In the UK we have a local 80m evening contest that runs monthly for data
modes. Both modes PSK and RTTY are used in this contest and to make a good
score both modes have to be used.
PSK31 (note the 31) suffers from two distinct disadvantages compared to
RTTY. The first is fundamental and that is often it just does not work as
the propagation changes the phase faster than the transmission. The second
is it is much slower to make a Q than RTTY.
The solution is very simple use PSK63, in other words go faster. The first
problem is mitigated as the phase change of the modulation is twice as fast
as before and therefore gives less time for the propagation to change the
phase. The second is Q rate goes up as the characters are sent twice as
fast.
There is a downside as going twice as fast means the SNR is decreased but
almost all Qs in this contest are above the minimum SNR this is not a
problem in practice.
Go faster still ah then you are up against SNR and other effects like
frequency selective QSB. Fortunately RTTY with the right decoder has
frequency diversity with its two tones and in these conditions often RTTY
will provide excellent copy while PSK provides none.
So do not get fixated on PSK31 start thinking PSK63.
73 David G3YYD
-----Original Message-----
From: RTTY [mailto:rtty-bounces@contesting.com] On Behalf Of Jeff AC0C
Sent: 24 February 2017 05:37
To: jim@rhodesend.net; Bill Turner
Cc: RTTY Reflector
Subject: Re: [RTTY] RTTY vs PSK31 on Field Day
For FD, run both modes. You will have better Q rates on RTTY but it's
possible you may run out of guys to work if FD activity on RTTY is light
that year. So moving to PSK will let you keep running but the Q rate will
be less as there will be more casual ops there and the occasional longwinded
exchange will pop up from time to time.
73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie
-----Original Message-----
From: Jim Rhodes
Sent: Thursday, February 23, 2017 11:15 PM
To: Bill Turner
Cc: RTTY Reflector
Subject: Re: [RTTY] RTTY vs PSK31 on Field Day
Yes, but sometimes you need to move data.
Jim Rhodes
K0XU
On Feb 23, 2017 11:04 PM, "Bill Turner" <dezrat@outlook.com> wrote:
> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Fri, 24 Feb 2017 04:44:11 +0000 (UTC), Tim wrote:
>
> > In a real-life emergency would everyone crowd PSK signals into 2 -3 KHz?
>
> REPLY:
>
> In a real life emergency, the mode to use is SSB. It's much faster,
> doesn't require a computer and conveys urgency much better than any
> digital mode.
>
> I love the digital modes, but when life and/or property is at stake,
> give me a mike.
>
> 73, Bill W6WRT
> _______________________________________________
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> RTTY@contesting.com
> http://lists.contesting.com/mailman/listinfo/rtty
>
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