T&T: Fwd: dsc radio

[Peter Bennett]

I expect that this would only occur with SC-101 type radios, as these
have a single receiver that scans between Ch 70 and your selected
channel.  However, it is, in my opinion, not likely to be a
significant problem, as a DSC transmission will be very short. It
would only be a problem if there is a continuous signal (like the
mentioned signal generator, or an open mic on Ch70 from a non-DSC
radio).  It is probably something that owners of SC-101 radios should
be aware of, but shouldn't cause great concern.

Class D DSC radios have a separate channel 70 receiver, so this
problem won't occur with them.

Some (many? most?) SC-101 receivers have a menu selection to turn off
the Ch 70 scan - a friend's came with the scanning turned off, and we
wondered why he couldn't receive my DSC calls, until he read the book,
then checked the setting.

Saturday, March 10, 2007, 11:57:15 PM, PrncessKHY wrote:

Pac> Okay....this is shamelessly stolen from Latitude 38's March  
Pac> letters.....don't recall this being addressed on our forum?
Pac> Anyone care to  comment???  (If 
Pac> I've missed some exchanges and this is passe, please  forgive, and beatings
Pac> shall begin at daybreak).
 
Pac> Seriously, tho, depending on the circumstances, the consequences could be
Pac> dire.....would appreciate the collective wisdom of the group....

Pac> Kathy Youngblood
Pac> m/v Mystic Moon, Selene 53

Pac> DSC SIGNALS INTERRUPT RADIO  TRANSMISSIONS
Pac> In my opinion, your new DSC marine radio may be a can of  worms. In many DSC
Pac> radios, the DSC signals will interrupt voice operation of  the radio. These
Pac> signals can't be heard, but if there are a lot of them, they  can make the DSC
Pac> radio unusable for voice communications. In cases of critical  construction or
Pac> ship docking, captains should not activate the DSC function of  their radios.
Pac> A radio technician can check your DSC radio with an RF  signal generator. The
Pac> DSC functions are enabled in the radio by installing the  MMSI number. Put
Pac> your radio on an active weather channel, and then have the  radio tech generate
Pac> an RF signal on 156.525 MHz. If this signal turns off your  weather channel
Pac> reception, you have a problem DSC radio. This radio can be  disabled at any time
Pac> by DSC activity or other signals without your knowing  it.

Pac> Guntis Ositis
Pac> Ositis  Communications
Pac> Orinda


-- 
Peter Bennett, VE7CEI    Vancouver, B.C., Canada
Lien Hwa 28 (AKA Polaris 30) "Sea Spray"
GPS and NMEA info: http://vancouver-webpages.com/peter 
Vancouver Power Squadron: http://vancouver.powersquadron.ca