is a founding member of The James Millen Society and has been
interested in Millen equipment since the early 1990's. Originally
the society webpage was part of Don's personal website and was
simply called "The Millen Page".
Pictured above shows Don's personal Millen setup.
In the rack assembly from top to bottom we start with a 90903
scope used as a transmitter modulation monitor. Immediately below
is the 90801 transmitter proceeding to the 90831 modulator. The
lower half of the rack contains two DC power supplies. The upper
supply is for regulated low voltage plate requirements and is
set for +250 VDC. This supply also provides all the negative bias
voltages required by the transmitter/modulator combination. Although
at first glance it appears to be a Millen power supply, it is
not! This supply started life as a Lambda commercial 200-325VDC
100mA regulated vacuum tube unit. The logo plate on the front
was created on transparent sticker material using a laser printer.
The sticker was applied to a bare piece of aluminum plate which
provides the same appearance of the reverse printed logo plates
used by Millen. This supply originally provided a high current
AC filament voltage. However that transformer output was reverse
feed into another filament transformer, rectified and regulated
to provide all the necessary negative bias voltages. In addition,
a high voltage sensing circuit was added that disables the 250VDC
output until the main transmitter/modulator high voltage (600VDC)
becomes active. The lower unit in the rack is a Millen 90281 High
Voltage power supply. It provides the aforementioned 600VDC. In
the current configuration the plate switch on the 281 supply is
all that is required to switch the setup between transmit and
receive. Including receiver muting and remote activation of the
transmitter VFO. "True vintage push-to-talk or is that switch-to-talk."
Directly to the right of the transmitter rack
is a National HRO-5TA1 receiver. Although technically not a Millen-era
receiver, as it was manufactured in the 1946/47 time frame or
nearly seven years after Millen left National, it retains the
look and basic circuit architecture of the earlier HRO's. The
5TA1 version is the last of the black HRO receivers and was soon
afterward replaced by the less famous HRO-7 which still used the
same basic design but began using miniature tubes. This HRO-5TA1
is in almost perfect original condition, including tube ID stamping
on the gray painted chassis. The only non-original items are being
some of his coil units are from earlier series HRO's.
Directly on top the receiver is a Millen 90711
VFO. Probably one of the best VFO's ever manufactured! Accurate,
stable and it can not be damaged even with a direct short circuit
of it output. Since the VFO's output is designed to drive low
impedances many users have connected it up directly to an antenna
and made contacts. Above the VFO is the matching speaker for the
HRO receiver. Not shown in the picture, but placed directly on
top of the speaker, is a Millen 92101 antenna preamplifier which
is used for 10 meter operations. The preamplifier is mentioned
as it was the first Millen piece Don aquired.
Don has many other items in his Millen collection,
many pictured elsewhere on this site, including his rare and much
sought after DFP-201 prototype receiver. For further personal
information about Don you can check out his webpage.