World Maker Faire – Bring-A-Hack meetup

In the tradition of Jeri Ellsworth’s famous Bay Area Maker Faire parties, tonight (September 25) there will be an informal meetup at Spritzenhaus in Brooklyn at 8:30 pm. If you’ve got an interesting piece of hacked together hardware to show off bring it! If not come anyway.

Spritzenhaus is located at 33 Nassau Ave, Brooklyn, NY 11222


RADARduino Update – Testing Partially Populated PCBs

As a partially built kit, the RADARduino boards need to be tested before being packaged and sent to customers to verify that the assembly of the RF section is successful and meets specifications.

Contains an RF power meter, Doppler simulator

Contains an RF power meter, Doppler simulator, a host computer (Raspberry Pi), and interface to an external oscilloscope for measuring system performance.

I have built a special piece of test equipment that in conjunction with a test fixture will allow for testing of transmitted output power and receiver functionality.  The box is still under construction and will eventually interface with an external oscilloscope and contain a built-in RF power meter.  This box replaces several pieces of costly test equipment with common off-the-shelf RF components.

Holds the PCB in place while pogo pins and fuzz buttons make electrical contacts to pertinent traces and pads.

Holds the PCB in place while pogo pins and fuzz buttons make electrical contacts to pertinent traces and pads.

Over the next couple weeks as I finish this box, I will test the new prototype boards and verify the clamshell fixture as well as the test box functionality.

Prototype RADARduino partially built - ready for test

Prototype RADARduino partially built – ready for test



Radarduino Update!

It has been a long haul getting this kit ready.  The last year has presented some personal issues that have slowed progress to a halt.  I’m glad to report that things are no back on track and progress is being made.

I have 4 production ready PCBs that I’m going to populate and test over the next few weeks.  These will be used to develop and evaluate my factory acceptance test.  Since the kit will come with a partially assembled board, that portion needs to be tested on a specially built fixture.

Additionally, I’ve begun work on the user manual/assembly guide.  This document will contain all the information needed to build a RADARduino, technical information including schematics, and bill of materials.

Finally I’ll be experimenting with antennas and coming up with a solid design that will give good performance.

I’ll be updating this regularly, so stay tuned.  I’m also going to be announcing a crowdfunding campaign to launch the RADARduino!



A Brief History of Herley/CTI DRO Synthesizers


I recently had the opportunity to meet John Odell, the man behind the family of Dielectric Resonant Oscillator (DRO) Phase Locked Loop (PLL) frequency synthesizers sold under the Herley/CTI name.  I told him that hams are big fans of his designs and wondered if he’d share some of the story on their design, modification, and history.

First, for those who aren’t familiar with these units, check out the family of products at Kratos’s site (the new owners of this product line).  A search on eBay shows that surplus units are available in a range of frequencies.

Historically, hams started in the 1950’s with klystrons, then in the 1980s moved to Gunn diodes, and “brick” oscillators (cavity type diode multipliers) and some managed to get phase locked sources with that arrangement.  Those brick oscillators provided exceptional low noise performance at the cost of long term frequency stability, as most people did not phase lock their ~100 MHz references.  In the mid-late 1990s, silicon based synthesizers became decent, (from Qualcomm, National, etc.) at least for small multiplications (from 2.5 Ghz times 4 to 10 GHz). In the early 2000s, the Herley/CTI (and competitors) oscillators became available with much better pahse noise performance and the ability (with dual loop versions) to lock to convenient frequencies like 10 MHz which could be disciplined to a GPS or Rubidium source.  This solved the problem of low phase noise and long term frequency stability.  Builders are using Herly/CTI DRO oscillators in radios from 10 GHz through 144 Ghz with multipliers, sub-harmonic mixers, etc.

Before getting into the technical details and history of the PDROs, a bit about John Odell himself.  I asked John to tell us a little bit about himself and how he ended up designing the Herley/CTI oscillators:

I started in oscillators at Sperry Corporation in Phoenix Arizona in 1985 at the age of 24. I worked on a 9.345GHz Electrically Tuned DRO used in a LNB for weather radar. I was also fortunate enough to be in the advanced development group at Sperry where we designed some of the first successful MMIC’s using the new Triquint foundery service. I designed monolithic oscillators, mixers and amplifiers with a great group of young engineers. From Sperry I went to a GaAs start up in NJ and when it folded, I went to CTI to develop the PDRO product line. I always liked analog electronics, and oscillators because of the nonlinear challenges.

