Compaq FLEX-5000A User Manual

PRODUCT REVIEW

140

123

140

20 kHz Blocking Gain Compression (dB)

2 kHz Blocking Gain Compression (dB)

-40 +30

-40

+35

110

2 kHz 3rd-Order Dynamic Range (dB)

20 kHz 3rd-Order Intercept (dBm)

2 kHz 3rd-Order Intercept (dBm)

110

†

20 kHz 3rd-Order Dynamic Range (dB)

-20

-70

Transmit 9th-order IMD (dB)

-35

Transmit 3rd-Order IMD (dB)

-34

-54

pr032

80 M

20 M

Dynamic range and intercept values with preamp off.

Intercept values were determined using -97 dBm reference

Key:

† Off Scale

Key Measurements

Summary

FlexRadio Systems FLEX HF/50 MHz Transceiver

-5000A

Reviewed by Rick Lindquist, WW3DE NCJ Managing Editor

As we said in May 1998 QST when reviewing the first commercially available strictly computer controlled Amateur Radio transceiver, the Kachina 505DSP: “The relegation of functionality from hardware to software and firmware opens broad vistas of future capability.” Are we there yet? Or did our flight to nirvana get canceled? A decade down the road, Kachina is kaput in the amateur market, and the newer software defined radio (SDR) technology remains far from ubiquitous in the modern ham shack. FlexRadio Systems now represents the vanguard of equipment manufacturers prodding the Amateur Radio community into the SDR era.

Let’s face it: Most equipment in today’s ham stations reflects only incremental improvements in well-established wireless technology, form factor and human user interface. Additionally a “knob mentality” persists, despite Kachina’s confidence, expressed 10 years ago, that owners of its milestone radio would embrace mouse-and-keyboard operating to the extent that knobs would become “superfluous.” In 2005 FlexRadio Systems nudged things off the dime again with its SDR-1000. The FLEX-5000A raises the software-

Mark J. Wilson, K1RO

defined ham radio bar another notch.

Expanding Your Vocabulary

Just as hams once fretted about grid drive, overmodulation and key clicks, the very nature of SDRs has given rise to a new crop of issues with names like “latency” and “sampling rate.” This is serious technology, and it’s not necessarily for the faint of heart.

In an SDR, analog RF signals are converted to a digital bit stream, and everything happens at that level using digital signal processing (DSP) techniques before conversion back to analog. As FlexRadio explains, its SDR is “essentially a direct-conversion receiver, but the mixing of the LO [local oscillator] to create a 9 kHz IF makes it appear a lot like a dual-conversion receiver.” Something called a quadrature sampling detector (QSD) — 0°, 90°, 180° and 270° — is at the heart of all FLEX models. This generates the “I” in-phase composite and “Q” quadrature signals. Are your eyes glazing over yet?

FlexRadio points out that directconversion receivers like the SDR-1000 and FLEX-5000A don’t require band-pass or roofing filters. Because the QSD doesn’t respond to signals below its passband but is susceptible to odd harmonics above its LO

Product Review Editor



Bottom Line

The FLEX-5000A builds on the success of the SDR-1000, retaining the top-shelf radio performance and adding features. The package is far less complicated, shedding the many wires, cables, boxes and connectors that characterized the SDR-1000. Be prepared to experiment with the software and settings to get the most from this radio, however.

k1ro@arrl.org

From July 2008 QST © ARRL

frequency, FlexRadio uses a low-pass filter to block signals above its cutoff frequency. The rationale here, the company explains, is that low-pass filters have lower loss and wider component tolerance than band-pass filters.

While indisputably a direct descendant of the SDR-1000, the FLEX-5000A is a new and far slicker model that makes the earlier unit seem more of a beta test product than something ready for shrink wrap. A lot has changed in the intervening years; some has remained essentially the same.

PowerSDR — the Face of the Future?

In Zen terms, the radio is one with its GPL open-source PowerSDR software. Well, not quite. As FlexRadio Support Staffer Dudley Hurry, WA5QPZ, told me, “80% of the radio is in the computer.” Not only does PowerSDR serve as the radio’s virtual front panel, or con- sole, it handles all DSP functions, including modulation, demodulation, metering (digital and analog) and filtering. The black box with its hypnotic bright blue pilot light provides the physical portals — and many of them — into and out of the virtual world where the real radio resides.

For the benefit of Flex cognoscenti, our unit ran PowerSDR version 1.10.4, at the time the latest Official Release, throughout the review process. It is important to keep in mind that any review of a software defined product is a snapshot in time. FlexRadio and their user community are constantly working on enhancements and upgrades to this product. As time marches on, the FLEX-5000A with a later version of the software will be different from the radio reviewed here. Many of the concerns and observations we make might be resolved by the time you read this, or at some time in the future. The operation, performance and feature set change regularly in both obvious and subtle ways.

For those who enjoy adventures in software, new PowerSDR test versions are available for download on a regular (sometimes daily) basis. To take advantage of the latest version under development you must install and set up TortoiseSVN, a program that manages the various files and versions (SVN stands for Subversion). The SVN releases may have solved some of the issues described in this review and can be evaluated by the user community as development progresses. Eventually, after extensive testing, the changes find their way into the next Official Release.

