Ramsey Electronics FM10A User Manual

Page 13

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FM10A frequency range selection

Capacitor C16 sets the frequency range of the FM10A. Values for C16 are
as follows:

Desired Transmitter Frequency Range C16 Value

Lower end of FM band ..........(88-94 MHz) .... 27 pf
Middle portion of FM band ...(91-100 MHz) ... 22 pf
High end of FM band ...........(95-108 MHz) ... 18 pf

If you are not sure "where" you wish to place your FM transmitter in the FM
band, we suggest you solder an initial "trial" C16 capacitor with a small
amount of lead-length to spare, so that it is easy to salvage and replace.
This will enable you to properly test your FM10A and then at a later point,
you may change C16 as desired.

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49. Install C16, either: 18, 22 or 27 pf.



CHOOSING AN OPERATING FREQUENCY

[A] It really is NOT sufficient to just "check" the FM band for an empty
frequency, using the FM portable radio closest at hand. It is your
responsibility to carefully research what FM stations can be listened to with a
good system within the transmitting range of your FM10A. This is especially
important in the low end of the FM broadcast band (88-92 MHz), where there
are numerous medium power National Public Radio stations perhaps outside
your own town, but which your neighbors may enjoy receiving, using a good
receiver and outdoor antenna. Interfering with such reception is a direct
violation of federal law. The most reliable way of finding a truly open
frequency on the FM band is to check the band with a very good FM
receiving system using an external antenna. If you do not have access to
such a radio, most modern car radios (with exterior antenna) are very
sensitive and usable to help you know what stations your neighbors really
can be receiving on a particular frequency.

[B] In choosing an operating frequency, remember that most "digital-tuning"
receivers, whether portable, mobile or hi-fi, are designed to tune in 200 KHz
increments and therefore might not receive well a signal operating between
these pre-tuned standard broadcasting frequencies. In order to comply with
Part 15 of FCC regulations, it is your responsibility to determine carefully that
your operation will not cause interference to broadcast reception. Please
study Appendix A of this manual before using your FM10A.

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