In regards to the origin of the DRO business for CTI:

The DRO business was a natural evolution from the cavity oscillator business, It offers comparable phase noise, at a smaller size, lower cost, lower power with higher reliability. Customers where and continue to be  Satcom providers, Military for communications, EW sytems and radar, and Point to Point radio customers. The largest use by far is for Point to Point radio. Back in the 1999-2000 time period there was a big push for point to multipoint communications, and CTI sold 10’s of  thousands of these PDRO’s to several companies. Two of the main suppliers got out of the business and some of the old stock got sold to surplus and is available on Ebay..  The 2.25” x 2.25” x .625” became the industry standard back in the early 90’s. it was a good size for frequencies in the 6 to 40 Ghz frequency range.

One of the questions that frequently comes up among hobbyists is how to modify PDROs for different frequencies.  On that subject, John says:

 The tuning adjustment can be used to lock to additional  comb frequency ( multiples of the reference input) for example a unit that is built for 12.3 GHZ locked to an external 100MHz reference can probably be tuned approximately -100MHz to +200MHz   and lock to between 12.1GHz to about 12.4GHz at multiples of the 100MHz reference. This should be done while monitoring the phase lock voltage pin on the front of the DRO. As tuning screw is adjusted the phase lock voltage will move from 1V to about 12V for a 12V unit. Once the tuning screw is tuned outside of the lock range the unit will sweep and you will see a clipped sign wave signal at the phase lock pin, continue to adjust the tuning screw until the unit relocks and a DC voltage is present on the phase lock voltage pin. Adjust the tuning screw further to set this voltage at VCC/2 (6 volts for a 12V unit, 7.5 V for a 15V unit). With the dual loop version, you would need to reload the PLL chip on the crystal and change the crystal frequency to change the internal crystal loop, and I would not recommend doing this as it is out f the scope of most Ham hobbyists.

I also asked John about how to modify the oscillators to operate beyond the normal range of the DRO.

The DRO frequency is determined primarily by the Dielectric Resonator Puck. These pucks have a dielectric constant of around 32 to 36 so it is hard to change there frequency with material and the material must be of a high Q, or it will degrade the oscillator phase noise. Some users have used a diamond file to file the edge of the puck towards the back of the unit (opposite the output connectors) to raise the frequency about 2 percent. This should be done on a constant 45 degree angle. You must be careful to not apply too much pressure to cause the puck to come unglued and you must  clean and discard of  ground resonator powder from  the unit using a Q-TIP wetted with alcohol. I MUST WARN YOU THAT THE RESONATOR POWDER IS A KNOWN CARCINIGEN AND SHOULD NOT BE BREATHED IN OR INGESTED, SO I DO NOT RECOMMEND THIS PROCEDURE FOR TUNING THE FREQUENCY.


I solicited a couple of microwave email lists for questions.  Several people asked for schematics and some very detailed design information which is obviously proprietary and not available.  Here are the remainder of the questions and their answers:

3.  Does he have a suggestion of the best way to add varactor fine adjustment to the internal crystal osc so that I can phase lock it to an eternal reference?

I don’t recommend this. I recommend buying an external reference unit and locking it to an external reference that is a sub multiple of the frequency you want to run at and then adjusting the tuning screw to lock the unit to the external reference. Look at this crystal osc. available from Digikey. This and a PLL chip can go a long way. Again Have Fun!
4.  Sampling phase detector parts as monolithic assembly of parts have become difficult to find. I’d be curious to know if he’d experimentally compared the performance of discrete and monolithic SPDs.

Discrete SPD’s have been built that work up into the 16GHz range with the correct layout and PLL circuit. Good luck with this and have fun.

5. What would the performance hit of a discrete one would be not using chip and wire?

Most of the SPD PLL’s are made with surface mount components and work up to 18GHz if designed correctly using a monolithic SPD.

I would like to thank John Odell of Kratos for taking the time to answer these questions and provide us with a look into one of our favorite pieces of surplus electronics.

