Topband: Feeding multiple beverages

[Tom Rauch]

> I have been able to get away with
> using a common ground system and
> match transformers for multiple
> beverages emanating from one point.
> (I switch on the high-Z side).

My dislike for doing that comes from years of measuring relays and 
switching systems. I think people would be amazed at how poor some 
relays are, and some layouts.

While a reasonable RF layout will minimize crosstalk, it is far too 
easy for people who do not work with RF to miss something. 

The bad part is unless we measure the system in a controlled 
environment, we might not be aware of any problems magnitude.

Better to be safe in a case like this, because the cost and time 
difference and inconvenience between low Z switching and high Z 
switching is minimal, plus it helps make sure common grounds are 
avoided. Too many who work in RF daily do not understand RF layouts, 
let alone casual builders.

Metal poles, mistermination, sloping wire ends, and other things we 
needlessly worry about are immeasurable in the final results but 
crosstalk, common mode, and ground loops are well documented and 
easily measurable and calculated.73, Tom W8JI
W8JI@contesting.com