According to FlexRadio, the majority of owners use three versions of PowerSDR. They have the current Official Release for backup and benchmarking, their favorite stable SVN release for most operating, and the latest SVN release to play with. More information and a setup guide are available

From July 2008 QST © ARRL

Table 1 FlexRadio FLEX-5000A, serial number 5107-5268

Manufacturer’s Speciﬁcations Measured in the ARRL Lab

Frequency coverage: Receive, 0.01-65 MHz; Receive, as speciﬁed (sensitivity transmit, 1.8-2, 3.5-4, 5.3305, 5.3465, degrades below 0.2 MHz).

5.3665, 5.3715, 5.4035, 7-7.3, 10.1-10.15, Transmit, as speciﬁed. 14-14.35, 18.068-18.168, 21-21.45, 24.89-

24.99, 28-29.7, 50-54 MHz.

Power requirement: 12.4-15.2 V dc; Receive, 1.6 A; transmit, 17 A; receive, 1.5 A (typical); transmit, 25 A (max). tested at 13.8 V dc.

Modes of operation: SSB, CW, AM, FM, As speciﬁed. FSK, AFSK.

Receiver Receiver Dynamic Testing

CW sensitivity, 500 Hz bandwidth, preamp Noise Floor (MDS), 500 Hz bandwidth: off/on: –123/–133 dBm. Preamp Off On

1.0 MHz –122 dBm n/a

3.5 MHz –119 dBm –129 dBm 14 MHz –119 dBm –132 dBm 50 MHz n/a –128 dBm

Noise ﬁgure: Not speciﬁed. 14 MHz, preamp off/on: 28/15 dB.

AM sensitivity: Not speciﬁed. 10 dB (S+N)/N, 1 kHz, 30% modulation: Preamp Off On

1.0 MHz 4.4 µV n/a

3.9 MHz 6.3 µV 1.6 µV 50 MHz n/a 3.7 µV

FM sensitivity: Not speciﬁed. For 12 dB SINAD: Preamp Off On 29 MHz n/a 0.64 µV 52 MHz n/a 1.4 µV

Blocking gain compression: Not speciﬁed. Gain compression, 500 Hz bandwidth: 20 kHz offset 5/2 kHz offset

Preamp off/on Preamp off

3.5 MHz 123/120 dB 123/123 dB 14 MHz 123/122 dB 123/123 dB 50 MHz n/a/118 dB n/a

Reciprocal Mixing (500 Hz BW): Not speciﬁed 20/5/2 kHz offset: –99/–99/–99 dBc.

Third-Order Intercept, 2 kHz offset: +30 dBm 39 dBM.

ARRL Lab Two-Tone IMD Testing Measured Measured Calculated Band/Preamp Spacing Input level IMD level IMD DR IP3

3.5 MHz/Off 20 kHz –25 dBm –119 dBm 94 dB +22 dBm –10 dBm –97 dBm +33 dBm

14 MHz/Off 20 kHz –20 dBm –119 dBm 99 dB +30 dBm –6 dBm –97 dBm +39 dBm 0 dBm n/a

14 MHz/On 20 kHz –33 dBm –132 dBm 99 dB +17 dBm –18 dBm –97 dBm +21 dBm

14 MHz/Off 5 kHz –20 dBm –119 dBm 99 dB +30 dBm –6 dBm –97 dBm +39 dBm

14 MHz/Off 2 kHz –20 dBm –119 dBm 99 dB +30 dBm –6 dBm –97 dBm +39 dBm

50 MHz/On 20 kHz –33 dBm –128 dBm 95 dB +15 dBm –22 dBm –97 dBm +16 dBm

Second-order intercept: Not speciﬁed. Preamp off/on: +63/+59 dBm.

from the FlexRadio Web site.

FlexRadio says PowerSDR will continue to be open source, although certain control functions are defined in closed-source firmware in order to meet FCC requirements to restrict transmissions on unauthorized frequencies (the radio provides for MARS and non US band operation).

flexibility than virtually any other transceiver I’ve ever seen and possibly any other radio on the market. I was disappointed in PowerSDR’s look and feel, however. The latest version of PowerSDR is a Windows 98 implementation in a Vista world. Although more feature laden, cosmetically it’s very similar to the SDR1000’s “front panel” of an earlier PC epoch.

But even TV’s “Ugly Betty” has a boy-

Ugly Betty

The FLEX-5000A offers more features and

friend. It’s what lies behind PowerSDR’s stodgy, less-than-stylish appearance that

Manufacturer’s Speciﬁcations Measured in the ARRL Lab

QS0807-PR01

0.02 0.04 0.06 0.08 0.1

10 10

-180

-160

-140

-120

-100

-80

-60

-40

-20

QS0807-PR03

QS0807-PR02

fc-4

kHz

fc-2 fc+2 fc+4f

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

FM adjacent channel rejection: Not speciﬁed. 20 kHz offset, preamp on: 29 MHz, 59 dB; 52 MHz, 44 dB.

