moRFeus: A Low Cost Wideband Signal Generator and Frequency Mixer
During development of the Outernet project the engineering team developed several tools to help them in their RF testing. One tool that they created has now been developed further into a commercial product that they are calling 'moRFeus'. moRFeus is a small handheld RF signal generator and frequency mixer. It can be used to generate an RF tone at any frequency between 85 MHz - 6 GHz and to upconvert or downconvert signals via the mixer with an input/output frequency range between 30 MHz - 6 GHz. This type of tool is useful for people working with RF hardware as it can be used for testing and prototyping.
morRFeus is currently selling for US$149 over on CrowdSupply, and the units are ready to ship out soon. They note that the current price is a special, and that it may be increased in the future. We think that this is a fairly good deal considering that similar products can cost much more. If you are interested in the technical details the datasheet includes figures on phase noise and conversion losses. There is also a user guide that explains how the buttons work, and what each screen on the menu is for. The morRFeus press release reads:
Outernet launches sales for wideband frequency converter and signal generator with complete field-level configuration.
Today, Outernet announced the launch of moRFeus - a wideband (30MHz - 6GHz) frequency converter and signal generator with complete field-level configurability. The product is available on Crowd Supply for $149. The price will increase after the 30-day launch campaign.
The device has an LCD display and button interface for complete field-level configuration - from setting the LO frequency to toggling between mixer and generator mode, and more. It’s in a precision-milled all-aluminum enclosure for durability and aesthetics.
moRFeus was built for hams and hackers, people with a traditional amateur radio background, as well as a makers and researchers that are interested in RF experimentation. It was designed for easy integration into a wide variety of RF projects.
In mixer mode, moRFeus enables dynamic frequency up- and down-conversion. In generator mode, it is one of the most, if not the most, affordable tools to generate a stable +/-2.5 ppm CW signal. Additional information on features, specifications, and performance metrics can be found in the datasheet.
The team already has 100 units in stock and another 900 are going through final assembly and quality assurance in Chicago. The first 100 units will ship one week after launch and orders beyond the initial stock will ship within 30 days of the close of the campaign, or earlier.
Outernet has been working on novel RF projects since the founding of the company in 2014. moRFeus was developed because from an internal need for a wideband field-configurable frequency converter for testing purposes. The company identified a huge gap in the market for a solution that met the needs of others with similar problems add their own. Outernet’s founder describes the development process:
“The idea was hatched about a year ago because we needed an easy, quick way to dynamically up-and down-convert the various radios we were experimenting with for a new product. By the summer of 2017, we had our first prototype and functional firmware. The design still required some slight tweaking. The current version of moRFeus is its third iteration. Oddly enough, the last phase of the project, industrial design, ended up being the most time-consuming. We worked with a local designer/machinist with decades of experience to come up with a custom-made all-aluminum enclosure.”
For more information and to purchase moRFeus, visit Crowd Supply.
Furthermore the product features, description, and also some of the applications and use cases for moRFeus are quoted below:
Features
- RF Input Frequency: 30MHz–6GHz
- RF Output Frequency: 30MHz–6GHz
- LO Frequency: 85MHz–5400MHz
- Fractional-N Synthesizer
- LO Step Size: 1.5–3Hz1
- 2.5 ppm precision TCXO
- USB programmable
- Generator/Mixer Function Toggle
- Input IP3 +23dBm
- Small, Portable Form Factor
- Adjustable Mixer Bias Current
- LCD Display With Backlight Feature
- Button Control Interface
- Dimensions: 88mm x 38mm x 68mm
- Weight: 7.4 oz
Product Description
moRFeus is a 30MHz–6GHz programmable Fractional-N wideband frequency converter and generator designed for low spurious emissions and dynamic configuring of the LO frequency. moRFeus is designed for easy integration into popular RF environments using SMA connectors and is powered using an external micro-USB 5V supply. The LCD display and button interface provide a dynamic way to program the mixer LO frequency in the field with a step size of 1.5–3Hz.1 The device is USB programmable, enabling automatic operation from a PC (must be running Linux). Dynamic toggling between mixer and generator modes adds to field-level functionality. An optional bias voltage of 5V is available via RF choke to the mixer input to supply active antenna systems.
Applications
- Wideband Radios
- Distributed Antenna Systems
- Diversity Receivers
- Software Defined Radios
- Frequency Band Shifters
- Point-to-Point Radios
- WiMax/LTE Infrastructure
- Satellite Communications
- Wideband Jammers
- Remote Radio Heads
- Frequency Up/Down Conversion
- Automated Test Equipment (ATE)
- Wireless Communication Systems
Review and Testing
The Outernet team sent us a moRFeus unit for testing a few days ago. It comes in a portable 3.5 x 2.7 x 1.5 inch (8.9 x 6.9 x 3.8 cm) conductive milled aluminum enclosure and weighs 7.4 ounces (210 grams). The construction is very solid, and should easily survive being thrown around in a carry bag, although we'd still advise caution as the LCD screen is not protected by a window.
The unit is powered via a standard micro USB port. After connecting a USB cable the unit immediately powers up shows a frequency selection screen on the LCD display. Five small buttons are used to control the interface, and we found it very easy to adjust the output frequency using these buttons.
Using the interface the unit can be switched between the "Generator" and "Mixer" modes. In the generator mode moRFeus simply generates a CW tone at the desired frequency. In the mixer mode moRFeus takes an input signal, mixes it with the generated tone and puts the result on the out port. Mixing a signal with a tone is the core concept behind devices like upconverters, downconverters and tuners. For example, by generating a mixing tone at 2 GHz with the moRFeus, we are able to view 2.4 GHz WiFi signals at 2.4 GHz - 2 GHz = 400 MHz.
In the screenshot below we set moRFeus to run in mixer mode with the LO frequency set at 2 GHz. This allows us to view an active WiFi signal at 2.475 GHz using an Airspy and the SpectrumSpy software. The Airspy can only tune up to 1.8 GHz by itself, so it can't view the WiFi band directly. Of course to use as a proper downconverter filtering is required to remove any images and interfering signals, but by being able to easily change the LO frequency you are able to move the signals around quite easily to avoid images or interference.
Unfortunately one limitation is that moRFeus' lowest input frequency is 30 MHz, so it can't be used to upconvert HF signals.
moRFeus also works well as a standard RF signal generator, and we were able to get a clean CW tone on any frequency between 85 MHz - 6 GHz.
moRFeus also shows up a a device on the PC, and the team write that it is possible to control it programatically via Linux, however documentation for this does not exist yet although it is scheduled to be released later. We would love to see a sweep feature which should be possible with PC control.
In conclusion if you are looking for a low cost signal generator or mixer to use in your experimental RF projects, then moRFeus certainly does seem like a good deal. A tool like this is very handy to have in your RF kit.