-Tony KC6QHP

10 GHz Beacon Project

Over the last few weeks I’ve been working on a new project, a prototype of a new product. I don’t have a name for it yet, but it is essentially a beacon transmitter.  Beacons are frequently used in the amateur microwave radio hobby as location markers and as a means for testing receivers.  During a contest, a beacon in a known fixed location can be used to establish a heading.  Since microwave antennas are typically high gain, it is really important to know your heading.  Additionally a beacon can be useful in studying propagation between two points.  In Southern California, there are several beacons on the 10 GHz band including one with wide coverage on Frazier Mountain.

Historically, beacons have been built by individuals or clubs who have access to some great spot on a tower or a mountain, as well as access to the parts and test equipment required to get one on the air.  The goal of my beacon project is to put together a kit that will allow more people to put up beacons in more places.  I am basing the kit on my two existing products, the OpenSynth PLL synthesizer, and the TimesFour multiplier.  Since the OpenSynth is based on a fractional PLL, it is possible to achieve the narrow frequency steps required for use in crowded bands.  Also, since the OpenSynth has a microcontroller, it is relatively easy to program in a CWID routine that uses FSK to generate a Morse code identifier.

The guts of the beacon. From top down, TimesFour multiplier, OpenSynth PLL at ~2592 MHz, bias tee circuit.

The guts of the beacon. From top down, TimesFour multiplier, OpenSynth PLL at ~2592 MHz, bias tee circuit.

My first major design choice was packaging and location of the electronics.  There are two ways to make a beacon, one in which the electronics are located indoors, and the other has the electronics on the tower next to the antenna.  I decided that for ease of installation and lower cost, I would have the electronics on the tower.  For the 10 MHz reference though, I chose to keep that indoors.  This allows builders to use their choice of high stability 10 MHz sources, from an ovenized crystal to a GPS locked Rb standard.

To get power to the beacon, as well as the 10 MHz, I designed a small bias tee board which also has ESD and reverse voltage protection as well as a fuse.  Microwave beacons are often installed in harsh locations and it is important to protect the sensitive electronics appropriately.

Bias Tee circuit with ESD and lighting protection.  Also a 10V linear regulator.

Bias Tee circuit with ESD and lighting protection. Also a 10V linear regulator.

For an antennas, it is hard to beat the slotted waveguide antenna.  A beacon transmitter should have an omni-directional horizontal pattern, but very little vertical radiation.  The slotted waveguide antenna does this very well, and a local ham Dan, W6DFW makes some very nice ones!

Slotted waveguide antennas machined from WR-90 copper waveguide

Slotted waveguide antennas machined from WR-90 copper waveguide

Finally, a suitable enclosure is necessary.  Suitable means that it provides protection against a harsh environment (rain, dust, wind, snow, ice, EMI, RFI).  The enclosure I’m using is a die cast aluminum housing which is both waterproof and has an EMI/RFI gasket as well.  Beacons can be installed on the same tower as high powered broadcast transmitters, so it is critical to keep everything very well shielded.

After assembling all the pieces and programming the synthesizer, I put the prototype beacon on my apartment roof in Redondo Beach, California.  I have it mounted to an existing DirecTV dish mount.  I’m interested to see how long this will last before the landlord starts asking questions!

The experimental beacon installed at KC6QHP

The experimental beacon installed at KC6QHP

In one week of operation I have gotten reception signal reports from as far away as La Jolla, CA (100 miles south), and Gorman, CA (70 miles to the north).  Other hams more local to me have also reported hearing the beacon from their homes.  I would call this first prototype succesful, and am very interested to see how things hold up in the weather over the next few weeks.

Below is a screen capture of my beacon being received by Rein W6SZ at his home in Rancho Cucamonga, a distance of almost 50 miles.

Screen Shot of my beacon signal being received at W6SZ

Screen Shot of my beacon signal being received at W6SZ

Here’s a recording of my beacon as heard from Mt. Soledad in La Jolla, CA by Kerry, N6IZW.

There’s plenty of work to do before this becomes a product including the design and construction of an amplifier.  The beacon currently puts out ~75 mW of power which is enough for some applications, but it is handy to have more power, so that will be coming.  I also need to look at humidity venting options, RF filtering, and issues related to getting a good 10 MHz signal up different lengths of coax.

