[OZAPRS] TNC

[Ray Wells]

Thanks, Gordon,

True DCD is really an absolute necessity for a *normal* TNC for HF.

My old TNC 220 has *software* DCD which is about as useful as a bucket 
with no bottom - and it doesn't function in KISS mode! Having said that, 
the software DCD on the Baycom USCC>4, four port card is brilliant.

All the MFJ1270B's (TNC2 compatible) have the State Machine and they 
never miss a beat on HF or VHF.

When I originally tried HF with the TNC220 I found the radio mute had to 
be so tight that I was not able to decode otherwise useful signals. YMMV.

I run unmuted audio regardless of TNC or Baycom modems, which gives a 
speed advantage by not having to wait up to hundreds of milliseconds for 
the rx mute to release.

Ray vk2tv


Gordon Taylor wrote:
> Ray,
> 	Not sure if it's true DCD or just a squelch type control.
>
> The threshold knob/setting has to be advanced enough so that the DCD light
> is not on when there is no signal. i.e noise.  Otherwise the radio will
> never Tx, so I don't think it's true data detection.
>
> Regards,
> Gordo VK4VP
>
> -----Original Message-----
> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
> Behalf Of Ray Wells
> Sent: Wednesday, 13 January 2010 11:24
> To: Australian APRS Users
> Subject: Re: [OZAPRS] TNC
>
> Gordon,
>
> Does the PK232 have the State machine for DCD detection, or is it like 
> my TNC220 that requires the radio have a mute facility?
>
> Ray vk2tv
>
> Gordon Taylor wrote:
>   
>> Sam,
>> 	I use a TT3 for HF, I found the Open Tracker was too hard to use as
>> you have to load firmware for 300 baud.
>>
>> In regards to a PK232, there really are no mods apart from issuing the
>> following from say hyper terminal.
>>
>>
>> VHF=OFF
>> HBAUD=300
>>
>>
>> Then when going back to VHF use;
>>
>> VHF=ON
>> HBAUD=1200
>>
>> You need to remember that the tone frequencies are different in the
>>     
> PK-232,
>   
>> so to get it to work on 10.14760 USB, you need a dial frequency of
>>     
> 10.14709
>   
>> USB.
>>
>> This last bit of info is on http://www.aprs.net.au/hf/aprs-hf and various
>> other sites.  Pick the group based on the TNC and then check the frequency
>> to be used.
>>
>>
>> Regards,
>> Gordo VK4VP
>>
>> -----Original Message-----
>> From: ozaprs-bounces at aprs.net.au [mailto:ozaprs-bounces at aprs.net.au] On
>> Behalf Of Samantha
>> Sent: Tuesday, 12 January 2010 17:40
>> To: OZAPRS at aprs.net.au
>> Subject: [OZAPRS] TNC
>>
>> Hey Guys
>>
>>
>> I am looking for a tnc to be used in a mobile situation. I have a eeepc
>>     
> and
>   
>> a usb gps to use.
>> Into a cheap handheld.
>>
>> What is the most efficient way to do mobile for HF?
>> What is suggested for the tnc
>>
>> I am also looking for the mods for a pk232 to be used for aprs hf as well
>>     
> if
>   
>> someone could point me in the correct direction
>>
>>
>> thanks
>>
>> Sam
>> vk4fq/vk4ttt
>>
>>
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>>   
>>     
>
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