(January 25, 2008)

We have been working on a reflectometer upgrade daughtercard that will retrofit to all existing Micro908 instruments in the field in order to provide increased accuracy and functionality.  This will be made available "at cost" to all existing Micro908 owners, as desired, and will be incorporated into the the main pc board for the next round of kitting done later this year.  We expect to have this REFL2 daughtercard upgrade available at Dayton this spring.

(January 10, 2008)

Someone recently asked for a comparison between the Palstar ZM-30 and the Micro908 ...

The Palstar ZM-30 (http://www.palstar.com/zm30.php) is a licensed, derivative design of the Micro908 that has a ruggedized case and different power control (timer-based on/off for main power and LCD backlight).  But it does not have any of the modular/extensible features of the Micro908 (DSPx, nonvolatile memory, audio amp, kbd and paddle inputs).  All in all it's a good instrument that received a pretty good independent review by ARRL labs in the April 2005 issue of QST (I think).  We licensed it to Palstar and they have implemented a subset of the overall capabilities. Palstar didn't use the daughtercard hardware arrangement, but instead designed everything onto the motherboard. But other than the features corresponding to these missing hardware items, the software is functionally identical. (The ZM30 also has neat power-on circuit that allows auto-poweroff, as well as the built-in LCD backlight control and timeout capability.)

Advantages of the Palstar ZM-30:
- Sold as an assembled/tested unit
- Rugged aluminum case
- Auto power on/off control & built-in blacklight display
- Support of an established, professional company known for building solid instruments

Advantages of Micro908:
- Sold as a kit (if you built up an ATS-3B, you will certainly have no problem.)
- Modular construction (controller, DDS, DSP daughtercards)
- Hardware platform has additional components: DSP, audio amp, nonvolatile memory, paddle/kbd/aux/audio connectors.
- Additional software programs can be field-loaded to use the Micro908 as an Antenna Analyzer and DSP Audio Filter. (Other programs soon to be available (at Dayton) include Memory Keyer, Morse Keyboard, and a Digital Modem Controller.
- Hardware and software design is all open and under GPL license for anyone's use in creating new or custom versions of existing programs.

Both the ZM-30 and the Micro908 optionally connect to a PC for the use of utility programs, Link908 and Plot908, to plot and display SWR and Z, and provide remote control of the instruments.  And the software for both instruments can be upgaded in the field over this serial connection to the PC, allowing for new software releases to be loaded up.

(November 2, 2007)

Here's some juicy updates on the major upgrade design projects that have been in motion this spring/summer for the Micro908. 

 

REFL DESIGN UPDATE

Someone asked what the "compensated linear" reflectometer redesign approach was.  REFL2 is a linear version of the original design but with diodes fully matched and compensated using the Grebenkemper method ("Calibrating Diode Detectors", Aug 1990 QEX)).  We also have the ALC in there to keep the DDS signal level at a contant level, and the math chip is still on the board to facilitate complex computations with the advanced coax features. 

 

I've updated the Micro908 web page with a ton of new detail concerning this second REFL design approach. Read all about the REFL designs here.  I think most of you guys will find it interesting.  Joe and I are still characterizing REFL2 performance, but so far it is looking like a better overall solution and we may well end up going with this one.

 

OTHER DESIGN FRONTS ...

 

PSK31

I'm making my way through porting the NUE-PSK engine (i.e., the PSKcore DLL from AE4JY) over to the DSPx card. This will enable all Micro908 owners who have the DSPx card to soon have their Micro908 operate as a digital modem, standalone from any controlling PC.  Nice field option!

 

GRAPHICAL DISPLAY

Also as part of the ongoing NUE-PSK Digital Modem project, design partner W8NUE and I have the single LCD 164x64 graphic display working ... and now it's an easy "port" of this software driver and LCD over to the Micro908.  This will enable all Micro908 owners to upgrade to this graphic display to show plots of SWR, R and X, as well as Smith Chart results of the antenna/feedline performance ... right on the unit. 

 

USB MEMORY PORT

This option will allow one to add support for a USB memory stick (thumb drive, etc.) that will store different programs that will run on the Micro908 (AA-908 versions, AF-908 filter program, Keyer program, PSK-31 program), *and* antenna analyzer data files. So you could easily store all these files in a filesystem on a modest 16MB thumb drive and transfer to/from your Micro908 in this manner.  Pretty cool.

 

MANUAL UPDATE

A general overhaul of the manual has been in progress this summer that catches up all the changes, new calibration approaches, new features & commands, new PC tools for analyzing and plotting, etc.  This will be a welcome help for all newcomers to the Micro908 platform, I'm sure.  Further, we're making it semi-pocket-sized such that it fits into the side pocket of the nifty Micro908 Carrying Bag option.  (You all took advantage of that offer, right?  Not sure how many we have left.)  Top it off with a spiral binding and laminated front/back covers printed in color, and you'll have a graet reference manual for using your instrument.  We'll be making the PDF available to everyone, of course, but if you wish to get the printed version as I described, we'll be making that available "at cost".

 

MOTHERBOARD PCB Update

We recently had to put in for another run of Micro908 pc boards in order to replenish kit stock, so we took the time to correct all the little "gotchas" that require builders to put cuts/add/mods to their boards before even starting the project.  You all know what I mean.  So as of right now, all new Micro908 Kit orders going out the door have a pcb that is totally current with everything we've all learned over the last three years of shipping the kit!  No mods required.  So if you heard of someone hesitating on getting a kit for this reason of needing to wade through lots of updates on the Builder's Notes page, tell them the log jam is cleared :-)

 

73, George N2APB

     and Joe N2CX