[pskmail] Re: Preliminary results of multiple PSK carriers with Pskmail
- From: John Douyere <vk2eta@xxxxxxxxx>
- To: pskmail@xxxxxxxxxxxxx
- Date: Mon, 13 Feb 2012 20:48:41 +1100
Hi Steve, thanks for your support.
I am going to the snowies for a week and I will try these new modes for
sure.
I hope the bad weather will stay in Sydney..hihi
all the best,
73, John
On 13/02/2012 4:51 PM, "Steve" <stevez@xxxxxxxxxx> wrote:
> I find your work and your informative descriptions of what you're doing
> always very interesting.
>
> Thanks John.
>
> Steve.
>
>
>
> On 02/13/2012 03:56 PM, John Douyere 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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