[hfsig] LinLink... PTC's risks

Jack Taylor jack at n7oo.com
Mon Aug 23 13:28:27 EDT 2004

Debate about WinLink (and related topics) can be found at:


73 de Jack

----- Original Message ----- 
From: "Robert McGwier" <rwmcgwier at comcast.net>
To: "TAPR HF Modes SIG Mailing List" <hfsig at lists.tapr.org>
Sent: Monday, August 23, 2004 7:00 AM
Subject: RE: [hfsig] LinLink... PTC's risks

Amen.  It is useless to have Homeland Security buy into this and
then to have us look like fools if SCS goes out of business.  That
may never happen but  it cannot be allowed to be a possibility in this
situation.  Our European friends, who are barred by law from even
considering doing "public service work" as we in the US practice it,
are not interested in the details of our needs maybe but we cannot
afford to ignore them.  We need an open standard that can be duplicated
by many.

If SCS made everything public, which they will not,  we would have
to modify it so that it would not be interoperable.  Can you even imagine
the egg on your face when your local fire truck company, asking for more
RC Cola and moon pies for desert, comes on the frequency at the same time
as the Governor of your state sending a system wide emergency alert during
a large scale Hurricane alert and blocks that same message for many minutes?

The SCS PTC does not check the channel for occupancy.  I hope this little
parable/example makes it clear to you why this is a disaster and the
lamest possible system design I have ever seen for HF communications.
The SCS does not grade the channel for suitability to carry the information.
It just starts banging and uses ARQ to attempt to bang it through.
If we do not have a system that "sounds the channel" and picks the
most suitable one (as is done by HF ALE automatically) then I can't
understand how we are serving a need.  Not good.

I don't wish to knock the fine folks who are currently sitting on the
digital committee (sorry) but they did not have their thinking caps
on while they were screaming at each other and threatening each other
with lawsuits and chose a poor standard since it was existing.


-----Original Message-----
From: hfsig-bounces at lists.tapr.org
[mailto:hfsig-bounces at lists.tapr.org]On Behalf Of Haineault,Bruno
Sent: Friday, August 20, 2004 9:58 PM
To: 'TAPR HF Modes SIG Mailing List'
Subject: RE: [hfsig] LinLink... PTC's risks

But you haven't addressed the important point of OEM survivability:

As the PTC-II and III waveforms are proprietary, what happens if SCS ceased
to exist? Would all of the users be left out in the cold?

I would only consider PTC-II/III for such an important task >IF< the OEM
agreed to move the waveform into the public domain. IMHO, an acceptable
alternative would be if they at least committed to move it into the public
domain IF they decide to close down.

MIL-STD-188-110A is public while several characteristics of 110B are still
licensable. However, as there are several 110B modem manufacturers out
there, I would be less worried if one vendor bit the dust.

Putting all of your eggs into one basket (SCS') is risky as it is a
single-source protocol and there are no "legal" alternatives.

Bruno, W6AFK

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