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Re: FT-847 and 9600 Baud Packet



Hi Jon,

Jon Ogden wrote:
> 
> OK,
> 
> I am stumped!  This isn't directly a satellite question, but since I am
> going to likely be using this setup on the 9600 birds some time, I ask this
> here.
> 
> I just got a 9600 baud packet modem and set it up to use with my FT-847.  I
> set the packet speed on menu 23 to 9600.  However, I couldn't connect to
> ANYTHING except my TH-D7A 9600 baud HT but even that was difficult.

I'm using the 847 on with the 9600 baud PacSat's, rather successfully.
I've found the deviation is VERY critical with respect to 9k6
performance. I spent some time with my old TAPR DevMeter and fiddled
with the audio drive from my TNC to get 3.0 khz deviation. 9k6 drive
levels are just about IMPOSSIBLE to set by ear. 

> 
> Originally I was on UHF and then I changed band from 432 to 2M and I was
> able to connect easily to my local DX cluster.  I remembered that the packet
> rate setting was different for each band.  I had never changed the setting
> on 2M to 9600 baud.  So I went in and changed it.  I couldn't connect to the
> cluster.  Changing back to 1200 baud connected me.
> 
> I went back to my 432 frequencies and changed the packet speed setting in
> the radio to 1200.  It worked fine.  I was able to connect to a local node
> w/o a problem.
> 
> So what gives?  Why does setting the packet speed setting inside the radio
> to 9600 baud not work?  Note, I am not changing ANYTHING with the speed of
> the modem.

I BELEIVE that the 1k2 and 9k6 settings in the setup menu change the
signal routing in the radio, i.e. whether the TNC signals go through the
audio chain, or direct to the discriminator/modulator. With out access
to a BERT (bit error rate tester) it's hard to say exactly what's going
on with your particular equipment.

You didn't say how well you were receiving 9k6 packets. If you're
receiving OK, just having trouble connecting, then I think we get right
back to the deviation issue. If you know someone in the land mobile
radio business, you might be able to get some help adjusting your
deviation. I'm lucky enough to have a ham friend that works for
Motorola, and he checked my setup with his service monitor. Seems my
cheap little TAPR DevMeter is really very close to "right on the money".

BTW, what TNC are you using?

Hope this helps a little,

73 de John AA2BN
> 
> Help??
> 
> 73,
> 
> Jon
> KE9NA
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