[pskmail] Re: Preliminary results of multiple PSK carriers with Pskmail
- From: John Douyere <vk2eta@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Mon, 13 Feb 2012 21:15:45 +1100
Thanks Bernie,
Yes it is great to see several servers running in North-America.
I also tested 3 x psk125 this evening and that gives a 55% speed
improvement on psk250 for a 475 hertz bandwidth and it looks very good. So
that could be of value too while staying under 500hz.
73, John
On 13/02/2012 6:05 PM, "Bernard Dekok" <kc9sgv@xxxxxxxxx> wrote:
> Thank you John,
>
> The U.S. is starting to take note of PSKMail.
> Hopefully we will have lots more servers here soon.
>
> Keep up the good work, please.
>
> Bernie,
> KC9SGV
>
> On Sun, Feb 12, 2012 at 10:56 PM, John Douyere <vk2eta@xxxxxxxxx> wrote:
>
>> I just wanted to share some of the initial tests of PSK and PSKR multiple
>> carriers and I have to say I am pretty happy so far. I tested 2 x PSK500R
>> and 3 x PSK500R and it is still pretty robust.
>>
>> I had definitely multipath reception in the waterfall and despite that I
>> had very few repeats. 2 x PSK500R gives us 10% more speed than PSK500 but
>> it **looks** more robust from today's observations, in a 1200Hz bandwidth.
>>
>> 3 x PSK500R gives 55% more speed than PSK500 BUT at almost 4 times the
>> bandwidth!
>>
>> I also tested 2 x PSK500 and that really flies with a 17174 bytes email
>> document (text only) downloaded in 2 minutes 25 seconds from the receive of
>> the FM command to the TX of the FA command. That is 7,107 characters per
>> minute, in a 1200Hz bandwidth...not bad at all.
>>
>> Another way to look at it: that is 5.92 characters per minute per Hertz
>> of bandwidth, **in real life, with QRM and block repeats**, not theoretical
>> best case!
>>
>> The theoretical best case of 2 x PSK500 with a 1 seconds TX delay on both
>> sides is 8,078 characters per minute net speed or 6.7 CPM/Hertz with the
>> current ARQ overheads.
>>
>> If we increase the number of blocks of data per transmission to 16
>> instead of 8, we get a net speed of almost 9,400CPM. Then reduce the delay
>> on each side to 1/2 second and we get over the 10,000CPM in the same 1200Hz
>> bandwidth.
>>
>> I will also test the 4 x PSK500 and 4 x PSK500R on FM too and report.
>>
>> The next development steps will be to switch the "Nitrous Oxide ON" with
>> 4 PSK and maybe 8 PSK.....
>>
>> I'll keep you posted.
>>
>> 73, John (VK2ETA)
>>
>>
>>
>>
>>
>
>
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