Vectronics HFT-1500 User Manual download pdf (Page 5)

From February 2003 QST © ARRL

PALSTAR AT1500CV

The Palstar AT1500CV is a T-network

tuner solidly constructed in a compact alu-

minum enclosure. Inside, the metering and

SWR bridge circuitry are encased in their

own aluminum boxes. The moderately

sized variable capacitors are mounted side

by side and feature large calibrated dials

and silky smooth vernier tuning that al-

lows for precise adjustment. Palstar indi-

cates that newer units incorporate a roller

bearing assembly which makes inductor

adjustment smoother. The roller inductor

is quite large. It is an air core silver plated

edge wound coil with heavy-duty ceramic

forms. Control of the inductor is via a le-

ver handle and mechanical turns counter.

It is not as smooth as some of the other

tuners and tends to lurch as it is rotated

during fine adjustments. The cross-needle

meter displays SWR and average forward

and reflected power in 300 and 3000 W

ranges, with no option for peak power

metering. It is illuminated with 12 V from

an included wall adapter.

Achieving a 1:1 SWR on the G5RV

was possible on all bands from 80 through

10 meters at its rated power maximum of

1000 W single tone. Similar results were

noted on the inverted L. Although the tun-

ing chart provided in the manual does not

include settings for 30 meters, the tuner

easily matched both antennas on that band.

This tuner has a solid feel to it and doesn’t

creep around while making adjustments.

In laboratory tests, the AT1500CV had

more difficulties on 160 meters than on

other bands. A 1:1 SWR was only obtain-

able with the 25 and 50-

Ω

loads. Even at

those loads, the power losses at 160 meters

were measurably greater than those on

other bands at the same loads. The vari-

able capacitors are 240 pF maximum,

which explains the 160 meter performance.

The tradeoff results in lighter weight.

Antenna connections on the back panel

include three coax inputs. Two are avail-

able direct or through the tuning network

and one is bypassed straight through. The

bypass output can also be used with an

optional 4:1 balun available for $39.95.

Balanced or single wire feed lines are at-

tached to Delrin terminal posts with wing

Front panel of the Palstar AT1500CV.

Rear panel connections on the Palstar AT1500CV.

Interior circuitry of the Palstar AT1500CV.

nuts. Longer threaded material on the ter-

minal posts would be a welcome improve-

ment and make attachment of larger gauge

wire much easier.

In one isolated circumstance during

lab testing, our engineer felt an RF bite

on 10 meters through the metal portion

of the inductor crank. This did not seem

to be a pervasive problem, and Palstar in-

dicates that the grounding on the crank

has also recently been improved.

Manufacturer: Palstar, Inc, 9676 N

Looney Rd, PO Box 1136, Piqua, OH

45356; tel 937-773-6255; fax 937-773-

8003; www.palstarinc.com. Price:

$429.95, optional 4:1 balun $39.95.

Table 4

Palstar AT1500CV

SWR

Load (

Ω

)

160 m

80 m

40 m

20 m

10 m

8:1 6.25 Power Loss % No Match 25 16 12 12

1.5 SWR BW 1 2 >5 3

4.1 12.5 Power Loss % No Match 16 13 <10 11

1.5 SWR BW 2 4 >5 >5

2:1 25 Power Loss % 21 13 <10 <10 <10

1.5 SWR BW 2 3 >5 >5 >5

1:1 50 Power Loss % 13 <10 <10 <10 <10

1.5 SWR BW 3 >5 >5 >5 >5

2:1 100 Power Loss % No Match <10 <10 <10 13

1.5 SWR BW >5 >5 >5 >5

4:1 200 Power Loss % No Match <10 <10 <10 12

1.5 SWR BW >5 >5 >5 >5

8:1 400 Power Loss % No Match <10 <10 <10 <10

1.5 SWR BW >5 >5 >5 5

Notes

“No Match” means that a 1:1 SWR could not be obtained.

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).

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