Ham Shack & Annie <scroll this page>
Machine Shop & Rolling Stock
Battery Back-Up Power & Coal Furnace
"Billy Bob" the goat
Field Day 2001
Machine Shop Additions 2002
GO-9 Radio Set
Wireless Internet Site
Field Day 2005
KO7R's QTH in Cedar Fort, UT.
Mosley Tribander, 2 m beam, balun (common feedpoint) for inverted vee antennas
on 40,75 & 160m.
KO7R operating his favorite mode in his hamshack.
In addition to SSB, Dan likes to work CW, particularly mobile, using an old hand key attached to his leg. By copying in his head, he can carry on a CW QSO while driving, drinking a soda and eating a burger. But if you're riding with him, don't try to carry on an in-person conversation with him while he is doing it.
This rig was 100% homebuilt by Dan in 1965. It operates on 40 & 75 meters. It employs two 6CB5 sweep tubes (Dan maintains they are undiscovered star performers as far as sweep tubes go) with an output power of 300+ watts in both CW & SSB modes. Power supply (including 12VDC supply shown below pix 4-7) is external. Speaker is internal (see 3rd pix).
I built this power supply somewhere around 1964, in Livermore, CA. The
inspiration for it (as well as the SSB transceiver it powers) came from the
Swan single-banders prevalent at the time, coupled with the availability of
an Arnold Silectron tape-wound (cut) core. Wanting maximum power and
voltage stability, I hand made and wound two bobbins with High B+, Low B+,
bias, collector and feedback windings. I used four 2N174 germanium power
transistors, spike-protected with a zener diode clipping circuit which
clamped negative spikes at less than a volt and positive spikes at around 20
volts (on the 2N174 collectors. I cooled its heatsinks with 24 volt surplus
blower connected from +12volts to -12 volts (I installed a completely
separate generator, solid state voltage regulator and battery just for the
ham gear, connected for positive ground). This power supply supplies 1100
volts at 400 ma. to the transceiver, plus the low B+ of around 300 volts,
and negative 100 volts or so for bias. On a trip to MO in 1967, one of the
windings on one bobbin shorted out (Oklahoma humidity). At my in-laws'
house, I simply pulled it out and ran it with only one bobbin/winding, and
saw no loss in power output. That is the way it has run ever since. I put
a relay in series with the bleeder resistor, so that as soon as B+ comes up
(about 100 milliseconds), it pulls in and removes the DC starting bias from
the bases of the 2N174s, leaving them in true Class B operation, for greater
efficiency. It oscillates at about 180 Hz, which makes filtering easy. On
the +/- 50 amp meter mounted on the dash of my car, "Hello test" would
produce meter swings of between 40 and 50 amps. If I didn't keep the belt
tight, I could voice-modulate the belt squeal on the auxiliary generator.
The Heinemann circuit breaker was a later addition, after removing the
Dan Metcalf KO7R
1952 John Deere "A" Tractor which KO7R uses to farm his 17 acres.
Rebuilding and operating old engines and machinery in general is
one of KO7R's great interests. This is a '20s vintage Fairbanks-Morse
1.5 Hp headless engine, which runs on gasoline and was used to power
a horse-drawn orchard sprayer.
More Pictures of KO7R & his interests and equipment
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