[FADCA] Would this work for HIGH speed?

[Rick Muething]

Chuck,All

Yes the site did look interesting including the data radios shown there.
They may offer some good alternatives.

I also have had an opportunity to do some initial testing with the new Icom
ID-1 (D-Star) data radios. The initial results look encouraging but we are
really just starting testing over longer hauls.
These are really plug and play data radios (also work on FM voice and
Digital Voice). The data rate is 128K bits/second and delivered about 80-90
K bits per second net (before any compression gains) on typical file
transfers. They interface with a Ethernet cable (data port) (no TNC
required) and a USB cable (or front panel) for radio control.
Power is 1 or 10 watts at 1.2GHz. Sensitivity is 2 uv for the data mode. TR
switching is very fast (< 10ms) Current street price is about $1400 (with
front panel, mike etc) but I suspect will come down.  When you start
comparing the price to the dedicated high speed data radios + high speed
modems it is in the same ball park. The ID-1 is built to the D-star open
spec so there will likely be competition if this catches on.  A few ARES
groups are in the process of evaluating these for emergency work and trying
to get funding through homeland security.

So far we are testing with the WL2K Paclink and Telpac modules where the
ID-1 can be made to look just like a wireless Ethernet connection. The setup
is fairly simple. Since they operate using TCPIP for data it should be
fairly easy to incorporate into any OS version switch.

There are some nice commercial quality beams available (up to 18 dBd) for <
$200 from M squared. I wonder if someone could do a realistic path analysis
and see if these could handle backbone links with reasonable antenna heights
and 16 db antennas?

73,

Rick KN6KB

-----Original Message-----
From: fadca-bounces at mailman.qth.net
[mailto:fadca-bounces at mailman.qth.net]On Behalf Of Chuck Hast
Sent: Friday, February 25, 2005 09:28 AM
To: Florida Amateur Digital Communication Association
Subject: Re: [FADCA] Would this work for HIGH speed?


On Fri, 25 Feb 2005 03:34:49 -0500, Bill Sinbine <n4xeo at bellsouth.net>
wrote:
> Do you think this might be a option to get some high speed links going
with
> the Motorola radios?
> If they have the proper frequency on the if this might be a option and
> would let us get above 19200 baud. This would come out less than the Tait
> radios are and would go much faster.
> Does someone know if these would work in the radios we are using now?
>
> I'm looking at putting one in my ft-847 for sat work and this is how I got
> the thought.
>
> Just a snip from the web site listed below.
>
> Amateur-satellites with 38400 Baud FSK-modulation (G3RUH) are in the orbit
> since 1999. First packet-radio digipeaters with 76 kBaud are operative in
> Germany. With the IFD, you can expand the capabilities of most amateur
> radio receivers to high speed data reception as 38400, 76800 and up to
> 153600 Baud.
>
> Principle of function: The IF signal of your amateur radio receiver is
> tapped directly behind the rf frontend (1st mixer) and connected to the
> input of the IFD module. There, the signal is converted to a second IF
> frequency of  10,7 MHz by a mixer circuit and a fixed frequency crystal
> oscillator. The IFD assembly is available for most common IF frequencies
> e.g. 71 MHz, 45 MHz, 21,4 MHz, 13,45 MHz or 47,43 MHz (FT736) or 10,7 MHz.
> The bandwidth of the IFD amplifier is standard 110 kHz for 76 kBit/s
> maximum data rate. Wider filters (300 kHz / 156 kBaud) or narrower types
> (80 kHz / 38 kBaud) are available upon request.
>
> http://www.symek.com/g/ifd.html
>
> 180.00 EUR
> Euro   =   237.535 USD
> United States Dollars
> 1 EUR = 1.31964 USD 1 USD = 0.757785 EUR
>

What about the TX side. This is interesting. It deals with the If filter
issues
on the RX side, but many radios have BW limiting in the TX stages and
when you jumper it out you get into other issues. But the idea looks good.



--
Chuck Hast
To paraphrase my flight instructor;
"the only dumb question is the one you DID NOT ask resulting in my going
out and having to identify your bits and pieces in the midst of torn
and twisted metal."
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