Tony,
Thank you very much for the information.
See you on the air,
philw de ka1gmn
On Fri, Aug 7, 2009 at 3:01 PM, Tony wrote:
>
>
> Hello Phil,
>
> >Very interesting. What simulator are you using? philw de ka1gmn
>
> I use Moe Wheatley's PathSim with VAC to route the digital mode
> audio. Pangram text is used to test throughput.
>
> It's important to make sure that the audio amplitude is the same for each
> mode when testing to keep things evenly matched.
>
> Tony -K2MO
>
>
>
> - Original Message -
> From: Phil Williams
> To: digitalradio@yahoogroups.com
> Sent: Friday, August 07, 2009 2:48 PM
> Subject: [Norton AntiSpam] Re: [digitalradio] Olivia - Contestia Tone /
> Bandwidth Configuration
>
>
> Very interesting.
>
> What simulator are you using?
>
> philw de ka1gmn
>
>
>
> On Fri, Aug 7, 2009 at 3:59 AM, Tony wrote:
>
>
> All,
>
> It's interesting to see how the different Olivia mode configurations
> compare when put through the HF path simulator.
>
> I ran Contestia through the simulator this evening and these are the
> results. Olivia 16/500 is shown for reference.
>
> CONTESTIA 500Hz
>
> Tones BandwidthChar/sminimum SNR Words Per Minute
>
>4500 7.81
> -6db 94
>8500 5.86
> -9db 70
> 16 500 3.90
> -13db46
> *16 500 2.00
> -14db24
> 32 500 2.44
> -15db29
> 64 500 1.46
> -17db17
> 128 500 0.85
> -20db10
>
> *Olivia 16/500 mode
>
> CONTESTIA 1000Hz
>
> Tones BandwidthChar/sminimum SNR Words Per Minute
>
>4 1000Hz 15.6 -3db
> 187
>8 1000Hz 11.7 -6db
> 140
> 16 1000Hz 7.8 -9db
> 94
> 32 1000Hz4.9 -12db
> 59
> 64 1000Hz 2.9-14db
> 35
>
> CONTESTIA 250Hz
>
> Tones BandwidthChar/sminimum SNR Words Per Minute
>
> 4 250 3.91
> -12db 46
> 8 250 2.93
> -13db 35
> 16 2501.95
> -15db 23
> 32 2501.22
> -17db 15
> 64 2500.73 -
> 20db 8.8
>
>
> It's clear by looking at the chart that the slower the throughput, the
> better the weak-signal performance. This no doubt has to do with symbol rate
> etc (experts comments welcome). Reducing the number of tones by half will
> yield 1-to-4db better weak signal performance, but at the cost of slower wpm
> rate.
>
> The nice thing about being able to change the configuration is that it lets
> you try different combinations to squeeze the most out of the modes to suit
> conditions.
>
> The modes with the higher tones are extremely sensitive so the skies the
> limit in terms of weak signal work as long as you don't mind the slow pace.
>
> It pays to take a good look at each configuration and compare; for example;
> Conestia 32/500 mode vs. Olivia 16/500.
>
> The Contestia mode is 5 wpm faster and slightly more sensitive than Olivia.
> This simple change lets you pick-up the pace without sacrificing weak signal
> performance.
>
> For those who are conscious about spectrum; take a look at Contestia modes
> 8/250 and 64/1000Hz.
>
> They both have the same wpm speed and nearly the same sensitivity, but the
> 8/250 mode performance is the same and it does it in 1/4th the bandwidth.
>
> Getting late here so will have to wrap it up and let the group look at the
> figures and send some feed back.
>
> Hope you all find it interesting...
>
> Tony -K2MO
>
>
>
>
