Filing an STA

FCC rules stipulate that when a station is operating at a variance from its licensed parameters for more than 10 days, Special Temporary Authority (STA) is required.  The reasons for requesting an STA are varied but could include things like:

  • Damaged transmission equipment
  • Loss of transmitter site or building use
  • Loss of tower
  • Eviction
  • Facilities upgrade or renovation
  • Natural disaster

The loss of transmission tower at WUPE-FM falls into one of those broad categories.  Thus, we have filed a STA with the FCC for temporary transmission facilities while a new tower is being constructed.  Since the old tower is completely lost, we specified a new tower location, new height above average terrain (HAAT), new ERP and environmental certification.  To gather that information, several steps were needed:

  • Obtain new tower location.  This was done with a GPS receiver and verified on itouchmap.com.  Once the NAD83 position was obtained, it needed to be converted to NAD27 for the FCC filing.  The FCC has a conversion tool on their website.
  • HAAT calculation is fairly simple, use the HAAT calculator tool on the FCC website.  For this, the antenna radiation center height Above Mean Sea Level (AMSL) is needed.  Using a topographical map, find the ground level AMSL, convert it to meters, then add the radiation center height above ground level (AGL).
  • The Effective Radiated Power (ERP) calculation is also simple; Transmitter Power Output (TPO) minus system losses (transmission line and antenna gain). It is easiest to do this in dBm, e.g. convert the TPO from Watts to dBm, then add or subtract the gain or losses in dB, convert the final product back to Watts.
  • The environmental statement is slightly more tricky.  Basically, the filer is certifying that the STA complies with all environmental regulations including OET-65 (RF exposure limits).  Since the temporary antenna is significantly lower than the original, some investigation is required.  For this, there are two methods to demonstrate compliance; ground measurements with a NARDA meter, or RFR worksheets which are a part of the broadcast station renewal form, FCC-303s.

I have taken the RF worksheet sections out of the 303s and separated them into the FM RF Worksheet and the AM RF Worksheet.  These worksheets are not effective for large tower farm type sites where there are too many variables and RF contributors to be accounted for.  The calculations on the worksheets are not conclusive, however, if the facility in question falls under the limits, it is generally accepted as being in compliance.   Taking ground measurements with a NARDA meter is the definitive method for determining RFR compliance.  Since this is a relatively simple site, the worksheet calculations should be sufficient.

The worksheet calculations show that the RFR is with in both the controlled occupations limits and the uncontrolled general population limits.

WUPE-FM temporary antenna RFR worksheet
WUPE-FM temporary antenna RFR worksheet

The position of the new temporary pole verified on itouchmap.com:

itouch_nadams

It is never good to be operating at a varience from licensed parameters without notification of the FCC. Such things could lead to fine or other problems for the broadcaster.

WMHT’s former analog transmitter

During the digital TV conversion in the US, all broadcast television stations installed new transmitting equipment and antennas.  Most stations ended up on a different frequency than their original analog channel.  In Albany, New York, all of the TV stations moved to a common transmitter site and installed their antennas on a single tower.

home of WRGB, WTEN, WNYT, WXXA, WMHT, and WCWN
Albany DTV tower, home of WRGB, WTEN, WNYT, WXXA, WMHT, and WCWN

For more on the Albany DTV site, check out the NECRAT page: www.necrat.us/albdtv.html

So, what happened to the old Analog TV sites in Albany?

For the most part, after the analog turn off on June 12, 2009, the sites have sat empty.  Such is the case with the former WMHT site.

Sign outside of former WMHT transmitter building
Sign outside of former WMHT transmitter building

This old sign about sums up the end of analog television.

Former WMHT Comark analog transmitter
Former WMHT Comark analog transmitter
Former WMHT analog transmitter wide shot
Former WMHT analog transmitter wide shot
Former WMHT operator position
Former WMHT operator position

The former transmitter operator desk. Maintenance log is still open. From the looks of things, they opened the circuit breakers and walked away. Everything remains intact from the antenna to the klystrons and exciters. It does appear that the coolant has been drained from the system. Other than that, it seems like the whole thing could be restarted with minimal effort.

