WATERTOWN, N.Y. — Over the
past three years, we knew WFRY(FM)’s main transmitter was on its last legs and
would need replacement. Last spring that moment occurred.
WFRY requires a TPO of 24.5 kW and we had reviewed several
transmitters of several manufacturers, both tube and solid-state.
WFRY does not operate HD Radio, and it is not being
considered for the foreseeable future, even though this was an option with most
units. Watertown, N.Y, is a modest
market and even though WFRY is the top-ranked station, budgetary considerations
were the primary concern.
Solid-state FM transmitters were substantially more
expensive and there are questions about future semiconductor parts
Broadcast Electronics’ quote for an FM-25T tube transmitter was
competitive. WFRY’s sister station WCIZ(FM) has operated since 1986 with a Broadcast
Electronics FM-3.5A transmitter that has been reliable. This gave us confidence
that the cost of ownership of the BE FM-25T would be reasonable too.
Another plus was that the power supply cabinet could be
separated from the control/IPA and final PA cabinets. Our building dimensions
required this capability. The FM25T uses a 4CX20000A final PA tube with a
modular solid-state IPA driver. Interestingly, the FM-25T is basically the same
transmitter as BE’s larger FM-30T and FM-35T models. It was reassuring to know
that our transmitter would be running with a comfortable design margin.
Our FM-25T was delivered within 30 days of our order. BE
specs each of the two cabinet assemblies at approximately 1,800 pounds. There
were several pallets. A forklift enabled delivery just inside our building and
then into place. The externally-mounted low-pass filter and several other parts
were packed separately. The cabinets are all 31.5 inches deep and 70 inches
tall. The PA/driver/control cabinet is approximately 57 inches wide, while the
power supply comes in at 34.5 inches wide.
We realized that the output network of the BE design
requires a frequency determined length of vertical line at the transmitter
output. And we made sure there was enough ceiling clearance!
The transmitter assembly and hookup were uneventful. All interconnecting
wiring was well-tagged and the manual and installation instructions clear. The
power supply to PA cabinet connection required a 1-inch metallic conduit. We
hired a local electrician to do the AC hookup and install the conduit for us.
The 4CX20000, driver module installation and interconnection
hookup were easy and straightforward. The remote interface connections are all
conveniently located and should work well with most remote control units. When
powered on, the transmitter tuned up easily to the required TPO.
The FM-25T has automatic power control and auto-restart on
power failure features that save remote control programming. Status lights are
provided for major items and metering is adequate.
The power supply cabinet is passively ventilated. Both the
PA and IPA cabinets have blowers with high-quality air filters. The only “problem”
we had with the transmitter was due to our relatively small building and
high-capacity air conditioning system. The air-flow sensor in the transmitter is
extremely sensitive, using a set of air hoses and a diaphragm switch to insure
proper cabinet pressures. Our building pressure changes caused intermittent air-interlock
trips. BE helped us diagnose this and sent us a new pressure switch. The air
filters must be kept very clean, which is good maintenance practice anyway.
Overall, we have been very happy with our new Broadcast
Michael F. Ring, CE is chief engineer with Stephens Media Group station WFRY(FM), WCIZ(FM), WTNY(AM) and WNER(AM).
For information, contact Tim Bealor at Broadcast Electronics
in Illinois at (217) 224-9600 or visit www.bdcast.com.