[AMRadio] Thermocouple rf ammeter

John Lawson jpl15 at panix.com
Sat Feb 10 11:07:49 EST 2007

   The only 'drawback' to the internal-TC RF ammeters, is that the meter 
must be physically near the feedline, or whatever source of RF you're 

   At low and medium power HF frequencies, this usually isn't a big 
problem, but as powers and freqs go up - it becomes more and mmore of a 
consideration - also, in the event of significant transient meteorological 
electrical events - read 'lightning strike' - the cool little RF ammeter 
is going to be your "fuse"...

   Also - inserting one meter in a balanced line is going to unbalance it 
by some (probably slight) amount.

   That's the one thing I didn't like about the MFJ - it's got four binding 
posts on the back, and has to sit in the feedline - which, 450-ohm 
hard-drawn copper stranded wire - is not that easy to arrange.



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