2012 10 GHz and Up Cumulative Contest

This year marks my ~15th time participating in the ARRL’s 10 GHz and Up Cumulative Contest.  The purpose of the contest is to further the state of the art in Amateur Radio equipment and operation at frequencies of 10 Ghz and above (my personal favorite end of the Amateur Radio spectrum).

Each year over the course of two weekends, participants attempt to communicate with one another (exchanging very basic information including callsigns and a geographical locator code).  Points are determined by a combination of number of unique stations contacted per band, as well as the sum of the distance between stations for each contact.

Two categories exist, the first being “10 GHz only” and the second includes participants who make contacts on bands above 10 Ghz. the reason for this is that 10 GHz is much more popular and contacts are significantly easier than on the higher bands.  This distinction encourages different kinds of competition (requiring different operational and technical skills)

This year I competed in the 10 GHz and Up category.  I made 110 contacts on 10 GHz, 10 contacts on 24 GHz, and 1 on 47 GHz.  My longest contacts on each band are: 351 km on 10 GHz, 103 km on 24 GHz, and 56 km on 47 GHz/

For the first weekend I took a trip to the local San Bernardino Mountains, specifically to Green Valley Lake, where some relatives have a cabin.  I stayed the night and on Saturday morning drove to the top of Keller Peak.

KC6QHP’s 10 GHz radio set up below the Keller Peak fire lookout tower

For portable operation I power my microwave radios with large sealed lead acid batteries.  These are a pain to move around but provide sufficient energy to operate the power hungry radios for a full weekend without recharge.  A full load with all 5 radios running can approach 100 watts (in receive mode).

Keller Peak, at 2317 m (7882 ft) high makes for a great spot to operate microwave radios.  AT&T took advantage of this decades ago with the installation of a hardened microwave backbone site  at the top of the mountain back in the days before fiber optics.

After several hours of working stations as far away as San Diego, and into California’s Central Valley, the sky started to get very dark, and I decided to pack up for the day.  Rain does not mix well with sensitive electronics, and lightning does not mix well with me.

Later in the day I drove back towards home and finally set up near the Marine Exchange of Southern California, a former Nike Missile site and before that, Fort MacArthur.

10 and 24 GHz radios adjacent to Fort MacArthur / Marine Exchange in San Pedro, CA

From this point I made a few contacts, and then headed home to Redondo Beach for final late night contacts.

On Sunday I operated from home and made some nice contacts on 10 and 24 GHz.  I always enjoy working microwave from indoors, it just shouldn’t work 🙂

For the September weekend I operated entirely from home because I was sick and didn’t have the energy to haul tons of equipment out.  I had planned on heading to San Diego and operating from Mt. Soledad and making some attempts on the 79 GHz band.

Instead, I operated from home and made lots of great contacts including my first indoor 47 GHz contact with Steve W6QIW at Secret Site 51 (a name us hams have given to ITT’s Loop Canyon Test Facility and former Nike site LA-94).  This was a 56 km contact, which is not bad for the 6mm band, but even more exciting because my radio was indoors, looking out through a window towards a house across the street!

I operated two 10 GHz radios from home, including one I put on the roof with an omni-directional slotted waveguide antenna.

Slotted waveguide X-band antenna. Note the warning sign in the background!

Well, that’s a wrap for 2012!  I am looking forward to more mountaintop adventures next year.

Here are a couple pictures from previous years…

Tony KC6QHP and Doug K6JEY (background) on Signal Hill in 2011

Chris N9RIN and Ben KD0EJT on Frazier Mountain in 2011


First Customer Kit Builds Completed!

Dave, WA6CGR was the first customer to put together and test OpenSynth synthesizers.  He built up two units this past weekend and tested them out in his very well equipped lab.

First customer built OpenSynth

Dave comments

“This 2556 MHz synthesizer is the best microwave synthesizer I have ever built. If you ca solder surface mount components, then this project will be easy for you too! The construction time is about two hours and no intermediate testing is required unless you feel more comfortable doing so. Both units that I built worked immediately after applying power and reference signal. Also, both units provided +7 dBm power output and the spectrum was extremely clean. I am a very happy customer – Dave – WA6CGR”

2556 MHz output on spectrum analyzer

Dave is building a 10 GHz radio for his wife, and is using an OpenSynth in conjunction with a DB6NT transverter.

OpenSynth driving a DB6NT transverter

He measured the noise figure of the DB6NT unit with OpenSynth at 1.43 dB

Noise Figure of DB6NT transverter with OpenSynth Synthesizer

Thanks Dave for sending in these results and great pictures!


OpenSynth Kit Preparation

Today I put together the first 17 OpenSynth Kits.  This took a LONG time, part of which was figuring out how to do things.  For the next batch I’m going to be recruiting some help, there are lots of tasks that can be done in parallel…

First task is to lay out all the parts.

OpenSynth parts as they come from the various suppliers

Next I started by organizing all the passive, non-ESD sensitive parts such as capacitors and resistors.  These are placed onto a piece of card stock with double sided tape, and then covered with self-laminating sheet material.

Passive Non-ESD sensitive parts

Close-up of one of the Passives cards

Next up was the mechanical parts – connectors, wire, and the heat sink.  The wires were cut to length, heat sink adhesive cut and applied (it comes in a large double-sticky sheet) to the heat sinks.  Parts were then placed into ESD bags, sealed and tagged.

