Re: [Xlog-discussion] Xlog with IC-746

[Joop Stakenborg]

Op ma, 13-12-2004 te 21:49 +0000, schreef Matt Dawson:
> On Saturday 11 Dec 2004 13:52, Gary Mackey (K8EHB) wrote:
> > Is anyone else running an IC-746 (non PRO model) with hamlib support
> > enabled ?
> 
> Yes, it does the same on a friend's machine with the 746. I simply disabled 
> the S meter support in Xlog. Rigctl, with the l STRENGTH command shows -18 
> (my reckoning puts this at about S6, which is what the S display is showing)  
> with no signal (dummy load). Perhaps a bug in the back-end? It may be worth 
> taking a look at the code and seeing what is done with the output of the 
> radio. This is clearly a hamlib rather than an xlog issue.

Calibration of the S-meter values in hamlib is done with a calibration
table for most of the icom rigs. The are converted by a call to
rig_raw2val(), which looks up the calibration and does some
interpolation when needed.

The calibration table for the ic746 looks like this:

#define IC746_STR_CAL { 16, \
        { \
                {   0, -18 }, \
                {  10, -16 }, \
                {  27, -14 }, \
                {  45, -12 }, \
                {  60, -10 }, \
                {  76, -8 }, \
                {  89, -6 }, \
                { 100, -4 }, \
                { 110, -2 }, \
                { 120, 0 }, \
                { 125, 2 }, \
                { 129, 4 }, \
                { 133, 6 }, \
                { 138, 8 }, \
                { 142, 10 }, \
                { 146, 12 } \
        } }

I think it is pretty obvious what kind of conversion is done here. Since
S9 should return 0, a value of 120 returned from the IC-746 will
calibrate against S9. What surprises me about his table is that the
right hand values don't match the 6 dB steps for S-meter values.

The IC-703 seems to be better calibrated:

#define IC703_STR_CAL { 17, \
        { \
                {  45, -60 }, \
                {  46, -54 }, /* S0 */ \
                {  54, -48 }, \
                {  64, -42 }, \
                {  76, -36 }, \
                {  84, -30 }, \
                {  94, -24 }, \
                { 104, -18 }, \
                { 113, -12 }, \
                { 123, -6 }, \
                { 133, 0 },  /* S9 */ \
                { 144, 10 }, /* +10 */ \
                { 156, 20 }, /* +20 */ \
                { 170, 30 }, /* +30 */ \
                { 181, 40 }, /* +40 */ \
                { 192, 50 }, /* +50 */ \
                { 204, 60 }  /* +60 */ \
        } }

If either you or Gary send me a calibration string for the IC-746, I can
update the hamlib code for this rig.

Thanks,
Joop PG4I
-- 
Joop Stakenborg <address@hidden>