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Author Topic: 900 Mhz CB - Link - 80 channels  (Read 5411 times)

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Offline Ramjet

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Re: 900 Mhz CB - Link - 80 channels
« Reply #4 on: April 17, 2010, 12:58:39 PM »
I'm thinking about putting a lot together,
that way it will cut the shipping cost down.

I'm also waiting on some new antenna parts to arrive so that
I can bundle up some radios with antennas to suit.

I'm guessing at around $200 each programmed with microphone.
The radio's I have now don't have any microphones.

If someone wants to make their own antenna's that would help.

Ramjet.

Offline BuNtEr

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Re: 900 Mhz CB - Link - 80 channels
« Reply #3 on: April 17, 2010, 12:52:49 PM »
Price ?
What can i say but just that

Offline Ramjet

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Re: 927 Mhz CB - Link - 80 channels
« Reply #2 on: April 16, 2010, 04:59:53 AM »
Sorry to confuse readers about Euro UHF CB and Australian UHF.

The 927 meg allocation in Australia is a garbage dump of cordless phones
that takes out the entire 80 channels in 30 cordless phone channels between 927.0125 - 927.985
These cordless phones can be heard for some long distances, and only require very low power to go
some long distances. But, most phones and handsets operate most of the time in the same room,
let alone outside.

These make nice private link radios, the odds of anyone interfering with each other is remote,
even if a cordless phone interfered with a neighbours phone, all it takes is one user to hit the change channel
button.

Now, Aus is apparently allowing Motorola Spread Spectrum walki talkies , somewhere on 900 mhz.
Does anyone know where? These babies can go a watt or so and have considerable range, privacy,
they only stay on one frequency a few seconds before jumping to another one in a 40 channel config.
They also use a different form of modulation that scanners can't monitor. 
These radios can be set up like telphone numbers, you can set a code and only those who know the code can
call you or you can set something that is group generic.

I'd like to know what freqencies these radios are using?
I suspect its in the low end of 900.

Anyone got any other information?

Are there other 900 mhz allocations in Aus that have heaps of garbage on a non interference basis?

Regards

Ramjet
 

Offline Ramjet

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900 Mhz CB - Link - 80 channels
« Reply #1 on: April 06, 2010, 03:09:40 PM »
Recently a European UHF CB enthusiast ordered 933/934 Mhz Kenwood TK-841
that is, it does 15 Watts narrow band FM and very nice receive ability.

see pic



It took a great deal of effort and time to be able to program it for
two banks of 80 channels in 933 and 934. 
The regular software will not do outside 935-939 mhz.
to get it to do outside that spectrum, it requires modification of the
binary information but once it's programmed, you can see weird channel
numbers and the actually frequency programmed.

You can select RX only or TX "Talkaround" that is simplex,
you can also select standard 39 mhz repeater offset,
TX is 39 mhz down. OR you can set it up so that
it acts like a duplex channel with the RX & TX being almost anything
in the range.

Its known to be good on RX below 927 and to as high as about 950 mhz
The TX can be from 880 to 950.


Now, I programmed another one up for the USA Amateur Band that uses 927
however, that band of 927.000 -927.985 is used exclusively for Cordless Phones.

If you go up to 928 you will see that its used for "spread spectrum" data etc, and
its also used as a garbage dump part of the spectrum for electricity meters.

Yagies on this frequency , have double the elements for the same boom length
and are capable of very long ranges point to point for linking etc.

I have a bunch of these radios, and can also include portable antennas etc.
NO MICROPHONES Included, uses eight pin RJ45 standard connections.
I will have some microphones later.

I will throw in programing of 80 channels.

Serious enthusiasts only.

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