Wire, connectors, heat sinks

The next step was to program the microcontrollers and put all the ESD sensitive parts into small plastic foam-lined ESD safe boxes.

ESD parts and microcontroller programming

Finally it is time to seal up the bags!  Some of the parts (the LEDs and microcontrollers are humidity sensitive, so this step included adding dessicant packs and humidity indicator cards to the special humidity resistant bags before themal sealing.

Final kit assembly

Well that is about it!  After this, both the passive component card and ESD parts bags will be put into padded mailing envelopes and headed out the door!

Getting Started in Amateur Microwave Radio

You might be interested in Amateur Microwave Radio if you:

  • Are interested in experimenting with RF and microwave technologies
  • Are interested in learning about microwave signal propagation
  • Want more points in UHF/VHF microwave contests
  • Want to build cutting edge equipment using exotic technologies
  • Like the idea of taking your home built radios to mountain-tops for microwave contesting
  • Are interested in setting new records or trying new techniques in the field of microwaves
  • Want to bounce signals off the moon!

Microwave radios on top of Signal Hill in Long Beach, CA

Microwave Amateur Radio is a hobby within a hobby, namely Amateur of “Ham” radio.  Amateur Radio operators are licensed by the government to transmit signals in selected bands across a broad spectrum from as low as 1.8 MHz all the way up to 250 GHz!


In the United States, the majority of amateur microwave radio activity occurs during annual contests, including the ARRL 10 GHz and Up Cumulative Contest.  During this annual two-weekend contest, microwave enthusiasts take their radios outside to make contacts with one another, frequently from the tops of mountains due to the line-of-sight nature of microwaves.  These contacts are usually voice (single-sideband suppressed carrier) or CW (Morse Code).  Points are awarded for a combination of distance between contacts and number of unique call signs collected.  Most activity occurs in the 10 GHz band, but extra points are awarded for any higher bands used including lightwave communications!

Microwave Amateur Radio enthusiasts being enthusiastic about microwave radio

Microwave Amateur Radio enthusiasts being enthusiastic about microwave radio (Kerry N6IZW and Greg K6QPV)

Nearly all Microwave Amateur Radio enthusiasts build radios at some point, but many start off by borrowing someone’s spare radio to get started.  This enables the first-timer to get on the air and experience microwave radio first hand.  There are a number of clubs around the world whose members are more than willing to help out newcomers to the hobby.  In addition to technical mentoring, the clubs often have access to or ownership of sophisticated, costly test equipment that a newcomer will be hard pressed to find elsewhere.  Finally, many clubs hold regular meetings where items of technical interest are presented.

Clubs in the United States:

There are many clubs and individuals around the world focused on Microwave Amateur Radio including:


Modified 10 Ghz power amplifier

Modified 10 Ghz power amplifier

If you can’t find a club near you, there are other ways to get on the air.  A number of manufacturers sell kits and parts for building your own microwave radios with only minimal test equipment required.  These include:

79 GHz mixers

A pair of 79 GHz mixers

An important aspect of Microwave Amateur Radio is the re-use of surplus electronics.  Some of the technologies and equipment used in microwave radio are prohibitively expensive when purchased new.  Microwave Amateur Radio enthusiasts pride themselves on taking old surplus electronics and modifying (or hacking) it for their own use.  Some examples of this include Rubidium frequency standards, YIG synthesizers, Travelling Wave Tube Amplifiers, dish antennas, point-point microwave and millimeter-wave data link radios, satellite communications equipment, etc.  Lots of this can be found on eBay and at local surplus electronics stores.

Lots of documentation exists for hardware modifications:


So if you want to get started in Microwave Amateur Radio, take a look at the links above, read about what others are doing, and get in touch with a Microwave Ham and get building!

KC6QHP doing microwaves

Tony, KC6QHP on Frazier Mountain copying a signal on the 47 Ghz band

Good Luck and I hope to see you on the microwave and millimeter wave bands soon!



Progress Is Still Being Made…

Still working out little issues with a couple models of the synthesizers.  In the meantime, I have put together a pair of x4 mutliplier boards with outputs from 8-12 Ghz in the low band unit, and 11-13 Ghz on the high band unit.  Both put out +16 dBm or more.

Low Band multiplier - 8-12 Ghz


11-13 GHz multiplier

11 - 13 Ghz output x4 multiplier


3006 MHz and 1152 MHz synthesizers

3006 MHz and 1152 MHz synthesizers

2556 MHz and 2160 MHz Synthesizers

2556 MHz and 2160 MHz Synthesizers

Getting Closer to Production

I have now finished the assembly of my 3rd revision of the synthesizer board.  This version features ultra low noise voltage regulators, an improved layout, an additional LED, and more user definable I/O pins.

Rev. 3 Prototype Board

Front side of the board showing synthesizer module, microcontroller, etc.

Welcome to Reactance Labs

Welcome to the Reactance Labs website.  Launched November 14, 2011

I am currently developing a low cost miniature frequency synthesizer kit for use in microwave amateur radios.  I will also use this site to publish technical articles and information.

More to come!

-Tony    KC6QHP