Call sign: K5jxh  
A new toy:        (See files , Doc's and stuff here)

FYI: The real SARC-110 will set you back $400 state side . ( their real  home page is here) for home grown tools U.S.A. for HF see this (17 to chose from).


Antenna Analyzer  (AA) day: (this is my indirectly imported clone or about $75 bucks)
SARK-100 to the the rescue?  (sold in different kit  levels and  this kit can be confusing ...)
I can and do , run mine with 8 , cheap dollar store AAA batteries. (remotely) for a cost of $2... (once you buy the missing battery holders, wire them in SERIES for 12vdc duty)
Pro's : It works good, and is cheap. In a solid steel chassis, near battle ship strong, runs on dirt cheap AAA batteries, even from Dollar store.( $1 x2 = 8 batteries ALK)
Con's, No software, no battery holder, manual. (but all super easy to get), no cables, in most cases, but all easy to find, no power pack.

This device is more fun than a barrel full of monkey's. Mine is based on the AD9851 (DDS) chip. And 2 Analog Devices RF amps.
The reflectrometry is done via the chip CY8C29466 (Cypress MPU) already obsolete, wow.!  Now we know why the new tool is 110... at the least...
The cheapest Sark version will take minor work to get going, see my warnings below.   (Most hams this is not a problem, in the spirit of DIY, home brew and not needing plug and play magic)
 
Rules not told by most makers: (what I call kits)
The line power jack needs, 14v to 19 vdc.  The Mouser Delta MDS-030AAC15 works.(as do all these)

Do not try to run this unit off  any +12v power  pack (or lower), the regulator needs 2 volts more that 12v to run.  (7812 chip inside sets those rules , nothing else). 
Do not us an A.C power pack. It needs DC power . I use one 2amp pack in my shack for many of my toys.
Like my SB104, says , "only runs on a running car", for the same reason, no LDO regulator used here.  (a low drop out regulator would have been a better choice. here...)

The battery chamber  is empty new,  it's designed for NiMH batteries and charges them.
Do not use    alkaline/ or Drycells (carbon zinc) on line power, or  they will get hot and leak if you plug in the above power pack with these wrong batteries.
But if you keep the line power pack, or wall wart, attached to this unit, do not use any battery inside, unless it is NiMH.
If you want cheap remote usage ,just use the below AAA 2 holders with 8 dollar store
alkaline AAA batteries, and it works great, and very low cost.
This AA device, model 100, now obsolete is sold in a stripped down form, for a low price, seen on fleabay. 

The battery pack missing, is hard to find, it's very thin, here is one that fits ,.  ( size is AAA, (5.2 x 4.9 x 1.2)cm/ {2.04 x 1.92 x 0.47inch} (L x W x H) 
 The 1.2cm thickness above is very limiting, and key to success, here.
I talked to them and...
There reasons: are here:
  1. The NiMh batteries, are $8 to $30 a set, walmart sells them for $24, plus tax.  so its not provided.   " the old, Batteries not included deal"
  2. The holders missing keep the price low so users not needing protable uses save money. (why not offer it as an option I say....)
  3. The power pack will nor work in all countries, (I do see exceptions but they are expensive , $25 or more)
  4. The manual is not included, (too many languages) they tell me , email me after the sale and we will send it, (I'm still waiting)
  5. The software is missing, sure.  That be extra and not offered at time of sale, my guess is the software is only in Chineese (seen it and its hard to understand.....)
more rules...

The battery side D.C. load regulators do  not need a minimum  of 13.8vdc to run,  and you can run "Dollar store", alkaline batteries in it, but do not plug in the line power with the wrong batteries present.
This is not new, all things that run batteries tell you, not to run the wrong batteries. (for many reasons)
The battery drives only a 7805 reg, so at 7vdc it will drop out. 12vdc would have to drop below 7v to have the reg go off line.
An LM317 reg. chip changes the batteries. 
Recap on rules
  • 14v to 19vdc power pack 1 to 2 amps min.
  • Do not charge the Alk or drycells with above pack plugged in, only charge the NiMh batteries and nothing else.
  • The battery pack only needs 12vdc to run (even less or weak batteries run). with any batteries you can find.

