Monday, August 27, 2018

Retraction: SUCK 100 does not suck nearly as bad as I thought..

Boy howdy! I sure got egg all over my face on this one!

Often in my career as a software developer, I would lapse into a childish tantrum and blame everything else on my software's failure and I found one fact to be almost axiomatic: the louder I complained, the more certain it was that the problem was my fault! Below, I unloaded on the Sark 100 antenna analyzer that I brought back from the morgue slab, calling it a worthless piece of shit, in effect, and barely worthy of the money and time I expended. Well, I am here to chow down on a huge plate load of crow.

Like the old aphorism goes: READ THE F**KING MANUAL!

That is, I got hold of one here and, after perusing it, I find that this little unit is the bargain of the year! Firstly, this disclaimer: this applies to the "original" kit which was derived/created by EA4FRB and is archived on this site.


As you will see, the SARK 100 was discontinued in 2011 and has been superseded by the SARK-110 which is an ass-kicker of an analyzer with a hefty price tag. You interested? Look it up. This is about the SUCK SARK-100. Also, another caveat: this is about the Chinese eBay SARK-100 ripoffs so I cannot vouch for that at present. But, based upon what i read in the manual, the little unit is blessed with a lot more features than I originally thought.

For example what follows is a summary of what I found and will confirm in the next few days.

OVERVIEW
The SARK100 SWR Analyzer Kit is a measurement instrument which determines antenna system performance across the HF/6M amateur bands without the need of connecting the transmitter to the antenna. It is ideal for checking the resonance, bandwidth, and SWR in an easy and fast way. The meter also measures the resistance, reactance, and the magnitude of the impedance.

The analyzer is comprised of a single double-sided printer circuit board PCB (145mm x 81mm) containing all components, controls, and a 2x16 LCD display with backlight; all inside an enclosure that allows in-hand use. The enclosure holds an 8-cell AAA battery pack enabling convenient field use.
The analyzer design is based on a DDS signal generator, a PSoC microcontroller, and a reflectometer for the impedance measurements. The features and flexibility of the PSoC microcontroller allows for a simple hardware design. The design provides an USB interface to allow FW updates and uploading of the real-time measurements to the PC. The development environment is the free PSoC Designer tool and the
code has been programmed in 'C' language allowing along the USB update capability the easy customization of the code without the need of acquiring any tool.

BASIC SPECS
Frequency Generation & Control
o 1 - 60 Mhz
o Source impedance: 50 Ohms
o Stability: +/- 100 ppm
o Spectral Purity: Harmonics down >- TBD dB beyond 60 MHz
o Step Size: User configurable increments of 100 Hz, 1 kHz, 10 kHz, and 100 kHz

Usable Measurement Range
o SWR: 1.0 to 9.99
o Impedance: approx. 5 to 2000 ohms

RF Output
o Adjustable: 2.0 Volts pp (typ)

Power supply
o External: 13.8 to 19 Volts DC, 500mA
o Internal: 8xAAA 1000mAh NiMH cells (Chinese knock-off has mini battery cavity)
o Charging time: 12 hours (charge rate 0.1C) (Chinese knock-off N/A)

Controls
o Pushbuttons (5): "MODE", "BAND", "CONFIG", "SCAN", "UP", "DOWN"
o Switch: "POWER ON"

Connectors
o RF Out: BNC (Chinese knock-off is SO-239)
o USB: Mini-B receptacle
o External power: 2.1mm Power Jack (center pin positive)

Instrument Capabilities
o Measure antenna electrical parameters: SWR, impedance
(resistance + reactance), capacitance, inductance
o Measure feedpoint impedance
o Measure ground loss
o Adjust antenna tuners and determine loss
o Measure inductors and capacitors
o Measure coax transmission line (SWR, length, velocity
   factor, approximate Q and loss, resonant frequency,
   and impedance)
o Measure and determine optimum settings for tuning stubs:
   SWR, approximate Q, resonant frequency, bandwidth,
   impedance
o Determine characteristic impedance of transmission line
o Determine length of ¼ and ½ wave phasing lines
o Coaxial Cable Loss
o Determine antenna tuner loss
o Measure balun loss
o Measure inductor Q
o Estimate quartz crystal parameters
o Measure magnetic loop resonance and SWR

..so, it's these last items that intrigue me the most as it appears as though there's a lot more smarts behind the little beast than meets the eye. If those have been carried over to the Chinese eBay knockoffs, then, at $60-70, they are quite the steal. And I rather suspect that, since EA4FRB created this with an eye to open source development, theyre's a good chance that our Asian merchants have incorporated a lot of the functionality into their offerings.

Will get back to you as more is discovered. But, for the present, I am so stoked to discover this that I ordered a $50 version that is now appearing.

Gonna be an exciting voyage of discovery.

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