Another example from my blown up shit collection, pictures archive:
The harmonic filter from a Broadcast Electronics FM-30T. This actually started in the bullet connector to the 3 inch hardline on the output side of the filter.
Again, I did not install this myself, someone else did. Cutting 3 inch hard line is pretty straight forward. When using a field flange, the outer and inner conductors are cut flush. Both conductors should be de-burred and filed smooth. It only takes a little thing to start an arc with 30 KW of FM power, so once again, attention to detail is key to avoiding these things.
Fortunately, BE sent along replacement parts for the harmonic filter and the line section was replaced.
As promised, here is the AM transmitter site maintenance check list. This is for a generic directional AM station with a backup transmitter, generator and an RF STL.
Usual disclaimers apply.
AM site Maintenance checklist
A. Visit site, Check following:
- Check critical transmitter values against last logged value
- Check forward/reflected power on main transmitter
- Check and reset any overloads
- Check signal strength on STL against last logged value
- Check generator fuel level
- General check of building, look in all rooms, inspect for damage from vandalism, Leaking roofs, obvious signs of trouble, take steps to correct.
B. Visit site, Check following:
- Do a full multi-meter log, (includes tower phase angles, loop currents), run backup transmitter into dummy load.
- Start and run generator for 5 minutes, check block heater, hoses, belts, oil and antifreeze levels
- Calibrate remote control meters with transmitter meters, log it*
- Check all tower fences for integrity and locked gates*
- Complete Items 3, 4 and 5 under weekly maintenance.
C. Visit site, Check following:
- Complete 1 through 5 under monthly maintenance.
- Check all air filters, clean or replace as needed.
- Check frequencies of all transmitters, STL receiver, and log.
- Complete quarterly tower lighting and painting inspection*
D. Visit site, Check Following:
- Complete 1 through 5 under quarterly maintenance.
- Conduct monitor point readings for all directional antenna patterns*
- Check base current readings for day/night towers. Ratio.*
- Clean backup transmitter
- Place backup transmitter on air and clean main transmitter.
E. Check all licenses and authorizations for accuracy. Make sure that all renewal cards etc are in public file and are posted at control point.*
F. Visit site, Check following
- Complete 1 through 5 under Bi-yearly maintenance
- Equipment performance measurements (NRSC, Harmonics, frequency)*
- Complete service of generator
- Complete Inspection of towers, check for vertical and plumb, check guy wire tensions, retension as needed.
- Check property for anything out of the ordinary
- Repair driveway as needed
General maintenance that is completed on an as needed basis
- Re-fill fuel generator fuel tank when drops below 50 percent
- Empty trash, sweep floors, dust.
- Cut/remove vegetation inside tower fences, spray herbicide as needed
- Water proof tower fences every 2 years
- Paint exterior of building
- Replace tower lights*
- Paint towers*
*These are FCC inspection items, pay close attention if you do not want a fine.
That is it, a .pdf version of this file can be downloaded here.
Community radio station WOVV signing on:
They are not there yet, according to their web site, anticipated sign on is not until spring of 2010.
Remember when all radio stations were community radio stations? The CNN report now calls this “old-style radio.” It is sort of funny how these little radio stations, built mostly by volunteers with donated money, get it. A radio station is supposed to be about community service. It is sad that broadcasters with both the means and methods to reach these isolated people have ignored them. Because, you know, there is very little money in community service.