[OZAPRS] Maxon DM-2550 and TinyTrak3

[Michael Carey]

Yep, 2 x .1uF one each across input to ground and output to ground, and 
a 100 uF Electro on the output.

Andrew Rich wrote:
> DO you have caps across your LM317 
>
> -----Original Message-----
> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au]On
> Behalf Of Michael Carey
> Sent: Monday, 28 May 2007 5:55 PM
> To: VK / ZL APRS Users
> Subject: [OZAPRS] Maxon DM-2550 and TinyTrak3
>
>
> 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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