The N3FB Repeater

High over Southwest Pennsylvania ,
this is the N3FB repeater!
Operating since 1991 with 1,000 watts of radiated power and receiver sites in Canonsburg, Scenery Hill and Pittsburgh , it is my goal to make it very easy for you to get into this machine.
Each receiver site 'listens' on the input frequency of 448.650 MHz with a PL tone of 131.8. That site then retransmits what it 'hears', on a different link frequency, to the main site in Canonsburg. There a LDG voter selects the best audio and routes it to the transmitter on 443.650 MHz using a PL tone of 131.8. Oftentimes the receivers are switched back and forth while in mid-conversation without the listeners even noticing it.
The N3FB machine establishes a link with the N3RNX machine that operates on 146.955 (-) with a PL of 131.8.
During times of utility power outages, the system continues to operate on standby batteries. The system operates at a reduced output power in order to conserve those batteries. This can be noticed by the short tail and also the change in the initial announcement to a generic one that says "this is the N3FB repeater".
Comments, suggestions, and questions are always welcome. Contact Frank HERE
Link times are as follows:
Monday - Friday: 6:30AM - 9:35 AM
Monday - Friday: 3:30 PM - 6:50 PM
Saturday: 6:30 AM - 9:35 AM - (for breakfast meetings)
Second Thursday each Month: 7:01 PM - 10:30 PM (for the Club's Meeting)
Each Sunday: 8:55 PM - 9:45 PM (for the Club's weekly net)
While the on time is firm, the off time is approximate. The system will not disconnect a QSO that is in progress, instead the 2 meter link will disconnect after 3 ½ minutes of inactivity on both repeaters.
The link can be brought up by entering DTMF code 95 and then dropping the carrier. This will announce that the link is on and the machine will establish the link and keep it active until it has not been used for 3 ½ minutes.
Additional codes do the following:
123 = Announce the current time and date
1 = machine says "seventy three"
2 = machine says "seventy three to you too"
12 = Will immediately disable the link to the 2-meter machine
95 = brings up and announces the link to the 146.955 machine
You must drop carrier before and after each of these codes.
Recent observations and maintenance:
11/26/06 - After last week's changes to the voter, I noticed a difference between the 2 meter and 440 audio. The 440 audio was louder than the 2 meter audio. I changed the 2 meter radio as I was not happy with the performance of it in general. I did not make any adjustments to the voter but I did adjust the controller. I found that the 440 receive audio was loud and the 2 meter receive audio was soft. I adjusted the appropriate controls to balance the audio levels while KB3GMU painted the one remaining 4x8 exterior wall.
11/19/06 - Site visit today with Jim, WB4GCS. Plan was to tune up the voter and get it to be happy. We found that the preamp on the Cannonsburg site had failed and was acting like a 20 db pad. It was removed and suddenly Cannonsburg could hear again. The bad news is that another problem has developed at the Scenery Hill site. It has been disabled until I can make a guess at what it may be and plan another site visit. The voter tuning went well and the system is feeling much better than it has in a long time.
9/25/06 - The echo chamber effect is happening almost daily. It is most likley a problem in the controller. I have sent an e-mail to the controller manufacturer requesting assistance. I will keep this list advised as to the progress.
9/30/06 - I checked and recorded operation of duplexer and added a low pass filter that was set for 500 MHz to receive path at the Canonsburg site. I returned the Canonsburg site operations to the GE receiver instead of the (temporary) Motorola receiver. This appears to have solved the echo chamber effect (I hope). Please advise if you notice this effect is still present. I attempted to adjust voter so that it would not favor the Pittsburgh site , which it has been doing lately. I also checked the transmit frequency and found it to be right on!
9/25/06 - The echo chamber effect is happening almost daily. It is most likley a problem in the controller. I have sent an e-mail to the controller manufacturer requesting assistance. I will keep this list advised as to the progress.
9/13/06 - Worked on making the wiring in the repeater cabinet better. Replaced single turn pots on the voter with 10 turn pots to provide more sensitive adjustments. That change required a calibration of the system. While that was in progress, I noticed that the Scenery Hill receive site went off line while I was adjusting the levels. As I was not yet done with that site, I have locked it out because I do not know how it will play with the rest of the system. I am scheduled to go to that site early Friday morning, so that should provide the opportunity to correct the problem.
9/11/06 - Paint interior of shack white. Digi-peater and repeater were down as I removed everything from the walls. Both systems were back on line by 10 PM.


9/5/06 - General cleanup of the site interior and caulk the new exterior walls. I called site manager of Scenery Hill site to make arrangements to service that receive site, which is not receiving well because I forgot to turn on the receiver's preamp. When I do make it to the (SCY) site it will be off-line for a few days until I can calibrate the levels at the main site.
9/2/06 - Entire system including digi-peater was down for a while this afternoon (it is OK now) as I worked on finishing the interior carpentry. All interior walls and ceiling are complete. The heater has been re-connected. The A/C now is on a separate breaker. No leaks into the inside of the shack at all! I finished insulating the walls of the shack with some surplus insulation that I found and I replaced the 200 watt light bulb with a 80 watt fluorescent shop light. 
8/31/06 - Continued the carpentry at the shack. Caulked the door and worked on the interior face of the front wall. Re-installed the heater and lowered the temp on the A/C - inside temp was 86! Still need to wire in the heater and controls.
8/27/06 - Site visit to continue carpentry. Noticed some water leakage on the inside floor by the front door.
8/18/06 - A rebuilding of the shack is taking top priority over receiver adjustments now that the weather is good and that good weather will soon be slipping away into fall. Thanks go to master carpenter, Randy, N3ZK, for the use of his skills and tools in rebuilding the shack. Also, assisting with this project was Brian, KB3IFR and Dave, KB3NCD.
8/17/06 - After a user reported on 8/16 that the system was keying constantly, the main receive site was remotely disabled to temporarily correct the problem until a site visit could be arranged. That visit to the site determined that the local receiver was being activated by the transmitter. I retuned the filters on the transmitter's final amplifiers and this problem has been remedied.




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