FM two-tone, third-order IMD dynamic range: 20 kHz offset, preamp on: Not speciﬁed. 29 MHz, 59 dB*; 52 MHz, 44 dB*; 10 MHz offset: 52 MHz, n/a.3

S-meter sensitivity: Not speciﬁed. S9 signal at 14.2 MHz: preamp off, 50 µV; preamp on, 50 µV.

Squelch sensitivity: Not speciﬁed. At threshold, preamp on: SSB, 14 MHz,

0.28 µV; FM, 29 MHz, 0.22 µV; 52 MHz, 0.6 µV.

Audio output power: 10 dBV at 600 Ω. As speciﬁed.

IF/audio response: Not speciﬁed. Range at –6 dB points, (bandwidth): CW (500 Hz): 345-856 Hz (511 Hz),

Equivalent Rectangular BW: 499 Hz; USB: 141-2851 Hz (2710 Hz); LSB: 140-2850 Hz (2710 Hz); AM: 71-3293 Hz (3222 Hz).

Image rejection: 70 dB. First IF rejection, 43 dB5; image rejection, 88 dB.

Transmitter Transmitter Dynamic Testing

Power output: HF and 50 MHz: SSB, CW, HF: CW, SSB, FM, typically 100 W high, FM, 100 W (high); AM, 25 W (carrier) <1 W low; AM, typ. 25 W high, <1 W low; 50 MHz: CW, SSB, FM, typ 99 W high, <1 W low; AM, typ. 25 W high, <1 W low.

Spurious and harmonic suppression: HF, 51 dB; VHF, 61 dB. HF, >55 dB; VHF, >65 dB Meets FCC requirements.

SSB carrier suppression: >55 dB. HF, 51 dB; VHF, 54 dB. Undesired sideband suppression: >55 dB. HF, 61 dB; VHF, 60 dB. Third-order intermodulation distortion (IMD) 3rd/5th/7th/9th order (worst case band):

products: –33 dB PEP at 100 W on 14 MHz. HF, –34/–40/–48/–54 dB PEP; VHF, –21/–32/–39/–40 dB PEP.

CW keyer speed range: Not speciﬁed. 1 to 60 WPM. CW keying characteristics: Not speciﬁed. See Figures 1 and 2. Transmit-receive turn-around time (PTT release 29 ms.

to 50% audio output): Not speciﬁed. Receive-transmit turn-around time (tx delay): 25 ms.6

Not speciﬁed. Composite transmitted noise: Not speciﬁed. See Figure 3. Size (height, width, depth): 9 × 9.3 × 12.4 inches; weight, 13 pounds.

Price: FLEX-5000A, $2799; antenna tuner option, $299; RX2 second receiver, $649.

*Measurement was noise-limited at the value indicated. **Varies with CW pitch setting.

The level indicated is where the sound card’s ADC went into overload. Gain compression

could not be measured because of this behavior.

An input level of 0 dBm was higher than the ADC overload level, so the test was not performed.

No IMD product could be detected.

Audio output is dependent on external ampliﬁed speakers.

Spur near the IF frequency. Note: The IF is in the audio range, so IF rejection will not

affect RF performance.

Measurements made with 1.6 GHz dual-core processor. Turnaround time may be faster with

higher speed CPU.

Figure 1 — CW keying waveform for the FLEX-5000A showing the ﬁrst two dits in full-break-in (QSK) mode using external keying. Equivalent keying speed is 60 WPM. The upper trace is the actual key closure; the lower trace is the RF envelope. (Note that the ﬁrst key closure starts at the left edge of the ﬁgure.) Horizontal divisions are 10 ms. The transceiver was being operated at 100 W output on the 14 MHz band.

Figure 2 — Spectral display of the FLEX5000A transmitter during keying sideband testing. Equivalent keying speed is 60 WPM using external keying. Spectrum analyzer resolution bandwidth is 10 Hz, and the sweep time is 30 seconds. The transmitter was being operated at 100 W PEP output on the 14 MHz band, and this plot shows the transmitter output ±5 kHz from the carrier.

really counts. The current maximum sampling rate (more on this topic later) permits viewing 192 kHz of band spectrum, with immediate access to both VFOs as well as to the panoply of major functions, most common, some less so. You access most functions via buttons, sliders, menus and sub-menus or tabs.

“Light Years Ahead”

What the FLEX-5000A brings to the table

now is a far less complicated Amateur Radio

package that’s free of the surfeit of wires, cables, boxes and connectors that characterized the SDR-1000. (Further eliminating the need for wires is VAC [virtual audio cable], third-party software that routes signals for digital programs to and from the FLEX5000A.) As one “Flexer” remarked on the FLEX-5000A Web site, “fit and finish are light years ahead of the SDR-1000” and “it looks like a professional radio.”

This ham radio system essentially consists

Figure 3 — Spectral display of the FLEX-5000A transmitter output during composite-noise testing. Power output is 100 W on the 14 MHz band. The carrier, off the left edge of the plot, is not shown. This plot shows composite transmitted noise 100 Hz to 1 MHz from the carrier.

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