Tony – KC6QHP

Navigating Export Restrictions For Small Electronics Businesses

Disclaimer:  I am not a lawyer, nor has a lawyer reviewed this material.  The following are suggestions and general information about export controls.  This information is not legal advice and should not be treated as such.  This article discusses issues pertaining to United States Export Controls and may not be applicable anywhere else.  Treat this article as a simplified introduction only!

Do the acronyms ITAR, USML, ECCN, EAR, CCL mean anything to you?  If you are involved in selling electronics they should be!  Over the last several years, a large number of people (including myself) have gone into the business of designing and selling electronics kits and products.

Starting up a small business requires a lot of effort in understanding issues not directly related to designing and selling products.  These include accounting, sales tax, income tax, business licensing, and obtaining a re-seller’s permit.  One more to add to that list should be export controls.

Unfortunately, export controls are a vast, complex topic to understand in detail.  Many large companies have whole departments of people and lawyers dedicated to this issue.  For most people running a home/hobby business, it is impractical to have an export control department, and legal advice in these matters is prohibitively expensive.  All is not lost though, as a basic awareness of export control issues is better than none, and may be sufficient.

What are export controls and do they affect me?

Export controls are in place primarily for issues of national security, but also for issues of non-proliferation of weapons, human rights, regional stability, terrorism, trade sanctions, etc.  These controls take the form of regulations on what can and cannot be exported, and to whom.  Some things can be exported easily, others require special licenses, or cannot be exported at all!

Whether export controls apply to you mostly depends on what it is you are selling.  If you are selling ANYTHING that could have potential application to the above list, then you need to be aware of and comply with appropriate regulations.  As you might expect, this covers a tremendous amount of goods and services.

By the way, an “export” may not be what you think it is…. Clearly the shipment of hardware across a border is an export, but so is giving a non-“U.S. person” protected technical information even if they are inside the U.S.!  (A “U.S. person” by the way is a U.S. citizen or permanent resident who does not work for or represent a foreign government or business.)  If you design a product that is export restricted, it’s design and software may be too.


Let’s go back to those acronyms for a moment so you can get an idea of some of the players in this export control business…

USMLUnited States Munitions List:  This is a list that describes items covered under ITAR..   Essentially, this is a list of items designed for military use, and items with no non-military use.  Determining whether something falls under this list can be a little tricky, and in fact, the government is in the process of being more explicit about it.  An example of something found on the ITAR list is certain types of image intensifiers or “night-vision goggles”.

ITAR International Traffic in Arms Regulations:  ITAR is a set of regulations for products that are listed in the USML.  ITAR is handled by the State Department and governs the export of goods of military use.

CCL – Commerce Control List:  This is a very long list of goods, services, technology (could be software, designs, etc).  Generally things that don’t fall onto the USML will fall on to the CCL list if they have dual-use (can be used for civilian and military purposes).

ECCN – Export Control Classification Number:  This number is assigned to an item that falls under the jurisdiction of the CCL.  It is basically a section number of the CCL describing the good/service/technology in question.


How do I know if my product/technology is export controlled, and to what extent?

The way to determine if your product is export controlled is to carefully read through the CCL and USML and see if you can find a matching description to your product.

Generally speaking for most in the hobby electronics business, products will generally fall under the CCL or under EAR99 (indicating that no license is required to export to non-embargoed countries, denied persons, prohibited end users/uses etc. etc.)

However as the line between hobby use and military use is becoming less clear (think autopilots on UAVs, thermal imagers etc.) it would be wise to also look at the USML and make sure your product doesn’t fall under that list.

If you still have doubt (and these documents are still not 100% clear on things) there are means for having the government decide for you.  This is the surest way to know your product classification should you have doubt.  ITAR calls it a Commodity Jurisdiction and for the CCL, it is a Commodity Classification


My product now has a classification number, now what?

If you have gotten this far, you should probably start reading more details on the various web sites, because it starts to get a bit more detailed.  Suffice it to say, there are lists of countries to which some things can be exported without license and others which require a license, or are banned.

There are a number of responsibilities associated with exporting, generally they are more stringent with ITAR items, including registration with the State Department, collection of documentation of the end use, end user, etc.  There are also lists of people inside and outside the U.S. who have been banned from  receiving exports all together.  These lists have to be checked for each export.

