[OZAPRS] Desense to 2m voice repeater from APRS digi ??

Warren VK3BYD vk3byd at wia.org.au
Fri Oct 19 08:15:39 EST 2007


Geoff,

I am glad you only ask the simple questions :)

This area can be quite complex as there is SO many variables when it comes

to interference / desense.

Some pointers from my experiences with the VK3 network,

Antenna, vertical separation between the antennas provides much isolation 
than horizontal separation.



The type of filter used, some repeater filters only offer a notch for the 
opposed port and therefore provide little protection from anybody else.



You need to decide how much interference you can live with, some maybe a 
single band pass on your radio and a notch filter for the voice repeater 
depending on the type of diplexer used.



The amount of RF other users on the site will also make it harder for you.



 Possible the hardest part is the perception of the local voice repeater 
maintainer and users of how things have changed since you put that bl__dy 
aprs digpeater one air :)



Good Luck

Warren VK3BYD

----- Original Message ----- 
From: <geoff at gatwards.org>
To: "VK / ZL APRS Users" <ozaprs at aprs.net.au>
Sent: Thursday, October 18, 2007 12:49 PM
Subject: [OZAPRS] Desense to 2m voice repeater from APRS digi ??


> We are looking at installing several new digipeates throughout NSW, but
we
> have had a few little concerns with possible de-sense to co-sited 2m
> repeater equipment.
>
> With the current VK3/5/7 (and 4?) digipeater installations, does anyone
> have any information regarding the amount (if any) of filtering required
> to knock the desense issues out ??    We do have one particular site
that
> is about as close as we can get to the 2m voice segment, with a repeater
> on 146.650, the local Rx frequency is 146.050, only just above our
> 145.175.  The problem is that although we can get the digipeater itself
in
> without any issues, space is at a premium and we might not be able to
> install the cavities required.
>
> Anyone got any experience in this area ??
>
> Our co-sited digis in Sydney are with 70cm repeaters so this issue
didn't
> come up :(
>
> Thanks,
> Geoff  VK2XJG
> _______________________________________________
> Ozaprs mailing list
> Ozaprs at aprs.net.au
> http://aprs.net.au/mailman/listinfo/ozaprs 
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