Compaq FLEX-5000A - Manual (Page 4)

From July 2008 QST © ARRL
of the FLEX-5000A box and the PC. It of-
fers 100 W (PEP) on all bands 160 through
6 meters, general-coverage receive (0.01-
65 MHz, same as the SDR-1000) and lots and
lots of features, including several that weren’t
available on the SDR-1000. For example, the
newer model offers substantial improvement
in CW operation, VOX capability and other
novel and useful amenities, plus some impres-
sive performance statistics (see Table 1).
The close-in two-tone third-order IMD
dynamic range of the FLEX-5000A remains
comparable with that of the SDR-1000 and
of some of the best transceivers on the mar-
ket. On the SDR-1000, the best IMD DR
on 14 MHz at 2 kHz spacing was 99 dB at
the medium preamp setting, but as much as
10 dB worse at other preamp settings. On the
FLEX-5000A we measured 99 dB on 14 MHz
at all spacings, with or without the preamp.
The FLEX-5000A includes some features
that became viable simply because today’s
average PC is a lot more powerful than the
ones common in 2005. By the same token,
continued upward mobility of PC technology
is bound to further improve the FLEX-5000A
down the road, so enhanced performance and
additional features remain moving targets. In
addition, faster video cards can improve radio
performance by offloading of the CPU.
FlexRadio got rid of the gaggle of wires
that shackled the SDR-1000 and its associ-
ated high-end sound card by using a FireWire
(IEEE-1394) interface to handle signals
between the black box and the PC. Hurry ex-
plained that several essential “threads” travel
up and down the FireWire cable, including
receive and transmit I and Q signals (essen-
tially the radio’s IF) and receive and transmit
audio. The FireWire cable may be up to 10
feet long.
The “functional equivalent” of the SDR-
1000’s sound card and USB control now
resides in the FLEX-5000’s hardware. These
include low-level control and communica-
tion functions needed to run the specific
hardware. The FLEX-5000A has a device
driver just like any other PC peripheral. The
user must enter both the desired sampling
rate and buffer size into the driver dialog
box — which sets up the FireWire connection
parameters and something called “operating
mode” — as well as in the PowerSDR Setup
menu (or “form,” as FlexRadio calls them).
Our unit had the optional automatic antenna
tuner (ATU) installed. It can produce a rather
disconcerting symphony of grinding and whir-
ring as it tries to come to terms with whatever
load you have attached to one of the three
SO-239 connectors on the box’s rear apron
(Figure 4). The ATU has semi-automatic and
automatic settings as well as memory capabil-
ity. You can set the maximum SWR threshold
(up to 3:1). Unless you have the ATU tab open
on your screen, however, you may not know
right away if the tuner couldn’t find a match.
Although a tuner fault will not necessarily
switch the ATU to bypass mode, a red
HIGH
SWR warning will flash when you transmit.
The FLEX-5000A’s transmit and receive
signal paths are completely independent,
opening new horizons of opportunity.
For example, at press time
an optional full-featured
second receiver, known
as RX2, was poised to
provide the potential for
SO2R — single-operator,
two radio capability — in
a single box.
Knobs? We Don’t
Need No Stinkin’
Knobs!
Anyone who’s ever
used a Kachina, Ten-Tec
Pegasus or SDR-1000 — or, for that matter,
ever controlled a conventional transceiver via
computer or Internet — appreciates that the
most significant part of the learning curve
is getting used to mousing rather than tried-
and-true dial twisting and button pushing.
FlexRadio’s slogan is “Real radios don’t
need
knobs!”
Mouse control is an acquired taste. Think
of it this way: The front panel of the FLEX-
5000A is the graphical user interface of a
computer program, and, for better or worse,
the mouse has become the de facto control-
ler for programs ranging from accounting to
word processing. Last time I was in a Best
Buy store, the array of computer mice and
adjunct control devices was astonishing.
The FLEX-5000A’s tuning controls en-
able all the usual capabilities you’d expect
on a conventional Amateur Radio transceiver
and more. You can set (or reset) the tuning
step anywhere from 1 Hz to 10 MHz with a
mouse click, lock the VFO, operate “split,”
dump the contents of one VFO into the other,
equalize VFOs and listen to two frequencies
at the same time with the click of a button.
One disappointment was the minimal
“scratch memory,” a feature I’ve always
found extremely handy in contests. Clicking
SAVE retains a frequency, mode and filter,
but only for a single frequency. Some adept
programming that already may be on the
drawing board very likely could overcome
this minor deficiency.
The FLEX-5000A gives you a num-
ber of ways to tune. On the panadapter
display — the one you’re likely to use the
most — the radio lets you put a signal in
its crosshairs. Then click, you’re there,
aside from a little fine tuning (FlexRadio
calls this “ClickTune”). You can do the
same thing with the waterfall display. It’s
possible to choose a split panadapter/waterfall
or any combination of the two, as shown in
Figure 5. At the PowerSDR window’s normal
size, the menu to access this feature may not
be visible. It’s below the main console win-
Figure 4 — Rear view
of the Flex-5000A.
Note the real analog
connectors here.
Switching computers Midstream
The “right” computer is key to satisfactory operation of the FLEX-5000A. We
started out with a high-end HP/Compaq dc7700p, which has an Intel E6300 Core
2 Duo processor (2 MB of L2 cache, 1066 MHz bus) running at 1.8 GHz. It was
equipped with 2 GB of memory, a RAID hard drive system and Windows XP Pro.
After we noted performance that was at odds with FlexRadio’s experience, the
manufacturer suggested that we try a Compaq Presario SR5310F with an Intel
Pentium E2140 Dual-Core processor (1 MB of L2 cache, 800 MHz bus) running at
1.6 GHz. This inexpensive machine came with 1 GB of memory and the Vista Home
Premium operating system. ARRL installed a FireWire card and removed the fancy
video card and all unnecessary applications that might bog down the processor.
Switching to the SR5310F demonstrated that you don’t need a blazing-hot,
high-end computer to run a FLEX-5000A. On the other hand, there were occa-
sions when it seemed that more computer muscle would have resolved some of
the issues we encountered. The FLEX-5000C model has a built-in Intel Core 2
Duo processor computer with 1 GB of RAM and XP Pro. — Rick Lindquist, N1RL