Former WMHT Onan DFN 350 backup generator
Former WMHT Onan DFN 350 backup generator

There were two Onan DFN 350 backup generators. With a TV transmitters, it is vitally important to run the cooling system after shutdown. The idea here is that both generators in parallel could run the whole station, if one generator failed, then the cooling system would still run and cool the klystrons.

Former WMHT site kitchen
Former WMHT site kitchen
Former WMHT tower, wave guide and WVCR antenna
Former WMHT tower, wave guide and WVCR antenna

The former WMHT tower, which currently holds the WVCR-FM, WXL-34 (NOAA weather radio), and W44CT-D (Three Angles Broadcasting) Low power TV transmitter.

Current site occupants; WVCR-FM and W44CT-D
Current site occupants; WVCR-FM and W44CT-D

These equipment racks and the NOAA weather radio transmitter in the other room are the only active equipment at this site.

WMHT-TV Chanel 17 (488-494 MHz) signed on 1962 from this site.  The Comark transmitter was installed in 1984.  The station’s analog ERP was 2000 KW visual, 200 KW aural.

It is an interesting site.

Decomissioning a NEXTEL site

Remember when “NEXTEL (b-b-b-beep), how business gets done…” Well, not anymore. NEXTEL was purchased by Sprint in 2005 and their product lines were combined.  Thus, all of these old NEXTEL sites have become redundant and switched off.  This particular site was co-located with one of our FM radio clients, which required a power reduction while the old equipment was removed from the tower.  I took the time to grab a few pictures of the process:

Former NEXTEL communications equipment room
Former NEXTEL communications equipment room

All of the equipment was removed from the equipment shelter. This site has been switched off since June of 2013 and everything in it is destined for the scrap yard.  This equipment worked on the 800 MHz band, which has been re-purposed for Public Safety and Critical Infrastructure, e.g. government users.  These racks and radios look like they were expensive:

NEXTEL equipment racks and radios
NEXTEL equipment racks and radios

Speaking of expensive, this site had over 4,500 feet (1,370 meters) of 1 5/8 inch foam coax, which was cut up and scrapped.  At today’s prices, that cost $13.25 per foot.

Scrapped transmission line
Scrapped transmission line

The tower was rigged:

Rigging tower to remove antennas
Rigging tower to remove antennas

Each of the three panel sector mounts were removed and lowered to the ground.

Dropping cellular panel antennas
Dropping cellular panel antennas

The NEXTEL antennas were mounted at the 260 foot (80 meter) level of a 395 foot (120 meter) tower. It took some time to remove all of the antennas and equipment from the tower.

Cellular panel antenna array being removed from a tower
Cellular panel antenna array being removed from a tower

I looked on the Sprint website and could not determine if they still offer a push to talk service option (direct talk).  With all of the communications options available today, I do not expect there would be much call for it.

For old times sake, here is an old NEXTEL commercial from many years ago:

They did have a good marketing department…

The PIROD PRLC-A tower lighting controller

PIROD tower company has been around for a while, thus there are likely many of these tower light controllers out in the field.  They perform a vital service in controlling and monitoring tower lights at remote transmitter sites maintaining a safe operating environment for aircraft and compliance with FCC rules.

PIROD was sold to Valmont in 2004, Valmont no longer manufactures or supports the product.  All is not lost, however, as XCEL Tower Controls does support it and parts are still available through them.

These units were fairly rugged, had good surge suppression on the incoming AC lines and are designed for easy access to service parts.

PIROD PRLCA tower light controller, WRKI Brookfield, CT
PIROD PRLCA tower light controller, WRKI Brookfield, CT

This particular controller is being installed at WRKI in Brookfield, CT.  We are adding toroid cores to the tower lighting circuits coming off of the tower because the last controller has been mostly destroyed by lightning.  It is a tall tower, on top of a tall hill, thus it gets struck by lightning many times over the course of a year.

WRKI tower, Brookfield, CT
WRKI tower, Brookfield, CT

The block diagram looks like this:

PIROD PRLCA block diagram
PIROD PRLCA block diagram

Click for higher resolution.

The basic schematic looks like this:

PRCLA tower light controller schematic
PRCLA tower light controller schematic

Click for higher resolution.

The entire manual can be found here, (medium sized .pdf) courtesy of John Brickley of EXEL tower controllers.