Probably the best place to start is the Commerce Department’s introduction to Export Control.

If you think you have a USML item, check out Getting Started at the US State Department.

My suggestion is that if you have a new product in mind, before doing a ton of development work, read through these lists and see if what you are thinking about is worth the effort.  If you end up with a USML item, you’ve got a lot of work and cost ahead of you.  Likewise, if you have something controlled by the CCL that can only be exported to say Canada then you’ve got some serious license application work ahead of you if you choose to export to other places.

While this subject is tricky, sometimes vague, and requires lots of reading, it is worth while, and required for the legal export of just about anything.  The good news is that the government recognizes the difficulty and has ways of helping figure out where your product stands.  Finally, there is reform happening now which will roll out over the next several months that should help make this process easier.

One area I have seen little mention of is Open Source and how it pertains to export control.  Does anyone know anything about this?



RADARduino Prototype Testing and Revision 2 Details

UPDATE: February 25, 2014:  The RADARduino has received a commodity classification from the Department of Commerce as 6A008.b.  Since the design itself will be open source, all of the technology will be freely available.  Check back here for more details soon.


It has been some time now since the last post here about the RADARduino.  Back in November I wrote an entry on the RADARduino prototype build.  Since then a lot has gone on here at Reactance Labs.  We have managed to get all 3 main functions of the RADARduino tested out and have successfully produced plots of Doppler shifts from moving objects (cars), a plot of range vs. time for a moving target, and taken data (still working on processing it) for Synthetic Aperture Radar.

Along the way there have been lots of lessons learned and from those I have revised the original prototype board and am now waiting for the next version to come in the mail, with assembly slated to begin in the next couple weeks.

Doppler Testing

For this test I built up a test housing using a small metal enclosure I bought at the local ham swap meet a few years ago.  I machined an antenna mount from aluminum and attached it to the front using a dovetail slide. This allows me to easily swap the antennas to the stepping linear rail carriage described later.


Test bed for Doppler testing

In Doppler mode, the voltage controlled oscillator (VCO) puts out a continuous tone at a fixed frequency.  The reflected signal is a frequency shifted version and speed can be determined.  We used some modified Python scripts from here.  The routine generating the plots isn’t polished yet, but the result makes sense.

In the image below, each red trace corresponds to a passing car.  As the car approaches, the measured velocity is at it’s peak (and the correct value).  As the car passes, the angle to the car rapidly reduces the effective Doppler speed making it look as though the car is very rapidly decelerating.

Doppler plot of cars passing me on Aviation Blvd. in Redondo Beach, CA.

Doppler plot of cars passing me on Aviation Blvd. in Redondo Beach, CA.

Doppler mode offers the most instantly gratifying experience with the RADARduino because you can actually hear the result in real time.  Setting the radar on the dash board and plugging the output into a car stereo auxiliary input is pretty interesting.  At a standstill you can hear cars passing.  When driving, you can hear nearby obstacles as you pass them.  It sounds much like a racetrack with high revving race cars passing by.

Another trick with Doppler mode is using it for surveillance.  In the very rough demo below, I recorded music by pointing the antennas at a metal cone speaker.

Range Testing

The second function to test is ranging.  In this mode, the Radar operates in chirped mode. The VCO output frequency is linearly increased from 5.4 to 6.0 GHz.  It does this every 20-40 msec.  A sync pulse is generated by the Arduino (which also commands the DAC on the RADARduino) to alert the Python script to the beginning of the chirp.  The code then computes the range to each reflection and plots this over time.  In the image below, I carried a home made corner reflector and walked away from the radar and then back towards it.  The plot shows my distance increase, then decrease.

Ranging data generated using a hand held corner reflector

Ranging data generated using a hand held corner reflector

It should be noted that this graph (while poorly scaled) shows the range of the first prototype RADARduino using the low gain Vivaldi antennas.  As the range to target increases to maximum, the signal level diminishes substantially. A circuit change made in revision 2 addresses this issue.

 Synthetic Aperture Radar

Unfortunately we have not yet processed the SAR image from this test, due to issues with getting the Python script working right.  However, we believe we have good data and are quite close to getting an image.  I’ll update this entry as that happens.  Our test setup for this experiment uses a motorized rail system that I built.  A 9 foot long section of rectangular aluminum tubing serves as the rail, and a carriage riding on small bearings holds the RADARduino and antennas.  The carriage is moved by means of a stepper motor directly driving a rubber R/C car tire which presses against the rail.