Last rule, never transmit into this device, or any signal generator, for that matter. (or BOOM)
end rules:



This thing is FUN!
USE an antenna analyzer. See if the antenna or feed line is messed up. I used HAM  Steve's  "
AK4R" software.   (if you buy a real store bought SARK110 the software is better but costs way more.  )
I bought  a SARK 100 kit, from Kentucky in fleabay, not from China direct ship, so I can could return it or ask questions in English.  (no need, it works like dream, I love this THING ! makes a grid dip meter , a relic....
The LCD on the front panel is limited ,to what you see below, use the software !
This  device is like a tiny radar  and sends out a small RF signals standing waves, and the echo's are digitized (reflectometry) and logged,  using real software via the USB cable, one can see what is out there on the Feed line.
It has  swept RF signal generator inside, it is no toy.
 I posted lots of photos  here to see all that. (these tool can be used as an L-C-R meter too.) wow.  (Get one , and play with it, it is a very useful  low cost  tool)
Manual mode set to 14.3 MHz freq.  1.59 is SWR,  61, is the Z on the line (Z means Impedance)  (use this mode remotely; say up on a tower?)

Keep in mind it has an onboard transmistter, very weak is called a signal generator,
Best it to test the above tool when you first get it doing simple things, shorts, opens, then a known resistor.
The manual shows, lots of tests, to do , to validate the tool and educate the new user, try a CAPacitor next. (start simple work up.?)

If you buy the tool from China, you must email them after you get it and ask via email or "ask seller a question" on Fleabay, and get the manual, that way.
I tested a 470pF cap at the tools connector. and at 1.8MHz,  calculated 188 ohms X sub c, reactance.  Xc.
 Xc= 1/ x F x C      / means Divide. x means times . In this classic equation for Xc.
I tested like 5 resistors, (carbon) from 10 ohms to 200, and all read perfectly. (compared to a real OHM meter, accurate) 
If you have some known Inductors test them with XsubL  =  2π x F x L   (inductive reactance) in ohms.  It will show up on right side of graph below.  
Z means Impedance (the combined effects of R/L and C.)
This tool can even check tank circuits and allow you tune one, by hand, easy. (try it, its a load of fun )
What great training aid for kids,  show them the simple math, then build a tank circuit, then prove it works with the above.  Concept, build, and Validate.
By the way, I have a dirt cheap  ESR meter, that works just like this, sends out a low  freq, RF  signal and does math and does R,C,L , diodes and transistor beta , all for $10.

See the block diagram here,  its not trivial at all.( by Ham  EA4FRB )

Ham "AK4R" , Steve's program looks like the below, 
The software needs a working COM port, via USB cable,  as in all things like this, the Com port must be be found in Windoz Device manager, (see mine shows COM6?) then set the AK4r settings window to the same com port,#6.
If you don't do this it can't communicate.  
The best way to test the tool is per the manual, is to make  a hand held, R-C-L tank circuit.  (you make it, tune it as you wish)
Buy the wayP
Just don't key-up and transmit your PA, into this nice tool. or boom. happens, you let the smoke out. (same with a real Spectrum Analyser, boom smoke out)

Thanks STEVE  AK4R !  What easy software to use. (Windows10)  Contact him on eham.com, the price is RIGHT.
I got my SARK100. It works great.  Its works rock solid, no quirkiness, in the software.

 
I tried all the tests in the book,  Xsub L ,X sub C, LC, LCR,  my transmission line tests and antenna  tests. (you must ask for the book or google it)
Once simple components function and read out... , we then do the below.
You can test transmission lines, and  antenna's yes,  you sure can tune said antennas. (antenna trimming is now easy, trunned longer to shorter)
You test any antenna tuner using this tool to see that it works at any frequency you want to use. See if the tuner has dead spots, and all that...
The next tests, are the most fun, the input to my   Tuner. (the tuner was pre-tuned by me, nulled out at 7.2mhz )

Then I scan it below.  " SARK to TX connector port on Tuner, tuner coax to G5RV antenna +balun."   (AT2KD, dials  a   L116, A0 and T0)
 If you were OCD, one could put this use the data below to ultra fine tune the tuner...
The below would be a good test to see see if that roller inductor inside had dead spots.

   ( SWR is NOT  always proof of  RESONANCE     Resonance is when X sub L = X sub C,  (inductance = capactance) at a specific frequency.
Photo 1:  Lookin into my TUNER: AT2KD tuned to about 7.2mHz.  This is out to my  dipole on the other end.


