Compaq FLEX-5000A manual PowerSDR the Face of the Future?, Ugly Betty, Receiver

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

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.

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 prod- uct. 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 (some- times 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 re- leases may have solved some of the issues described in this review and can be evalu-

Receiver

CW sensitivity, 500 Hz bandwidth, preamp off/on: –123/–133 dBm.

Noise figure: Not specified.

AM sensitivity: Not specified.

FM sensitivity: Not specified.

Blocking gain compression: Not specified.

Reciprocal Mixing (500 Hz BW): Not specified

Third-Order Intercept, 2 kHz offset: +30 dBm ARRL Lab Two-Tone IMD Testing

Band/Preamp	Spacing	Input level
3.5 MHz/Off	20 kHz	–25 dBm
		–10 dBm
14 MHz/Off	20 kHz	–20 dBm
		–6 dBm
		0 dBm
14 MHz/On	20 kHz	–33 dBm
		–18 dBm
14 MHz/Off	5 kHz	–20 dBm
		–6 dBm
14 MHz/Off	2 kHz	–20 dBm
		–6 dBm
50 MHz/On	20 kHz	–33 dBm
		–22 dBm

Second-order intercept: Not specified.

Receiver Dynamic Testing Noise Floor (MDS), 500 Hz bandwidth:

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
14 MHz, preamp off/on: 28/15 dB.
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
For 12 dB SINAD:
Preamp	Off	On
29 MHz	n/a	0.64 µV
52 MHz	n/a	1.4 µV
Gain compression, 500 Hz bandwidth:1
	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
20/5/2 kHz offset: –99/–99/–99 dBc.
39 dBM.
Measured	Measured	Calculated
IMD level	IMD DR	IP3
–119 dBm	94 dB	+22 dBm
–97 dBm		+33 dBm
–119 dBm	99 dB	+30 dBm
–97 dBm		+39 dBm
n/a2
–132 dBm	99 dB	+17 dBm
–97 dBm		+21 dBm
–119 dBm	99 dB	+30 dBm
–97 dBm		+39 dBm
–119 dBm	99 dB	+30 dBm
–97 dBm		+39 dBm
–128 dBm	95 dB	+15 dBm
–97 dBm		+16 dBm

Preamp off/on: +63/+59 dBm.

ated by the user community as development progresses. Eventually, after extensive test- ing, 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 the FlexRadio Web site.

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

Ugly Betty

The FLEX-5000A offers more features and

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 SDR- 1000’s “front panel” of an earlier PC epoch.

But even TV’s “Ugly Betty” has a boy- friend. It’s what lies behind PowerSDR’s stodgy, less-than-stylish appearance that

From July 2008 QST © ARRL