VL-1000 Quadra HF Linear
Inside Views (Click picture for larger
1. Top view: Power Amplifier Stage and Low-Pass Filters
- The PA stage consists of four push-pull modules, each comprising a pair
of Motorola MRF150 MOSFET devices. Each MRF150 is rated at Po = 150W. The amplifier thus
has a 20% safety factor, but is operated somewhat conservatively at 1 kW P.E.P (1.8 to 30
MHz) to maintain optimum IMD3 (< -30 dB relative to peak 2-tone). The PA is de-rated to
500W P.E.P. output on HF RTTY/FM (1 hr. transmit time at 100% duty
cycle), and on 6 meters.
Click here for Quadra brochure.
Download an MRF150 data sheet. Click here for detailed specifications.
here for Yaesu Quadra System page. Click here for
Top view: PA Stage & LPF
2. Bottom view: Heatsink and Autotuner
- The machined aluminum heatsink is cooled by two large muffin fans,
visible at the rear of the RF cabinet. The autotuner is a T-network, with a
tapped shunt inductor
switched via relays and two series air-variable capacitors driven by stepping motors. The
SWR matching range of the tuner is 1:3 ~ 2:1 (160m), 1:3 ~ 3:1 (all other HF bands) and
1:2 ~ 2:1 (6m). The tuner insertion loss is 0.5 dB. When enabled, the
tuner is in the signal path on both transmit and receive; it thus serves as
a tracking preselector. The tuner is cooled by a small muffin fan mounted on the tuner
shield cover (not shown).
Bottom view: heatsink and autotuner
3. Controller Board with 16-bit Processor; Interface Information; FL-7000
- The controller board is the "brain" of the Quadra. It
incorporates a 16-bit micro-processor, which controls band selection, autotuner operation,
amplifier housekeeping and protective functions. Sensors in the PA stage and autotuner
send status information to the controller.
Download Bill, N4ATS'
VL-1000 CPU (Q1001) VDC Pinout Template.
here for information on interfacing
the Quadra to an Icom exciter or to the
Kenwood TS-590S/SG , TS-950SD/SDX or TS-990S, and here for information on interfacing
the Quadra to a Yaesu FT-1000MP, MkV,
FT-2000 or FTDX-9000 with complete QSK capability. Click here for
Yaesu FT-847 interfacing information.
Download Quadra/Elecraft K3
and FL-7000/Elecraft K3
interface documents by Tom NØSS (SK). Click
here to view FL-7000 info, and here
for Bill, N4ATS' authoritative FL-7000 site.
Controller board (behind front panel)
4. The VP-1000 Power Supply, top view; Reviews and Tests
- Inside the VP-1000 cabinet is a 2.5 kVA switching power supply, cooled
by two large muffin fans. These are visible at the rear. The mains circuit breaker is to
the left of the fans. The VP-1000 delivers 48V DC at 50A when operated on 220V mains
(reduced to 35V when the
LOW key is
pressed for 500W output.) The
acceptable mains voltage range is 100 to 235V, 50/60 Hz. RF power output is de-rated to
500W P.E.P. with 120V mains. (In general, 120V operation is not recommended,
as it stresses the VP-1000.) Click
here for Bert, N8NN's VP-1000 repair procedure. Click
here for eHam Quadra reviews. Click
here for ARRL product review (ARRL members
for RSGB Quadra review (courtesy VA3CR). Click
here for my Quadra mini-review.
Click here for an
ALC overshoot test.
VP-1000 PSU module
5. Display Screenshots
Main screen, showing peak & average power, PA
drain current and SWR. The operator can toggle SWR/PA drain voltage. Click here
to download Quadra info.
Autotuner screen, showing instantaneous tuning capacitor
settings and SWR whilst tuning. You can see the capacitors rotating! Click
here for ARRL Quadra review (members
- Load analyzer screen, showing SWR at tuner input (dash)
and output (dot) vs. frequency. The frequency resolution is selectable.
If SWR > 3:1 at tuner output, the Quadra goes off-line. This feature protects
against damage due to antenna-system failure.) Click
here for a general discussion of solid-state HF amplifiers.
6. User Manuals (PDF)
Copyright © 1999-2017 A. Farson VA7OJ/AB4OJ (including images). All rights reserved. Last updated 05/01/17.