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[Linrad] Re: Linrad-03.05

Hi Leif,

Am I the only member of this group checking out this SDR-IQ
calibration thing?

We are making progress, but there are still some strange issues.

1. The calibration does now work :-)

2. If I go into the "SDR-IQ" screen (U or XXU), and make a change to
the sampling correction,
usually at the end of that data entry, I can hit D for SSB mode and go
back into Linrad.
But just sometimes Linrad objects that the "input sampling speed has
and insists on me reentering ALL the parameter data (FFT settings).
There seems to be little pattern to when this happens.
If I make small changes to the sampling correction, like 100, 200, 300
etc, I can get straight back into Linrad,
but if I make a big change, say from 0 to -827, then I have to reenter
But another time I tried -100, -200, -400, -600, -800, and only on the
last change did I have to reenter everything!
Can you make any sense from that?

3. Just an incidental point, but when Linrad does object and require
everything to be reentered,
it gives the old and new sample rates (e.g. 95238 and 95236).
These are naturally very close after decimating by 700 from 66.667MHz,
when the sampling speed change is only a few hundred Hz.
Some decimal places would help to highlight the difference.
Ah.... maybe by chance I have just hit on the problem above!
Does Linrad require everything to be reentered only when the integer
value of the sampling speed changes?
It would be nice if I could make sampling speed corrections without
having to reenter everything!

4. This one is really weird!
Once I have made a sampling speed correction and got my input test
signal of 144.125MHz spot on in Linrad,
if I then exit Linrad and restart Linrad, the test signal appears spot
on 144.095MHz (28.095MHz).
Hit X to view the parameters, everything looks ok, hit B to go back
into SSB, and the signal is back on 144.125MHz!
I can do this consistently - it happens every time!
Incidentally MAP65-IQ also shows the signal on 144.095 when this

Over to you!

73  Guy  VK2KU

On Apr 6, 12:30 am, Leif Asbrink <l...@xxxxxxxxxx> wrote:
> Hi Guy,
> > I am having trouble getting Linrad v3.05 to run.
> > I had a brief "play" earlier today.
> > The prompt about sampling frequency correction is not very explicit,
> > no units or limits stated, but I am assuming that what is wanted is
> > the
> > clock frequency correction (or error, which is the opposite) in Hz.
> > There seems to be an upper limit of 10000, but no lower limit.
> The lower limit is -9999 (I changed it to -10000 for pedagogic reasons...)
> Also replaced correction by shift to make (Hz) become visible;-)
> > My sampling frequency is in fact about 850Hz low at 66.7MHz.
> > I tried entering 800, -800 and even zero.
> > The entry is accepted and can be saved.
> > But then Linrad complains about having zero sampling frequency,
> > and then hangs!
> > Am I doing something stupid? Probably!
> No. I did.
> I have now uploaded 03-05a which I hope will be OK.
> 73
> Leif / SM5BSZ
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