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Re: Doppler correction?



Hi John,

I made an experimental version of InstantTune that
updates the radio 4x as fast. This should limit the
"chirp" to less than the 50 Hz that Hamscope
can handle.

I will email it to you to try out. The only file
changed is the TSR executable, "itunetsr.exe"
Just copy this to your c:\it directory and overwrite
the old one. This one is version 1.20A

If anyone else wants to try it, let me know and I
will email it to you. It is not a big file (around 43K)

I am a little concerned about the amount of cpu
used as InstantTune was designed to limit the amount
of cpu needed. As long as you are using a PC from this
century though, you should be OK.

I tested this new version on a 30MHz, 80386
machine running DOS 5.0/Win3.11 that doesn't
have a math co-processor. Tracking FO-20
(which has a 70 cm downlink) on a high elevation
pass for about 30 minutes, it seemed
to work fine with an FT-847 and serial port
rate of 9.6K bps.

You didn't mention what type of radio you were using
so I'll just mention that some radios may not like
getting hit this quickly with updates.

Try it and let me know if you think this will do it.


Thanks and 73,
Tony AA2TX

---

At 09:00 PM 11/11/2003 +0000, johnheath wrote:

>Thanks for the hints and tips.
>
>Checked Cute-1 on a high pass today. Max elevation 55 degrees.
>ITUNE was updating my FT847 RX frequency by 130Hz at a time near TCA
>!!
>
>This jump was too much for Hamscope, the AFC will only give +/- 50Hz.
>
>73
>John  G7HIA, M3BBX
>
>
>
>---
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----
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