Hi Julian,

you have it correct. Dual messages are also used for compound callsigns, in that case the "Prefer Type 1 Messages" is not relevant.

73
Bill
G4WJS.

On 07/04/2021 13:40, Julian wrote:

Ok, thanks.

Does that mean that if you tick the type 1 box, it will only send a callsign/4 digit locator and power, whether or not you enter a 6 digit locator in the settings box?

Presumably, if it only sends 4 digit locators, the distance will be to the centre of the IO80 square?

Is the "preferred type 1" actually a mandatory instruction to use type 1 then, or are there circumstances where it can still do otherwise?

Julian, G3YGF

On 06/04/2021 21:01, Bill Somerville wrote:

On 06/04/2021 20:16, Julian wrote:

Can someone please explain the significance of the callsigns being in <angle brackets>, the Locator getting truncated when the callsign is not in angle brackets, and the distance alternating, (58km is the correct one) on every alternate period on wsjt and FST4W 120/300?

I can't see any explanation in the manual...

Hi Julian,

if a user enters a 6 character gridlocator into WSJT-X then the 50-bit WSPR payload cannot covey that extra information, instead the single message WSPR format is switched to a dual message format where the callsign, 4 character gridsquare, and transmitter power are sent in the first, and a hash code representing the callsign, the 6 character gridlocator, and the power are sent in the second. So long as you have received the first message at some point, the hash code in the second message will be translated back to a callsign. The angle brackets tell you that the call was not in the message received.

If you have entered a 6 character gridslocator into WSJT-X but do not want to send the two message protocol then you can check the "Prefer Type 1 messages" option, as you have done.

73
Bill
G4WJS.