[FADCA] Re: Digital Voice over our links?

[fadca@mailman.qth.net]

My comments below...

> -----Original Message-----
> From: bud Thompson [mailto:budt@cfl.rr.com]
> Sent: Thursday, October 17, 2002 05:38 PM
> To: fadca@mailman.qth.net
> Subject: [FADCA] Re: Digital Voice over our links?
> 
> 
> Deltona
> Thursday Oct 17 1725EST
> 
> Interesting turn of events... In the 80s in Denver, I 
> petitioned repeater groups to let us add subcarrier digital 
> data communicaaitons to their carriers so we would not have 
> to duplicate the sites and gear.  I did the same in Las Vegas 
> in the 90s.
> 
> You can imagine the response I got in both venues!

Yes, and probably some was not printable on a list like this.
You were probably also thought to be a crackpot and idiot, I
know that mentality well, it is the same one I have crossed
when I have had to do such things as use a language not local
to the area (i.e. Spanish on a English used repeater or
English on a Spanish system, both here and in Latin America,
so some of our local radio police are not alone by any measure)
not because I wanted to but someone needed help and as hams we
should do so. But there are so many very narrow minded people
with blinders on. You just have to go on and do what is right.
I have even had to run packet over a repeater every once in
a while, in Costa Rica we would do it on the squelch tail,
it was funny how much we could get through by doing that,
and for a long time we fooled the radio police telling them
it was video intermod from the near by tv transmitters
(radio police are also notoriously gullable B-] )


> 
> It may come to pass that the reverse will happen... We (will) 
> have the sites and the digital know how - but we won't say no.

Yes, because we do realize that this is the only way to push the
envelope forward, as it is, those people you were dealing with
are the same ones who have kept us using voice technology that
is 30-50 years old, while everyone else is going on to digital
we still are pretty much stuck in the past... What is it that
part 97 says about experimenting and moving technology forward?

> 
> It's not clear to me - but my guess is that our move to LINUX 
> FPAC would facilitate this as the FPAC routers are supposed 
> to be transparent to the protocol - izat right, Chuck?

Yes, and what is not quite there if we can get some coders on
board with us can be done as it is not magic.

In fact to keep bandwidth down over the radio I would use TCP
as little as possible using UDP, and where possible spoofing
or using what we have inherent in the network. A AX.25 link
over FPAC with good signal paths is reliable and there is not
a reason for stuff to get lost, as we speed those links up we
will find that they can carry more and more data. In many ways
our network resembles much more a ATM network. ATM like our
network uses VC's instead of DG's, but it uses a fixed packet
size of I think it is either 53 or 57 bytes, keeping the packets
small so it can handle digital voice and video in real time.

If a repeater is colocated with a FPAC switch then it should
not be too big of a deal to get the data into the switch.

By way one piece of software that you should pull down is
Speak Freely, it has codecs that span the whole spectrum of
band widths, there is one that is for very slow speed links
the audio is not real good in terms of fidelity but you can
clearly understand it (what is most important in our activity
many times) SpeakFreely is what is used by the IRLP project
and it comes in LINUX and Windows. The LINUX version is a set
of modules that allows you to also build up conference servers
and user directories, The Windows version allows Windows users
access to a very flexable and extremely useful piece of VoIP
software, and the best part is the source is available for both
platforms, address is www.speakfreely.org
Pull it down and play with it...

> 
> In repeater/digital voice transfer service radios would need 
> to be capable of high duty cycle service. I'm guessing the 
> duty cycle would increase by a factor of 2x or better 
> compared to 9.6kb ax.25 data transfers.  That said, I see no 
> reason for an increase in Power Output as wold be the case 
> for comparing digital modes to analog voice.. so maybe there 
> is a trade off there.
> 
> Now, to keep my feet on the ground and be focused on the here 
> and now... need to get the Melbourne switch moved.
> 

> 
> --- StripMime Report -- processed MIME parts ---
> multipart/alternative
>   text/plain (text body -- kept)
>   text/html
> The reason this message is shown is because the post was in HTML
> or had an attachment. Attachments are not allowed.
> Please post in Plain-Text only.---

Bud, are you running HTML vice text? Looks like it from the
error message above. 


*****************************************************************
This e-mail and any files transmitted with it are confidential and are
intended solely for the use of the individual or entity to whom it is
addressed. If you have received this transmission in error, please notify
the sender immediately and destroy any hard copies you may have printed and
remove all copies of the e-mail from your hard drive. Opinions, conclusions
and other information in this message that do not relate to the official
business of Utility Partners, Inc shall be understood as neither given nor
endorsed by it.

Visit us on the web at http://www.utilpart.com 
*****************************************************************