146.910 Tyson's Corner Repeater

Revised October 6, 2006

The Association’s “91” repeater is located in Tyson’s Corner together with the 440 machine and future 6m machine.  The machine is currently operating single site.  A General Electric MASTER II Repeater with a General Electric MASTRII Power Amplifier running at 130 watts feeding a 6db gain Celwave yields 250 Watts ERP.  The repeater controller is a CAT-1000.  At the current time, there are no PL tones on the repeater output.     

Random noise and ‘kerchunks’ are filtered out of the repeaters through the insertion of a slight delay in the audio path between the controller and the transmitter.  In addition to preventing the repeater from being brought up by spurious signals, this feature also permits full muting of incoming DTMF tones during autopatch and other operations.

The  repeater has three operating modes: Normal, Night, and Net.  Normal mode is the automatic mode that we normally hear the repeater operating in.  The kerchunk filter, is enabled, the autopatch is enabled, and the voice ID is every ten minutes when the repeater is in use.  The Night mode disables the autopatch, except for 911, and the voice ID.  The repeater still IDs in CW every ten minutes that the repeater is in use.  Net mode changes the courtesy beep to a single 1000 hz tone and CW ID only.  The repeater is in Night mode from 23:00 each night to 5:00 each morning and occurs automatically.

To properly activate the repeater’s special functions, the DTMF tones generated by your radio must be recognizable by the controller.  If you are having difficulties with a tone-activated feature, your tone pad can be tested by the repeater by identifying yourself clearly and sending a 5 followed immediately by up to 32 digits.  When you release your PTT switch, the repeater will read back everything it recognized after the initial 5.  “Sierra” is read back for * and “P” is read back for #.  To check a key for intermittent operation, send it several times.  The repeater should read back the digit once for each time it was pressed. 

Single transmissions are limited to a maximum of three minutes.  When the incoming carrier drops, the repeater will reset the timer, sound a courtesy tone and identify itself if it hasn’t done so within the last ten minutes.  If the timer expires while a carrier is present, the repeater will announce “Repeater Time Out” and shut down its transmitter.  Once the incoming carrier is dropped, the transmitter will be re-enabled and the repeater will announce “Repeater Time Out Canceled” and return to normal operation.

For more information, please Contact us at the addresses provided.

Copyright 1999-2006, Northern Virginia FM Association