[OZAPRS] Maxon DM-2550 and TinyTrak3

[Mike Zwingl oe3mzc]

had kind of same problem with Carrier Detect on my TT3 and FT100. It even 
blew the Squelch switching transistor in the Yaesu FT100, so that it was 
always open and I had to replace the tiny smd transistor.

The CD adjustment of the TT3 is very very critical and also shows 
temperature drift and dependency of supply voltage.
To correct this, I had to insert a small transistor amplifier to make the 
audio sufficient strong for the CD circuit of the TT3.
This amplifier also servers as decoupling between radio and TT3.
Now its ok for 2 years.

by the way: the OPENTRACKER ot1x does not show this problem.

vy 73 de Mike
OE3MZC / VK3FPF

----- Original Message ----- 
From: "Peter VK1NFI" <vk1nfi at netspace.net.au>
To: "VK / ZL APRS Users" <ozaprs at aprs.net.au>
Sent: Tuesday, May 29, 2007 3:30 AM
Subject: Re: [OZAPRS] Maxon DM-2550 and TinyTrak3


>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
>>> _______________________________________________
>>> Ozaprs mailing list
>>> Ozaprs at aprs.net.au
>>> http://aprs.net.au/mailman/listinfo/ozaprs
>>>
>>>
>>>
>>
>>
>>
>>
>
>
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