Friday, May 30, 2008

Namaste 3.4 GHz Interference Study Update

Update #2 from Kerry Banke N6IZW, on the interference study for 3.4GHz.

Thursday, May 29, 2008

Namaste Link Analysis

Link analysis from Team Namaste. Posted for review.

Downlink Proposal

Downlink physical layer proposal. Open for review.

Tuesday, May 27, 2008

Tuesday Challenge for 27 May 2008

Tuesday Challenge for 27 May 2008.

Reply to the list, or to Michelle.

Thursday, May 22, 2008

APCO 25 Interoperability

Emergency communications interoperability through an APCO-25 terrestrial interface has been proposed.

This would increase emergency communications usability and increase opportunities for funding.

Here is a short introductory article on APCO-25.

Here is an industry article about APCO-25.

Here is the project home page.

There is an information page of interest at the same site as the home page.

People "in the know" refer to the standard as P25.1, meaning APCO project 25 phase 1, which is the current phase. Phase 2 and up are in development.

What I'd like to do is explore the idea of using a cognitive radio module to handle the interoperability. This would rely upon Tom Rondeau's work, as explained in his dissertation.

What I need are people that are interested in taking on the responsibility of supporting this terrestrial module for Namaste. This means learning the standards well enough to assist in writing and reviewing requirements, establishing the feasibility of using cognitive radio technology to bridge between our IP layer and external APCO-25 waveforms, and then supporting the design effort. After that comes build, test, and verification.

In the short term, soaking up knowledge about phase 1 is what I'm after, in order to write quality requirements.

Who is interested in this area of the project and wants to get started?

-Michelle W5NYV

Downlink Data Rate Discussion

The goal of this document is to give a summary of the expected performance. I'd like to capture discussion of the effects that different proposed modulation schemes have in terms of capacity, system complexity, and bandwidth utilization.

Namaste SuperPortable User Interface Design Document

Namaste SuperPortable User Interface Design Document
22 May 2008

The Namaste SuperPortable is a portable amateur radio satellite communications device designed for text communications, low-bandwidth data, and position location information. Applications include portable amateur radio use as well as emergency communications. This document concerns the development of requirements for the Namaste SuperPortable User Interface.

1. Text communications
2. Low bandwidth data connection through Ethernet port
4. Antenna Pointing Assistance


1. 0-9+ keypad
2. Small display
3. NMEA-compatible GPS
4. Ethernet for external data device
5. Bluetooth for external keyboard
6. Antenna
7. Radio
8. Processor
9. Power
10. Enclosure

See appendix A for the Interface n-Square Diagram

Functional Requirements
Text Communications Requirements

The operator must be able to display, edit, send, sort, print, and search received and stored text.
The operator must be able to address text messages from either direct entry or an address book.
The operator must be able to edit, sort, and search the address book.
The operator must be able to send a message to multiple addresses.
There must be an indication of pending messages.
The delivery of messages must be reliable.
There must be an indication of message delivery failure.
There must be a read-only audit trail of all incoming and outgoing messages with timestamp.
The operator must be able to monitor text messages.
The operator shall be able to use Templates in order to accomplish text communications.
Low Bandwidth Data Requirements

The operator must be able to send and receive low bandwidth data through the Ethernet port.
The delivery of data must be reliable.
There must be an indication of data delivery failure.
The operator shall be able to use Templates in order to accomplish low-bandwidth data communications.

GPS/APRS Requirements

Position location information from the GPS system must be available when enabled.
The optional GPS feature requires connection of an NMEA-compatible GPS receiver.
The functions of APRS must be supported.
Settings for APRS will include at a minimum ham call, path, beacon enable, beacon interval, and status message.
The operator shall be able to use Templates in order to use GPS and APRS functions.

Antenna Pointing Assistance

The antenna pointing function must provide azimuth and elevation data for all satellites usable by the ground station.
The antenna pointing function must provide signal strength indication.
The operator shall be able to use Templates to obtain satellite pointing information.

Interface Requirements

The display must be large enough to allow the operator to read and edit text.
The 0-9+ keypad must be large enough to allow the operator to type in text using a standard mobile keypad layout.
Antenna must provide enough gain to close the link.
Uplink digital mode bandwidth must be accomplished within 20kHz.
Downlink digital mode bandwidth must be accomplished within 100kHz.
Power connections must provide sufficient voltage and current.
Power scheme must be selected for portable and mobile applications.
Ethernet port must provide an Ethernet connection.
Bluetooth connection must support an optional external keyboard.


Templates are text files specifically designed to enhance ease of use for the ground station. They are similar to forms. Templates can be preloaded or they can be created and edited by the operator in the field using the keypad or the optional external keyboard. There are several types of templates.

1. GPS/APRS Templates
2. Address Book Templates
3. Message Templates
4. Antenna Pointing Templates

These templates provide a way to configure and operate the station. In general, a template is a text file with fields that are tagged in a way that makes it easy to select and edit them. For example, the operator selects a template, and can “tab” between the parts of the text that are flagged as fields.

The rest of the text file can be edited, but is intended to be preloaded.

It shall be possible to send a specially tagged text message that then can become a new template. For example, a damage assessment form sent to the station for the operator to fill out and return, instead of relying upon a back-and-forth question-and-answer session. Another example would be an address book for the particular place or event, sent out to all stations located at a particular place or participating in a particular event, in order to provide complete contact information for all participants. Templates can also be used for the body of outgoing messages, so that commonly used phrases or sections of a message or report do not have to be typed in. Antenna Pointing Templates, along with position location information, would include the information needed to locate satellites.

Open Questions

Gateways to commonly used services need to be identified and possibly supported.
Specifications concerning durability need to be made.
Support for an external display needs to be discussed.

Revision History
Version 1.0 released 22 May 2008

Appendix A - Interface n-Square Diagram
See original document for this table. It will not format correctly in text.

Tuesday, May 20, 2008

Tuesday Challenge for 20 May 2008

Tuesday Challenge for 20 May 2008

Here is the Tuesday Challenge for Namaste. Reply to the list to claim the task and post work.

Draft document will be drawn up starting next Tuesday, when a new challenge will be posted.

We may be interested in looking at including some sort of function, such as a module to be mounted on or with the half-meter dish, which will alarm the operator to the presence a person walking through the main axis of the beam produced during transmission. Since levels in the main beam exceed the limits of Maximum Permissible Exposure mandated by the FCC, we're interested in helping the operator easily comply with the regulations involved.

Here's the current Bulletin 65 worksheet for Namaste:

The Tuesday challenge for this week is to propose solutions for this situation.

Tuesday, May 13, 2008

Namaste News Volume 1 Issue 1

Newsletter handout prepared for Dayton 2008.

Monday, May 5, 2008

Super Portable Overview

Overview and questions about the super-portable (handheld) Namaste ground station project.

Sunday, May 4, 2008

Thomas Rondeau's Cognitive Radio Dissertation

Here is Dr. Rondeau's dissertation. Please check it out and participate in the formation of specifications for the terrestrial interface module.

Friday, May 2, 2008

Updated Dayton Forum Documents

Updated documents for the 2008 AMSAT forums at Dayton Hamvention.