Hijack v469: Tuner tweaks

Posted by: mlord

Hijack v469: Tuner tweaks - 29/03/2007 00:14

Hijack v469 is now released, featuring:
  • Fixed a bug in the fake_tuner logic.

  • Added Hijack Menu item for "Tuner: DX/LO Mode"
  • Added Hijack Menu item for "Tuner: IF2 Bandwidth"
  • Added Hijack Menu item for "Tuner: Wideband AGC"

Basically, the three new menu entries are temporary, in that I plan to disable them by default in future builds, while leaving the source code intact.

But for now, they are enabled, because I want your help(!) to find out if they actually ever improve anything.

So, if you have a tuner module (factory or PCATS), then play with these three settings and see if you can ever detect any difference in reception. I can't, which is why I'm asking for others to help out.

Please report back here with any info on a particular setting that helped, or just to say "nothing seems different on any setting".

EDIT: these new settings are NOT remembered across resets/power-cycles.

Thanks!
Posted by: newguy1

Re: Hijack v469: Tuner tweaks - 29/03/2007 00:33

I'll check it out.Should I just try one at a time ot a combination of settings?
When you say "see if you can detect any difference in reception" I assume you mean clearer reception/less static or do you mean something else?
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 29/03/2007 03:25

Quote:
I'll check it out.Should I just try one at a time ot a combination of settings?
When you say "see if you can detect any difference in reception" I assume you mean clearer reception/less static or do you mean something else?


Any combination, any perceptible difference whatsoever.

Thanks!
Posted by: larry818

Re: Hijack v469: Tuner tweaks - 29/03/2007 04:57

Hi, is it possible to force the signal strength to full? I don't use the tuner because it's hilly here and the player software varys the volume with signal strength. At least, I'm assuming it's in the software.

Thanks!
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 29/03/2007 09:58

Quote:
Hi, is it possible to force the signal strength to full? I don't use the tuner because it's hilly here and the player software varys the volume with signal strength. At least, I'm assuming it's in the software.


I don't know about that. But the IF2 Wideband and AGC adjustments could (in theory) make a difference there. And that's what we're trying to find out here.

-ml
Posted by: andy

Re: Hijack v469: Tuner tweaks - 29/03/2007 12:55

I use the tuner most days, on the move. I'll get the latest Hijack loaded over the weekend and give it a good test next week.
Posted by: larry818

Re: Hijack v469: Tuner tweaks - 29/03/2007 13:32

I'll give it a try!
Posted by: frog51

Re: Hijack v469: Tuner tweaks - 29/03/2007 14:05

I have it on my main empeg now and was wondering about options. Would you prefer them tested independently (ie tomorrow I'll try the first one, Saturday the next? Or are you just open to having them all messed with?)
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 29/03/2007 14:09

Quote:
I have it on my main empeg now and was wondering about options. Would you prefer them tested independently (ie tomorrow I'll try the first one, Saturday the next? Or are you just open to having them all messed with?)


Just mess away to the limits of imagination. If you actually manage to notice any effects, then perhaps try to isolate things. But I didn't notice anything here from any combination of the settings.

The new code is definitely sending the correct bits to the tuner for each setting, and I doubt that the empeg radio PIC firmware is diddling with things, but one never knows for sure with closed-source stuff.

EDIT: I suppose I might hook up the logic analyzer directly to the RF module and find out -- that would produce rather definitive evidence, one way or the other.

Cheers
Posted by: canuckInOR

Re: Hijack v469: Tuner tweaks - 29/03/2007 18:31

Quote:

  • Added Hijack Menu item for "Tuner: DX/LO Mode"
  • Added Hijack Menu item for "Tuner: IF2 Bandwidth"
  • Added Hijack Menu item for "Tuner: Wideband AGC"


Out of curiosity, is there a pointer to what those things mean?
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 29/03/2007 18:54

Quote:
Quote:
  • Added Hijack Menu item for "Tuner: DX/LO Mode"
  • Added Hijack Menu item for "Tuner: IF2 Bandwidth"
  • Added Hijack Menu item for "Tuner: Wideband AGC"


Out of curiosity, is there a pointer to what those things mean?


