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Changing Side tone

troysk8
 
Edited

I would like to change the side tone to 600 hz. I seen in the code where I can do that. What I'm unsure is where to adjust for the offset or if I need too. Anyone done it yet successfully? 

Thanks,

Troy KF7SEY

Charles W. Powell
 

Yes, I did.  I can send you the file I used to flash my Hilltopper.  If you want it, send a private e-mail to nk8o at arrl dot net.

72,

Charles

On Sep 10, 2018, at 2:14 PM, troysk8 <kf7sey@...> wrote:

[Edited Message Follows]

I would like to change the side tone to 600 hz. I seen in the code where I can do that. What I'm unsure is where to adjust for the offset or if I need too. Anyone done it yet successfully? 

Thanks,

Troy KF7SEY

troysk8
 

I successfully changed my Hilltopper to use a 600 hz tone instead of the 800 hz. I will be posting a video on YouTube here in the near future on it.
Thanks Charles for all the help. 

73, De KF7SEY

Charlie Crapotta, NA2CC <pccmd@...>
 

But do you have to alter the bandpass for the audio stage?

Dave Benson
 

Charlie-

It's not strictly neccessary- here's the tradeoff:  That audio stage stage has a low 'Q' value of 2.  As such, its response will be down about 3 dB at 600 Hz. I assume that Chas didn't find that objectionable enough to pursue it further.

If you do want to change the audio passband,  the values of the 820 and 2200 pF capacitors should be increased by 25-30%. Perhaps the easiest way to do this is to parallel additional caps on the underside of the board.  That would work out to 220 pF and 560 pF respectively. That should bring the peak audio response down close to 600 Hz.

If you do try that, please let us know if you find the change worthwhile.

73- Dave Benson, K1SWL


On Fri, Dec 21, 2018 at 4:30 PM Charlie Crapotta, NA2CC <pccmd@...> wrote:
But do you have to alter the bandpass for the audio stage?

Charles W. Powell
 

I would point out that 3 dB is the smallest detectable change for the human ear.  The bigger problem is stations tuning 300-400 Hz off frequency, especially on the high end. Then the audio filter really does work well and you are scrambling to adjust the RIT.  It’s useful to know how to adjust the RIT, with a  >1 second hold of the tuning button.

72,

Chas - NK8O

On Dec 22, 2018, at 5:29 AM, Dave Benson <davek1swl@...> wrote:

Charlie-

It's not strictly neccessary- here's the tradeoff:  That audio stage stage has a low 'Q' value of 2.  As such, its response will be down about 3 dB at 600 Hz. I assume that Chas didn't find that objectionable enough to pursue it further.

If you do want to change the audio passband,  the values of the 820 and 2200 pF capacitors should be increased by 25-30%. Perhaps the easiest way to do this is to parallel additional caps on the underside of the board.  That would work out to 220 pF and 560 pF respectively. That should bring the peak audio response down close to 600 Hz.

If you do try that, please let us know if you find the change worthwhile.

73- Dave Benson, K1SWL

On Fri, Dec 21, 2018 at 4:30 PM Charlie Crapotta, NA2CC <pccmd@...> wrote:
But do you have to alter the bandpass for the audio stage?


Charlie Crapotta, NA2CC <pccmd@...>
 

Hmmmmmmm.  OK, thanks to all. I do not have a EE background so all information is much appreciated. 
I established a ‘const unsigned int’ which I will initialize to 650 for now, and substitute it for “800” in the code. Of course I will flash the ATMega in the socket on my Arduino Uno. 
Charlie
NA2CC
l