Re: [amsat-bb] New amateur satellite ideas

["John B. Stephensen" <kd6ozh@xxxxxxxxxxx>]

Development projects with engineers geographically dispersed are especially
difficult to manage and 20 MBPS is ambitious for an amateur HEO satellite.  If
this is still the TDM bent pipe approach, acheiving the necessary EIRP at low
cost at the ground station will be a challenge. I had a few email exchanges with
Phil a year or more ago about accomodating small earth stations and TDM vs FDM
on the uplink.

The DCP-1 is very similar to the USRP -- the main difference is a 32-bit MCU
rather than an 8-bit MCU. My goal was to get the cost as low as possible so that
more people could afford to duplicate it. The sampling rate is 24.576 MBPS
adjustable +/-90 PPM and the maximum bandwidth of the analog front end board is
5.8 MHz. The lower sampling rate means that the basic chip set
(ADC/DAC/FPGA/MCU/USB) is $50 in small quantities.

I'll look into attending the meeting.

73,

John
KD6OZH

----- Original Message -----
From: "Robert McGwier" <rwmcgwier@comcast.net>
To: "John B. Stephensen" <kd6ozh@amsat.org>; <amsat-bb@amsat.org>
Sent: Monday, 02 August, 2004 01:26 UTC
Subject: RE: [amsat-bb] New amateur satellite ideas


> Without going into a tremendous amount of detail why, etc., for the
> time being,  I am in charge of transponders for Eagle.  Others are
> holding positions or have positions of project technical leadership,
> and project management and I for one hope that all shakes out and
> settles down before the annual meeting.  Phil, Tom Clark, Rick
> Hambly, and I presented a top level view of what we might do for
> a useful digital transponder for C band and what it might ental.  There is
> a lot of work to be done on the ground elements as well as the
> spacecraft elements.  The reasons for my being shoved forward
> with a electric cattle prod in my back for the transponders will
> become clearer as the project leadership tells the story of where
> we are headed for now, and that is likely to be at the annual
> meeting.  Suffice it to say, it is ambitious, it is forward looking,
> and the team appears to be excellent with new faces, old faces,
> and I encourage others to become involved.  If few Mbps >= 20,
> then your hardware might be interesting and we would certainly
> look at it.  If we cannot achieve what we want at 20 Mbps,
> then we might drop back in speed but that is the design goal.
> I am using the USRP (which is remarkably similar to what you
> have proposed and talked about on this forum earlier) as a slower
> speed version to do experimentation and development.  Even the
> DC and AM broadcast band experiments (2m, 70cm, etc.) have a
> very interesting twist.  Come to the ANNUAL MEETING and if you cannot,
> order copies of the proceedings.
>
> Caveat:
> AMSAT-NA is an equal opportunity exploiter ;-) and the more warm
> bodies there are to exploit the better.
>
> Bob
> N4HY
>
>
> -----Original Message-----
> From: John B. Stephensen [mailto:kd6ozh@verizon.net]
> Sent: Sunday, August 01, 2004 7:04 AM
> To: Robert McGwier; amsat-bb@AMSAT.Org
> Subject: Re: [amsat-bb] New amateur satellite ideas
>
>
> Its good to hear that work is proceeeding. I was worried after checking Phil
> Karn's web site and seeing that it hadn't been updated in two years.
>
> A few months ago I volunteered as the ARRL HSMM RMAN UHF project leader and
> am
> busy with the development a DSP-based transceiver for high-speed digital
> communication. The design will be published in QEX starting in the
> November/December issue. For terrestrial links, an OFDM modem will be
> implemented. However the hardware is completely programmable and could be
> used
> to implement a PSK or FSK link at a few MBPS. It would be nice if hams
> interested in satellites and HSMM could have interoperable hardware.
>
> I let my AMSAT membership lapse so I haven't received the AMSAT Journal in
> the
> past year and I couldn't find much information on the current web site. Who
> is
> the best person to contact to talk about coordinating efforts?
>
> 73,
>
> John
> KD6OZH
----
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