UHF 40 Compatible with UHF 80

Hi all,
I did a search in the articles and the threads but didn't find an answer.

I have just upgraded to an 80 channel UHF and took my old 40 channel handhelds out to check reception.

Not good. Garbled reception from both the 80 channel and the 40 channel - not able to distinguish any of the conversation.

The obvious answer is NO, but maybe there is a setting that lets the 80 channel sets send and receive to a 40 channel set.

Anyone know?

bill
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Reply By: garrycol - Sunday, Feb 03, 2013 at 16:49

Sunday, Feb 03, 2013 at 16:49
Channel 1 on the 40 channel system is the same as Channel 1 on the 80 Channel system and so forth up to Channel 40 so there should be no compatibility issues.

How close were the two radios - was the distortion caused by being too close?

Garry
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Follow Up By: The Explorer - Sunday, Feb 03, 2013 at 16:53

Sunday, Feb 03, 2013 at 16:53
Yes - I have used my 80 channel radio to communicate with 40 channel units and based on this limited experience see is no reason why channel 1-40 shouldn't work. So suspect it maybe another problem, too close as suggested or maybe aerial/wiring issue.

Cheers
Greg
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Follow Up By: olcoolone - Sunday, Feb 03, 2013 at 17:06

Sunday, Feb 03, 2013 at 17:06
Garry read my reply below re compatibility.
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Follow Up By: garrycol - Sunday, Feb 03, 2013 at 17:15

Sunday, Feb 03, 2013 at 17:15
I have not had any issues on trips I have been on between 40 channel and 80 channel radios. I have had problems with poor quality radios like Oricoms and other cheap brands but that is even when 40 channels are talking to 40 channels etc.

Quality of radio is more the issue rather than 40/80 channel compatibility.

Garry
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Follow Up By: olcoolone - Sunday, Feb 03, 2013 at 17:24

Sunday, Feb 03, 2013 at 17:24
We have seen different, we have had this problem with our 40 channel Icoms trying to talk to our 80 channel Icoms.

The same goes with our GME handhelds.
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Follow Up By: Member - bbuzz (NSW) - Monday, Feb 04, 2013 at 11:11

Monday, Feb 04, 2013 at 11:11
Yes, they were close - inside the house versus the shed (about 30 metres away).

I use the portables for reversing the van into a carport so we will always be close when using them that way.

I will go up the road and use channel 1 for another test.

Anyone know who re-programs the channels as mentioned below?

Thanks for the advice

bill
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Reply By: olcoolone - Sunday, Feb 03, 2013 at 17:05

Sunday, Feb 03, 2013 at 17:05
According to ACMA it is 100% comparable and you will not have any problems....... BULL!

What a scam, the older 40 channel radios used what they called wide band on the 40 channels and the 80 channel radios use narrow band on all 80 channels.

We had big problems when we went away with a group of people a few years ago..... we had a new 80 channel Icom IC-F6063 commercial radio (yes under 5w) and we could not hear every one and they could not hear us all the time..... broken conversations.

One of the guys on out trip sells GME products and the first thing he said to us "are you using an 80 channel radio", he said he gets a lot of farmers complaining that there new radio will not work with the old radios.

We ended up reprogramming the radio for 1-40 wide band and 41-80 narrow band, this fixed the problem.

As time went on other manufactures started realising there was a big problem...... the funny thing is not a 40 channel radios suffer this problem.

Transport companies and farmers were up in arms about it...... we have UHF radios in all our service vehicles to use on mining and construction sites and this has turned into a BIG OH&S issue for us.
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Follow Up By: Bazooka - Sunday, Feb 03, 2013 at 17:52

Sunday, Feb 03, 2013 at 17:52
Does the fact that you can reprogram the 80ch models to get the desired result indicate that the standard is okay but the implementation by manufacturers is not - ie they aren't concerned about backwards compatability?
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Follow Up By: Bonz (Vic) - Sunday, Feb 03, 2013 at 21:15

Sunday, Feb 03, 2013 at 21:15
Sounds like he's programmed 1-40 as wide band and 41-80 narrow band. Manufacturers will always program fully wide (40 ch) or narrow (for 80ch).

I have just programmed the 80ch's into my icom and havent had any issues.
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Follow Up By: olcoolone - Sunday, Feb 03, 2013 at 22:07

Sunday, Feb 03, 2013 at 22:07
What you will find is the transmit from a wide band 40 channel radio sounds like it is breaking up on an 80 channel radio and the transmit from an 80 channel radio sounds deaf and muffled on a 40 channel radio.

Standard out of the box 80 channel UHF radios have to be programmed with 80 channels set at narrow band, they are not allowed to mix narrow and wide band..... this is done so eventually in the future all UHF CB radios will be narrow band and the older 40 channel wide band radios will die from natural extinction.

When this happens we will take out radio back to the dealer and get it reprogrammed with all narrow band channels.
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Follow Up By: Bazooka - Monday, Feb 04, 2013 at 12:15

Monday, Feb 04, 2013 at 12:15
Thanks for the explanation Olcoolone. Explains why I get a mix of garbled and clear stuff on 40 when I'm up and down the highways.
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Reply By: patsproule - Monday, Feb 04, 2013 at 17:15

Monday, Feb 04, 2013 at 17:15
Quoting a post of mine from another forum (Pajeroclub) that might help explain....

Yup, this is a big problem with the changeover. UHF is FM - Frequency Modulated. The carrier frequency deviates either side of centre to the amplitude (volume) of the audio signal. The larger the volume the greater the deviation. Broadcast FM radio deviates up to 75khz from it's carrier frequency. Any more and it can interfere with adjacent transmissions so it is limited. In UHF CB they have halved the allowable deviation from 5khz (40 channel) to 2.5khz (80 channel) even on the existing base 40 channels. This is where the room for the extra 40 channels comes from - splitting the space of the existing 40. However a radio set up to receive 5khz deviation (40 ch unit) will hear 2.5khz transmissions (80 ch unit) at half the volume. This changeover also reduces the possible dynamic range of Uhf CB, so while we get more channels we loose quality. Bit like the digital TV changeover (mpeg2 compression at low bit-rates is nasty!).

What can you do? See if your radio can be programmed back to 40 channels. Some can, some cant. Or buy all your friends 80 channel radios.
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