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Field strength meter
FS-3 was a field strength meter, also known as a
signal level meter (SLM),
developed and built by Sadelco
in Weehawken (New Jersey, USA) in the mid-1970s [1].
The meter was used for several decades by radio and
television engineers for adjusting antennas and measuring signal
strength in TV and CATV 1 installations. The meters were also used for
locating clandestine transmitters.
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The FS-3 is housed in a sturdy metal enclosure and measures 20 x 12 x 8 cm.
It is usually stored in a
leather carrying case
from within which
it can be operated. The device is fully self-contained,
with only the antenna connected
externally. Power is provided by internal 9V batteries, or by an external
AC mains adapter.
The FS-3 is suitable for the reception of AM and FM signals,
and has two tuners that are referred to as the LOW and HIGH band tuners.
The actual frequency range is determined by the model number.
The unit shown here is the FS-3CE.
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It is suitable for 47-230 MHz (VHF) and 470-860 MHz (UHF) and has a
separate tuning knob for each tuner. The audio from the intercepted signal
can be demodulated and monitored via a small built-in speaker. One 6dB
and three 20dB attenuators can be inserted in the antenna path, which
can be useful when handling strong signals, or when
operating it in close proximity of a station.
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In the Netherlands, the FS-3CE was used heavily during the 1970s and 80s
by the Dutch Radio Monitoring Service (RCD),
when the country was flooded by illegal CB stations 2 (27 MHz) and by so-called radio pirates, operating music stations
in the VHF FM broadcast band (100-108 MHz).
The FS-3CE was sometimes used as a portable unit,
but was also used as
part of the complete intercept and direction finding (DF) installation
shown in the image on the right. In this case, the installation is housed
in a small 19" rack, with the FS-3SE clearly visible at the bottom left [5].
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The 19" rack was placed on the passenger seat of the intercept vehicle,
in such a position that it could be operated easily by the driver, who
was also the law-enforcement officer.
For a detailed description of the remaining equipment in the rack,
please refer to our page about the RCD.
FS-3 meters are still popular today and can occasionally be found on auction
sites such as eBay. They are most useful for locating the source of local
interference and can still be used to locate a clandestine radio station
(pirate).
In the mid-1980s, the FS-3 range was succeeded by the FS-4.
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CATV = Community Access Television, or Community Antenna Television.
CATV has since become synonymous with Cable Television
➤ Wikipedia
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At that time, the use of the Citizen's Band was still illegal in the
Netherlands.
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All controls and connections of the FS-3CE are at the control panel,
and can be accessed without removing the device from its black leather
carrying case. The unit is powered by four 9V block batteries that are
installed at the rear, or alternatively by an external AC mains adapter
that can be connected to one of the sockets on the control panel.
The unit is turned ON with the switch at the top left.
An antenna should be connected to the 75Ω PL-259 socket 1
at the bottom right.
To the left of the antenna socket are four black switches, each of which
represents an attenuator. There are three 20dB attenuators an one that
does just 6dB. The red switch at the center is used to select between the
HIGH and LOW tuner, each of which has its own frequency dial.
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Some units were fitted with BNC socket at this position.
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Model
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Low tuner
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High tuner
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Remark
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FS-3
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?
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?
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FS-3C
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54-216 MHz
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470-812 MHz
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VHF & UHF
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FS-3SC
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54-216 MHz
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216-300 MHz
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VHF & Super Band
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FS-3CE
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47-230 MHz
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470-860 MHz
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European variant
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FS-3D
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?
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?
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Sadelco was founded in 1960 by Harry Sadel and became well-known for its
development and production of field strength meters,
later also known as CATV signal level meters or SLM.
The line started around 1961 with the FS-1, which was soon
followed by the FS-2 and several years later by the immensly popular
FS-3 series.
The FS-3 was available for many years in quite a few variations.
It was eventually succeeded by the FS-4 and later by digital alternatives.
Company founder Harry Sadel was born on 6 September 1920 and started
his business in Canada during the 1950s. In 1960, he moved to the
United States, where he founded Sadelco.
In 1985, on the 25th anniversary of the company, it was announced
that his son Joe Elliot (Joey) was to become director of R&D at Sadelco.
He would later become vice-president of the company [4].
Harry Sadel passed away on 11 October 2002 at the age of 82.
After 54 years in business, the company closed its doors in 2014.
Warranty and service of existing equipment and parts is taken over by
RCB Calibration LLC, a company run by former Sadelco employee Rob Bredin.
[3]
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- Sadelco
75 W. Forest Ave.
Englewood, NJ 07631
United States
Phone: 2015693323
E-mail: sales@sadelco.com
Website: www.sadelco.com
- Registered address
96 Linwood Plz
Fort Lee, NJ 07024
United States
- RCB Calibration LLC
Continued support for Sadelco meters
Phone: +1 800-569-6299
Website: www.rcbcal.com
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ADF
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Automatic Direction Finder
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AM
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Amplitude Modulation
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CATV
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Community Access Television
Also used as abbreviation for Community Antenna Television,
and later as a common expression for Cable Television.
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FM
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Frequency Modulation
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FS
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Field Strength
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RCD
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Radio Controle Dienst
Radio Monitoring Service in the Netherlands. Currently known as AT.
➤ More
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RDF
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Radio Direction Finder
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SLM
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Signal Level Meter
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UHF
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Ultra High Frequency
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VHF
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Verhy High Frequency
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© Crypto Museum. Created: Monday 12 December 2016. Last changed: Friday, 16 August 2019 - 08:49 CET.
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