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Re: JUly 2001 President's Letter

Nick raises an interesting point.

Where I live (the People's Republic of Massachusetts,)
putting up any serious antenna (AO-10 class) is a major headache.
Heck, it took me 3 years to get the environmental permits
to put up silly little deck over my driveway!

For me, anything that reduces the size of antennas is a
huge help. On the other hand CPU power is cheap and even
specialized hardware is not a problem.

While not everywhere in the US is quite as restrictive,
many hams here in the US DO have to live with these

As Nick suggested, the same may be NOT be true in other countries
where hardware is restricted by tarrifs, import restrictions etc.
On the other hand TDMA is not exactly an exotic technology and
and if most of the processing can be done in software, it sure sounds
like a winner to me for (almost) everyone.

Tony AA2TX

At 07:56 AM 7/25/01 -0400, Nicolaus Sallay wrote:

>----- Original Message -----
>From: "Phil Karn" <karn@ka9q.net>
>To: <n.sallay@internext.com.br>
>Cc: <nn0dj@wiktel.com>; <amsat-bb@AMSAT.Org>
>Sent: Monday, July 23, 2001 3:36 AM
>Subject: Re: [amsat-bb] JUly 2001 President's Letter
>Hello Phil,
>- thank you for your return and questioning.Sorry for the late reply.
>I will try to explain my point.........
>( this message is not addressed to the volatile readers, so please no
>threads nor flames)
> > >- After reading the above decisions, I am concluding that a huge part
> > >of world's Ham population has been excluded from the possibility of
> > >operating this new bird due to the high tech specifications and the
> > >cost involved, as well as the removal of V/U capabilities.  TDMA looks
> > >very much like an elitist project.  Further, and for hams outside USA,
> > >the difficulties to get hardware at reasonable prices, will
> > >drastically reduce participation. Unfortunately AO-40 has serious pro-
> > >blems and we lost AO-10's replacement
>- at least for me, TDMA, time division multiple access, dividing time 
>the hardware/software to control and setup this access control system used to
>optimize the use of a channel, seems difficult to build and use, maybe also
>expensive, considering our tax laws and the eventual need of specific tools
>for measurement and tuning, which are unavailable in my part of the country.
>(and I am shure, in other locations also)
>So far we do not have access to companies who eventually have means
>to help us, like telecommunication services,universities or other. Most of
>them use go no go type equipment to maintain their stations.
> >
> > I'd like to know why you feel this way. One of my major motivations
> > for proposing this project is to reduce the size of the antennas
> > required to work amateur satellites with good results. Thanks to
> > restrictive covenants, the enormous (and costly) antennas required by
> > the current generation of amateur communications satellites constitute
> > far more of an "elitist barrier" than the complexity of any digital
> > scheme.
>  - I am ,was not a aware, of restrictive measures in setting up antenna
>systems. I fortunately do not have this problem and building V and U
>antennas do not present a handicap, my setup is home made and
>working well since AO-13. Sorry,I do not dare to compare a digital
>system with a antenna setup.
>I am still very happy with the mode B way of working and now starting to
>loock into the S band possibilities
> > I also fail to understand why hams outside the USA should have
> > difficulties getting the required hardware at reasonable prices. That
> > is, if you consider the cost of ordinary amateur transceivers to be
> > reasonable, as they're by no means cheap.
>As far as I have seen, in the USA, the possibilities of obtaining hard-
>ware and parts at low cost, is extremely easy due to the continuos
>improvement in technology and it "does not matter very much" if during
>a set up you smoke a part. A US$ 1,00 part for me will cost almost 4
>times more than for you.
>You are right, a ordinary amateur transceiver is a expensive piece of
>equipment but most amateurs managed to buy a V/U multi mode
>transceiver. As an example let us see,take an FT 990 and a TS 790A
>top line selection, at his time top line, or still is. You do the same 
>today with a 847 for less than the half price
> > Most of the signal
> > processing will be implemented in software running on commodity PCs,
> > and I think it's fair to expect commodity PC hardware to get even
> > cheaper and more readily available than amateur transceivers.
>The hard thing is if you do not have the tools, the availability of knowledge
>to assist you correctly (technology) plus the worst, material and availability
>at low cost, it is better to stay away.
> > Phil
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
>Best regards,
>Nicolaus Sallay - PP8DA
>Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org