[OZAPRS] codan 8528 and TT3

Mitch rodney at melecom.com.au
Mon Aug 13 09:54:50 EST 2007

> Tim VK2HLT wrote:
>>Gday guys,
>>Anyone have any info on connecting a TT3 to the Codan 8528 mobile ? I
>> have
>>both items and are keen to hear from anyone who may have already done
>> this.
>>Tim VK2HLT
>>Ozaprs mailing list
>>Ozaprs at aprs.net.au
> Every commercial HF radio I've encountered has balanced microphone
> audio. To ensure that balance remains I insert a small audio transformer
> between the unbalanced TNC/whatever audio source and the radio. I
> generally rewire the DIN socket to suit. In a similar vein there has not
> been a source of unmuted rx audio available at a socket or test point.
> I've chased up a suitable rx audio point with a CRO. Your radio may be
> different but that is my experience.
> Ray vk2tv
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> Ozaprs at aprs.net.au
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Hi Tim,

Using a TT3 and a 9323 here. Found the relevant info via the NET and
Google. Not sure about your radio but the 9323 has a 15 PIN socket (DB15)
with 12V, TX audio, including the audio from the mic. A toggle switch
connects the hand mic and disconnects the TT3 audio making voice usage
straight forward.

Most CODAN radios have the voice squelch which is great for mobile
operation, but that squelch circuit will cut the APRS packet, thus the
audio to the TT3, to avoid TX during a packet, can be from the speaker out
but delay sufficiently the carrier detect settings in the TT.

For 100W TX output from the TT's audio out I had to decrease the resistor
that feeds the potentiometer.

73 de Rod, VK5KFB

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