Delay in ADSB transmission?

[BobR]

Can anybody explain why I sometimes receive aircraft on my list without a position report on the map who after a couple of minutes suddenly give me a return on the map.

I can't understand why I am not getting the ADSB data when I am getting all the other info only to then get it some minutes later?

I have noticed it a lot recently with aircraft that I know are ADSB enabled?

Cheers,

Bob

[AirNav Support]

This happens as ADS-B data is larger in terms of data and packets compared to Mode-S. Hence you can get slightly further reception of Mode-S as its less likely to have errors in the data if the data is smaller.

Usually this means you might get a Mode-S contact first with an aircraft for a 30 seconds then it becomes ADS-B and then Mode-S when it leaves your reception.

[BobR]

Thanks for the reply.