[OZAPRS] Help with MJF-1270b and UI-View32

Ray Wells vk2tv at exemail.com.au
Sun Dec 30 21:17:42 EST 2012


Things I would check .....
1. Is the comport speed set correctly to match the settings in the 
application. e.g. 9600
2. Is the radio data rate set correctly to 1200bps - DIP switches 6, 7, 8.
3. Is the HF/VHF switch in the out position for VHF

Going a little deeper, I'd check the audio into the TNC from the radio 
to see how close the two tones are to being the same level. The Exar 
decoder chip in the MFJ1270B is particularly intolerant of the high tone 
(2200Hz) being lower in level than the low tone (1200Hz) and will refuse 
to decode if the levels are too different. The TNCs need about 200mV p2p 
for reliable decoding.

Have you used a terminal program to try to talk to the TNC. You should, 
at very least, see the TNC message when the TNC is powered up. This can 
confirm comport speed, etc. I don't know what the latest terminal 
program is for Windows (I use Linux) but hunt around. If you can talk to 
the TNC with the terminal program you are well placed to conduct various 
tests as suggested by Gordon vk4vp.

I have 8 MFJ1270B TNCs (all bought second hand) that have seen service 
at HF, VHF and UHF and I must say I've never had a reason to doubt the 
tone frequencies on any of them, but ........

Ray vk2tv

On 30/12/2012 3:09 PM, Phil Kern wrote:
> Hi Guys,
> Recently dusted off an old MJF-1270b which I used to use with 'packet' 
> many years ago.
> Now trying to configure this with UI-View32. I'm unsure about the 
> config within the Comms Setup Area.
> It appears to be connected on the default setting. Just can't  seem to 
> decode anything on the terminal screen.
> Have followed the Config Guides on aprs.net.au Aprs via Internet seems 
> to decode correctly.
> Any help or pointing me in the right direction, would be greatly 
> appreciated.
> Cheers
> Phil
> _______________________________________________
> OZAPRS mailing list
> OZAPRS at aprs.net.au
> http://lists.aprs.net.au/mailman/listinfo/ozaprs

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