[AMRadio] Telephone line bandwidth for AM Phone Patch


Jim candela jcandela at prodigy.net
Tue May 20 23:35:55 EDT 2003


	All,

	This is a little off subject, but just a little. Sometimes when we
use a phone patch on AM, we can get better results matching phone line
impedances, and maybe a little lead, or lag to help equalize (or add
pre-emphasis) to the available bandwidth. I am sure this was studied years
ago when professional baseball games were broadcast from the announcer's
booth, and then piped for hundred's of miles down telephone lines, and then
using the remoted audio to modulate broadcast AM transmitters. 
	This all occurred to me today when I made my house DSL ready. Four
lines (with a common beginning) now each have a DSL filter at the end before
going into a telephone, or modem. I have NEVER been able to connect to the
internet at a rate higher than 28.8 Kbs. Today after installing DSL filters
(including one at the computer modem), my connection is 48.8 kbs!!!! I just
might cancel the DSL which starts tomorrow, and keep the filters. So what
technology is in use with these filters? How do they apparently result in
improved connection speeds? Is it terminating the line in it's
characteristic impedance, or increasing the longitudinal balance? 

	Remember the answers to these questions need to be discussed in a
manner that will help us AM hams have more fidelity when we remote our
stations, or use a phone patch, or download the AMRADIO reflector's email.

Regards,
Jim candela
WD5JKO













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