Alex capturing SAR data.

Alex capturing SAR data.

The setup was done outside my apartment, and we got lots of interesting looks and some questions from the neighbors.  Some thought I was building a death ray.  I won’t challenge that 🙂  I stood out in the street holding the corner reflector to act as a really huge target.  The radar cross section (RCS) of a corner reflector is ginormous.  I will post the SAR image as soon as we have it available!

Updates for Revision 2

A number of items were improved on the second board spin.  I am currently waiting for that board to come in, so no promises on what works yet 🙂

  • The on-board SMT boost converter has been replaced with a single through-hole part.  This reduces noise and complexity with a slight increase in cost
  • Precision voltage reference for DAC now supplies reference for the IF amp.  Dramatic improvement in noise floor (no USB, digital, boost converter noise).
  • DC blocking cap between IF port of mixer and IF amp has been increased (error)
  • DC blocking cap has been added between IF amp and anti-aliasing filter
  • Trim-pot has been added to the IF amp.  Gain adjustment was found necessary between Doppler and Chirped modes.  Future incarnations may feature digitally adjustable gain or AGC.
  • A resistor has been added in series with the sync pulse output to allow user adjustment should it be required.
  • The sync pulse inhibit switch has been removed.  This can be easily implemented off-board should the user want it.  Given the digital control, it seemed outdated.
  • A copy of the RF gain stage has been added as a transmit driver.  This will increase the output power from ~4 dBm to ~15 dBm which should definitely help increse the range of the unit.  The cost is a bit more DC and a few more dollars in components, but will be worth it!
  • Other minor changes including more test points and component swaps have been made.

Sneak Peek!

Coming soon, an airborne demo!

Lightweight aluminum housing with audio recorder and bluetooth enabled Arduino for an upcoming airborne demo!

Lightweight aluminum housing with audio recorder and bluetooth enabled Arduino for an upcoming airborne demo!




Prototyping the RADARduino

UPDATE: February 3, 2014:  The RADARduino has received a commodity classification from the Department of Commerce as 6A008.b.  Since the design itself will be open source, all of the technology will be freely available.  Check back here for more details soon.

For those of you who read IEEE Spectrum magazine, this month’s edition includes an article called “Coffee-Can Radar” which details author David Schneider’s experiences in building a short range radar based on the work of Dr. Gregory Charvat, who in 2011 taught a short course at MIT on Cantenna Radars.  This course has spread to other institutions including to the University of California Davis, University of Vermont, Michigan State University, MIT Lincoln Labs, etc.

Dr. Charvat’s FMCW (frequency modulated continuous wave) radar project uses a collection of connectorized Mini-Circuits components for the RF section, and several traditional components on a breadboard for the back end processing and VCO (voltage controlled oscillator) control.  Antennas are of the “cantenna” type, and the whole system operates in the 2.4 GHz band with an output power of ~ 10 mW.

I decided that this project called for a kit version built on a single printed circuit board.  So I started thinking about how to modify the project to expand on Dr. Charvat’s work, as well as provide backwards compatibility.

In thinking about ways to expand the usability of the radar, I decided that instead of controlling the VCO with a ramp generator chip, I’d use an Arduino microcontroller with a DAC (digital to analog converter).  This allows for the arbitrary generation of radar waveforms and frequency chirps, in addition to USB computer interface.

The first major component change was to integrate the RF components, which meant finding suitable surface mount parts for the LNA (low noise amplifier), mixer, VCO, buffer amplifier, and power splitter.  At this stage I decided to increase the frequency to the 5.8 GHz band which allows for the use of smaller antennas.

On the back end, I switched from a discrete anti-aliasing filter to an integrated part, and added a boost converter to generate the +12V required to control the VCO over its usable range.

This past week, we started assembly of the first prototypes, which are nearly ready for testing.

The first part of the assembly is the surface mount RF components.  It is planned that this portion of the circuitry will come pre-assembled, as there are too few people with reflow soldering capabilities, and packaging SMT components is time consuming.

