Re: [RTTY] Multi Computer SO2R with N1MM

[Jay WS7I <ws7ik7tj@gmail.com>]

If there is "any single time that their is 2 transmitted signals you are 
in violation and are not a Single Operator.  All SO#R operators need to 
run a hardware device to preclude this situation.  This is nothing new 
at all.  Just the over looking by the group that it isn't a problem.  It 
is quite easy to put a system in place and to find stations that are 
running on two bands at once.  44 Ms of overlap means 2 signals and this 
means you are illegal.
Also it depends a great deal what you are using for PTT and also what 
radios are interfaced and which modem you have selected to use.
If the 20-40Ms gap is right then it needs to be controlled and at least 
100Ms it sounds like from this study.  But again. it should be absolute 
hardware control and not a software situation.
2-Signals EVER is illegal.

On 2/22/2013 5:04 PM, Mark n2qt wrote:
> In W0YK's email on AA5AU's WPX notes in talking about using N1MM
> for multicomputer SO2R he stated:
>
> "I found that the interlock is very slow and 2-3 characters overlap
> transmission from both radios.  OTOH, no software interlocks can 
> guarantee
> the absence of two signals, if even for milli-seconds, so the operator is
> responsible via a hardware interlock to not transmit simultaneously."
>
>
> Since I had used this approach to operate SO#R I decided to measure
> any possible overlap.  I would set one rig to cq and then interrupt it by
> transmitting on the other rig.  I did this where one rig was 
> controlled by
> a networked computer and then with the more typical single computer
> N1MM SO2R.  I used a storage scope to look at the rf output from the
> rigs.
>
> For the networked computer configuration the the worst case was 566ms
> of overlap with typical overlaps of over 400 ms.   As Ed stated this 
> is long
> enough for several characters to be sent in violation of one signal at 
> a time.
> Some other interlock is needed for rule compliance.
>
> However when using N1MM in its more typical single computer SO2R mode,
> it is obvious the programmers worked to eliminate this overlap. There 
> typically
> was a 20 - 40 ms gap with NO RF emitted, between one rig's transmit 
> signal
> dropping and the second rig's transmit coming up.  After many 
> sequences I did
> manage to get one series where there was just about 44ms of overlap.  
> This
> is well less than one half character's worth of time.  I personally 
> feel good about
> this performance.
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