Topband: Loud clicks -- Hot Switching

[GEORGE WALLNER]

G'day TopBanders,

Hot switching -- or delayed PA RX/TX switching -- is a far 
more common problem than is generally realized.

During a recent DXpedition I heard a lot of stations and a 
significant percentage of them had some problem with their 
PA RX/TX switch. At the RX end problem manifests itself in 
the truncation or omission of the first dot of the 
call-sing's leading character. After a while you learn 
that OA1xxx is really JA1xxx, M0xx is really W0xx, NA3xx 
is really RA3xx, and so on. Many of them probably had T/R 
switching problems. (There have been some claims that the 
AGC of the K3 can cause the leading leading dot become 
inaudible. Maybe so, but I heard the same phenomena on an 
Icom 746, which has a conventional AGC.)

The problem is hard to detect by listening to one's own 
signal. From close up 100W sounds the same as 1000W. I 
recommend that if you use an amplifier, you should check 
your signal with an oscilloscope.

George, AA7JV