[BC] AM Air Quality

[Dave Hultsman]

Good comment Kyle
 
I recall a small local AM station on 1490 in Texas, was located about two miles from their transmitter site. I was always impressed  with two things they had.   Their Air monitor sounded as good as the audio going out and they had a remote control system that had four meters that operated all the time.  Plate Voltage, Plate current, Remote Base Current and Modulation were all visible simultaneously. Their audio was from a Millen or Misner solid state HI-Fi crystal radio that was available from Allied Radio or any supplier.  Used No AC except for a audio line amp.  It was tuned to the AM frequency with a 15 foot outside antenna.  The remote control was homemade and used about five pairs on phone lines. Everything was metered to ground. The had high power & low power , raise/lower and off for control.  The lines were cheap since it was only two miles.
 
Dave
 
In a message dated 11/24/2010 1:15:31 A.M. Central Standard Time, kyle at circuitwerkes.com writes:
>In fact, simple crystal sets are quite hi-fi.   But they lack both sensitivity
>and selectivity.  Getting good audio performance while keeping the sensitivity
>and selectivity added cost.   Starting with the first pocket transistor radios of
>the 1950s, the push was on to build cheaper radios, not bettter ones.   When
>FM became a desirable addition to radios, it could be added cheaply and still
>sound good, whereas AM used tight IFs to get the sensitivity and selectivity up. 
>If the IFs are loose, then more stages are required leading to higher manufacturing
>costs.