[App_rpt-users] tone sent in usbradio setting

[David McGough]

Hi Pierre,

The Bessel-null method for setting deviation certainly works and can be 
accurately performed with a $15 rtl-sdr style receiver.

Note that the tone frequency generated from app_rpt is 1000 hertz. And, 
this frequency will work fine for testing, as explained in this video:

https://www.youtube.com/watch?v=lWcFqsh7ZvQ


73, David KB4FXC


On Wed, 21 Jun 2017, Pierre Martel wrote:

> Hi I am trying to find what is the frequency of the tone sent when we use
> the command radio tune txvoice??
> 
> I am asking cause if it would be 1247 hz we could use the bessel null
> methode to adjust our tx to 3hz with just a simple rtl-sdr and sdr#
> 
> the theory behind this is a bit complcated but at a certain frequency and
> level the carrier is completly or almost completly off.
> 
> this can easily be seen on a spectrum analyzer. but our sdr# are like
> spectrum analyzer.
> 
> so if we would want a 3khz deviation we need to send a 1247 hz signal and
> adjust the levels till the main carrier disapear on the spectrum analyzer.
> 
> the maths are this 3000/2.405=1247
> 
> you can see the theory at use here:
> 
> https://www.youtube.com/watch?v=8IBOYoIV5m8
> 
> So if there is a way to decide the tone we want we could use that methode
> to adjust or repeater deviation ( for the voice part at least)
> 
> now if we wanted to adjust the deviation for the ctcss, this is another
> story. but could it be calculated by the voice level setting if sent on the
> same output?
> 
> thanks for listening to my crazy idea ;-)
> 
> By the way you can set a radio with a sound card attached to it a known
> level and use that as the signal to adjust the rxvoice level also. since we
> can set that with simple audio generating software available free online
>