From February 2003 QST © ARRL
Front panel of the Vectronics HFT-1500.
Rear panel connections on the Vectronics HFT-1500.
Interior circuitry of the Vectronics HFT-1500.
VECTRONICS HFT-1500
The first thing you notice about the
HFT-1500 is the LED bar graph on the front
panel, which is used to display relative
peak forward power. The bright green bar
graph is adjusted to its maximum scale with
a level control on the front panel to a known
forward power reading on the cross-needle
wattmeter. While it doesn’t show actual
power readings, it does give a quick visual
indication of peak power. The cross-needle
meter displays only average power and
SWR in two power ranges selected by a
pushbutton switch. The traditional T-
network design uses two 4.5-kV variable
capacitors adjusted with large comfortable
knobs and very smooth vernier tuning. This
tuner stays put on the desk while you uti-
lize a lever handle and gear driven 5 digit
mechanical turns counter to adjust the air
wound roller inductor.
Tuning the 160-meter inverted L and the
G5RV on all bands except 10 meters was
easily accomplished, with no problems
handling 1 kW. In the field, the best SWR
that could be obtained on 10 was 2.33:1;
this is possibly due to the additional “load-
ing” when a human touches the all-metal
inductor crank. The ARRL Lab adjusted
the inductor with a wooden pencil in some
cases to obtain a match.
The HFT-1500 provides two coax inputs
and a third that completely bypasses the
tuning network. The balanced and single
wire inputs are Delrin terminal posts con-
nected to a large single core 4:1 voltage
balun.
In some circumstances during lab test-
ing, our engineer felt RF bites through the
metal portion of the inductor crank. Later
units feature a metal shaft bushing, which
provides a better ground. This was not ex-
perienced in field testing, but tuner adjust-
ments were not made at high power.
Manufacturer: Vectronics, 300 Indus-
trial Park Rd, Starkville MS 39759;
tel 662-323-5800; fax 662-323-6551;
www.vectronics.com. Price: $459.95.
Table 6
Vectronics HFT-1500
SWR
Load (
Ω
)
160 m
80 m
40 m
20 m
10 m
8:1 6.25 Power Loss % 45 42 16 15 8
1.5 SWR BW 1 <1 2 5 >5
4.1 12.5 Power Loss % 32 31 11 <10 <10
1.5 SWR BW >5 >5 3 >5 >5
2:1 25 Power Loss % 19 24 <10 <10 <10
1.5 SWR BW 2 1 >5 >5 >5
1:1 50 Power Loss % 12 <10 <10 <10 <10
1.5 SWR BW 3 >5 >5 >5 >5
2:1 100 Power Loss % 12 <10 <10 <10 <10
1.5 SWR BW 3 >5 >5 >5 >5
4:1 200 Power Loss % <10 <10 <10 <10 <10
1.5 SWR BW 4 >5 >5 >5 >5
8:1 400 Power Loss % <10 <10 <10 11 16
1.5 SWR BW 4 >5 >5 >5 4
Notes
Power losses are expressed as a percentage. A 21% loss of power is 1 dB.
The 1.5-SWR Bandwidth (SWR BW) represents the bandwidth over which an SWR of
1.5:1 or less was maintained as a percentage of the measurement frequencies
(1.8, 3.5, 7.2, 14.2 and 29.7 MHz).
(3 pages)
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