The Book for Sark100 shows a test devices,  that is a Series, tank circuit, with 47 ohm Resistor,  68uH inductor and  62pf CAP.
I assembled their string of parts.
The results are below.  What a powerful tool.
Photo 2: (a series TANK circuit)  (the tool has Capacitance, and inductance, Impedance, and SWR test modes  via its "red mode button" )



You can tune and trim antennas best at the antenna., check that the antenna is ok and check transmission lines for opens or shorts or?,  or check antenna  bandwidth.
You can even tune the antenna tuner and get a better tune with  this tool.
Find bad transmission line connectors (rust or loose or bad)
Open lines, crushed lines, soaking wet lines,  shorted, or dead open lines.
Make no mistake this AA device is not as good on tranmission line as a TDR.
 

CABLE TESTS:
Next is my testing 4 new (2foot) cables that added to 8ft total, connected in series with 4 BNC barrel coupling and the input with a 6db pad, the has 84 ohms resistance.(measured) (just using the 84 ohms as a default source impedance)
I am attempting to find the reflection point off the open end of that cable. I did a full scan, from 1MHz to near 60. 
The lowest resistance will my (pad resistor of 80ohm) the 1/4 WL  is 8.275 feet, (a the stated velocity)  As you can see I measured the reflection below in the RED peak.
RG-62 (for my SB300) is 92ohm coax (characteristic, impedance)
Photo3: Using the equation for velocity factors, & my calcs. Shows the  same frequency that this scan found. 24.6MHz.  (keep in mind  if your cable is too short, I can't scan it, due to MHZ limits of  this SARK100.
 

The below gif animation shows, what happens on the ends of a dipole or even just one coax line,  The 1/4 wave point, on  one side peaks for voltage, and will cause a reflection when not matched properly, in this case Infinity (air)

 
Swept antenna's
Next  UP, Photo-4: G5RV direct connected, (deep scanned)  keep in mind this has open wire ladder  450ohm (window) feed line to the Dipole wire.) One can see why 20 meters works so good. (low reflections)


more later, ...



Files and sources of documents.
A Video: here.(offset youtube)

The manual is here (offset) but watch out  most sites with PDF are now all full of viruses, (use real Adobe readers, from its true source, only, uncheck the 2 boxes seen there, at Adobe !)

The schematic, I found is here by MR,  EA4FRB (ham) – Melchor Varela ( direct to his site)

This device (AA) needs to communicate in Serial mode, for the PC software to work like above , the cable USB attached, the PC must emulate the old old serial standards, called "RS232", or more accurately, TTL-232(levels).
Know this, long long ago, the PC makers removed all the real (9/25 pin) RS232 ports,  (Lap tops lead the way and bam every maker did this to save $$$), but gee, MCU's need it.
The chip in the AA box, is a FT232 chip, and matching driver, to make all that magic happen.
Since I have no idea, what OS (operating system) others use? (Windows, 3.2/95/98/XT/7,8,10) for sure you do need a matching driver  ,the older the  OS is the more true that is.
Power on the AA now , all things connected.
In Windows 10 , W10, you turn on the AA device, and the O.S, does it's magic PnP plug and play(pray) mode , immediately. (let it, say YES)
Best is to have the device manager DM (in CP, control panel) up and see what port was assigned, usually COM port 4 and up. (this com port in DM will pop up fast at the AA power up moment)
Last ,wiggle the APPlications, comm port NUMBER seen here,  to match what you found in DM. 
Press Analysis button and it starts scanning.

Problems:
If push gets to shove, then force load the FT232 driver from the makers link above.
I think the Baud rates are set automatically via the nice AK4R applications seen above.

More facts on Serial data: (short but sweet)
Why is this FT232 chip present?  (there are 2 wires. transmit and recieve, TX/RX) (it takes more than 8 wires to do that, with parallel data, (with must have control logic)
TTL-232 is a device (in this case a chip) that converts, serial transmitted data to parallel,  that which the PC processor can use. (this saves having 7+ more wires of data connected, like seen on relic printers, long ago...)
AA >> TTL232>>FT232>> USB, to PC  What this path does is make the AA USB compatible, with your PC. (old serial to new serial)

The difference between RS and TTL 232, is that Latter TTL , has the +12v and -12v driver chips missing(MC1488) , that former allows long 100meter transmission lines using high voltages, but is not a problem as our wires are very short.
The RS version have vastly better noise immunity.
This "TTL" method  is an  abridgement of the RS standard, and very useful. (read, every ones MCU box loves to do this)   As you can see, design rule for  serial data, is at what distance? (#1)
The RS232 was originally used on complex modems. (thus all those many wires and signals) but was long ago used on all terminals and many printers, (far distances in some noisy printer room was common practice)
Here is an example of the whole cable and hidden chip , so you can see how it works , focused ,This cable would connect to almost any typcial  microcontroller.(MCU)

version 1.  11-30-2016