[OZAPRS] UHF APRS freqs in VK
vk2tv
vk2tv at exemail.com.au
Mon Nov 13 07:55:23 AEDT 2017
70cm will get a lot worse when we eventually loose 440-450MHz, and
that's just a matter of time as spectrum gets sold off.
Ray vk2tv
On 12/11/17 19:42, Scott Evans wrote:
>
> Well bandplans come and go and I'm really struggling to get my head
> around the 5/7 splits just to avoid the LIPD allocation. Ok yes
> there's some sections of the 70cm band that have dedicated use (space,
> weak signal etc) another frequency allocation that is just silly,
> 439.200 being set aside for digital voice (P25, DSTAR, DMR and C4FM)
> also doesn't quite make any logical sense to me. But what would I
> know? 🤔
>
>
> On Sun., 12 Nov. 2017, 19:32 Glen English VK1XX,
> <glenlist at pacificmedia.com.au <mailto:glenlist at pacificmedia.com.au>>
> wrote:
>
> Hi Scott
>
> yeah 439.1 which is USELESS DUMB IDEA I EVER HEARD OF , I see it
> in the
> bandplan.
>
> why ? because it is too close to easily diplex into existing 70cm
> repeater systems that it might have to share with. Whoever came up
> with
> 439.1 had NFI.
>
> Two problems
>
> 1) requires lots of filtering and or loss to combine with 438-440
> transmitters
>
> 2) Because the digi would need to RECEIVE next door to the 70cm
> repeater
> transmitter, it will just get knocked over with TX noise unless you
> throw something like 3 x 6" 3/4 wave cans at it.... like no way.
>
> Canberra city is going on 442.975
> Ginini will go on 442.775 , tentatively, barring staying out of
> the way
> of numerous UHF repeater links..
> Maybe they should go on 12.5k offsets to stay clear. hmm.
>
> 200kHz apart in the same region is far enough that sidebands and spurs
> from one TX (say on 442.775) will not get into the other receiver (say
> on 442.975)
>
> :-)
> g
>
>
>
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