[OZAPRS] Maxon DM-2550 and TinyTrak3

Peter VK1NFI vk1nfi at netspace.net.au
Tue May 29 11:30:23 EST 2007


I also think that if you follow Andrews idea (which is fine) you need to 
get a small pre-amp to bring the audio to a sufficient level to trig the 
CD on the Tiny3.
Peter 1NPW has successfully done it I think, although if I remember 
correctly it was with a Tiny2??

Or the other possibility is I have my wires crossed and back to front 
and am thinking of another project???

Pete VK1NFI


Dion Bramich wrote:
> The CD line doubles as a power save input I think, so if theres
something  
> happening there its probably putting the radio to sleep.  I have 2  
> trackers built on Maxon modules and TT3s with CD, with no problems.
>
> Dion.
>
> On Mon, 28 May 2007 17:55:21 +1000, Michael Carey  
> <michaelcarey at internode.on.net> wrote:
>
>   
>> Hi Everybody,
>> I'm turning a TinyTrak3, Maxon DM-2550 and a Garmin GPS-15 into a
>> transportable APRS tracker. So far my plan is to jam the whole lot,
plus
>> a small gel battery into a small Pelican case.
>> I've made up a small LM-317 based regulator for the DM-2550, providing
>> the transceiver with 10V. I also planned on using the carrier detect
>> output from the DM-2550 to stop the TinyTrak3 from stomping on other
>> transmissions.
>> It's about here I have come across something weird... I'm powering the
>> TinyTrak3 from the same 10V regulated supply as the DM-2550. If I apply
>> power to the regulator (connected to both the DM-2550 and the
TinyTrak3)
>> the DM-2550 goes into a non-operational state, no transmit, no receive.
>> I originally thought it was the fault of the DM-2550 and Garry was
happy
>> to swap it over, but it's the same story with the replacement.
>> I've got a WXtrak/DM-2550 combo in a half built Peet Bros based weather
>> station which seems to exhibit the same problem, but _only_ after I
>> connected the CD line of the TinyTrak3 to the DM-2550. Without the CD
>> line connected, there is no problem.
>> If I unplug the DM-2550 and connect it up again, things are OK and will
>> be as long as the power supply in maintained. And here is the weird
>> part... if I run the combination from a 9.6V NiCd battery pack, I have
>> no problems. If I power the TinyTrak3 from a seperate supply (prior to
>> the regulator circuit for instance), it's OK as well.
>> Has anyone in the list seen this problem with the DM-2550 before?
>> Regards,
>> Michael.
>> VK5ZEA
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>> Ozaprs at aprs.net.au
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>>
>>
>>     
>
>
>
>   


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