[TenTec] Station setup

[Stuart Rohre]

To all,
Yes it matters.
It is always a good idea to keep all instruction manuals and sheets and keep
them in a folder near the station operating position for just such
references.  Once you get everything set up in a given station, make a block
diagram of how everything is connected and how long each coax jumper is,
etc. Put that in your log or the instructions folder(s).  Never know when
you might need to reconfigure to clean behind the desk, etc.  and this will
save invaluable time that you could be operating.

Now, ALL SWR power meters commonly on the market today, and in the past have
been spec'd for 50 ohms in and out, or 72 ohms in and out.  In other words,
it expects to be between the 50 ohm transmitter output and the 50 ohm input
side of a transmatch. (Or two equal impedance points which the name "SWR
bridge" implies, as most bridges are equal height at the ends, or nearly
so.) When the transmatch is tuned properly, then you have minimum swr, and
50 ohms equivalent at the input of the transmatch showing lowest swr on the
meter.  When the transmatch is not properly tuned you have some mismatched
impedance at the input, and high indicated swr.  You will not get accurate
readings on the output side of the transmatch, for it will be some complex
impedance making a step between the transmatch circuit and the combination
of antenna and feedline, which will likely include not an exact match at the
antenna end.  Thus, readings of swr at this dynamic and changing point as
frequency is varied would not be accurate, and might at worst give you wrong
settings of the transmatch to match the transmitter.

73, Stuart K5KVH



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