Ramsey Electronics FM25A Assembly And Instruction Manual - page 23
FM25A
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Here are the primary "dos and don'ts" picked from the current FCC Rules, as of
May, 1990. This is only a brief look at the rules and should not be construed to
be the absolute complete legal interpretation! It is up to you to operate within
the proper FCC rules and Ramsey Electronics, Inc. cannot be held responsible
for any violation thereof.
1. In the past, no "two-way communications" use of the 88-108 MHz FM
broadcast band was permitted.This prohibition does not appear in the cur-
rent edition of Part 15. Previous editions of Part 15 discussed "wireless mi-
crophones" (such as Ramsey FM-1, FM-4, etc.), while the June 23, 1989,
revision eliminates this discussion in favor of more detail regarding com-
puter and TV peripherals and other modern electronic conveniences. How-
ever, it is not immediately clear that the 1989 revision of the FCC Rules
Part 15 necessarily "cancels" previous regulations. Laws and rules tend to
remain in force unless they are specifically repealed. Also, FCC Rule 15.37
discusses "Transitional Provisions for Compliance with the Rules," and
states in item (c): "There are no restrictions on the operation or marketing
of equipment complying with the regulations in effect prior to June 23,
1989."
2. It is the sole responsibility of the builder-user of any FM broadcast-band
device to research and fully avoid any and all interference to licensed FM
broadcast transmission and reception. This instruction manual gives you
practical advice on how to do a good job of finding a clear frequency, if one
is available.
3. For some frequency bands, the FCC sets 100 milliwatts (0.1 watt) as the
maximum permitted power output for unlicensed, home-built transmitting
devices, and that the combined length of your antenna and feedline
(coaxial cable or other) must not exceed 10 feet. The technical standards
for 88-108 MHz are very different, primarily concerned with band width and
RF field strength.
4. FCC Rules do not differ for "stereo" or "monaural" transmissions.
5. Broadcasting on the grounds of a school (AM emissions only) is specifically
permitted and encouraged between 525 and 1705 KHz under Part 15.221.
Use our AM-1 AM radio broadcast kit for this use.
6. FCC Rule No. 15.239 specifically addresses operation in the 88-108 MHz
FM broadcast band for which your FM25A transmitter kit is designed. How-
ever, this Rule does not, by itself, tell you everything you need to know
about using a device of this kind. Therefore, we are noting a series of Part
15 regulations which should be observed:
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a. The "bandwidth" of your transmission is limited to 200 KHz, centered on
the actual operating frequency. Since 200 KHz is enough spectrum space
for several different FM stations, this is a "generous" limitation designed to
accommodate cruder FM devices. Properly built and adjusted, the FM25A