How to Listen to Duplex Marine?

[Forly192]

On the Uniden BC125AT, how does one listen to duplex frequencies when the ship and shore frequencies are different?

Is there a way to program the two matching frequencies into the scanner?

Thanks.

 

[marksmith]

Not really.

However, when I monitor marine traffic, I usually have little or no delay programmed, and also just scan the marine channels.

I find that doing these two things let the speed of the scanner do its job to increase the odds you will follow a duplex conversation, most of which are ship to shore calls.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[ecps92]

Yes - program them in two different channels

Depending on where [pls update your profile] there is actually LITTLE or LOTS of use of the Duplex Channels.

Here in the US of A - little use, except for the ole Marine Radio Operators which are now Automated Radio Check Systems, or a few VHF 20 Repeaters

On the Uniden BC125AT, how does one listen to duplex frequencies when the ship and shore frequencies are different?

Is there a way to program the two matching frequencies into the scanner?

Thanks.

 

[majoco]

most of which are ship to shore calls.

How come scanners and receivers are "cell phone blocked" in the USof A but not the marine telephone frequencies? Hope no-one wants to put a feed onto the internet or else scanners will be "marine VHF blocked" too!

 

[marksmith]

I think there are vhf marine feeds some places. Most don't monitor stuff like duplex marine ship to shore, but USCG and the main lower marine operating frequencies.

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others

 

[ecps92]

With the advent of Cellular and now everyone having Smartphones, the use of a Marine Operator [Patch] has been long retired. Atleast here in the US of A, those channels have been re-allocated for other Maritime purposes

And we won't go down that Rabbit Hole as feeds were not the cause of Cellular being Blocked, which is a DEAD issue anyway since they are no longer Analog

How come scanners and receivers are "cell phone blocked" in the USof A but not the marine telephone frequencies? Hope no-one wants to put a feed onto the internet or else scanners will be "marine VHF blocked" too!

 

[majoco]

True Duplex? Where both people can talk at the same time and be heard simultaneously at the other end? The only way I can think of is two radios, one for each frequency - unless you've got lots of money for a WinRadio G39DDCe where you can listen to two frequencies at once.

 

[n4jri]

True Duplex? Where both people can talk at the same time and be heard simultaneously at the other end? The only way I can think of is two radios, one for each frequency - unless you've got lots of money for a WinRadio G39DDCe where you can listen to two frequencies at once.

I think you're referring to 'full duplex' which is not taking place with marine radios AFAIK. What actually takes place is usually referred to as 'half-duplex' (each person transmits on a different freq, but no one can hear while transmitting). In older books, I can remember it being referred to as 'two frequency simplex.'

Here in Virginia, I don't know of any duplex except SeaTows automated radio checks on Ch-20 in Norfolk.

Most of the older 'public correspondence' channel pairs have been leased here to the Virginia State Police for use in its VHF P25 trunked system inland. I usually have to lock out the 'B' channels to avoid hearing STARS when I'm scanning marine.

As Bill described, you can listen to them by scanning both freqs (or the whole band including them) with your delay turned off. Works fine. I do it all the time in other applications.

73/Allen (N4JRI)