TIP: Click on subject to list as thread! ANSI
echo: scanners
to: RALPH MOWERY
from: ROBERT FORTUNE
date: 1996-08-19 10:12:00
subject: Impedance Mismatch

SH>is just a 300-->75 transofrmer and I'm inputting the 75Ohm into
SH>my scanner..  Does feeding the 75 Ohm input into the 50Ohm scanner
SH>input really make "that much" of a difference or is the difference
SH>pretty much minimul almost non-existant?   One last question..
RM>Antenna impedance is the stated value only over a range of frequencies
RM>the antenna is designed for .  When you use the FM antenna outside the
RM>range of about 88 to 100 mhz it will no longer be 300 ohms and probably
RM>not 300 even over that large of range.  For receiving, it usually makes
RM>no noticable difference to many users.  There is just too large of a
RM>frequency range to hold the given value.  I would try using a 75 to 300
RM>ohm balun mainly because it converts the twinlead to coaxial cable.  You
RM>probably won't notice much difference if you just connected directly.
   Ralph,
   If you attach a 75 ohm antenna to a handheld scanner's 50 ohm antenna
   connection, will doing so cause damage to the scanner? TIA
- Robert Fortune
 * OLX 2.1 TD * My mind is made up. Don't confuse me with the facts!
--- Maximus/2 3.01
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