View Single Post
  #15   Report Post  
Old April 1st 10, 02:15 PM posted to rec.radio.shortwave
dave dave is offline
external usenet poster
 
First recorded activity by RadioBanter: Jan 2009
Posts: 5,185
Default Grundig 750 or Grundig G3

Geoffrey S. Mendelson wrote:
Bob Dobbs wrote:
When there is audio (modulation) present, there most certainly is a carrier,
otherwise it's suppressed and therefore problematic for sync-det.
If someone were to modulate their SSB signal with anything close to a steady
tone the sync-det could possibly get a lock.
note* - there isn't a way to engage the sync-det in either of the SSB modes on
the only radio I have that has it.


No. Most ham rigs made since 1980 don't actually produce an AM signal, they
produce a double sideband reduced carrier signal. Ham rigs produce a signal
by taking an AM signal and running it through a filter to remove
the carrier and the other sideband.

Their "AM" mode signal is made by recombining the the upper and lower sideband
signals, with only a tiny residual carrier.

Most AM receivers can receive this signal, but there is no carrier to lock
on to, so I doubt that a sync detector can lock onto them.

Geoff.



My last 2 transceivers have used DSP chips to produce various forms of
modulation.