michael

The only question I can find in your post is

"So can someone shed some light why we apparently needed 80 channels?"

And to be clear, my answer to that was

"If you don't need it then don't get it. Simple. \

Others DO have issues with crowded channels which this goes some way to resolve."

What was the other question that I missed? Try as I may, I can't find any others.

Boobook, i just read the intro of the Legislation.. Apparently the changes are primarily for extra channels.. Surprises me somewhat... considering govts dont really do too much for the common man!! Michael

I am just a layman as far as the 40/80 channels go. As I understand it, we now have 40 channels spacing at 25 K khz. in the same area of the spectrum we now have 80 (77) channels spaced at 12.5 Khz. The new 40 channels will be 1A, 2A, 3A, up to 40 A. will not the original 40 channels still be in the same place? So my 40 channels will still be in the same place 1, 2, 3, - - - - - 40. As I said, I am a layman as far as this electricary goes and am willing to be enlightened. Sounds to me like another Government grab for cash. Steve.

I think it is more about moving voice communications to the narrow band width.
Apparently narrow band is clearer for voice transmissions The current wider band is better suited for data communications. The extra channels are just a bonus as cb uhf will still operate from 476.425 mhz to 477.400mhz only with 12.5 channel spacings instead of the current 25.

Just my thoughts and happy to be corrected.

Cheers Teza

Ok I'll see if I can explain the changes.

There is a band of UHF spectrum allocated to CB unlicenced use. It was 476.425 Mhz ( CH 1) to 477.4 MHz ( Ch 40). At the time it came out 15 or so years ago 25 KHZ ( or 0.25 MHZ) spacing was about as good as cheaply priced equipment could get, divide the differnece by 25khz and you get 40 channels.

As time has moved on, so has technology. Now radios can easily work at 12.5Khz, known as narrow band in this context, as well as the 25khz at reasonable cost. Even 6.25 or less is available for some commercial radios.

So the ACMA, the government authority responsible for this stuff has said that by using the narower 12.5khz channel width, 80 channels can be accommodated in the same spectrum space as the old 40, hence this change.

So the exiisting 40 channels stay in the same spot, but are now narrower, and only use half the space in between. That creates space for the channels 41 to 80 halfway between each of the channels.

So in terms of frequency use it now goes
CH1
Ch41
Ch2
Ch42
...
Ch39
Ch79
Ch40
Ch80

But the new radios are set up so you see it as 1 - 80. So the new channels 1 - 40 are in the same spot as the old 40 channels. The new channels 41 - 80 are half way in between.

It's a bit like a bench with 40 people sitting on it and someone says "pull in your gut and let a new person sit in between each of you". The bench is the same width but it now takes 80 people, but they all have to be skinnier.

In addition ACMA are aware that some channels are important and may not interoperate with the standard properly given that it is old equipment. Specifically this is the old Channels 5, 22 and 23. So the new adjacent channels 45, 62, and 63 are not able to be used ( at least for a while anyway) to protect these services of emergency repeaters, and data. Thats why it is 77 channels not 80 in reality.

So now there are people using equipment with either 40 wide channels, or 80 narrow channels, for the main part they are interoperable but there are small incompatibilities. So ACMA in their wisdom said you can use either but the old system has to go by 2016 ( from memory).

Hope this makes sense.

Hi Boobook,

Your explanation was so simple yet clear that even an electronic dummy like me got a pretty good handle on it (I think).
If I may could I ask what no doubt will seem a somewhat dumb further question. So 4 UHF sets operating within range of each other, two are the older 40 channel jobbies and the other two the new beaut 80 channel ones.
If the 2 new ones are talking to each other and the 2 old ones are talking to each other how would they affect each user if for example the 40 channel sets are on say ch 18 and the new ones are on an adjacent new channel.
I hope you can understand my ramblings.... after reading that lot I'm not sure even I do.....lol..... but I can't think of any other way to ask it.

Cheers
Pop

Pop, firstly if they are 80ch or 40 channel units, and they are all on channel 18 then they will all be able to talk to each other. Then if as you say the oldies are on channel 18 and the new ones nearby are talking to each other on say Channel 67 or 68 which are the next adjacent channels down and up from 18, then there will generally be no interference unless they are very close, then you could get some crosstalk, in other words you might hear some distorted sounds, a bit like a distant hard to hear signal. In fact you hit the nail on the head as to why channels 45, 62 and 63 have been delayed. These are called "guard channels" as they provide a guard or buffer so this doesn't happen at all on channels 5, 22, 23.

*most* of the time it should be ok in practical situations though. It is a bit like 2 radio stations clashing if they are close in frequency. Generally there is no problem but sometimes if there are two distant stations that are close in frequency you get crosstalk, same principle.

I am not sure how bad it will be in practice, but you would hope our beloved communications authority did some testing and have some experience....

Australia's UHF CB system came into operation in 1978/79 and was supposed to replace the 27 mhz by 1982. The removal of the 27 mhz system was realised to be virtually impossible for the same reasons that finally allowed for legalisation of the 27 mhz system in 1977 - the sheer volume of radios in use. I can't see too many people giving up the old 40 ch UHF's for the same reason and there is no way Spectrum Management Australia could enforce it.

Cheers Darryn

Thanks Boobook, I think I have a better handle on it now


Cheers
Pop

"It's a bit like a bench with 40 people sitting on it and someone says "pull in your gut and let a new person sit in between each of you"."

Picking on the poor ol Fat man once again....lmao

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eighty matey replied:
... I reckon nearly everyone will move to the 80 channel sets soon enough.


I hope not eightly matey. The less the better. Especially the suburban hoon / sewaring brigade. Let 'em stay on the bottom 40 channels I say. That's the main reason I am interested in 80 channels personally speaking.

I have to upgrade. My set has started to get unreliable at times and that doesn't suit me.

I guess we'll find the idiots that need to bag out truck drivers to get their jollys, or tell how to make the perfect cup of coffee (constantly) will change to maintain their audience.

It's time for a change. I'll accept it.

eighty matey.

Seems the 3440's shipping now are upgradeable to the 80 channel spec (with the factory software provided to dealers) - but more $$$ of course :-o)..... They have 57 extra RECEIVE ONLY channel slots too that can be user programmed (questionable value for most, I expect). The new spec has virtually killed off any market for used UHF's anyway - wait and see is my stance - my 40's might still see me out :-o).

Oh.... and ..... UHFcb.com.au is useful.

Not only that DJ, but if you join this forum, someone has done the hard work for you.

Yahoo IC400 group

Though the Icom 440 cannot be upgraded and at this stage Icom are not releasing a 80 channel version of it.

Garry