Micro908 News Blog

Blogging on Micro908 "news & happenings"



(October 15, 2010)

The REFL3 reflectometer project is proceeding well in beta trial and we may produce a daughtercard upgrade kit available for all Micro908 owners to buy and install if they wish.

(March 15, 2010)

Hi all,

It's been a while and just wanted to let you all know the Micro908 project is still alive and well here.  Some exciting new steps are about to be happening, and here's a preview ...

MassCon Presentation & Use of Micro908

I wanted to point you over to a presentation that design partner N2CX and I did together at a conference this past weekend up in Massachusetts called MassCon ...  http://www.midnightdesignsolutions.com/MidnightLoop/index.html

For the past year or so we’ve been working on a new STL (magnetic loop antenna) design and we found the Micro908 Antenna Analyzer to be of immense value during the development, field trial and documentation of things.  You can see the use of the instrument about mid-way in the slide deck.  No other instrument that would have worked to help us achieve the results we got!


Now that this major milestone has passed, I’m able to focus near exclusively back on the REFL2 project in order to finish off the accuracy improvement project.  As a reminder, this daughtercard can be added to all existing Micro908s, if desired (it’s not mandatory), and it will be available at cost for all current Micro908 owners.  It will be added to the kits for new Micro908s being ordered, with a corresponding price hike, which by definition will be more than just the cost of the parts.

Further, it’s likely there will be an incremental step that is proving to improve performance without going the full “REFL2 path.”  Stay tuned for this news, as I’m just about ready to unveil this improvement.

(BTW, if you are new to this Micro908 list, REFL2 is a small project add-on to improve accuracy of the Micro908 impedance and SWR readings.  See http://www.amqrp.org/kits/micro908/REFL/refl2.html for more detail.)
Displaying Raw Impedance Z
Someone mentioned that it would be useful to optionally display raw impedance (i.e., in the form of scalar value Z) instead of complex impedance R +/- jX.  We made some quick tests here and agree (a lot), so there will shortly be an updated software version containing this feature.

Amazing “HC908 VFO” Program also works in Micro908!

Last month I had a little time to work on a request of a friend to provide improved VFO software for the HC908 + DDS-60 card combination.  We’ll I got carried away and developed some software using those common daughtercards that is really quite useful ... Multiple memory, frequency offset, and frequency scaling for controlling a SoftRock transceiver.  You can see this project at http://midnightdesignsolutions.com/HC908VFO/index.html.  

But the best news about this HC908 VFO software is that it also runs on your Micro908 instruments!  Since the Micro908 also uses the HC908 and the DDS-60 components, and the rotary encoder and LCD display, all you need to do is dial up the “Load New Software” function and load the hc908vfo_3a.s19 file from the website, and you too will be running the VFO program on your Micro908.  Connect the RF output up to your transceiver and you’ll be off and running with a nice, stable and controllable Micro908 VFO.  [Remember always to select Default Settings” after loading any new software into your Micro908].
Micro908 Overview Videos Posted on Website
Some time ago we created a videos that overviewed the Micro908 and it was placed on the Homebrewer Magazine CD set (see http://midnightdesignsolutions.com/index.html), but for some reason didn’t make it to the Micro908 website ... Duh!  So they are there now.  Check the top of the Micro908 page page for these links ( http://www.amqrp.org/kits/micro908/index.html).  Hope you find it interesting and helpful in understanding the instrument.

Okay, that should suffice for a “coming out party”!  I’ve recently been completing a number of Micro908 Kits for guys who got stalled, so more and more instruments are starting to appear again.  Let me know if you are having trouble finishing up your kit and we’ll gladly provide some reasonably-priced assistance.

Meanwhile, hope to hear from those of you who are successfully using the Micro908 (like me on a regular basis), and stay tuned for some exciting things happening soon.  We’re hoping to have things unveiled well before the Dayton Hamvention!

73, George N2APB

(May 19, 2008)

Just got back from the Dayton Hamvention - we had a great time at the AmQRP booth demonstrating the Micro908 and discussing things with current Micro908 owners who came by.
We had the new kits for sale and sold every one of them that we brought.  (Not to worry, as we have many more in stock ready to ship as soon as the orders come in.)
We also unveiled the new PCB for the latest kit.  This is the one containing all the mods that have accumulated over the four years that this product has been in the field, and those using it won't have to make a single cut, add, twist or turn of a component to get the kit working.  Just as soon as I can update the ordering web page, this same new PCB will be available for sale to those who might wish to get it for use in place of their unstarted kit's pcb.  Of for those who are looking to homebrew their own Micro908.
We were showing the REFL daughtercard upgrade and the DM908 digital modem code, but they were not production available yet.  Sorry, but there was just not enough time leading up to the show to get this done.  But now that the dust has settled from this, and from a new business venture that has been months in the making and culminating at Dayton, Joe and I will be able to finalize these latest two projects and bring them to market.
We showed a Micro908 Road map that illustrates some exciting growth plans that are in the immediate months and culminating at next year's Dayton.  We'll put the Roadmap diagram on the website just as soon as I can, and it will show ...
- Today's Analyzer for flexible antenna analyzer, audio filter, memory VFO
- Add the REFL to improve accuracy, auto-level DDS output, Advanced math capability
- Add USB port for new programs, external data store
- Add Graphic Display for onboard plots
- Add digital modems software for BPSK
- Add DDS upgrade for VHF capability
- Add membrane QWERTY keyboad for integrated terminal capability
- Add HF transceiver to make fully-contained EmComm RF terminal
We'll also next have the updated Owner's Manual available in the coming week or two.  This is looking to be a nice updated summary of all the current features and operational guidance.
Can't tell you how many guys came up and stated their love for the basic/main features of the Micro908: signal stability, flexible platform (many functions), field upgradability, future growth, and basic utility for the scanning and plotting of antenna performance.  Sure was gratifying ... and inspiring for carrying onward along the Roadmap.

(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. 

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.
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!
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. 
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.
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".
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

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Page last updated:  April 2011