[OZAPRS] Fw: 40M APRS frequencies

[Glen English VK1XX]

And TX level shouldnt matter much at all unless you savagely overdrive it

there is only one tone there at a  time.

so there is no IMD

and since the tones are up at 1600 Hz, the harmonics will be outside the 
SSB filter....at least 20dB down.

On an all-digital radio, overdriving may causing aliasing distortion, 
(which would put sh1t everywhere)   if the input of the ADC was heavily 
clipped....  that's about all.

I would like to see a mod in Direwolf though that ramped up the tone 
level over  a few mS as not to hit the ALC hard, often overshooting.

g



On 4/12/2017 10:45 AM, Scott Evans wrote:
>
> Yes I have S9 noise here too but I'm using a vertical so noisy bands 
> kinda comes with the territory! 😉
>
>
> On Mon., 4 Dec. 2017, 09:50 Gavin Rogers, 
> <grogers at vk6hgr.echidna.id.au <mailto:grogers at vk6hgr.echidna.id.au>> 
> wrote:
>
>     I'd say mine. I'm using the incredibly technical interface of
>     using an audio cable from the headphone jack to the sound card :)
>
>     The antenna is a long wire, although resonant on 40m, I suffer
>     from S7-9 noise on all bands at all times (suburban areas, woo
>     hoo!) , hence my limited HF experience.
>
>
>
>     On 4 December 2017 6:41:11 am AWST, Scott Evans <vk7hse at gmail.com
>     <mailto:vk7hse at gmail.com>> wrote:
>
>         Hi Gavin,
>
>         Curious, but the mention of the audio level being too high, is
>         that saying that mine is or yours? 🤔
>
>
>         On Mon., 4 Dec. 2017, 09:25 Gavin Rogers,
>         <grogers at vk6hgr.echidna.id.au
>         <mailto:grogers at vk6hgr.echidna.id.au>> wrote:
>
>             Captured a handful of frames last night here in Perth on
>             40m. I guess it
>             works! Also is my first 40m digital RX, so that's nice :)
>
>             VK7HSE-4 audio level = 139(11/14)   [NONE]   __||___
>             Audio input level is too high.  Reduce so most stations
>             are around 50.
>             [0.2] VK7HSE-4>APRX29,WIDE2-1:!4259.56SI14718.64E#RasPi
>             iGate & Digi
>             Position, OVERLAY DIGI (green star) w/overlay I, >40 APRSmax
>             S 42 59.5600, E 147 18.6400
>             RasPi iGate & Digi
>
>             VK7HSE-4 audio level = 158(11/19)   [SINGLE] __::___
>             Audio input level is too high.  Reduce so most stations
>             are around 50.
>             [0.2] VK7HSE-4>APRX29,WIDE2-1:!4259.56SI14718.64E#RasPi
>             iGate & Digi
>             Position, OVERLAY DIGI (green star) w/overlay I, >40 APRSmax
>             S 42 59.5600, E 147 18.6400
>             RasPi iGate & Digi
>
>
>
>             73
>             Gavin
>             VK6HGR
>
>             On 3/12/2017 4:00 PM, Gavin Rogers wrote:
>             > On 3/12/2017 3:56 PM, Josh wrote:
>             >> Thanks Gerard.
>             >>
>             >> I had a minor issue with direwolf using the wrong tones
>             earlier, it
>             >> appears that
>             >> the config line "MODEM 300" will cause 1600 & 1800
>             tones to be used but
>             >> "MODEM 300 # [comment]" causes 1200 & 1800 Hz tones.
>             > Try using
>             > MODEM 300 7 at 30
>             >
>             > This will set up a number of modem frequency groups
>             that'll help with
>             > (mis)tuning:
>             >
>             > Channel 0: 300 baud, AFSK 1600 & 1800 Hz, D, 48000
>             sample rate
>             >         0.0: D 1510 & 1710
>             >         0.1: D 1540 & 1740
>             >         0.2: D 1570 & 1770
>             >         0.3: D 1600 & 1800
>             >         0.4: D 1630 & 1830
>             >         0.5: D 1660 & 1860
>             >         0.6: D 1690 & 1890
>             >
>             > Fairly unlikely I'll get anything here on Perth on 40m
>             on packet with
>             > my antenna but I'm curious on the performance of
>             Direwolf on HF so
>             > I'll have my station listening for a few days.
>             >
>             > 73
>             > Gavin
>             > VK6HGR
>             >
>
>             --
>
>                    Gavin Rogers                     |  Amateur radio
>             station VK6HGR
>             http://www.livingwaters.com/good  | http://vk6hgr.ampr.org/
>                             MSN/Skype/Email:
>             grogers at vk6hgr.echidna.id.au
>             <mailto:grogers at vk6hgr.echidna.id.au>
>
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>
>     -- 
>     Gavin Rogers mobile
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