The descriptions are very very techy, and you can read about them in the TEA6848H_3.pdf datasheet (that's the radio chip inside the RF module inside the empeg tuner).

DX(Distant)/LO(Local) should be self-explanatory to any who's ever used a 1980s-1990s car radio. Selecting LO mode simply attenuates the RF signal so that only the strongest stations can be found by auto-seek functions. Useful for people in huge cities, I suppose.

The IF2 Bandwidth has something to do with adjacent channel rejection, I think. It should be most useful in areas with tons of FM channels tightly spaced across the band. Or maybe I've got that totally wrong(?).

The Wideband AGC adjustment is for the signal threshold point for the Auto-Gain-Control (AGC). This should have noticable effects on weaker signals, I think.

Cheers
Posted by: frog51

Re: Hijack v469: Tuner tweaks - 31/03/2007 18:02

Had a good play over the last couple of days, and in the Lothians, where there are a number of channels I can't hear any difference with the DX/LO settings or the Wideband AGC.

I do think the IF2 bandwidth makes a slight difference (on Radio 1, 2 and 4) the wide setting sounds 'better' - the sound is just a little richer (very slightly, and sometimes I was wondering if I was imagining a change, but it seemed consistent with that setting)

Hope that is of some use
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 31/03/2007 20:16

Quote:

I do think the IF2 bandwidth makes a slight difference (on Radio 1, 2 and 4) the wide setting sounds 'better' - the sound is just a little richer (very slightly, and sometimes I was wondering if I was imagining a change, but it seemed consistent with that setting)

Hope that is of some use


Thanks. The default player setting for that is "Dynamic", which means it auto-adjusts the channel width to match interference conditions. It is believable that "Wide" might be better in some conditions, so you're probably not going insane here.

But "Dynamic" should be best nearly all of the time.

Cheers
Posted by: newguy1

Re: Hijack v469: Tuner tweaks - 01/04/2007 10:47

Quote:
Added Hijack Menu item for "Tuner: DX/LO Mode"
Didn't notice any changes.
Quote:
Added Hijack Menu item for "Tuner: IF2 Bandwidth"
Seemed to notice slight changes with WIDE mode.
Quote:
Added Hijack Menu item for "Tuner: Wideband AGC"
Didn't notice any changes.

It is difficult for me to compare the signals because when I change settings I get a loud/distorted? sound between settings.
EDIT:BTW I have a PCATS tuner.
Posted by: canuckInOR

Re: Hijack v469: Tuner tweaks - 02/04/2007 18:13

Quote:
The descriptions are very very techy, and you can read about them in the TEA6848H_3.pdf datasheet (that's the radio chip inside the RF module inside the empeg tuner).

Hmm... I think I understood your descriptions a bit better.

A point of clarification -- is this the chip in the empeg original tuner, or the new PCATs tuner? (i.e. should the hijack settings behave the same for both tuners?)

Cheers,
Posted by: mlord

Re: Hijack v469: Tuner tweaks - 02/04/2007 18:27

Quote:
Quote:
The descriptions are very very techy, and you can read about them in the TEA6848H_3.pdf datasheet (that's the radio chip inside the RF module inside the empeg tuner).

Hmm... I think I understood your descriptions a bit better.

A point of clarification -- is this the chip in the empeg original tuner, or the new PCATs tuner? (i.e. should the hijack settings behave the same for both tuners?)

Cheers,


That's the chip inside the factory tuner RF module. I've never opened up a PCATS RF module, so I don't know if it has the exact same chip or not. But whatever it has, it *is* software compatible with the factory tuner, so these settings/descriptions apply equally to both kinds.

Cheers