Technical information
Table Of Contents
- GoMobile Cover
- SGC – The SSB People
- Go Mobile at 500 Watts
- T a b l e o f C o n t e n t s
- I n t r o d u c t i o n
- C h a p t e r 1 C h a n g e s i n M o b i l e R a d i o
- C h a p t e r 2 O r i e n t i n g Y o u r s e l f t o 5 0 0 W a t t s
- C h a p t e r 3 DCP o w e r S u p p l y S y s t e m f o r a M o b i l e I n s t a l l a t i o n
- C h a p t e r 4 A n t e n n a s a n d G r o u n d s
- C h a p t e r 5 N o i s e S u p p r e s s i o n a n d S h o c k -M o u n t i n g
- C h a p t e r 6 I n s t a l l a t i o n P r o c e d u r e s
- C h a p t e r 7 I n s t a l l a t i o n V a r i a b l e s
- C h a p t e r 8 G o i n g M o b i l e a t 1 5 0 W a t t s
- Appendix A — QMS S y s t e m
- A p p e n d i x B — S e l e c t i o n o f E q u i p m e n t
- A p p e n d i x C — T e s t D a t a
- It all Adds Up
Noise Suppression
and Shock Mounting
Noise Sources
Three kinds of vehicle noise may be encountered:
ground/static noise (eliminated by following proper ground-
ing procedures in Chapter 4); engine noise; and accessory
noise.
Engine noise. Ignition noise is a principal source of elec-
tronic noise.
Diesel engines: Diesel engines do not make ignition noise,
having no high voltage spark plugs (perfect for mobile
radio). However, even in diesel-powered vehicles, engine-
related noise can come from the generator or alternator.
To eliminate a good deal of vehicle engine-related noise, it is
good engineering practice to install RF by-pass capacitors at
the battery and across the alternator terminals. The capaci-
tor doesn’t need to be especially large: .01 to .1 micro Farad
disk ceramic capacitors with a working voltage of 100 V will
do just fine. We recommend the use of non-polarized capaci-
tors: these are simpler to install because polarity may be
ignored.
Gasoline engines: Gasoline- or natural-gas-powered vehi-
cles have high voltage wiring for ignition spark plugs, which
causes a small amount of radio frequency energy to be
transmitted each time a cylinder fires. For example, an
eight-cylinder car running at 3,000 RPM, emits 12,000 little
sparks every minute. Four cylinder cars emit 6,000 sparks at
the same RPM.
The noisiest wire in the vehicle is the lead from the ignition
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© 1997 SGC Inc.
Chapter 5