How long are 40 ch UHF radios going to be around for?

Submitted: Thursday, Aug 06, 2015 at 18:01
ThreadID: 129889 Views:2354 Replies:3 FollowUps:12
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I noticed last week someone (PeterD?) with reference to another topic, said that these radios will only be around for another couple of years. Surely we can still use them along side of the 80 ch units. Don't tell me it's going to be like digital TVs where all the old faithfuls will be basically ditched?
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Reply By: Hoyks - Thursday, Aug 06, 2015 at 19:21

Thursday, Aug 06, 2015 at 19:21
The 80 ch radios are narrow band, so the extra 40 channels fit in 1/2 way between the old 40 channels (40ch had a 25MHz spacing, 80 ch have a 12.5MHz spacing).
The new radios are also smart enough to know what they are receiving, so while a old 40ch might not get the best reception when listening into a new 80ch transmitter, the 80ch will receive from the 40ch fine.

But, The Commonwealth Government give you until the 30Jun17 to upgrade to one of the newer radios. Going on how often any legislation regarding CB radios is enforced though, I don't think you will have much to worry about.

https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCMQFjABahUKEwjH0ff-jpTHAhXi26YKHY-HAlc&url=https%3A%2F%2Fwww.comlaw.gov.au%2FDetails%2FF2011L00862%2F6c4852a0-01a6-4282-82aa-75518d54f352&ei=TCXDVcf7C-K3mwWPj4q4BQ&usg=AFQjCNFTfdnA6rL-8T3tWhTXVoHXaco59A&bvm=bv.99556055,d.dGY&cad=rja
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Follow Up By: Zippo - Thursday, Aug 06, 2015 at 23:14

Thursday, Aug 06, 2015 at 23:14
You really meant 25kHz and 12.5kHz but were just seeing if we were awake ;-)
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Follow Up By: Hoyks - Friday, Aug 07, 2015 at 07:39

Friday, Aug 07, 2015 at 07:39
yeah, what he said.
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Follow Up By: Nomadic Navara - Friday, Aug 07, 2015 at 10:06

Friday, Aug 07, 2015 at 10:06
Quote "The new radios are also smart enough to know what they are receiving, so while a old 40ch might not get the best reception when listening into a new 80ch transmitter, the 80ch will receive from the 40ch fine."

There is nothing smart about these radios at all. The old and new channels have the same centre frequency. If you don't speak correctly into the microphone (WB transmitter) and don't fully modulate your transmission then the narrow band receivers will receive your transmission OK. If a narrow band receiver is receiving a fully modulated transmission then the side-bands at the edge of the signal will b clipped by the narrow IF filters and the received audio will be distorted a little (although you will only notice that if you have a set with good fidelity.)

The problem with using wideband transmitters in conjunction with narrow band receivers is adjacent channel interference. The wider bandwidth transmissions overlap the receiver bandwidth of the narrow band receiver operating on an adjacent channel. This does not cause much problem with mobile to mobile working when the parties are separated by a few kilometres spacing but it will affect the operation of receivers in repeater stations where the antenna is well elevated.

The above may not make much sense to those who think that a FM transmission is a single frequency varying in frequency with a maximum deviation of around 3.5 kHz. Those who understand radio transmissions know that the actual transmitted signal has side bands and those side bands spread far wider than those of AM transmissions.
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Follow Up By: Kilcowera Station Stay - Friday, Aug 07, 2015 at 17:35

Friday, Aug 07, 2015 at 17:35
This man knows what he's talking about! Peter I need you to come and have a look at the UHF in my plane! When I use it the people on the ground can only just hear me. It's too quiet. Cheers Toni
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Reply By: Bob Y. - Qld - Thursday, Aug 06, 2015 at 21:36

Thursday, Aug 06, 2015 at 21:36
Would be surprised if there won't be a ready market for 40 channel sets in country areas, Gerry. Bandwidth wouldn't be a worry if your nearest neighbour was 10, 20 or even 80 kms away.

Wonder if all the repeaters scattered around the country will have to be upgraded too, seeing they only use Ch 1-8 & 31-38?

Bob

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Follow Up By: Zippo - Thursday, Aug 06, 2015 at 23:13

Thursday, Aug 06, 2015 at 23:13
Bandwidth IS a worry for travellers. And the repeaters will need to be narrowbanded too (if they haven't already).
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Follow Up By: AlbyNSW - Friday, Aug 07, 2015 at 07:30

Friday, Aug 07, 2015 at 07:30
For the price you can buy a new 80ch for why would you bother to persevere ?
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Follow Up By: Nomadic Navara - Friday, Aug 07, 2015 at 09:39

Friday, Aug 07, 2015 at 09:39
Quote "Wonder if all the repeaters scattered around the country will have to be upgraded too, seeing they only use Ch 1-8 & 31-38?"

Where did you glean that gem? The number of repeater channels is being doubled as well as the total number of channels. The number of data channels (ch 22 & 23) is also likely to be doubled as well.

The successful introduction of repeater channels on the new channels will rely in part on getting rid of 25 kHz equipment.
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Follow Up By: Gronk - Friday, Aug 07, 2015 at 09:47

Friday, Aug 07, 2015 at 09:47
Not trying to sound like a grey nomad, but why would you spend $200 plus on a new CB when you didn't have to?
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Follow Up By: AlbyNSW - Friday, Aug 07, 2015 at 11:49

Friday, Aug 07, 2015 at 11:49
You are sounding very Grey Nomad LOL
You upgrade for the same reason you did for your oil lamp, kero fridge, vinyl records and analog phone
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Follow Up By: Nomadic Navara - Friday, Aug 07, 2015 at 16:03

Friday, Aug 07, 2015 at 16:03
"but why would you spend $200 plus on a new CB when you didn't have to?"

Who says you don't have to (unless you are a blatant law breaker?) When the final date for wideband equipment comes your equipment can no longer to be used for operation under the CB class licence. If you continue to use your wideband equipment you will be operating a transmitter without a licence. I know there is a low probability of being caught but if you are the maximum penalty is 2 yeas holiday.

The technical reason for not operating your wideband equipment is in part covered by my message in Reply 1.
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Reply By: pop2jocem - Monday, Aug 10, 2015 at 09:32

Monday, Aug 10, 2015 at 09:32
So in simple terms.

What channel will/is the new "truckies channel"? Was 40. Do they still use that channel assuming they have a new 80 channel set?

Will a 40 channel set still be able to communicate with an 80 channel set assuming they are both on channel 40? I'm talking about short distance, maybe 1 k or less.

Cheers
Pop


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Follow Up By: garrycol - Monday, Aug 10, 2015 at 10:05

Monday, Aug 10, 2015 at 10:05
Is still channel 40 - the old channels 1 -40 are still the same as channels 41-80 zipper between the old channels.

While there are some minor issues related to volume - the two systems talk to each other no issues.
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Follow Up By: AlbyNSW - Monday, Aug 10, 2015 at 19:23

Monday, Aug 10, 2015 at 19:23
I have upgraded to a 80ch unit and have no issue communicating with fellow travelers using 40 Ch units
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