The purpose of this document is to be a preventative frequently asked questions help document. Its goal is to prevent the following questions from becoming frequently asked. The topic of this document is of the NWSAMD product by Morris Softronics.
What does the NWSAMD product consist of? The NWSAMD product consists of a printed circuit board, a manual, and some optional PC software. At this time, no case, wiring looms or connectors are included, but they may become options. The product was intended for its recipient to case and wire into their existing equipment as desired.
What does the NWSAMD product do? One common function of the NWSAMD product is to decode/demodulate the specific area messages known as Emergency Alert System (EAS) and Weather Radio Specific Area Message Encoding (SAME) used by the U.S. national government and National Weather Service respectively. Both systems are very similar and interconnected. The end function after decoding of a SAM can be quite customized. Standard use will cause a Push To Talk (PTT) compatible output to be generated to immediately air the message broadcast by the alerting source. However, additional features can be requested by each customer for tailoring the NWSAMD to a specific function. You must contact Morris Softronics for further details on this topic though. The product could be capable of some forms of paging, among many other kinds of interfacing.
Does the NWSAMD product contain user configurable options and how are they configured? The NWSAMD board has many user configurable options even in its general application. All configuration is done via RS-232 compatible communications at 9600bps over a 3 conductor interface to a host computer. The NWSAMD product is not host dependant, but IBM PC compatible software is optionally shipped with the product. Any type of host capable of 9600bps RS-232 communications should be able to be used to configure the product. More discrete configuration must be done via user supplied hardware; however, which includes signal level translations and the like. The settings are saved to a non-volatile memory that will retain its memory for 100 plus years without power and will permit at least 10,000 changes.
Does the NWSAMD product have any future options? The NWSAMD product will certainly include future user requested software options, but the board also has expansion options for 2 future products. One expansion product that is almost complete is a second channel decoder. This permits the NWSAMD product to monitor two EAS and SAME equipped sources, but still only provides one destination option. Another product planned for future expansion is a DTMF decoder for additional control and configuration via a DTMF channel. The DTMF decoder will not and can not replace the RS-232 configuration methods described above. Both these planned expansion options can be used simultaneously.
What if my desired function can not be obtained with the NWSAMD product? Morris Softronics would be very welcome to hear what you are planning to do. We will consult with you, and may be able to make sure that a future product will do what you want, or can adapt the NWSAMD product to do it now. Many future products are already being thought of.
It was mentioned somewhere about location codes. What are these, where do I find mine? Location codes are what the EAS and SAME systems use to encode what areas the warning or other message is for. Location codes usually represent a county and are similar to the Federal Information Processing System numbers (FIPS) except that the first digit of a location code can represent just a portion of a county. You will usually want to talk with your local NWS office about what location code you are under and how they split up the codes in your area. EAS equipment may not always use the same codes as the NWS and so you may also need to talk to those related parties.
I want to put this on my amateur repeater which covers a couple of counties, will it work? You bet! The NWSAMD permits the entry of 16 location codes and permits optional EAS based matching of those codes. This allows you to decode all of the counties on a single NWS transmitter or just part of a single county. For repeater's that are large area coverage and also used for storm spotting, we don't suggest using a lot of location codes. Two or four counties is rather plenty.
Recent discussions have formed over whether automated warning broadcasts are legal over amateur repeaters. Are broadcasts from an NWSAMD legal? What is illegal about it? Part 97 is very large and is not very clear to exactly what is illegal. In many cases one section over rides another section. Our first suggestion is read all of Part 97 for yourself and think about it. Second we will be following up with details on our interpretation soon.
What is different about the options listed separately from "Future Expansion"? The options listed in the "Other Options" area all require modification to both the base product and the expansion products. The options are truly optional; they're not required to get the full function out of the product. They are provided for those who are concerned about the environment or who want to insure they have the highest quality product possible. Otherwise, the cost effective and economical parts we include by default are suited well for the average individual or organization.
What is special about the DC-DC Switching Regulator that makes it an option? The DC-DC Switching Regulator is an optional add-on to the NWSAMD product that produces a more efficient power source for the product. The linear regulator included by default converts the input voltage to a lower voltage for safe use by the product. However, it does this very inefficiently when used with high input voltages due to the lack of power conversion. A switching regulator is based on the principles of AC efficiency by converting the DC to a form of AC and then back again after the power has been converted. As such, a switching regulator can be considered to be more of a power regulator than a voltage regulator. The power output by a switching regulator is approximately the same as the power input. With a linear regulator, the current output is approximately the same as the current input. In all cases the voltage output is lower than the voltage input. Because power equals current times voltage, there is a substantial benefit at higher input voltages. The following tables should help.
All cases are 5 volts out at 100 milliamperes, or ½ watt output power. Voltage in volts, current in milliamperes, power in watts.
| Linear Regulator | Switching Regulator | |
| Voltage In | 12 | |
| Resulting Current In | 125 | 70 |
| Resulting Power In | 1.5 | 0.84 |
| Resulting Efficiency | 33% | 60% |
| Linear Regulator | Switching Regulator | |
| Voltage In | 24 | |
| Resulting Current In | 125 | 31 |
| Resulting Power In | 3 | 0.75 |
| Resulting Efficiency | 16% | 66% |
The above results are from the prototype we have built. The design of the prototype will probably be made available to interested parties who just can't wait. The actual results of the finished switching regulator may be different and will be posted. Approximate ETA for the switching regulator is 6 months. If you would like to ask questions or make comments please write us as directed on the product home page.
Due to the efficiency of the switching regulator, its an ideal candidate for use in battery powered applications, where the voltage drift of the battery will not effect efficiency. This means longer battery life with smaller batteries. It also means lower drain on other power sources.
Is this the last question? 'fraid so. If you have additional questions on the NWSAMD product, Morris Softronics is waiting to hear them. You may contact us at the addresses listed on the product home page.
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