A proper tank would be about 300-330 pF on the tune side (allowing for plate
choke reactance) and 2000 pF on the load. This requires 33 uH on the total
inductance.
Yaesu has way too little tank inductance and that causes the capacitance to
be excessive. This puts the Q up in the 20 range, which is not necessary.
It is possible it has an open load padding capacitor, because they are
notorious for going open, but the real fix is to correct the tank by
increasing inductance (which reduces loaded Q) so it "acts normal".
73 Tom
----- Original Message -----
From: "JC N4IS" <n4is@comcast.net>
To: <topband@contesting.com>
Sent: Sunday, April 20, 2014 10:57 AM
Subject: Re: Topband: How Increase 160m power on FL2100z
I owned a FT2100Z for several years and the power on 160m was the same as
other bands. I don't expect any design flaw. The original tubes are not
available anymore, the 572's tubes manufactures nowadays are different
and
optimized for audio applications and does not perform at the same level as
the originals 572's. You may just need more drive or change the input
circuit for 160m.
Regards
N4IS
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