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Re: Kenwood TM-D700



> on 2/9/00 06:26, Luis Martins at luis.martins@ruido-visual.pt wrote:
> 
> > Hi!
> > Is anyone out there using the Kenwood TM-D700 in the 9600 birds ?
> > Any input would be most welcomed.
> >
> > What about BBSs and DX Clusters ?
> >
> > As noted before in recent posts in the list, the TH-D7 isn't able to
> > work at 9600 for both rx and tx due to rx/tx delays which are quite slow
> > for fast rx/tx switching.
> >
> > Is TM-D700 ok ?

I've done some work with the TM-D700 on the 9600 bd birds using Wisp.

Bottom line is that it will work.  Some qualifications/comments:

The 5khz tuning step size is a bit "coarse" for doppler correction.

You will probably not be happy attempting this on omni antennas.  About
the best I could get was 150-200k on a good pass, much less on a poor
pass.  I consider this amount of data just enough to let me know what
I'm missing compared to a typical fixed station.  I think some other
people have done a bit better, and a lot of work in being done on this,
but I suggest at least a 3 el yagi on the receive side.  On TX, just
about anything (whip, etc.) is fine.  I'm looking for a cheap satellite
tracking mount for a telescope that runs off of 12vdc to make a portable
station (in a car) more feasible.

Computer frequency control and serial data flow to the TNC cannot occur
at the same time.  Some pretty clever work is being done in software to
quickly "pop out" of serial communications, retune, then go back to
talking to the TNC, but this is a limitation compared to a "satellite"
radio, e.g. IC-821 or FT-847.  Of course, with a 5 khz step, you only
have to retune a few times per pass anyway.

Having said all that, the TM-D700 is really the first "mobile" FM
Dual-Bander that has all the main attributes necessary for 9600 bd
Pacsat work:

Dual Band,
Full-Duplex Data
Ability to split packet data and send TX to one band, RX to the other
Ability to TX (PTT) on one band, and Frequency Control on the other.

I don't know of another FM mobile radio that can do that, although my
detailed research on the question is a few years old.

IMHO, I would not go out an purchase a D700 specifically to work the
9600 bd Pacsats using Pacsat protocol software - I'd go with a
"satellite" radio.  If, however, I had one for other reasons, I'd
certainly give it a try.

I have also been using mine for 70 cm, 9600 bd APRS operation, and it
appears to work great.  I've not tried any connected packet work with
it. I also really like the radio for 2 Meter APRS work, and 2m/70cm
voice work.

Hope this helps a little.  73 de Chas, W4HFZ
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