Dc Power Supply Considerations - Ramsey Electronics FX-440 Manual

DC POWER SUPPLY CONSIDERATIONS
Your Ramsey FM Transceiver is designed to operate from any stable DC
voltage source in the 12 to 15 volt range, from typical car, boat or plane
12V systems to a wide variety of battery packs or AC-P9wered DC
sources. In a pinch, you can get on the air for quite a while with 8 to 1
O
ordinary "D" cells! Our lab tests show only a
.93
amp current draw for
3
watts of RF output. We have just a few points of advice and caution:
1. Your DC supply should be able to provide a minimum of 1.0
amperes
in
continuous service.
2. Any battery setup capable of supplying 12-1 SVDC will serve
quite well.
3. Use of wall plug power supplies is NOT recommended.
Obviously, 12VAC output is not suitable. Most DC output
units do not have adequate voltage regulation.
4. Turn your transceiver OFF before re-starting the vehicle in
which it has been installed.
5. Replace F1 only with a 1 amp fuse.
6. If you power your transceiver from the
+
12V accessory
voltage available from other equipment, be sure that
source is rated for the 1 amp required.
7. Your transceiver circuit includes noise suppression at the DC
input and additional filtering at the VCO, primarily to
prevent ignition/alternator noise from bein9 introduced into
the FM modulation. If you hear ignition noise in the
receiver, the vehicle has a serious general problem.
Check your transmitted signal on another receiver before
mobile operation. Radio Shack sells a variety of
noise-suppression capacitors and chokes. The ultimate
solution, which has been tested, is to run the transceiver
from a smaller accessory battery.
If you plan to build a power supply for fixed-station use, there are
numerous construction articles in ham and electronics hobby
publications. A convenient new book featuring easy-to-find components
and clear explanations is Building Power Supplies (Radio Shack
276-5025.)
FX-440 Ref. 9