Spreading solder paste onto one of the boards using a Kapton stencil


Solder paste applied to the SMT pads


Alex KJ6WIL placing SMT components on the three prototype boards


SMT parts populated and ready for the oven


Prototype boards undergoing reflow using an OSPID controller and a hacked toaster oven


Nearly complete prototype next to an Arduino (VCO is missing, will be installed soon)


The radar stacked on an Arduino



As was mentioned in the caption, the VCO is missing.  Digikey sent the wrong part, but tomorrow the right ones should arrive and will be installed.  We are looking forward to the next stage which will be to fire it up and see what problems or issues we may run into.  RF is never easy to get right the first time!

-Tony KC6QHP





2012 Microwave Update Recap

I just got back from Santa Clara, California where I attended the 2012 Microwave Update  conference.  This is the 27th year of the conference which is a venue for the presentation and discussion of the latest and greatest in Amateur Microwave Radio technology and operation.  This year’s conference was held in the heart of Silicon Valley, near numerous RF/Microwave companies as well as surplus electronics hot spots such as the venerable HSC Electronic Supply.

On Thursday I drove up with Doug, K6JEY in the navigator’s seat.  We spent the trip solving the world’s problems and discussing a range of microwave related topics.

Our first stop was at HSC to test and pick up a signal generator.  I got a good deal on a microphone, but didn’t find any microwave gear I couldn’t live without.  We proceeded to the hotel and checked in.

That night after visiting the hospitality suite and chatting with other microwave enthusiasts, I scrambled to finish up my slides for my talk on reflow soldering.

Friday morning I got to see a number of interesting talks including a talk on simple 78-135 GHz equipment by a very creative Aussie, Alan VK3XPD.

Alan, VK3XPD showing his 100+ GHz filters made from semi-rigid coax outer conductor

Rex KK6MK and Lars AA6IW gave a nice talk on a great board they have put together for enabling 10 and 24 GHz dual band radios.  Next, Tom WA1MBA gave an entertaining talk on the culmination of a 1/2 decade project, a 78 GHz LNA for mass (a few dozen) production for amateur use.  Finally it was my time to get up and talk about Reflow Soldering for the Microwave Experimenter.

Giving my talk on reflow soldering

In between talks, the animated and entertaining Kent Britain WA5VJB auctioned off interesting items.  This included ovenized oscillators, power amplifier kits, etc.  Proceeds go to help pay for the conference.

Kent, WA5VJB auctioning off something (ATC chip cap kit I think)

In addition to technical talks, a room was set up with test equipment, including the latest and greatest spectrum and network analyzers from Anritsu going up to 125 GHz!  For most of us it was the equivalent of pacing around a Ferrari at a car show.  With prices to match!

This is the test equipment room. Pat N6RMJ is not an apparition, he just plays one at MUD.

Over in the vendor room, a number of us set up shop to sell our stuff.  This included my first in-real-life selling.  It would appear I need to put in some effort in to building a display of some sort 🙂

Telling Jeff WA3ZKR about my synthesizers and multipliers

No Ham Radio conference would be complete without a swap meet, so at MUD there were TWO!  Friday night was an indoor swapmeet…

Indoor swap meet at Microwave Update

We were honored to have an excellent keynote talk given by Professor Thomas Lee of Stanford University, and author of a book I used in school, The Design of CMOS Radio-Frequency Integrated Circuits.  Dr. Lee gave a great talk on the history of radio communications and the impact of innovations made along the way by amateur radio operators.

Dr. Thomas Lee giving his talk on radio history and the influence of hams.

Sunday morning brought an end to the activities, but not without another swap meet, this time outdoors, with more great stuff!  Some excellent deals were made and some microwave gear both new and decrepit changed hands.  This is the stuff that microwavers dream of.

Dishes for sale!

This is my second Microwave Update and certainly not my last!  I had a great time meeting people who I have talked to over microwaves, or by email.  I met new people, and got to know others better.  I learned, was amazed, intrigued, and motivated by the great work that amateur microwavers are doing.  These conferences are really a great way to promote activity and fellowship.  I’d like to thank the folks in the 50 MHz and Up Group who organized the event and to all those who came to participate.

Next year, Jeff Kruth WA3ZKR is hosting Microwave Update at Morehead State University in Kentucky, I’m already looking forward to it!

-Tony KC6QHP