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[AMPS] Tuners

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Subject: [AMPS] Tuners
From: (David L. Thompson)
Date: Thu, 12 Mar 1998 18:13:22 -0500 (EST)
The N4XM Xmatch is about the only tuner that will match the legal limit on
160 and 80 without getting hot.  It is expensive but look at the price of
the IC781 or the Alpha 87A.  If you are gonna spend the money for that type
of heavy iron then the Xmatch is your tuner.

All the other tuners work OK below 160 but you gotta be careful with very
high capacitive or inductive reactance...or else you will see a big arc and
smoke.  Even the big MFJ arced with 900W from a Clipperton L on 160.  Next
most expensive tuner is the Nye is nearly $900 now.

But at 100W you can take your pick.  Better to get the KW+ models as many of
the 100 to 300W are tricky.  I have an old Dentron Monitor JR and using an
80 full wave loop on Field day with a simple IC740 (80 to 90 w out) it will
arc.  So always tune with the lowest power available.

Why not the older Johnson Match boxes...they are 80 to 10 (no 160).  The KW
version will stand up to any current 3KW version on 80 to 10.

Only other choice is to always use antennas that have low SWR at 50 ohms so
the solid state gear won't upchuck (and maybe cut off).  Notice I said low
SWR at 50 ohms not a resonant antenna but thats another story and this is
the AMP not the antenna reflector.

Dave K4JRB 

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