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Transverters, software and simple digital tuning schemes.




Hello All.


While writing a response to another message a few minutes ago, an idea struck
me.  Firstly, the background is a combination of the following factors:

1.  I have (like many hams), multimode gear for 10m and 2m.
2.  To minimise expense and exercise electronics skills, I intend to build
transverters for the microwave bands, some of which will be used for P3D.
3.  I have discovered my 2m box will not tune while Txing (not a lot of fun for
Doppler correction!).

As a result, I came up with the idea of incuding voltage controlled VXOs in my
transverters, so the uplink and downlink frequencies can continuously adjusted.
In addition, with the addition of a D/A converter hanging off the printer port,
it should be possible to write a driver for curent tracking software that will
output an 8 bit number to the printer port, to be fed to the DAC and applied as
a control voltage, for the purpose of Doppler correction.

Now, everyone is going to say "but all transverters will be different!".  Yes,
this is true, but it should be possible to include a calibration sequence,
which will allow one to construct a lookup table in RAM (and stored on disk as
a "transverter definition file" for future reference), to bridge the gap
between "normalised" data from the software and the specific tuning voltages
required.

Just a thought to toss into the ring, and a bit of work would need to be done.

I, for one, refuse to spend $3000 on a black box when I could roll my own gear
for under $1000. :-)

Tony
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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