Re: [amsat-bb] Features in FT-847--Same Band

[Matt Bennett <kaisermuche@xxxxxxxxx>]

Don,

Excellent work! I wish I had consulted the group
earlier on this issue. I have actually been working
with another programmer to combat this problem for our
own cubesat project, but could not overcome the 10kHz
shift limitation. I will be sure to refer him to the
link you posted. Nevertheless, it would certainly make
it easier to all to have CAT-controlled SPLIT MODE to
adjust both up/downlink frequencies real time!

Thanks,

Matt Bennett
KF6RTB

--- "Don Woodward (KD4APP)" <kd4app@amsat.org> wrote:

> On Thu, 2005-12-22 at 15:11 -0800, Matt Bennett
> wrote:
> >   My other suggestion for the next Yaesu sat rig
> would be the ability
> > to control the SPLIT MODE tuning from the CAT
> interface. This is
> > because many airborne cubesats and the ISS operate
> on the same band,
> > and tuning must be performed by hand both cases.
> The necessity is not
> > so critical for 2m ops as it it for 70cm.
> > 
> 
> This can be done - the issue is addressed in my July
> 2004 paper at:
> 
>
http://www.sunsunsun.net/kd4app/Full_Doppler_on_the_FT847.htm
> 
> Basically ...
> 
> Several people have looked at the Yaesu FT-847 CAT
> command set and
> concluded it can’t do full Doppler control on
> “same-band� satellites
> like ISS – I.E. those where the TX and RX
> frequencies are in the
> same-band.  The premise of this belief was linked to
> a “10 kHz
> limitation�. The FT-847 CAT “offset� command
> appears to offer 10 Hz
> resolution, but anything entered beyond 10 kHz
> resolution is ignored -
> this is the only CAT function which is limited to
> this resolution – in
> fact all other frequency related commands offer as
> fine as 10 Hz
> resolution. 
> 
> The FT-847 cannot be used to work “same-band�
> satellites in “satellite�
> mode because the FT-847 satellite mode can’t have
> the same band for both
> the TX and RX sides.  
> 
> My work in this document is based on using the
> “Main Frequency VFO�
> rather than “satellite� mode. I will also
> utilize the “repeater shift�
> function� and the “offset� function.   All of
> the examples in this paper
> can be achieved using the existing CAT commands
> found on the FT-847.
> While the FT-847 CAT commands may have some
> limitations, a little bit of
> software can overcome these limitations and full
> Doppler correction can
> be achieved on “same-band� satellites like ISS
> and PCSAT.
> 
> I will leave it as an exercise to the reader to
> implement this method to
> achieve full Doppler correction.  A test of concept
> was performed under
> Linux and the expected results were achieved –
> unfortunately I don’t
> have the time to write a full blown same-band
> satellite Doppler
> correcting program for the FT-847 – I’d rather
> see the various
> tracking/tuner programs implement this in their
> code. 
> 
> 73's
> 
> Don Woodward
> KD4APP
> ----
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Matt Bennett
KF6RTB
UCISAT Communications Team Member
University of California, Irvine
www.ucisat.net
Just $16.99/mo. or less. 
dsl.yahoo.com 
----
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