locked What happens when --


w5ec
 

What happens when i double click on a CQer at 5 seconds after the start of the 15 second timer?
 My xcvr goes to transmit, but does it transmit the last 10 seconds of my call, or the first 10 seconds, or does it squeeze the full call in somehow?
What is it actually transmitting? Just curious.
Bill W5EC


Bill Somerville
 

On 18/01/2020 13:15, w5ec wrote:
What happens when i double click on a CQer at 5 seconds after the start of the 15 second timer?
 My xcvr goes to transmit, but does it transmit the last 10 seconds of my call, or the first 10 seconds, or does it squeeze the full call in somehow?
What is it actually transmitting? Just curious.
Bill W5EC
Hi Bill,

the transmitted message contains the information in the message, the error correction bits, and a checksum. These are distributed throughout the message payload, so it is not correct to say that some portion of the message only contains some portion of the information sent. At the receiving end there is a probability that the message will be decoded if up to roughly half the transmitted message is received with a reasonable signal quality. The probability of successful decoding is reduced by missing information but not by a great deal.

73
Bill
G4WJS.


Bill Somerville
 

On 18/01/2020 13:26, Bill Somerville wrote:
At the receiving end there is a probability that the message will be decoded if up to roughly half the transmitted message is received with a reasonable signal quality.
Sorry, that should say:

"At the receiving end there is a probability that the message will be decoded if roughly not less than half the transmitted message is received with a reasonable signal quality."

73
Bill
G4WJS.


w5ec
 

Thanks. That is good info.


Joe
 

Ah ha!  That explains why sometimes (often?) I get a response from a message sent to a station that I was very late clicking on (within the current transmit period).  Is the point of the hashing of the data in the packet to randomize it for some reason??

Thanks for the insight!

Joe/WQ6Q


Reino Talarmo
 

Joe,

If you by hashing mean the same as interleaving, then the reason is to distribute short QRM or QSB affects all over the transmission period as the error correction works better with single error bits than many continuous ones.

73, Reino oh3mA

 

>Is the point of the hashing of the data in the packet to randomize it for some reason??