[App_rpt] Setting up a simplex node

[Steve Rodgers]

Stephen,

See my responses below:


On Tuesday 06 February 2007 10:06, Stephen Brown Jr wrote:
> > We would like to suggest you plan to build a full-duplex system as this
>
> will provide much more flexibility than a simplex node.
>
> That brings up another interesting point that I failed to mention in my
> original posting. I am a little confused as to the definition of full
> duplex. When I think full duplex, I think that of like a telephone
> conversation where the caller and receiver can both talk at the same time.
> How exactly does this work in App_rpt? I only have one radio to work with
> with one simplex frequency, is this not intended for this type of setup?

Allthough simplex nodes can be deployed, they suffer from a number of 
drawbacks. The major deficeit is break-in capability. If you are listening to 
a busy  QSO on a linked system with a bunch of nodes connected, a simplex 
node cannot be used to break in to a that QSO since your simplex radio will 
always be transmitting and your receiver will be disabled. In addition, you 
will not be able to use remote bases on the system if they get tuned to busy 
channels. (This is a real problem with HF remote bases), and you'll be locked 
out of disconnecting from the remote base. Another minor drawback is that is 
is much more difficult to get the audio levels adjusted on a simplex node 
since you can't adjust transmit and receive levels at the same time. 

Full duplex will require two radios and a duplexer. (you will be essentially 
be building a repeater). Being able to transmit and receive at the same time 
from a user radio is not the primary advantage of building a full duplex 
node, but the added benefit to doing it this way is that you don't have to 
wait for any carrier drops before talking or breaking into an existing QSO, 
and on a linked system such as allstar link, this full duplex is really the 
only way to go.

>
> >BTW: We are working on a less expensive solution which requires 2 of
>
> inexpensive X100p FXO cards (around $10-$20) plus a modified ARIB, but it
> isn't >ready yet as it requires either changes to the ARIB, or an addtional
> external board.
>
> That sounds like a more economical solution. Do you plan on having this
> anytime soon?

We can't promise a delivery dats on this, but it is something we are persuing.


>
> One of the biggest things that attracted me to this project was openness. I
> think echolink and IRLP are excellent systems, but too closed and
> proprietary in nature which prohibits experimentation. I hope this project
> goes far!

Yep.

>
> 73's and tnx
> Stephen
> N1VLV
>
> On 2/6/07, Steve Rodgers <hwstar at rodgers.sdcoxmail.com> wrote:
> > John,
> >
> > You will need the following in addition to what you have already listed:
> >
> > 1. A digium TDM400 with one FXS daughterboard. Digium part number TDM10B.
> > This
> > is going to cost around $140.00. There is a Chinese knockoff of the
> > TDM400p
> > part number A400P10 for $93.00 which we haven't tested available from
> > openvox: http://www.openvox.com.cn/products_detail.php?genre_id=9&id=27.
> >
> > 2. One ARIB board. This board can be built for around $60-$70. Board
> > blanks
> > are available from us for $10 each plus shipping.
> >
> > 3. A modular to modular to modular telephone cable.
> >
> > We would like to suggest you plan to build a full-duplex system  as this
> > will
> > provide much more flexibility than a simplex node.
> >
> >
> > BTW: We are working on a less expensive solution which requires 2 of
> > inexpensive X100p FXO cards (around $10-$20) plus a modified ARIB, but it
> > isn't ready yet as it requires either changes to the ARIB, or an
> > addtional external board.
> >
> > Steve.
> >
> > On Tuesday 06 February 2007 07:43, Stephen Brown Jr wrote:
> > > Hi, I've been lurking on this list for quite some time and I am
> >
> > extremely
> >
> > > interested in setting up a simplex node to start playing with this.
> > > What exactly will I need besides the obvious(radio, computer, etc), I
> > > am
> >
> > little
> >
> > > confused on what type of FXS card I will need just for a single radio,
> >
> > all
> >
> > > the ones I have seen are fairly pricey. I will then need an ARIB board
> >
> > to
> >
> > > interface the radio to the FXS card correct?
> > >
> > > tnx and 73's
> > > Stephen
> > > N1VLV
> >
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