WA8LMF Mirror of WB4APR Website - 21 July 2008 TEMPn-N in all D700's

TEMPn-N and Field Day

APRS is a tactical-real-time-local digital communications network designed for rapid deployment in the field using come-as-you-are equipment for a LARGE number of simultaneous stations. APRS is PERFECT for Field Day with HUMAN operators at all stations. This is not at all what most APRS users are familiar with on a 24/7/365 basis.

But the ARRL Field Day rules make it difficult to use APRS on Field Day beacuse the APRS System on that Day must include one temporary and portable digi and be independent of the existing global APRS infrastructure on 144.39.


TEMPn-N is an ALTERNATE APRS emergency network hopefully on the North American APRS alternate input frequency of 144.99. This channel is normally used as a 144.39 +600 alternate input for low power stations to get cross digipeated over to 144.39 but without any congestion on the input. In this case, these cross band digis only need to support WIDE1-1 as an alias to serve this purpose. But they can also be set up to support TEMPn-N emergency digipeating too. In this case, they serve as the final hop to get packets from any temporary mobile D700 TEMPn-N operation into the 144.39 system.

BUT FOR FIELD DAY WE MUST USE ENTIRELY TEMPORARY SYSTEMS, so we must not operate on 144.99 that day, but 145.01. This allows us to SET UP during Field Day (or at any time!), an AD-HOC digital communications system for communications with as many Temporary APRS FD stations as we can. Using TEMPn-N allows for a near instantaneous shift of everyone's home and mobile and portable stations to an independent general purpose packet system for either Field Day or in response to an emergency when a WIDEn-N system cannot be reached.

USING the THOUSANDS of D700 MOBILES FOR TEMPORARY DIGIS: Although we have about 1000 permanent digis across the USA, we are overlooking the value of the THOUSANDS of mobile D700's that can act as digis if needed. The problem has always been that we do NOT want mobile digis 99.99% of the time, but it is a shame not to have them available when needed. The solution is to simply turn them on as digis ALL THE TIME, but only to support the path of TEMPn-N. This makes them always out of sight, but always useable if needed. (including Field Day!). They can be used on 144.39 if needed, but by having the permanent +600 alt-input digis listening for TEMPn-N traffic on 144.99 too, this gives those remote D700 emergency digipeaters a standby-ready-to- use-anytime link into the 144.39 network from afar.

The D700 mobile makes an excellent digi, but to activate the UITRACE parameter for digipeating, you must use a PC via the serial port and set "UITRACE TEMP" and "HID OFF". The radio will remember these settings. But since we can keep TEMPn-N in place always without problems for normal operations, it should become the permanent default of all D700 mobiles.

Other Mobile DIGI settings: The above TEMPn-N settings are independent of the front panel APRS menu functions for digipeating. For those, it is best to have the APRS MENU parameter called UIDIGI set to WIDE1-1 so that your digi can also act as a fill-in digi for other mobiles as needed. In most dense areas of APRS, the menu setting of DIGI should be OFF however, to avoid any unintentional QRM when not specifically needed.

See how to apply this to Field Day

Lets get the word out.
de WB4APR, Bob

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The Naval Academy is a registered user of APRS and WinAPRS. The purpose of this web page is to show several applications currently in use at this site and should not be considered as an advertisement or an endorsement of any commercial product. WA8LMF Mirror of WB4APR Website - 21 July 2008