[RTTY] PSK31 is faster (Was FD RTTY Question)

Wed Jun 27 07:55:55 PDT 2012

Hello Ty

When someone anwers my CQ with his exchange attached, I just ignore them. 
Happens 2 things: they go or they answer as the normal way.

73!

*********************
XE1EE
Alejandro Valdez O.
DXCC RTTY, SSB, CW
Mixed, 10, 15, 20 & 40
WAS, TPA & WAC
ARRL A1 Operator Club Member
www.dxxe.org
www.qsl.net/xe1ee
Twiter: @xe1ee
***********************

+++++ No mas SPAM ++++++
No me envíes cadenitas, oraciones y demás correos sin mi autorización.
Do not send me prays, chain letters and others without my permission.

--------------------------------------------------
From: <k3mm at verizon.net>
Sent: Wednesday, June 27, 2012 9:35 AM
To: <n8hm at arrl.net>; <aflowers at frontiernet.net>
Cc: <rtty at contesting.com>
Subject: Re: [RTTY] PSK31 is faster (Was FD RTTY Question)

> Yes, it's more of an operator problem than a mode problem...
>
> ...and what's with this business of answering CQ's with the exchange 
> attached?  This has turned into a real epidemic!  Do these people just 
> assume I'm working them without questioning whether others might be 
> calling?
>
> ...so I send my exchange and then many of them dont even acknowledge 
> receipt!  If they do, it's slow to come.  I have to send everything twice 
> to make sure the correct station answers!
>
> I wont even go into the ones that just jump on my frequency to call 
> someone that just answered my CQ...sometimes before it's even done.
>
> How do we stop this rude crap??
>
> Ty K3MM
>
>
>
>
> On 06/27/12, Paul Stoetzer<n8hm at arrl.net> wrote:
>
> This ignores the delay at the end of transmissions, which is quite
> annoying, plus the problem of PSK31 operators adding superfluous
> information. PSK31 operators, even in PSK31 contests, rarely use as
> few characters as are used in RTTY contests. For example, PSK31
> operators seem to always need to indicate which station they are
> calling instead of just throwing out their callsign.
>
> Yes, lower case would help. Now someone needs to write software that
> displays PSK31 in lower case as upper case!
>
> Your technical analysis that PSK31 is faster is correct, but it
> ignores real-world use. PSK31 operators need to shorten their
> exchanges and learn that the big knob on the front of the radio exists
> for a reason.
>
> 73,
>
> Paul, N8HM
>
> On Wed, Jun 27, 2012 at 9:02 AM, <aflowers at frontiernet.net> wrote:
>> Apologies for the provocative title, but the lamenting of PSK31's 
>> perceived slowness during the FD festivities prompted me to crunch some 
>> actual numbers. The question I thought to investigate was "how much 
>> slower PSK31 is vs. RTTY in various contest-like exchanges?" I'm giving 
>> my results for discussion. For the record, I have never participated in 
>> in a PSK31 contest, so this is all back-of-the-envelope math and not 
>> based on any kind of actual contest experience. I have other thoughts 
>> regarding PSK31 in contesting, but this message is strictly about 
>> information transmission speed.
>>
>> I took several messages that are typical of RTTY contests. For all 
>> messages I assumed a CR/LF at the beginning of the message. RTTY is sent 
>> with USOS on, 1.5 stop bits at 45.45b. PSK31 is sent in lowercase (more 
>> on this below) at 31.25b. (Given the recent thread on character encoding 
>> in email you may want to cut and paste the table below into a fixed width 
>> editor to get columns to line up right.)
>>
>> Message, Bits PSK31, Bits RTTY, Time PSK31, Time RTTY, PSK31 advantage
>>
>> <CR><LF>cq k0sm k0sm cq <EOT> 98 172.5 3.14 3.80 17.37%
>> <CR><LF>cq aa5au aa5au cq <EOT> 98 187.5 3.14 4.13 23.98%
>> <CR><LF>aa5au andy ny ny <EOT> 104 172.5 3.33 3.80 12.31%
>> <CR><LF>aa5au 4a wny <EOT> 72 150 2.30 3.30 30.19%
>> <CR><LF>aa5au 599 678 <EOT> 122 180 3.90 3.96 1.42%
>>
>>
>> It turns out its really quite hard to engineer a message where 31.25b 
>> PSK31 is slower than 45.45b RTTY! Even numeric exchanges, which are quite 
>> long in varicode end up being at parity or better. Replacing the CR/LF 
>> with a single leading space makes PSK31 even faster.
>>
>> Because of the variable-length encoding in PSK31 your own callsign could 
>> potentially take longer to send. This is a function of how many "unusual 
>> letters" you have in your callsign. Here are some examples, although it 
>> should be pointed out that "wa5zup" breaks nearly even with RTTY if you 
>> include leading and trailing spaces (which you would in a message), which 
>> are only one bit in varicode:
>>
>> n6ee 17 45 0.54 0.99 45.06%
>> aa5au 27 52.5 0.86 1.16 25.20%
>> k0sm 27 45 0.86 0.99 12.74%
>> 4x6z 35 60 1.12 1.32 15.16%
>> wa5zup 41 60 1.31 0.99 -32.51%
>>
>>
>> This begs the question as to why PSK31 is slow. How many people are using 
>> their RTTY macros in all caps for PSK31? PSK31 averages about 10 bits for 
>> capital letters, and exactly 6 bits for lowercase. One way to change this 
>> behavior would be to have contesting software always send lowercase, and 
>> if one wanted, always print uppercase on the screen for legibility. I 
>> can't imagine a contest where case would matter, and you get instant 
>> speed improvement and better copy without having to change your beloved 
>> macros. Like USOS for RTTY, forcing lowercase transmission would a kind 
>> of hack to make things go a little faster and improve copy, and people 
>> who don't know any better still reap the advantage of lower-case 
>> transmission by default. This seems to this armchair observer to be a 
>> much better solution to increasing the baudrate (and thus losing SNR) by 
>> switching to PSK63 or whatever I to overcome poor utilization of the 
>> character table.
>>
>> I hope this is helpful!
>>
>> Cheers,
>>
>> Andy K0SM/2
>> _______________________________________________
>> RTTY mailing list
>> RTTY at contesting.com
>> http://lists.contesting.com/mailman/listinfo/rtty
> _______________________________________________
> RTTY mailing list
> RTTY at contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
> _______________________________________________
> RTTY mailing list
> RTTY at contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
> 