The Yaesu VL-1000 Quadra
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
Click here for Yaesu Quadra System page. Click here
for Quadra FAQ's.
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.
Click here for information on interfacing
the Quadra to an Icom exciter or to the
Kenwood TS-590S/SG, TS-890S, 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. Click
here for instructions to
activate F SET and TUNE keys when using an FT-710 exciter with the Quadra.
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 240V,
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.
for eHam Quadra reviews.
Click here for ARRL product review (ARRL members
Click here for RSGB Quadra review (courtesy VA3CR).
Click here for my Quadra mini-review.
Click here for an ALC
overshoot test. When powered up idle, the VP-1000 draws ≈ 48 VA (43W,
assuming cos φ = 0.9) from the 240V mains.
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.
(Note: 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 © 1999-2023 A. Farson VA7OJ/AB4OJ (including images). All rights reserved. Last updated 11/28/23.