Bill -- there is an addendum page for the 2NT manual that gives you
the frequency ranges and drive levels required; I'm sending that to
you direct as I'm not sure it'll make it thru the mail list. I've
used the Norcal FCC-1/2 DDS VFO/counter to drive the 2NT. The DDS
board puts out enough to drive the rig on 80/40m since the rig only
requires about 1V RMS of drive (3.5 Mhz and 7 MHz respectively); for
20m and above it takes 4/12/4V RMS respectively at 7 MHz.
Although I have yet to try it here's a suggestion from W3CD that I
got a while back on how to step up the drive from the VFO to perhaps
meet the higher drive requirements:
From: "Bob Okas" <vinta...@earthlink.net>
Date: April 17, 2008 2:55:16 PM EDT
To: "'Dino Papas'" <k...@cox.net>
Subject: RE: Using the FCC-1/2 with a Tube Type Transmitter
Greetings Dino,
The matching network is a simple L-network that matches the 50 Ohm
output impedance of the FCC-2 to a higher impedance transmitter
input. The inductor is in series with the FCC-2 output and the cap
shunts the TX side of the network. The trick is determining what the
2-NT’s input impedance is. A good starting point is to guess around
1K. The network will offer roughly a 20x voltage step-up, which
should be adequate to drive the TC on the higher bands.
To determine what component values to use for the L-network, look at:
http://bwrc.eecs.berkeley.edu/Research/RF/projects/60GHz/matching/
ImpMatch.html
Use a Q value of 7 and you should get some reasonable values.
73,
Bob – W3CD
Hope this helps.
73 -- Dino KL0S
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