SYSTEM DIAGRAMS

Why make this information available?

We make this information available for these main reasons:

  1. Some have implied that operation of our 70cm system was without coordination from the recognized frequency coordinator for Southern California regarding the band of operation involved (SCRRBA). As it turned out, the major proponent of this position was the trustee of an uncoordinated system (per SCRRBA - disclosed in 1995 and reconfirmed in 1999) which also happened to occupy the same 70cm frequency pair as our system did. With our location to a new frequency as a result of the 70cm band realignment, this is no longer a significant issue.
  2. We see no security problem from the information presented here with regard to the operation of the system or any of its components, especially since we use custom firmware. Furthermore, it may be in the public interest to disclose this information so that the public can understand what operations occur in our system.
  3. Being able to view a live example may help new system trustees who are about to complete the coordination process for the first time - at least as far as the RFC paperwork is concerned.
Note: We have not published all of the information submitted in the Request for Coordination (RFC) packages, nor have we published references to all of the RFC documents. RFC documents and communication with SCRRBA which did not affect the operation of the system or require a revision to the system diagram have been excluded.

Here is an index into our coordination-related communications:

The Original RFC Information, filed during June 1994, appears to have been lost. Although Mr. Frank Collins, N6TAF, helped our trustee complete it, he did not retain a copy either. Additionally, no confirmation was issued with regard to SCRRBA's receipt of such. It is noted that SCRRBA was not sending confirmations to RFC's prior to 1995, nor was it acting like a frequency coordination group should, per a disclosure made by a SCRRBA officer at its September 1995 meeting. [SCRRBA has undergone some changes since, including annual meetings.]

The repeater was placed into operation on May 1, 1994, after listening for 4 weeks for a locally unused frequency. A scanner, placed into a mode where it will lock onto a frequency (and stop scanning completely upon detecting a carrier), was used looking at about 12 candidate frequencies, chosen due to the lack of publication of coordinated systems occupying them in our local area. (There were more than 12 frequencies that didn't have published systems, but the list was narrowed down by using an active scan - cycling through the 38 most common CTCSS tones while transmitting.) After the listening period, only 3 remained. [We don't know whether or not the signal activity detected on the other 9 frequency pairs was due to unpublished coordinated systems or un-coordinated systems - only that a local signal was detected and that interference was likely.] Next, we listened for an additional two weeks using amateur radio gear with increased sensitivity. Then, we simply chose the frequency pair which indicated that our operation would provide the least interference to an existing coordinated system. As it turns out, this also represented a co-channel situation with the existing coordinated system furthest away from our location - in Crestline, which was also convenient since our trustee, at that time, occasionally travelled to that area. After one month of operation without any interference noted, our initial RFC was submitted.


This page last revised on 2000/08/05.